Healthy dietary patterns, genetic risk, and gastrointestinal cancer incident risk: a large-scale prospective cohort study

BACKGROUND

Dietary patterns have been associated with several cancers, especially gastrointestinal cancer (GIC). However, whether a healthy dietary pattern could modify the risk of GIC among people with different genetic backgrounds is not clear.

OBJECTIVE

The objective of the study was to investigate how dietary patterns and genetic susceptibility contribute to the risk of GIC independently and jointly.

METHODS

This large-scale prospective cohort study included 105,463 participants in UK Biobank who were aged 40-72 y and cancer-free at baseline. Dietary intake (Oxford WebQ) was used to calculate dietary pattern scores including dietary approach to stop hypertension (DASH) score and healthful plant-based diet index (hPDI). Genetic risk was quantified by a polygenic risk score (PRS) comprising 129 known GIC-associated loci. Cox proportional hazards regression was performed to estimate the associations of dietary patterns and PRS with GIC incidence after adjusting for potential confounders.

RESULTS

Over a median follow-up of 11.70 y, 1,661 participants were diagnosed with GIC. DASH and hPDI were associated with 20% and 36% reductions, respectively, in GIC risk. Low PRS was associated with a 30 % decrease in GIC risk (HR: 0.70; 95% CI: 0.62, 0.79). Participants with healthy dietary scores at high-genetic risk had a lower GIC risk with HR of 0.77 (95% CI: 0.60, 0.98) for DASH and 0.66 (95% CI: 0.52, 0.84) for hPDI than those with unhealthy dietary score. Participants with both high-dietary score and low-genetic risk showed the lowest risk of GIC, with HR of 0.58 (95% CI: 0.45, 0.75) for DASH and 0.45 (95% CI: 0.34, 0.58) for hPDI.

CONCLUSIONS

Adherence to DASH and hPDI were associated with a lower risk of some gastrointestinal cancers, and these 2 dietary patterns may partly compensate for genetic predispositions to cancer. Our results advance the development of precision medicine strategies that consider both dietary patterns and genetics to improve gastrointestinal health.

Frequency of Adding Salt to Foods, Genetic Susceptibility, and Incident Type 2 Diabetes: A Prospective Cohort Study

CONTEXT

Excessive salt consumption is known to increase the risk of hypertension and cardiovascular disease, but the association between salt intake and incident type 2 diabetes has not been extensively researched.

OBJECTIVE

In this study, we aimed to investigate the relationships between the frequency of adding salt to foods and incident type 2 diabetes, as well as any potential interactions with genetic predisposition.

METHODS

We included 368 137 eligible participants, aged 37 to 73 years, from the UK Biobank. The frequency of adding salt to foods was assessed via a food frequency questionnaire.

RESULTS

During a median follow-up of 12.6 years, we documented 10 981 incident type 2 diabetes cases. After adjustment for major confounders, participants who sometimes, usually, and always added salt to foods had 7% (hazard ratio [HR]: 1.07; 95% CI, 1.03-1.12), 9% (HR: 1.09; 95% CI, 1.03-1.16), 28% (HR: 1.28; 95% CI, 1.19-1.38) higher risks of developing type 2 diabetes, respectively, than those that never/rarely added salt to foods (P for trend < .001). We found these associations to be consistent across stratified and sensitivity analyses. However, we did not observe any statistically significant multiplicative or additive interactions between the frequency of adding salt to foods and genetic predisposition regarding incident type 2 diabetes.

CONCLUSION

Our findings suggest that consuming salt regularly, regardless of genetic susceptibility, may increase the risk of type 2 diabetes. Therefore, public health interventions aimed at reducing excessive salt consumption may help prevent the onset of type 2 diabetes.

In the context of the triple burden of malnutrition: A systematic review of gene-diet interactions and nutritional status

Genetic background interacts with dietary components to modulate nutritional health status. This study aimed to review the evidence for gene-diet interactions in all forms of malnutrition. A comprehensive systematic literature search was conducted through April 2021 to identify observational and intervention studies reporting the effects of gene-diet interactions in over-nutrition, under-nutrition and micronutrient status. Risk of publication bias was assessed using the Quality Criteria Checklist and a tool specifically designed for gene-diet interaction research. 167 studies from 27 populations were included. The majority of studies investigated single nucleotide polymorphisms (SNPs) in overnutrition (n = 158). Diets rich in whole grains, vegetables, fruits and low in total and saturated fats, such as Mediterranean and DASH diets, showed promising effects for reducing obesity risk among individuals who had higher genetic risk scores for obesity, particularly the risk alleles carriers of FTO rs9939609, rs1121980 and rs1421085. Other SNPs in MC4R, PPARG and APOA5 genes were also commonly studied for interaction with diet on overnutrition though findings were inconclusive. Only limited data were found related to undernutrition (n = 1) and micronutrient status (n = 9). The findings on gene-diet interactions in this review highlight the importance of personalized nutrition, and more research on undernutrition and micronutrient status is warranted.

Impact of Lipid Genetic Risk Score and Saturated Fatty Acid Intake on Central Obesity in an Asian Indian Population

Abnormalities in lipid metabolism have been linked to the development of obesity. We used a nutrigenetic approach to establish a link between lipids and obesity in Asian Indians, who are known to have a high prevalence of central obesity and dyslipidaemia. A sample of 497 Asian Indian individuals (260 with type 2 diabetes and 237 with normal glucose tolerance) (mean age: 44 ± 10 years) were randomly chosen from the Chennai Urban Rural Epidemiological Study (CURES). Dietary intake was assessed using a previously validated questionnaire. A genetic risk score (GRS) was constructed based on cholesteryl ester transfer protein (CETP) and lipoprotein lipase (LPL) genetic variants. There was a significant interaction between GRS and saturated fatty acid (SFA) intake on waist circumference (WC) (Pinteraction = 0.006). Individuals with a low SFA intake (≤23.2 g/day), despite carrying ≥2 risk alleles, had a smaller WC compared to individuals carrying <2 risk alleles (Beta = −0.01 cm; p = 0.03). For those individuals carrying ≥2 risk alleles, a high SFA intake (>23.2 g/day) was significantly associated with a larger WC than a low SFA intake (≤23.2 g/day) (Beta = 0.02 cm, p = 0.02). There were no significant interactions between GRS and other dietary factors on any of the measured outcomes. We conclude that a diet low in SFA might help reduce the genetic risk of central obesity confirmed by CETP and LPL genetic variants. Conversely, a high SFA diet increases the genetic risk of central obesity in Asian Indians.

The interaction between Alternative Healthy Eating Index and MC4R rs17782313 gene variants on central and general obesity indices in women: a cross-sectional study

BACKGROUND

Previous studies have shown that the C allele of melanocortin 4 receptor (MC4R) rs17782313 and Alternative Healthy Eating Index (AHEI) are separately associated with obesity. However, no study has assessed the aim of this study which is to investigate the interaction between MC4R rs17782313 variants and AHEI and their association with central and general obesity indices.

METHODS

A total of 291 women with BMI ≥25 and aged 18-48 years enrolled in this cross-sectional study. All participants were assessed for body composition, anthropometric measures, dietary intake, and blood parameters. After obtaining data of dietary intake from the 147-item food frequency questionnaire (FFQ) the AHEI was calculated. MC4R rs17782313 SNPs were assessed using the restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

After adjustment for age, energy intake, physical activity, marital and economic status, the interaction between MC4R rs17782313 and AHEI was associated with hip circumference (HC) (β=-0.41, 95%CI: -0.77 to -0.05, P=0.02), body mass index (BMI) (β=-0.15, 95%CI: -0.29 to -0.02, P=0.02), fat mass (kg) (β=-0.28, 95%CI: -0.56 to -0.01, P=0.03), Visceral fat area (VFA) (β=-5.68, 95%CI: -9.55 to -1.80, P=0.004). The other measures that seem to be suggestively related to this interaction (0.05< P <0.07) are waist circumference (WC), waist-to-height ratio (WHtR), trunk fat (TF) (%), TF (kg), fat mass (%), and fat mass index (FMI).

CONCLUSION

Interaction between MC4R rs17782313 and AHEI can be related to some central and general obesity indices in overweight/obese women. This article is protected by copyright. All rights reserved.

The association of genetic susceptibility to smoking with cardiovascular disease mortality and the benefits of adhering to a DASH diet: The Singapore Chinese Health Study

BACKGROUND

Understanding the genetic predisposition to cardiovascular disease (CVD) may help to improve clinical intervention strategies. Lifestyle factors, such as diet, may differ among ethnic groups and may, in turn, modify individuals' risks to diseases.

OBJECTIVES

We examined the genetic predisposition to ever smoking in relation to CVD mortality and assessed whether such an association could be modified by dietary intake.

METHODS

A total of 23,760 Chinese adults from the Singapore Chinese Heath Study who were free of cancer and CVD at recruitment (1993-1998) were included in the study. A weighted genetic risk score (wGRS) was calculated to define the genetically determined regular smoking behavior (never or ever). Multivariable-adjusted Cox regression models were used to assess the association between the wGRS and CVD mortality. We also conducted a 1-sample Mendelian randomization analysis for ever smoking and CVD mortality.

RESULTS

Over a mean of 22.6 years of follow-up, 2301 CVD deaths were identified. A genetic predisposition to ever smoking was significantly associated with CVD mortality; the multivariable-adjusted HR of CVD mortality was 1.07 (95% CI: 1.03-1.12), with a per-SD increment in the wGRS. However, the Mendelian randomization analysis did not support a causal relationship between ever smoking and CVD mortality (OR, 1.13; 95% CI: 0.87-1.45). Additionally, the Dietary Approaches to Stop Hypertension (DASH) score significantly modified the association between the smoking wGRS and CVD mortality; the association between a genetic predisposition to smoking and CVD mortality was only observed among individuals with a low DASH score (P-interaction = 0.004).

CONCLUSIONS

A genetic predisposition to smoking was associated with CVD mortality in the Chinese population. In addition, we detected a significant interaction showing higher CVD mortality related to genetically determined smoking among those with lower DASH scores.

A combination of single nucleotide polymorphisms is associated with the interindividual variability in the blood lipid response to dietary fatty acid consumption in a randomized clinical trial

BACKGROUND

Blood lipid concentrations display high interindividual variability in response to dietary interventions, partly due to genetic factors. Existing studies have focused on single nucleotide polymorphisms (SNPs) analyzed individually, which only explain a limited fraction of the variability of these complex phenotypes.

OBJECTIVE

We aimed to identify combinations of SNPs associated with the variability in LDL cholesterol and triglyceride (TG) concentration changes following 5 dietary interventions.

DESIGN

In a multicenter randomized crossover trial, 92 participants with elevated waist circumference and low HDL cholesterol concentrations consumed 5 isoenergetic diets for 4 wk: a diet rich in saturated fatty acids (SFAs) from cheese, SFA from butter, monounsaturated fatty acids (MUFAs), n-6 polyunsaturated fatty acids (PUFAs), and a diet higher in carbohydrates (CHO). The association between 22 candidate SNPs in genes involved in lipid and bile acid metabolism and transport and changes in LDL cholesterol and TG concentrations was assessed with univariate statistics followed by partial least squares regression.

RESULTS

Endpoint LDL cholesterol concentrations were significantly different (cheese: 3.18 ± 0.04, butter: 3.31 ± 0.04, MUFA: 3.00 ± 0.04, PUFA: 2.81 ± 0.04, CHO: 3.11 ± 0.04 mmol/L; P < 0.001) while endpoint TG concentrations were not (P = 0.117). Both displayed consistently elevated interindividual variability following the dietary interventions (CVs of 34.5 ± 2.2% and 55.8 ± 1.8%, respectively). Among the 22 candidate SNPs, only ABCA1-rs2066714 and apolipoprotein E (APOE) isoforms exhibited consistent significant effects, namely on LDL cholesterol concentrations. However, several SNPs were significantly associated with changes in LDL cholesterol and TG concentrations in a diet-specific fashion. Generated multivariate models explained from 16.0 to 33.6% of the interindividual variability in LDL cholesterol concentration changes and from 17.5 to 32.0% of that in TG concentration changes.

CONCLUSIONS

We report combinations of SNPs associated with a significant part of the variability in LDL cholesterol and TG concentrations following dietary interventions differing in their fatty acid profiles.

Diet Modulates the Effects of Genetic Variants on the Vitamin D Metabolic Pathway and Bone Mineral Density in Mexican Postmenopausal Women

BACKGROUND

Macro- and micronutrients, such as proteins, vitamin D, and calcium (Ca), are important dietary factors that can modify bone mineral density (BMD). Genetic factors can interact with diet, affecting an individual's predisposition to osteoporosis.

OBJECTIVES

This study aimed to evaluate the associations between macro- and micronutrient intakes and BMD in Mexican postmenopausal women, and their interactions with genetic polymorphisms involved in the vitamin D metabolic pathway.

METHODS

We analyzed data from 317 postmenopausal women from the Health Workers Cohort Study, a longitudinal cohort studied in Cuernavaca, Mexico. Postmenopausal women participated in 2 data collection waves (2004-2006 and 2010-2011), with a mean time of 6.4 years. Dietary intake was assessed with a semi-quantitative FFQ. BMD (femoral neck, hip, and lumbar spine) was measured by DXA. Hybrid mixed-effects regression models were used to assess the associations of dietary macro- and micronutrients on BMD, after adjusting for confounding factors and for diet and single nucleotide polymorphism interactions.

RESULTS

At baseline, the median age was 57 years (IQR, 50-64). Mean femoral neck, hip, and lumbar spine BMDs decreased over time. We observed statistically significant longitudinal associations for diet (Ca, vitamin D, magnesium, phosphorus, and protein intake) and BMD. Increases of vitamin D, Ca, and protein intakes by 1 SD were associated with mean increases in the femoral neck BMD (0.083 SD, 0.064 SD, and 0.130 SD, respectively). Multiple significant interactions were identified between several loci (CYP2R1, CYP24A1, CYP27B1, VDR, and DHCR7/NADSYN1) and diet for BMDs (femoral neck, hip, and lumbar spine), mainly for protein intake.

CONCLUSIONS

Our data support associations of vitamin D, Ca, protein, phosphorous, and magnesium consumption with BMD in Mexican postmenopausal women and suggest possible gene-diet interactions. These results could facilitate future personalized nutrition recommendations to help prevent low BMD.

The Interaction Between Fatty Acid Desaturase-2 (FADS2) rs174583 Genetic Variant and Dietary Quality Indices (DASH and MDS) Constructs Different Metabolic Phenotypes Among Obese Individuals

Background and Aim: Genetic variation in fatty acid desaturases (FADS) has previously been linked to several diet-related diseases. We aimed to determine whether the FADS2 rs174583 variant interacts with the Dietary Approach to Stop Hypertension (DASH) score and Mediterranean dietary score (MDS) to influence cardio-metabolic risk factors among obese adults. Methods: This cross-sectional study was performed among 347 apparently healthy obese adults (aged 20-50 years). Dietary quality indicator scores (DASH and MDS) were generated using a validated 147-item Food Frequency Questionnaire (FFQ). The FADS2 rs174583 variant was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The gene-diet interaction was analyzed by the ANCOVA multivariate interaction model. Results: A significant interaction was observed between rs174583 and adherence to the DASH score in relation to serum triglyceride (TG) concentration among the female group (P Interaction = 0.046); CT-genotype carriers who were assigned to the second tertile of DASH compared with those in the first tertile had a lower TG level (P < 0.05). Another significant interaction was revealed between adherence to MDS score and rs174583 polymorphism on serum glucose levels (P Interaction = 0.044); the lowest mean of glucose level was observed in homozygous minor subjects (TT) in the third tertile of MDS, in comparison with other tertiles of this dietary index (P < 0.05). There was a similar significant interaction between DASH and rs174583 in relation to diastolic blood pressure (P Interaction = 0.038) among the male group. Additionally, a significant positive association was found between TT genotype and odds of having high TG both in the crude (OR, 3.21; 95% CI, 1.02-10.14) and adjusted (OR, 3.58; 95% CI, 1.07-11.97) models, taking into account different confounders. Conclusion: Adherence to the dietary quality indicators (DASH and MDS) modified the relationship between FADS2 rs174583 polymorphism and cardio-metabolic risk factors in obese subjects. Prospective cohort studies are needed to confirm the results of our study.

Effects of high fat diets and supplemental tart cherry and fish oil on obesity and type 2 diabetes in male and female C57BL/6J and TALLYHO/Jng mice

Obesogenic and diabetogenic high fat (HF) diets can influence genetic factors in disease development with sexual dimorphic responses. We investigated potential protective effects of tart cherry (TC), fish oil (FO) and TC+FO supplementation in TALLYHO/Jng (TH) and C57BL/6J (B6) mice fed HF diets. Male and female TH and B6 mice were weaned onto five different diets; low fat (LF), HF, and HF supplemented with TC, FO, or TC+FO and maintained. For both males and females on LF, TH mice were heavier and fatter than B6, which was accentuated by HF in males, but not in females. TH males, but not others, developed severe glucose intolerance and hyperglycemia on HF, with reduced mRNA levels of Adipoq and Esr1 in adipose tissue. Considering energy balance, locomotor activity was lower in TH mice than B6 for both sexes without diet effects, except B6 females where HF decreased it. Compared to LF, HF decreased energy expenditure, RER, and food intake (in grams) for both sexes without strain differences. In all mice, but B6 males, HF increased plasma IL6 levels compared to LF. No preventive effects of TC, FO or TC+FO were noted for HF-induced obesity or energy imbalance, but FO alleviated glucose intolerance in TH males. Further, TC and FO decreased plasma IL6 levels, especially in females, without additive or synergistic effects of these two. Collectively, obesogenic and diabetogenic impacts of HF diets differed depending on the genetic predisposition. Moreover, sexually dimorphic effects of dietary supplementation were observed for glucose metabolism and inflammatory markers.

Common Genetic Variations Involved in the Inter-Individual Variability of Circulating Cholesterol Concentrations in Response to Diets: A Narrative Review of Recent Evidence

The number of nutrigenetic studies dedicated to the identification of single nucleotide polymorphisms (SNPs) modulating blood lipid profiles in response to dietary interventions has increased considerably over the last decade. However, the robustness of the evidence-based science supporting the area remains to be evaluated. The objective of this review was to present recent findings concerning the effects of interactions between SNPs in genes involved in cholesterol metabolism and transport, and dietary intakes or interventions on circulating cholesterol concentrations, which are causally involved in cardiovascular diseases and established biomarkers of cardiovascular health. We identified recent studies (2014-2020) that reported significant SNP-diet interactions in 14 cholesterol-related genes (NPC1L1, ABCA1, ABCG5, ABCG8, APOA1, APOA2, APOA5, APOB, APOE, CETP, CYP7A1, DHCR7, LPL, and LIPC), and which replicated associations observed in previous studies. Some studies have also shown that combinations of SNPs could explain a higher proportion of variability in response to dietary interventions. Although some findings still need replication, including in larger and more diverse study populations, there is good evidence that some SNPs are consistently associated with differing circulating cholesterol concentrations in response to dietary interventions. These results could help clinicians provide patients with more personalized dietary recommendations, in order to lower their risk for cardiovascular disease.

The Impact of FTO Genetic Variants on Obesity and Its Metabolic Consequences is Dependent on Daily Macronutrient Intake

Numerous studies have identified the various fat mass and obesity-associated (FTO) genetic variants associated with obesity and its metabolic consequences; however, the impact of dietary factors on these associations remains unclear. The aim of this study was to evaluate the association between FTO single nucleotide polymorphisms (SNPs), daily macronutrient intake, and obesity and its metabolic consequences. From 1549 Caucasian subjects of Polish origin, genotyped for the FTO SNPs (rs3751812, rs8044769, rs8050136, and rs9939609), 819 subjects were selected for gene–diet interaction analysis. Anthropometric measurements were performed and total body fat content and distribution, blood glucose and insulin concentration during oral glucose tolerance test (OGTT), and lipid profile were determined. Macronutrient intake was analyzed based on three-day food records, and daily physical activity levels were evaluated using the International Physical Activity Questionnaire Long Form (IPAQ-LF). Our study shows that carriers of the GG genotype of rs3751812 presented lower body weight, body mass index (BMI), total body fat content, and hip and waist circumference and presented lower obesity-related markers if more than 48% of daily energy intake was derived from carbohydrates and lower subcutaneous and visceral fat content when energy intake derived from dietary fat did not exceed 30%. Similar results were observed for rs8050136 CC genotype carriers. We did not notice any significant differences in obesity markers between genotypes of rs8044769, but we did observe a significant impact of diet-gene associations. Body weight and BMI were significantly higher in TT and CT genotype carriers if daily energy intake derived from carbohydrates was less than 48%. Moreover, in TT genotype carriers, we observed higher blood glucose concentration while fasting and during the OGTT test if more than 18% of total energy intake was derived from proteins. In conclusion, our results indicate that daily macronutrient intake may modulate the impact of FTO genetic SNPs on obesity and obesity-related metabolic consequences.

The interaction between dietary Non-Enzymatic Antioxidant Capacity (NEAC) with variants of Melanocortin-4 receptor (MC4R) 18q21.23-rs17782313 locus on hypothalamic hormones and cardio-metabolic risk factors in obese individuals from Iran

Background: In the current study, we aimed to evaluate the interaction between dietary Non-Enzymatic Antioxidant Capacity (NEAC) and rs17782313 polymorphism on hypothalamic hormones and cardio-metabolic risk factors. Methods: A total of 287 subjects (aged 20-50 years, 147 males and 140 females) enrolled in the cross-sectional study. Dietary NEAC was assessed using databases of NEAC measurements compiled from outcomes for three different analyses: oxygen radical absorbance capacity (ORAC), ferric reducing-antioxidant power (FRAP), and total radical-trapping antioxidant parameter (TRAP) and genotyping for the near MC4R rs17782313 was carried out by Polymerase chain reaction-restriction fragments length polymorphism (PCR-RFLP) method. Results: The significant interactions were found between adherence to the dietary NEAC and MC4R rs17782313 in relation to high-density lipoprotein-cholesterol (HDL-C), glucose, α-melanocyte stimulating hormone (α-MSH), insulin and quantitative insulin sensitivity check index (QUICKI) (P _Interaction = 0.03, 0.01, 0.04, 0.04 and 0.04, respectively). In homozygous subjects for the minor allele, the serum insulin level and QUICKI in participants with the highest adherence to TRAP were significantly higher than those with the lowest adherence (p < 0.001). There was a significant inverse association between high ORAC score and risk of metabolic syndrome even after adjusting for potential confounders (OR: 0.33; 95%CI:0.13-0.81) and also a significant inverse association between high NEAC (ORAC, FRAP and TRAP assays) score and high triglyceride (TG) level was found in obese adults. Conclusion: In conclusion, our study found for the first time that the NEAC significantly interacts with the rs17782313 genotypes to influence several metabolic risk factors in obesity.

Nutrition and Genetics in NAFLD: The Perfect Binomium

Nonalcoholic fatty liver disease (NAFLD) represents a global healthcare burden since it is epidemiologically related to obesity, type 2 diabetes (T2D) and Metabolic Syndrome (MetS). It embraces a wide spectrum of hepatic injuries, which include simple steatosis, nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The susceptibility to develop NAFLD is highly variable and it is influenced by several cues including environmental (i.e., dietary habits and physical activity) and inherited (i.e., genetic/epigenetic) risk factors. Nonetheless, even intestinal microbiota and its by-products play a crucial role in NAFLD pathophysiology. The interaction of dietary exposure with the genome is referred to as 'nutritional genomics,' which encompasses both 'nutrigenetics' and 'nutriepigenomics.' It is focused on revealing the biological mechanisms that entail both the acute and persistent genome-nutrient interactions that influence health and it may represent a promising field of study to improve both clinical and health nutrition practices. Thus, the premise of this review is to discuss the relevance of personalized nutritional advices as a novel therapeutic approach in NAFLD tailored management.

Apolipoprotein E genetic variants interact with Mediterranean diet to modulate postprandial hypertriglyceridemia in coronary heart disease patients: CORDIOPREV study

BACKGROUND

We try to explore whether long-term consumption of two healthy dietary patterns (low-fat [LF] diet or Mediterranean diet [MedDiet]) interacts with the apolipoprotein E (APOE) single-nucleotide polymorphisms (SNPs: rs439401, rs440446 and rs7412) modulating postprandial hypertriglyceridemia (ppHTG) in coronary heart disease (CHD) patients.

METHODS AND RESULTS

We selected patients from the CORDIOPREV study with genotyping and who underwent an oral fat load test (FLT) at baseline and after 3 years follow-up (n = 506). After 3 years of follow-up, we found a gene-diet interaction between the APOE rs439401 SNP and MedDiet. Specifically, T-allele carriers in the MedDiet group showed a more significant decrease in postprandial triglycerides (TG: P = 0.03) and large triacylglycerol-rich lipoproteins (TRLs) TG (large TRLs TG; P = 0.01) compared with CC subjects. Consistently, the area under the curve of TG (AUC-TG; P-interaction = 0.03) and AUC-large TRLs TG (P-interaction = 0.02) were significantly lower in T-allele carriers compared with CC subjects.

CONCLUSIONS

The long-term consumption of a MedDiet modulates ppHTG through APOE genetic variants in CHD patients. This gene-diet interaction may contribute to a more precise dietary advice in CHD patients.

Fish and marine fatty acids intakes, the FADS genotypes and long-term weight gain: a prospective cohort study

OBJECTIVE

We tested whether genetic variants near fatty acid desaturases gene (FADS) cluster, which were recently identified to be signatures of adaptation to fish-rich and n-3 polyunsaturated fatty acids (PUFAs)-rich diet, interacted with these dietary factors on change in body mass index (BMI).

DESIGN

Three FADS variants were examined for gene-diet interactions on long-term (~10 years) changes in BMI and body weight in four prospective cohort studies.

SETTING

Population based study.

PARTICIPANTS

11 323 women from the Nurses' Health Study (NHS), 6833 men from the Health Professionals Follow-up Study (HPFS) and replicated in 6254 women from the Women's Health Initiative (WHI) and 5 264 Chinese from the Singapore Chinese Health Study (SCHS).

MAIN OUTCOMES

Long-term (~10 years) changes in BMI and body weight.

RESULTS

In the NHS and HPFS cohorts, food-sourced n-3 PUFAs intake showed interactions with the FADS rs174570 on changes of BMI (P for interaction=0.02 in NHS, 0.05 in HPFS and 0.007 in combined). Such interactions were replicated in two independent cohorts WHI and SCHS (P for interaction=0.04 in WHI, 0.02 in SCHS and 0.001 in combined). The genetic associations of the FADS rs174570 with changes in BMI increased across the tertiles of n-3 PUFAs in all the cohorts. Fish intake also accentuated the genetic associations of the FADS rs174570 with long-term changes in BMI (pooled P for interaction=0.006). Viewed differently, long chain n-3 PUFAs intake showed stronger association with long-term changes in BMI among the rs174570 T carriers (beta=0.79 kg/m² per g, p=3×10^-5) than the rs174570 non-T carriers (beta=0.16 kg/m² per g, p=0.08). Similar results were observed for fish intake.

CONCLUSIONS

Our hypothesis-driven analyses provide replicable evidence that long chain n-3 PUFAs and fish intakes may interact with the FADS variant on long-term weight gain. Further investigation is needed to confirm our findings in other cohorts.

Prioritization of Variants for Investigation of Genotype-Directed Nutrition in Human Superpopulations

Dietary guidelines recommended by key health agencies are generally designed for a global population. However, ethnicity affects human disease and environment-gene interactions, including nutrient intake. Historically, isolated human populations with different genetic backgrounds have adapted to distinct environments with varying food sources. Ethnicity is relevant to the interaction of food intake with genes and disease susceptibility; yet major health agencies generally do not recommend food and nutrients codified by population genotypes and their frequencies. In this paper, we have consolidated published nutrigenetic variants and examine their frequencies in human superpopulations to prioritize these variants for future investigation of population-specific genotype-directed nutrition. The nutrients consumed by individuals interact with their genome and may alter disease risk. Herein, we searched the literature, designed a data model, and manually curated hundreds of papers. The resulting database houses 101 variants that reached significance (p < 0.05), from 35 population studies. Nutrigenetic variants associated with modified nutrient intake have the potential to reduce the risk of colorectal cancer, obesity, metabolic syndrome, type 2 diabetes, and several other diseases. Since many nutrigenetic studies have identified a major variant in some populations, we suggest that superpopulation-specific genotype-directed nutrition modifications be prioritized for future study and evaluation. Genotype-directed nutrition approaches to dietary modification have the potential to reduce disease risk in select human populations.

Genome-Wide Association Study (GWAS) on Bilirubin Concentrations in Subjects with Metabolic Syndrome: Sex-Specific GWAS Analysis and Gene-Diet Interactions in a Mediterranean Population

Although, for decades, increased serum bilirubin concentrations were considered a threatening sign of underlying liver disease and had been associated with neonatal jaundice, data from recent years show that bilirubin is a powerful antioxidant and suggest that slightly increased serum bilirubin concentrations are protective against oxidative stress-related diseases, such as cardiovascular diseases. Therefore, a better understanding of the gene-diet interactions in determining serum bilirubin concentrations is needed. None of the previous genome-wide association studies (GWAS) on bilirubin concentrations has been stratified by sex. Therefore, considering the increasing interest in incorporating the gender perspective into nutritional genomics, our main aim was to carry out a GWAS on total serum bilirubin concentrations in a Mediterranean population with metabolic syndrome, stratified by sex. Our secondary aim was to explore, as a pilot study, the presence of gene-diet interactions at the GWAS level. We included 430 participants (188 men and 242 women, aged 55–75 years, and with metabolic syndrome) in the PREDIMED Plus-Valencia study. Global and sex-specific GWAS were undertaken to analyze associations and gene-diet interaction on total serum bilirubin. Adherence (low and high) to the Mediterranean diet (MedDiet) was analyzed as the dietary modulator. In the GWAS, we detected more than 55 SNPs associated with serum bilirubin at p < 5 × 10⁻⁸ (GWAS level). The top-ranked were four SNPs (rs4148325 (p = 9.25 × 10⁻²⁴), rs4148324 (p = 9.48 × 10⁻²⁴), rs6742078 (p = 1.29 × 10⁻²³), rs887829 (p = 1.39 × 10⁻²³), and the rs4148324 (p = 9.48 × 10⁻²⁴)) in the UGT1A1 (UDP glucuronosyltransferase family 1 member A1) gene, which replicated previous findings revealing the UGT1A1 as the major locus. In the sex-specific GWAS, the top-ranked SNPs at the GWAS level were similar in men and women (the lead SNP was the rs4148324-UGT1A1 in both men (p = 4.77 × 10⁻¹¹) and women (p = 2.15 × 10⁻¹⁴), which shows homogeneous genetic results for the major locus. There was more sex-specific heterogeneity for other minor genes associated at the suggestive level of GWAS significance (p < 1 × 10⁻⁵). We did not detect any gene-MedDiet interaction at p < 1 × 10⁻⁵ for the major genetic locus, but we detected some gene-MedDiet interactions with other genes at p < 1 × 10⁻⁵, and even at the GWAS level for the IL17B gene (p = 3.14 × 10⁻⁸). These interaction results, however, should be interpreted with caution due to our small sample size. In conclusion, our study provides new data, with a gender perspective, on genes associated with total serum bilirubin concentrations in men and women, and suggests possible additional modulations by adherence to MedDiet.

Deciphering the Role of the Non-Coding Genome in Regulating Gene-Diet Interactions

Protein encoding genes constitute a small fraction of mammalian genomes. In addition to the protein coding genes, there are other functional units within the genome that are transcribed, but not translated into protein, the so called non-coding RNAs. There are many types of non-coding RNAs that have been identified and shown to have important roles in regulating gene expression either at the transcriptional or post-transcriptional level. A number of recent studies have highlighted that dietary manipulation in mammals can influence the expression or function of a number of classes of non-coding RNAs that contribute to the protein translation machinery. The identification of protein translation as a common target for nutritional regulation underscores the need to investigate how this may mechanistically contribute to phenotypes and diseases that are modified by nutritional intervention. Finally, we describe the state of the art and the application of emerging ‘-omics’ technologies to address the regulation of protein translation in response to diet.

NADH Dehydrogenase Subunit-2 237 Leu/Met Polymorphism Influences the Association of Coffee Consumption with Serum Chloride Levels in Male Japanese Health Checkup Examinees: An Exploratory Cross-Sectional Analysis

Background: Nicotinamide adenine dinucleotide (NADH) dehydrogenase subunit-2 237 leucine/methionine (ND2-237 Leu/Met) polymorphism has been shown to modify the association of coffee consumption with the risk of hypertension, dyslipidemia, and abnormal glucose tolerance, and low serum chloride levels have been shown to be associated with all-cause and cardiovascular disease mortality. Therefore, the purpose of the present study was to investigate whether ND2-237 Leu/Met polymorphism influences the association of coffee consumption with serum chloride levels in male Japanese health checkup examinees. Methods: From among individuals visiting the hospital for a regular medical checkup, 402 men (mean age ± standard deviation, 53.9 ± 7.8 years) were selected for inclusion in the study. After ND2-237 Leu/Met genotyping, we conducted an exploratory cross-sectional study to examine the combined association of ND2-237 Leu/Met polymorphism and coffee consumption with serum electrolyte levels. Results: After adjusting for age, body mass index, habitual smoking, alcohol consumption, green tea consumption, and antihypertensive medication, coffee consumption significantly increased serum chloride levels (p for trend = 0.001) in men with the ND2-237Leu genotype. After these adjustments, the odds ratios (ORs) for low levels of serum chloride, defined as <100 mEq/L, were found to be dependent on coffee consumption (p for trend = 0.001). In addition, the OR for low levels of serum chloride was significantly lower in men with the ND2-237Leu genotype who consumed ≥4 compared with <1 cup of coffee per day (OR = 0.096, 95% confidence interval = 0.010–0.934; p = 0.044). However, neither serum chloride levels nor risk of low levels of serum chloride appeared to be dependent on coffee consumption. Conclusions: The results suggest that ND2-237 Leu/Met polymorphism modifies the association of coffee consumption with serum chloride levels in middle-aged Japanese men.

Epigenomics and metabolomics reveal the mechanism of the APOA2-saturated fat intake interaction affecting obesity

Background

The putative functional variant -265T>C (rs5082) within the APOA2 promoter has shown consistent interactions with saturated fatty acid (SFA) intake to influence the risk of obesity.

Objective

The aim of this study was to implement an integrative approach to characterize the molecular basis of this interaction.

Design

We conducted an epigenome-wide scan on 80 participants carrying either the rs5082 CC or TT genotypes and consuming either a low-SFA (<22 g/d) or high-SFA diet (≥22 g/d), matched for age, sex, BMI, and diabetes status in the Boston Puerto Rican Health Study (BPRHS). We then validated the findings in selected participants in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) Study (n = 379) and the Framingham Heart Study (FHS) (n = 243). Transcription and metabolomics analyses were conducted to determine the relation between epigenetic status, APOA2 mRNA expression, and blood metabolites.

Results

In the BPRHS, we identified methylation site cg04436964 as exhibiting significant differences between CC and TT participants consuming a high-SFA diet, but not among those consuming low-SFA. Similar results were observed in the GOLDN Study and the FHS. Additionally, in the FHS, cg04436964 methylation was negatively correlated with APOA2 expression in the blood of participants consuming a high-SFA diet. Furthermore, when consuming a high-SFA diet, CC carriers had lower APOA2 expression than those with the TT genotype. Lastly, metabolomic analysis identified 4 pathways as overrepresented by metabolite differences between CC and TT genotypes with high-SFA intake, including tryptophan and branched-chain amino acid (BCAA) pathways. Interestingly, these pathways were linked to rs5082-specific cg04436964 methylation differences in high-SFA consumers.

Conclusions

The epigenetic status of the APOA2 regulatory region is associated with SFA intake and APOA2 -265T>C genotype, promoting an APOA2 expression difference between APOA2 genotypes on a high-SFA diet, and modulating BCAA and tryptophan metabolic pathways. These findings identify potential mechanisms by which this highly reproducible gene-diet interaction influences obesity risk, and contribute new insights to ongoing investigations of the relation between SFA and human health. This study was registered at clinicaltrials.gov as NCT03452787.

Personalized Nutrition-Genes, Diet, and Related Interactive Parameters as Predictors of Cancer in Multiethnic Colorectal Cancer Families

To personalize nutrition, the purpose of this study was to examine five key genes in the folate metabolism pathway, and dietary parameters and related interactive parameters as predictors of colorectal cancer (CRC) by measuring the healthy eating index (HEI) in multiethnic families. The five genes included methylenetetrahydrofolate reductase (MTHFR) 677 and 1298, methionine synthase (MTR) 2756, methionine synthase reductase (MTRR 66), and dihydrofolate reductase (DHFR) 19bp, and they were used to compute a total gene mutation score. We included 53 families, 53 CRC patients and 53 paired family friend members of diverse population groups in Southern California. We measured multidimensional data using the ensemble bootstrap forest method to identify variables of importance within domains of genetic, demographic, and dietary parameters to achieve dimension reduction. We then constructed predictive generalized regression (GR) modeling with a supervised machine learning validation procedure with the target variable (cancer status) being specified to validate the results to allow enhanced prediction and reproducibility. The results showed that the CRC group had increased total gene mutation scores compared to the family members (p < 0.05). Using the Akaike’s information criterion and Leave-One-Out cross validation GR methods, the HEI was interactive with thiamine (vitamin B1), which is a new finding for the literature. The natural food sources for thiamine include whole grains, legumes, and some meats and fish which HEI scoring included as part of healthy portions (versus limiting portions on salt, saturated fat and empty calories). Additional predictors included age, as well as gender and the interaction of MTHFR 677 with overweight status (measured by body mass index) in predicting CRC, with the cancer group having more men and overweight cases. The HEI score was significant when split at the median score of 77 into greater or less scores, confirmed through the machine-learning recursive tree method and predictive modeling, although an HEI score of greater than 80 is the US national standard set value for a good diet. The HEI and healthy eating are modifiable factors for healthy living in relation to dietary parameters and cancer prevention, and they can be used for personalized nutrition in the precision-based healthcare era.

TAS2R38 Predisposition to Bitter Taste Associated with Differential Changes in Vegetable Intake in Response to a Community-Based Dietary Intervention

Although vegetable consumption associates with decreased risk for a variety of diseases, few Americans meet dietary recommendations for vegetable intake. TAS2R38 encodes a taste receptor that confers bitter taste sensing from chemicals found in some vegetables. Common polymorphisms in TAS2R38 lead to coding substitutions that alter receptor function and result in the loss of bitter taste perception. Our study examined whether bitter taste perception TAS2R38 diplotypes associated with vegetable consumption in participants enrolled in either an enhanced or a minimal nutrition counseling intervention. DNA was isolated from the peripheral blood cells of study participants (N = 497) and analyzed for polymorphisms. Vegetable consumption was determined using the Block Fruit and Vegetable screener. We tested for differences in the frequency of vegetable consumption between intervention and genotype groups over time using mixed effects models. Baseline vegetable consumption frequency did not associate with bitter taste diplotypes (P = 0.937), however after six months of the intervention, we observed an interaction between bitter taste diplotypes and time (P = 0.046). Participants in the enhanced intervention increased their vegetable consumption frequency (P = 0.020) and within this intervention group, the bitter non-tasters and intermediate-bitter tasters had the largest increase in vegetable consumption. In contrast, in the minimal intervention group, the bitter tasting participants reported a decrease in vegetable consumption. Bitter-non tasters and intermediate-bitter tasters increased vegetable consumption in either intervention more than those who perceive bitterness. Future precision medicine applications could consider genetic variation in bitter taste perception genes when designing dietary interventions.

Nutritional Genomics and Direct-to-Consumer Genetic Testing: An Overview

The increasing prevalence in polygenic diseases, such as obesity, cardiovascular disease, and type 2 diabetes, observed over the past few decades is more likely linked to a rapid transition in lifestyle rather than to changes in the sequence of the nuclear genome. In the new era of precision medicine, nutritional genomics holds the promise to be translated into tailored nutritional strategies to prevent and manage polygenic diseases more effectively. Nutritional genomics aims to prevent, treat, and manage polygenic diseases through targeted therapies formulated from individuals' genetic makeup and dietary intake. Direct-to-consumer genetic testing (DTC-GT) has become commercially available to equip individuals with information on their genetic vulnerability to different diseases. This information may potentially prompt behavioral changes against adverse factors. However, scientific evidence behind the clinical recommendations is a matter of continuous debate, and behavioral modifications after disclosing genetic information remain inconclusive. In this review, we provide an overview of nutritional genomics and related nutritional DTC-GT services and discuss whether available data are sufficient to be translated into clinical recommendations and public health initiatives. Overall, the scientific evidence supporting the dissemination of genomic information for nutrigenomic purposes remains sparse. Therefore, additional knowledge needs to be generated, particularly for polygenic traits.

Joint Effects of PON1 Polymorphisms and Vegetable Intake on Ischemic Stroke: A Family-Based Case Control Study

Paraoxonase 1 gene (PON1) polymorphisms and dietary vegetable and fruit intake are both established determinants of ischemic stroke (IS). However, little is known about whether these factors jointly influence the risk of IS. We analyzed the main effects of PON1, as well as the interactions between PON1 and dietary vegetable or fruit intake with the risk of total IS and its subtypes in a family-based case-control study conducted among 2158 Chinese participants (1007 IS cases and 1151 IS-free controls) from 918 families. Conditional logistic regression models, with each family as a stratum, were used to examine the association between rs662 and IS. Gene-diet interactions were tested by including a cross-product term of dietary vegetable or fruit intake by rs662_G allele count in the models. Each copy of the PON1 rs662_G allele was associated with 28% higher risk of total IS (p = 0.008) and 32% higher risk of large artery atherosclerosis subtype (LAA) (p = 0.01). We observed an interaction between rs662 and vegetable intake for both total IS (p = 0.006) and LAA (p = 0.02) after adjustment for covariates. Individuals who carry the rs662_A allele may benefit to a greater extent from intake of vegetables and thus be more effectively protected from ischemic stroke, whereas carriers of the G allele may still remain at greater risk for ischemic stroke due to their genetic backgrounds even when they consume a high level of vegetables. More studies are needed to replicate our findings among other populations.

Genetic variation of habitual coffee consumption and glycemic changes in response to weight-loss diet intervention: the Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial

Background: Coffee consumption has been associated with glucose metabolism and risk of type 2 diabetes.Objective: We examined whether the genetic variation determining habitual coffee consumption affected glycemic changes in response to weight-loss dietary intervention.Design: A genetic risk score (GRS) was calculated based on 8 habitual coffee consumption-associated single nucleotide polymorphisms. We used general linear models to test changes in glycemic traits in groups randomly assigned to high- and low-fat diets according to tertiles of the GRS.Results: We observed significant interactions between the GRS and low compared with high dietary fat intake on 6-mo changes in fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR) (P-interaction = 0.023 and 0.022, respectively), adjusting for age, sex, race, physical activity, smoking, alcohol, seasonal variation, and baseline values of the respective outcomes. Participants with a higher GRS of habitual coffee consumption showed a greater reduction in fasting insulin and a marginally greater decrease in HOMA-IR in the low-fat diet intervention group.Conclusions: Our data suggest that participants with genetically determined high coffee consumption may benefit more by eating a low-fat diet in improving fasting insulin and HOMA-IR in a short term. This trial was registered at clinicaltrials.gov as NCT00072995 and NCT03258203.

Macronutrient-specific effect of the MTNR1B genotype on lipid levels in response to 2 year weight-loss diets

Compelling evidence indicates that lipid metabolism is in partial control of the circadian system. In this context, it has been reported that the melatonin receptor 1B (MTNR1B) genetic variant influences the dynamics of melatonin secretion, which is involved in the circadian system as a chronobiotic. The objective was to analyze whether the MTNR1B rs10830963 genetic variant was related to changes in lipid levels in response to dietary interventions with different macronutrient distribution in 722 overweight/obese subjects from the POUNDS Lost trial. We did not find a significant association between the MTNR1B genotype and changes in lipid metabolism. However, dietary fat intake significantly modified genetic effects on 2 year changes in total and LDL cholesterol (P interaction = 0.006 and 0.001, respectively). In the low-fat diet group, carriers of the sleep disruption G allele (minor allele) showed a greater reduction of total cholesterol (β ± SE = -5.78 ± 2.88 mg/dl, P = 0.04) and LDL cholesterol (β ± SE = -7.19 ± 2.37 mg/dl, P = 0.003). Conversely, in the high-fat diet group, subjects carrying the G allele evidenced a smaller decrease in total cholesterol (β ± SE = 5.81 ± 2.65 mg/dl, P = 0.03) and LDL cholesterol (β ± SE = 5.23 ± 2.21 mg/dl, P = 0.002). Subjects carrying the G allele of the circadian rhythm-related MTNR1B variant may present a bigger impact on total and LDL cholesterol when undertaking an energy-restricted low-fat diet.

Precision Nutrition and Omega-3 Polyunsaturated Fatty Acids: A Case for Personalized Supplementation Approaches for the Prevention and Management of Human Diseases

BACKGROUND

Dietary essential omega-6 (n-6) and omega-3 (n-3) 18 carbon (18C-) polyunsaturated fatty acids (PUFA), linoleic acid (LA) and α-linolenic acid (ALA), can be converted (utilizing desaturase and elongase enzymes encoded by FADS and ELOVL genes) to biologically-active long chain (LC; >20)-PUFAs by numerous cells and tissues. These n-6 and n-3 LC-PUFAs and their metabolites (ex, eicosanoids and endocannabinoids) play critical signaling and structural roles in almost all physiologic and pathophysiologic processes.

METHODS

This review summarizes: (1) the biosynthesis, metabolism and roles of LC-PUFAs; (2) the potential impact of rapidly altering the intake of dietary LA and ALA; (3) the genetics and evolution of LC-PUFA biosynthesis; (4) Gene-diet interactions that may lead to excess levels of n-6 LC-PUFAs and deficiencies of n-3 LC-PUFAs; and (5) opportunities for precision nutrition approaches to personalize n-3 LC-PUFA supplementation for individuals and populations.

CONCLUSIONS

The rapid nature of transitions in 18C-PUFA exposure together with the genetic variation in the LC-PUFA biosynthetic pathway found in different populations make mal-adaptations a likely outcome of our current nutritional environment. Understanding this genetic variation in the context of 18C-PUFA dietary exposure should enable the development of individualized n-3 LC-PUFA supplementation regimens to prevent and manage human disease.

Effect of the interaction between diet composition and the PPM1K genetic variant on insulin resistance and β cell function markers during weight loss: results from the Nutrient Gene Interactions in Human Obesity: implications for dietary guidelines (NUGENOB) randomized trial

Background: Circulating branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) have been shown to be associated with insulin resistance and diabetes risk. The common rs1440581 T allele in the protein phosphatase Mg2+/Mn2+ dependent 1K (PPM1K) gene has been related to elevated BCAA concentrations and risk of type 2 diabetes.Objective: In the present study, we tested whether dietary fat and carbohydrate intakes influenced the association between the rs1440581 PPM1K genetic variant and glucose-metabolism traits during weight loss.Design: The rs1440581 PPM1K genetic variant was genotyped in a total of 757 nondiabetic individuals who were randomly assigned to 1 of 2 energy-restricted diets that differed in macronutrient composition (low-fat diet: 20-25% fat, 15% protein, and 60-65% carbohydrate; high-fat diet: 40-45% fat, 15% protein, and 40-45% carbohydrate). The changes in fasting glucose, fasting insulin, insulin resistance (homeostasis model assessment of insulin resistance) and homeostasis model assessment of β cell function (HOMA-B) were measured after a mean ± SD weight loss of 6.8 ± 3.4 kg over 10 wk and analyzed according to the presence of the T allele of rs1440581.Results: The rs1440581 T allele was associated with a smaller improvement in glucose concentrations after the 10-wk dietary intervention (β ± SE: 0.05 ± 0.02 mg/dL; P = 0.03). In addition, significant gene-diet interactions were shown for the rs1440581 PPM1K genetic variant in relation to changes in insulin and HOMA-B (P-interaction = 0.006 and 0.002, respectively). In response to the high-fat diet, the T allele was associated with a higher reduction of insulin (β ± SE: -0.77 ± 0.40 μU/mL; P = 0.04) and HOMA-B (β ± SE: -13.2 ± 3.81; P = 0.003). An opposite effect was observed in the low-fat diet group, although in this group the T allele was marginally (P = 0.10) and not significantly (P = 0.24) associated with insulin and HOMA-B, respectively.Conclusion:PPM1K rs1440581 may affect changes in glucose metabolism during weight loss, and this effect is dependent on dietary fat and carbohydrate intakes. This trial was registered at controlled-trials.com as ISRCTN25867281.

Association and Interaction Effect of AGTR1 and AGTR2 Gene Polymorphisms with Dietary Pattern on Metabolic Risk Factors of Cardiovascular Disease in Malaysian Adults

Gene-diet interaction using a multifactorial approach is preferred to study the multiple risk factors of cardiovascular disease (CVD). This study examined the association and gene-diet interaction effects of the angiotensin II type 1 receptor (AGTR1) gene (rs5186), and type 2 receptor (AGTR2) gene (rs1403543) polymorphisms on metabolic risk factors of CVD in Malaysian adults. CVD parameters (BMI, blood pressure, glycated hemoglobin, total cholesterol (TC), triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), and TC/HDL-C ratio), and constructed dietary patterns “vegetables, fruits, and soy diet” (VFSD), and “rice, egg, and fish diet” (REFD) were obtained from previous studies. Genotyping analysis was performed by real-time PCR using Taqman probes. The subjects were 507 adults (151 Malays; 179 Chinese; and 177 Indians). Significant genetic associations were obtained on blood lipids for rs5186 in Malays and Chinese, and rs1403543 in Chinese females. The significant gene-diet interaction effects after adjusting for potential confounders were: rs5186 × VFSD on blood pressure in Malays (p = 0.016), and in Chinese on blood lipids for rs5186 × REFD (p = 0.009–0.023), and rs1403543 × VFSD in female subjects (p = 0.001–0.011). Malays and Chinese showed higher risk for blood pressure and/or lipids involving rs5186 and rs1403543 SNPs together with gene-diet interactions, but not Indians.

Dietary starch intake modifies the relation between copy number variation in the salivary amylase gene and BMI

Background: Studies have shown conflicting associations between the salivary amylase gene (AMY1) copy number and obesity. Salivary amylase initiates starch digestion in the oral cavity; starch is a major source of energy in the diet.Objective: We investigated the association between AMY1 copy number and obesity traits, and the effect of the interaction between AMY1 copy number and starch intake on these obesity traits.Design: We first assessed the association between AMY1 copy number (genotyped by digital droplet polymerase chain reaction) and obesity traits in 4800 individuals without diabetes (mean age: 57 y; 60% female) from the Malmö Diet and Cancer Cohort. Then we analyzed interactions between AMY1 copy number and energy-adjusted starch intake (obtained by a modified diet history method) on body mass index (BMI) and body fat percentage.Results:AMY1 copy number was not associated with BMI (P = 0.80) or body fat percentage (P = 0.38). We observed a significant effect of the interaction between AMY1 copy number and starch intake on BMI (P-interaction = 0.007) and body fat percentage (P-interaction = 0.03). Upon stratification by dietary starch intake, BMI tended to decrease with increasing AMY1 copy numbers in the low-starch intake group (P = 0.07) and tended to increase with increasing AMY1 copy numbers in the high-starch intake group (P = 0.08). The lowest mean BMI was observed in the group of participants with a low AMY1 copy number and a high dietary intake of starch.Conclusions: Our findings suggest an effect of the interaction between starch intake and AMY1 copy number on obesity. Individuals with high starch intake but low genetic capacity to digest starch had the lowest BMI, potentially because larger amounts of undigested starch are transported through the gastrointestinal tract, contributing to fewer calories extracted from ingested starch.

PCSK9 variant, long-chain n-3 PUFAs, and risk of nonfatal myocardial infarction in Costa Rican Hispanics

Background: Previous studies have indicated that the cardioprotective effects of long-chain (LC) n-3 (ω-3) polyunsaturated fatty acids (PUFAs) may vary across various ethnic populations. Emerging evidence has suggested that the gene-environment interaction may partly explain such variations. Proprotein convertase subtilisin/kexin type 9 (PCSK9) was shown to have a mutually regulating relation with LC n-3 PUFAs and also to reduce the risk of cardiovascular diseases (CVDs). Therefore, we hypothesized that certain PCSK9 genetic variants may modify the association between LC n-3 PUFA intake and CVD risk.Objective: We determined whether a PCSK9 variant (rs11206510), which has been identified for early onset myocardial infarction (MI), modified the association of LC n-3 PUFAs with nonfatal MI risk in Costa Rican Hispanics.Design: We analyzed cross-sectional data from 1932 case subjects with a first nonfatal MI and 2055 population-based control subjects who were living in Costa Rica to examine potential gene-environment interactions. Two-sided P values <0.05 were considered significant.Results: We observed a significant interaction between the PCSK9 rs11206510 genotype and LC n-3 PUFA intake on nonfatal MI risk (P-interaction = 0.012). The OR of nonfatal MI was 0.84 (95% CI: 0.72, 0.98) per 0.1% increase in total energy intake from LC n-3 PUFAs in protective-allele (C-allele) carriers, whereas the corresponding OR (95% CI) in non-C-allele carriers was 1.02 (95% CI: 0.95, 1.10). Similar results were observed when we examined the association between docosahexaenoic acid, which is one type of LC n-3 PUFA, and nonfatal MI risk (P-interaction = 0.003).Conclusion: LC n-3 PUFA intake is associated with a lower risk of nonfatal MI in C-allele carriers of PCSK9 rs11206510 (n = 799) but not in non-C-allele carriers (n = 3188).

Interaction between Single Nucleotide Polymorphism and Urinary Sodium, Potassium, and Sodium-Potassium Ratio on the Risk of Hypertension in Korean Adults

Hypertension is a complex disease explained with diverse factors including environmental factors and genetic factors. The objectives of this study were to determine the interaction effects between gene variants and 24 h estimated urinary sodium and potassium excretion and sodium-potassium excretion ratios on the risk of hypertension. A total of 8839 participants were included in the genome-wide association study (GWAS) to find genetic factors associated with hypertension. Tanaka and Kawasaki formulas were applied to estimate 24 h urinary sodium and potassium excretion. A total of 4414 participants were included in interaction analyses to identify the interaction effects of gene variants according to 24 h estimated urinary factors on the risk of hypertension. CSK rs1378942 and CSK-MIR4513 rs3784789 were significantly modified by urinary sodium-potassium excretion ratio. In addition, MKLN rs1643270 with urinary potassium excretion, LOC101929750 rs7554672 with urinary sodium and potassium excretion, and TENM4 rs10466739 with urinary sodium-potassium excretion ratio showed significant interaction effects. The present study results indicated that the mutant alleles of CSK rs1378942 and CSK-MIR4513 rs3784789 had the strongest protective effects against hypertension in the middle group of 24 h estimated urinary sodium-potassium excretion ratio. Further studies are needed to replicate these analyses in other populations.

Dietary Protein Modifies the Effect of the MC4R Genotype on 2-Year Changes in Appetite and Food Craving: The POUNDS Lost Trial

Background: The melanocortin-4 receptor (MC4R) plays a pivotal role in the regulation of appetite and eating behavior. Variants in the MC4R gene have been related to appetite and obesity.Objective: We aimed to examine whether weight-loss diets modified the effect of the "obesity-predisposing" MC4R genotype on appetite-related measures in a randomized controlled trial.Methods: A total of 811 overweight and obese subjects [25 ≤ body mass index (BMI; kg/m²) ≤ 40] aged 30-70 y were included in the 2-y POUNDS Lost (Preventing Overweight Using Novel Dietary Strategies) trial. We genotyped MC4R rs7227255 in 735 overweight adults and assessed appetite-related characteristics, including craving, fullness, hunger, and prospective consumption, as well as a composite appetite score. We examined the effects of the genotype-by-weight-loss diet intervention interaction on appetite variables by using general linear models in both the whole population and in white participants only.Results: We found that dietary protein intake (low compared with high: 15% of energy compared with 25% of energy, respectively) significantly modified MC4R genetic effects on changes in appetite score and craving (P-interaction = 0.03 and 0.02, respectively) at 2 y, after adjustment for age, sex, ethnicity, baseline BMI, weight change, and baseline perspective phenotype. The obesity-predisposing A allele was associated with a greater increase in overall appetite score (β = 0.10, P = 0.05) and craving (β = 0.13, P = 0.008) compared with the non-A allele among participants who consumed a high-protein diet. MC4R genotype did not modify the effects of fat or carbohydrate intakes on appetite measures. Similar interaction patterns were observed in whites.Conclusion: Our data suggest that individuals with the MC4R rs7227255 A allele rather than the non-A allele might experience greater increases in appetite and food craving when consuming a high-protein weight-loss diet. This trial was registered at clinicaltrials.gov as NCT00072995.

Interaction of an S100A9 gene variant with saturated fat and carbohydrates to modulate insulin resistance in 3 populations of different ancestries

BACKGROUND

S100 calcium-binding protein A9 (S100A9) has previously been identified as a type 2 diabetes (T2D) gene. However, this finding requires independent validation and more in-depth analyses in other populations and ancestries.

OBJECTIVES

We aimed to replicate the associations between an S100A9 variant and insulin resistance and T2D and to initiate an investigation of potential interactions with the habitual diet in several independent populations.

DESIGN

We investigated the association of the S100A9 variant rs3014866 with insulin resistance and T2D risk and its interactions with diet in 3 diverse populations as follows: the CORDIOPREV (Coronary Diet Intervention with Olive Oil and Cardiovascular Prevention; n = 711), which consisted of Spanish white adults; the GOLDN (Genetics of Lipids Lowering Drugs and Diet Network; n = 818), which involved North American non-Hispanic white adults; and Hispanic adults who participated in the BPRHS (Boston Puerto Rican Health Study; n = 1155).

RESULTS

Meta-analysis indicated that T carriers presented a lower risk of T2D than CC carriers (pooled OR: 0.714; 95% CI: 0.584, 0.845; P = 0.002). In all 3 populations (CORDIOPREV, GOLDN, and BPRHS), we showed a significant interaction between the rs3014866 single nucleotide polymorphism and dietary SFA:carbohydrate ratio intake for the homeostasis model assessment of insulin resistance (HOMA-IR) (P = 0.028, P = 0.017, and P = 0.026, respectively). CC carriers had a significantly higher HOMA-IR only when SFA:carbohydrate intake was high (P = 0.045 for the CORDIOPREV, P = 0.033 for the GOLDN, and P = 0.046 for the BPRHS) but not when SFA:carbohydrate ratio intake was low.

CONCLUSIONS

The minor allele (T) of the S100A9 variant rs3014866 is associated with lower T2D risk in 3 populations of different ancestries. Note that individuals with the high-risk CC genotype may be more likely to benefit from a low SFA:carbohydrate ratio intake to improve insulin resistance as evaluated with the use of the HOMA-IR. These trials were registered at clinicaltrials.gov as NCT00924937 (CORDIOPREV), NCT00083369 (GOLDN), and NCT01231958 (BPRHS).

Common Variants in Cholesterol Synthesis- and Transport-Related Genes Associate with Circulating Cholesterol Responses to Intakes of Conventional Dairy Products in Healthy Individuals

BACKGROUND

Dairy intake has been associated with varying impacts on circulating cholesterol concentrations across nutritional epidemiology and intervention studies, with findings attributed mainly to differences in the nature of dairy products consumed or study designs. The contribution of the genomic architecture to such observations has yet to be revealed.

OBJECTIVE

We assessed the impact of multiple common genetic variations in cholesterol-related genes on responses of serum cholesterol to the recommended amount of dairy product intake in Canada.

METHODS

In a multicenter, randomized crossover design, 101 normolipidemic adults (n = 29 men and 72 women), with a mean ± SD age of 41.7 ± 16.7 y and a body mass index (BMI, in kg/m(2)) of 25.9 ± 4.3 consumed 3 servings/d of dairy [375 mL 1% milk-fat (MF) milk, 175 g 1.5% MF yogurt, and 30 g of 34% MF cheese] or energy-matched control products (juice, cashews, and cookies) provided within a prudent background diet for 4 wk each, separated by a 4- to 8-wk washout period. Serum lipid variables were determined by standard enzymatic methods by using an autoanalyzer. Candidate single nucleotide polymorphisms were assessed by TaqMan genotyping assay.

RESULTS

The responsiveness of serum total cholesterol (TC) and LDL cholesterol to the dairy compared with the control diet was associated with individuals' genotypes. The cholesterol transport gene ATP-binding cassette subfamily G, member 5 (ABCG5) rs6720173-GG homozygotes had higher concentrations of TC (+0.18 mmol/L; P = 0.0118) and LDL cholesterol (+0.17 mmol/L; P = 0.0056) relative to C-allele carriers (-0.07 and -0.06 mmol/L, respectively). The bile acid synthesis gene cholesterol 7α-hydroxylase (CYP7A1) rs3808607-G-allele carriers had higher TC (+0.20 to +0.28 mmol/L; P = 0.0026) and LDL cholesterol (+0.19 mmol/L for GT genotype; P = 0.0260) relative to TT homozygotes (-0.11 and -0.03 mmol/L, respectively). In addition, the cholesterol synthesis gene 7-dehydrocholesterol reductase (DHCR7) rs760241-A-allele carriers had higher LDL cholesterol (+0.26 mmol/L; P = 0.0399) relative to GG homozygotes (+0.06 mmol/L).

CONCLUSION

Genetic variations in ABCG5, CYP7A1, and DHCR7 may contribute to differing responses of serum cholesterol to dairy intake among healthy adults. This trial was registered at clinicaltrials.gov as NCT01444326.

Sugar-sweetened beverage intake, chromosome 9p21 variants, and risk of myocardial infarction in Hispanics

BACKGROUND

Chromosome 9p21 variants are among the most robust genetic markers for coronary artery disease (CAD), and previous studies have suggested that genetic effects of this locus might be modified by dietary factors. Intake of sugar-sweetened beverages (SSBs), which are the main dietary source of added sugar, has been shown to interact with genetic factors in affecting CAD risk factors such as obesity.

OBJECTIVE

We aimed to test whether SSB intake modified the association between chromosome 9p21 variants and CAD risk in Hispanics living in Costa Rica.

DESIGN

The current study included 1560 incident cases of nonfatal myocardial infarction (MI) and 1751 population-based controls. Three independent single nucleotide polymorphisms (SNPs) at the chromosome 9p21 locus were genotyped. SSB intake was assessed with the use of a food-frequency questionnaire and was defined as the frequency of intake of daily servings of sweetened beverages and fruit juice.

RESULTS

We showed a significant interaction between SSB intake and one of the 3 variants (i.e., rs4977574) on MI risk. The per–risk allele OR (95% CI) of rs4977574 for MI was 1.44 (1.19, 1.74) in participants with higher SSB consumption (>2 servings/d), 1.21 (1.00, 1.47) in those with average consumption (1–2 servings/d), and 0.97 (0.81, 1.16) in subjects with lower consumption (<1 serving/d; P-interaction = 0.005). A genetic risk score derived from the sum of risk alleles of the 3 SNPs also showed a significant interaction with SSB intake on MI risk (P-interaction = 0.03).

CONCLUSION

Our data suggest that unhealthy dietary habits such as higher intake of SSBs could exacerbate the effects of chromosome 9p21 variants on CAD.

Intake of Total and Subgroups of Fat Minimally Affect the Associations between Selected Single Nucleotide Polymorphisms in the PPARγ Pathway and Changes in Anthropometry among European Adults from Cohorts of the DiOGenes Study

BACKGROUND

Although the peroxisome proliferator-activated receptor γ (PPARγ) pathway is central in adipogenesis, it remains unknown whether it influences change in body weight (BW) and whether dietary fat has a modifying effect on the association.

OBJECTIVES

We examined whether 27 single nucleotide polymorphisms (SNPs) within 4 genes in the PPARγ pathway are associated with the OR of being a BW gainer or with annual changes in anthropometry and whether intake of total fat, monounsaturated fat, polyunsaturated fat, or saturated fat has a modifying effect on these associations.

METHODS

A case-noncase study included 11,048 men and women from cohorts in the European Diet, Obesity and Genes study; 5552 were cases, defined as individuals with the greatest BW gain during follow-up, and 6548 were randomly selected, including 5496 noncases. We selected 4 genes [CCAAT/enhancer binding protein β (CEBPB), phosphoenolpyruvate carboxykinase 2, PPARγ gene (PPARG), and sterol regulatory element binding transcription factor 1] according to evidence about biologic plausibility for interactions with dietary fat in weight regulation. Diet was assessed at baseline, and anthropometry was followed for 7 y.

RESULTS

The ORs for being a BW gainer for the 27 genetic variants ranged from 0.87 (95% CI: 0.79, 1.03) to 1.12 (95% CI: 0.96, 1.22) per additional minor allele. Uncorrected, CEBPB rs4253449 had a significant interaction with the intake of total fat and subgroups of fat. The OR for being a BW gainer for each additional rs4253449 minor allele per 100 kcal higher total fat intake was 1.07 (95% CI: 1.02, 1.12; P = 0.008), and similar associations were found for subgroups of fat.

CONCLUSIONS

Among European men and women, the influence of dietary fat on associations between SNPs in the PPARγ pathway and anthropometry is likely to be absent or marginal. The observed interaction between rs4253449 and dietary fat needs confirmation.

Interaction of dietary fat intake with APOA2, APOA5 and LEPR polymorphisms and its relationship with obesity and dyslipidemia in young subjects

BACKGROUND

Diet is an important environmental factor that interacts with genes to modulate the likelihood of developing disorders in lipid metabolism and the relationship between diet and genes in the presence of other chronic diseases such as obesity. The objective of this study was to analyze the interaction of a high fat diet with the APOA2 (rs3813627 and rs5082), APOA5 (rs662799 and rs3135506) and LEPR (rs8179183 and rs1137101) polymorphisms and its relationship with obesity and dyslipidemia in young subjects.

METHODS

The study included 200 young subjects aged 18 to 25 years (100 normal-weight and 100 obese subjects). Dietary fat intake was measured using the frequency food consumption questionnaire. Genotyping of polymorphisms was performed by PCR-RFLP.

RESULTS

Individuals carrying the APOA5 56 G/G genotype with a high saturated fatty acid consumption (OR = 2.7, p = 0.006) and/or total fat (OR = 2.4, p = 0.018), associated with an increased risk of obesity. We also found that A/G + G/G genotypes of the 668 A/G polymorphism in the LEPR gene with an intake ≥ 12 g/d of saturated fatty acids, have 2.9 times higher risk of obesity (p = 0.002), 3.8 times higher risk of hypercholesterolemia (p = 0.002) and 2.4 times higher risk of hypertriglyceridemia (p = 0.02), than those with an intake <12 g/d of saturated fatty acids. Similarly, LEPR 668 A/G + G/G carriers with a high fat total intake had 3.0 times higher risk of obesity (p = 0.002) and 4.1 times higher risk of hypercholesterolemia (p = 0.001).

CONCLUSION

Our results suggest that dietary fat intake modifies the effect of APOA5 and LEPR polymorphisms on serum triglycerides, cholesterol levels and obesity in young subjects.

Nutrigenetics of cholesterol metabolism: observational and dietary intervention studies in the postgenomic era

Cholesterol metabolism is a well-defined responder to dietary intakes and a classic biomarker of cardiovascular health. For this reason, circulating cholesterol levels have become key in shaping nutritional recommendations by health authorities worldwide for better management of cardiovascular disease, a leading cause of mortality and one of the most costly health problems globally. Data from observational and dietary intervention studies, however, highlight a marked between-individual variability in the response of cholesterol metabolism to similar dietary protocols, a phenomenon linked to genetic heterogeneity. This review summarizes the postgenomic evidence of polymorphisms within cholesterol-associated genes relative to fasting circulating cholesterol levels under diverse nutritional conditions. A number of cholesterol-related gene-diet interactions are confirmed, which may have clinical importance, supporting a deeper look into the rapidly emerging field of nutrigenetics for meaningful conclusions that may eventually lead to genetically targeted dietary recommendations in the era of personalized nutrition.

Dietary Fat Intake Modifies the Effect of a Common Variant in the LIPC Gene on Changes in Serum Lipid Concentrations during a Long-Term Weight-Loss Intervention Trial

BACKGROUND

Hepatic lipase (HL) plays a pivotal role in the metabolism of HDL and LDL. Recent genome-wide association studies have identified common variants in the HL gene (LIPC) associated with HDL cholesterol.

OBJECTIVE

We tested the effect of a common variant in LIPC on changes in blood lipids in response to weight-loss diets in the Preventing Overweight Using Novel Dietary Strategies Trial.

METHODS

We genotyped LIPC rs2070895 in 743 overweight or obese adults aged 30-70 y (61% women) who were assigned to high-fat (40% energy) or low-fat (20% energy) diets for 2 y. We measured serum concentrations of total cholesterol (TC), triglycerides, LDL cholesterol, and HDL cholesterol at baseline and 2 y of intervention.

RESULTS

At 2 y of intervention, dietary fat modified effects of the variant on changes in serum TC, LDL cholesterol, and HDL cholesterol (P-interaction: 0.0008, 0.004, and 0.03, respectively). In the low-fat group, as compared to the G allele, the A allele tended to be related to the decrease in TC and LDL cholesterol concentrations [TC (β ± SE): -5.5 ± 3.0, P = 0.07; LDL cholesterol: -4.8 ± 2.5, P = 0.06] and a lower increase in HDL cholesterol concentrations (β ± SE: -1.37 ± 0.69, P = 0.048), whereas an opposite effect in the high-fat diet group was evident [TC (β ± SE): 7.3 ± 2.7, P = 0.008; LDL cholesterol: 4.1 ± 2.3, P = 0.07], and there was no genetic effect on changes in HDL cholesterol concentrations (P = 0.54).

CONCLUSION

Dietary fat intake modifies the effect of a common variant in LIPC on changes in serum lipids during a long-term weight-loss intervention in overweight or obese adults. This trial was registered at clinicaltrials.gov as NCT00072995.

Dietary Fat Modifies the Effects of FTO Genotype on Changes in Insulin Sensitivity

BACKGROUND

The common variants in the fat mass and obesity-associated (FTO) gene have been associated with obesity and insulin resistance. Recently, studies also linked FTO variants with macronutrient intakes.

OBJECTIVE

We aimed to investigate whether diet interventions varying in macronutrients modified the effects of FTO genotypes on changes in insulin resistance.

METHODS

We genotyped FTO variants rs1558902 and rs9939609 and measured insulin resistance in fasting plasma samples at baseline and at 6-mo and 2-y visits in 743 overweight or obese adults (aged 30-70 y, 60% women) from a randomized weight-loss dietary interventional trial, the Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial. We assessed interactions between FTO variants and intakes of dietary fat and protein in relation to change in body weight and insulin resistance using generalized estimating equation models.

RESULTS

We found significant interactions between rs1558902 and dietary fat on changes in homeostasis model assessment of insulin resistance (HOMA-IR) and insulin (P = 0.003 and 0.004, respectively). Each risk allele (A) of rs1558902 showed a trend to be related to a 0.05-unit less reduction in both log(insulin) and log(HOMA-IR) among the participants assigned to low-fat diets (both P = 0.06), but this was not significantly related to reduction in those assigned to high-fat diets (both P > 0.1) during the 2-y period of intervention. Our data showed that the association between rs9939609 and changes in insulin resistance was not modified by diet macronutrient intakes.

CONCLUSIONS

Our results show that carriers of the risk alleles of rs1558902 benefit differently in improving insulin sensitivity by consuming high-fat weight-loss diets rather than low-fat diets. Still, given our data, we acknowledge it is difficult to determine whether fat or carbohydrate contributed to the observed associations.

CETP genotype and changes in lipid levels in response to weight-loss diet intervention in the POUNDS LOST and DIRECT randomized trials

Little is known about whether cholesteryl ester transfer protein (CETP) genetic variation may modify the effect of weight-loss diets varying in fat content on changes in lipid levels. We analyzed the interaction between the CETP variant rs3764261 and dietary interventions on changes in lipid levels among 732 overweight/obese adults from a 2 year randomized weight-loss trial [Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST)], and replicated the findings in 171 overweight/obese adults from an independent 2 year weight-loss trial [Dietary Intervention Randomized Controlled Trial (DIRECT)]. In the POUNDS LOST, participants with the CETP rs3764261 CC genotype on the high-fat diet had larger increases in HDL cholesterol (P = 0.001) and decreases in triglycerides (P = 0.007) than those on the low-fat diet at 6 months, while no significant difference between these two diets was observed among participants carrying other genotypes. The gene-diet interactions on changes in HDL-cholesterol and tri-glyc-erides were replicated in the DIRECT (pooled P for interaction ≤ 0.01). Similar results on trajectory of changes in HDL cholesterol and triglycerides over the 2 year intervention were observed in both trials. Our study provides replicable evidence that individuals with the CETP rs3764261 CC genotype might derive greater effects on raising HDL cholesterol and lowering triglycerides by choosing a low-carbohydrate/high-fat weight-loss diet instead of a low-fat diet.

Joint association of genome-wide association study-identified susceptibility loci and dietary patterns in risk of renal cell carcinoma among non-Hispanic whites

Dietary factors may affect risk of renal cell carcinoma (RCC). In an ongoing case-control study of RCC initiated in Houston, Texas, in 2002, we identified 3 empirically derived dietary patterns: "fruits and vegetables," "American/Western," and "Tex-Mex." Among 659 RCC cases and 699 controls, we evaluated associations of these dietary patterns with RCC risk and whether the associations varied by obesity status, smoking status, physical activity level, history of hypertension, and genetic variants previously identified via genome-wide association studies. Among persons in the highest categories of adherence versus the lowest, the "fruits and vegetables" dietary pattern was associated with an approximately 50% lower RCC risk (Ptrend < 0.001), while "American/Western" dietary pattern scores were positively associated with a 2-fold higher risk (Ptrend < 0.001). We observed synergistic interaction between the American/Western pattern and hypertension status: The odds ratio (highest tertile vs. lowest) among persons with hypertension was 2.23 (95% confidence interval: 1.43, 3.45), as compared with 1.76 (95% confidence interval: 1.16, 2.70) among persons without hypertension (additive Pinteraction = 0.01). A variant (rs718314) in the inositol 1,4,5-trisphosphate receptor, type 2 gene (ITPR2) was found to interact with the American/Western dietary pattern in relation to RCC risk (additive Pinteraction = 0.03). ITPR2 has been shown to affect nutrient metabolism and central obesity. Dietary patterns, genetic variants, and host characteristics may individually and jointly influence susceptibility to RCC.

Cfh genotype interacts with dietary glycemic index to modulate age-related macular degeneration-like features in mice

PURPOSE

Age-related macular degeneration (AMD) is a leading cause of visual impairment worldwide. Genetics and diet contribute to the relative risk for developing AMD, but their interactions are poorly understood. Genetic variations in Complement Factor H (CFH), and dietary glycemic index (GI) are major risk factors for AMD. We explored the effects of GI on development of early AMD-like features and changes to central nervous system (CNS) inflammation in Cfh-null mice.

METHODS

Aged 11-week-old wild type (WT) C57Bl/6J or Cfh-null mice were group pair-fed high or low GI diets for 33 weeks. At 10 months of age, mice were evaluated for early AMD-like features in the neural retina and RPE by light and electron microscopy. Brains were analyzed for Iba1 macrophage/microglia immunostaining, an indicator of inflammation.

RESULTS

The 10-month-old WT mice showed no retinal abnormalities on either diet. The Cfh-null mice, however, showed distinct early AMD-like features in the RPE when fed a low GI diet, including vacuolation, disruption of basal infoldings, and increased basal laminar deposits. The Cfh-null mice also showed thinning of the RPE, hypopigmentation, and increased numbers of Iba1-expressing macrophages in the brain, irrespective of diet.

CONCLUSIONS

The presence of early AMD-like features by 10 months of age in Cfh-null mice fed a low GI diet is surprising, given the apparent protection from the development of such features in aged WT mice or humans consuming lower GI diets. Our findings highlight the need to consider gene-diet interactions when developing animal models and therapeutic approaches to treat AMD.

The APOA1/C3/A4/A5 cluster and markers of allostatic load in the Boston Puerto Rican Health Study

BACKGROUND AND AIMS

The APOA1/C3/A4/A5 cluster encodes key regulators of plasma lipids. Interactions between dietary factors and single nucleotide polymorphisms (SNPs) in the cluster have been reported. Allostatic load, or physiological dysregulation in response to stress, has been implicated in shaping health disparities in ethnic groups. We aimed to determine the association between polymorphisms in the APOA1/C3/A4/A5 cluster with allostatic load parameters, alone, and in interaction with dietary fat intake in Puerto Ricans adults.

METHODS AND RESULTS

Data on demographic and anthropometric measures, lifestyle behaviors, and medication use, as well as blood and urine samples for biomarker analysis, were obtained from participants of the Boston Puerto Rican Health Study (n=821, age 45-75 y). The 12 polymorphisms analyzed were not associated with allostatic load parameters. Significant interactions were observed between dietary fat intake and APOA1-75 in association with waist circumference (WC), (P=0.005), APOC3-640 with diastolic blood pressure (DBP), (P=0.003), and APOA4 N147S and APOA5 S19W with systolic blood pressure (SBP), (P=0.001 and P=0.002, respectively). Puerto Ricans homozygous for the common allele of APOA1-75, APOA4 N147S and APOA5 S19W had lower WC and SBP when consuming <31% of total fat from energy, than participants with the minor allele. Participants heterozygous for APOC3-640 had lower DBP at total fat intake ≥31% from energy.

CONCLUSION

SNPs in APOA1/C3/A4/A5, as modulated by dietary fat intake, appear to influence allostatic load parameters in Puerto Ricans.

Insulin receptor substrate 1 gene variation modifies insulin resistance response to weight-loss diets in a 2-year randomized trial: the Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial

BACKGROUND

Common genetic variants in the insulin receptor substrate 1 (IRS1) gene have been recently associated with insulin resistance and hyperinsulinemia. We examined whether the best-associated variant modifies the long-term changes in insulin resistance and body weight in response to weight-loss diets in Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial.

METHODS AND RESULTS

We genotyped IRS1 rs2943641 in 738 overweight adults (61% were women) who were randomly assigned to 1 of 4 diets varying in macronutrient contents for 2 years. We assessed the progress in fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and weight loss by genotypes. At 6 months, participants with the risk-conferring CC genotype had greater decreases in insulin (P=0.009), HOMA-IR (P=0.015), and weight loss (P=0.018) than those without this genotype in the highest-carbohydrate diet group whereas an opposite genotype effect on changes in insulin and HOMA-IR (P≤0.05) was observed in participants assigned to the lowest-carbohydrate diet group. No significant differences were observed across genotypes in the other 2 diet groups. The tests for genotype by intervention interactions were all significant (P<0.05). At 2 years, the genotype effect on changes in insulin and HOMA-IR remained significant in the highest-carbohydrate diet group (P<0.05). The highest carbohydrate diet led to a greater improvement of insulin and HOMA-IR (P for genotype-time interaction ≤0.009) in participants with the CC genotype than those without this genotype across 2-year intervention.

CONCLUSIONS

Individuals with the IRS1 rs2943641 CC genotype might obtain more benefits in weight loss and improvement of insulin resistance than those without this genotype by choosing a high-carbohydrate and low-fat diet.

CLINICAL TRIAL REGISTRATION

http:www.clinicaltrials.gov. Unique identifier: NCT00072995.

ADAM17_i33708A>G polymorphism interacts with dietary n-6 polyunsaturated fatty acids to modulate obesity risk in the Genetics of Lipid Lowering Drugs and Diet Network study

BACKGROUND AND AIMS

The disintegrin and metalloproteinase ADAM17, also known as tumor necrosis factor alpha converting enzyme, is expressed in adipocytes. Importantly, elevated levels of ADAM17 expression have been linked to obesity and insulin resistance. Therefore, the aim of this study was to evaluate the association of six ADAM17 single nucleotide polymorphisms (SNPs) (m1254A>G, i14121C>A, i33708A>G, i48827A>C, i53440C>T, and i62781G>T) with insulin-resistance phenotypes and obesity risk, and their potential interactions with dietary polyunsaturated fatty acids (PUFA).

METHODS AND RESULTS

ADAM17 SNPs were genotyped in 936 subjects (448 men/488 women) who participated in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study. Anthropometrical and biochemical measurements were determined by standard procedures. PUFA intake was estimated using a validated questionnaire. G allele carriers at the ADAM17_m1254A>G polymorphism exhibited significantly higher risk of obesity (P=0.003), were shorter (P=0.017), had higher insulin (P=0.016), and lower HDL-C concentrations (P=0.027) than AA subjects. For the ADAM17_i33708A>G SNP, homozygotes for the A allele displayed higher risk of obesity (P=0.001), were heavier (P=0.011), had higher BMI (P=0.005), and higher waist measurements (P=0.023) than GG subjects. A significant gene-diet interaction was found (P=0.030), in which the deleterious association of the i33708A allele with obesity was observed in subjects with low intakes from (n-6) PUFA (P<0.001), whereas no differences in obesity risk were seen among subjects with high (n-6) PUFA intake (P>0.5)

CONCLUSION

These findings support that ADAM17 (m1254A>G and i33708A>G) SNPs may contribute to obesity risk. For the ADAM17_i33708A>G SNP, this risk may be further modulated by (n-6) PUFA intake.

Role of genetic factors in childhood obesity and in susceptibility to dietary variations

The concern about the current epidemic of obesity is heightened by recent data showing an increase in the prevalence of overweight and obesity in children and adolescents. As obese children are at increased risk of becoming obese adults, early identification of individuals at risk of becoming obese is important for the implementation of preventive measures. In that context, it is important to assess the role of genetic and nongenetic factors in childhood obesity as well as in susceptibility to dietary variations. This paper reviews recent data regarding the prevalence of obesity in childhood as well as the role of genetic factors in phenotypes related to obesity, with emphasis on studies conducted on children, when available. The existence of severe cases of obesity, such as those encountered in Mendelian syndromes of obesity or those caused by mutations in single genes, provides strong evidence for a role of genetic factors in the aetiology of childhood obesity. Furthermore, results from family studies suggest that the maximal heritability of obesity phenotypes ranges from about 30% to 50% and that the major affectors of body fat content, energy intake and energy expenditure are also influenced by genetic factors. Finally, there is increasing evidence that responsiveness to dietary intervention is genetically determined.