Biomarkers of Nutrition and Health: New Tools for New Approaches

Common Limitations and Challenges of Dietary Clinical Trials for Translation into Clinical Practices

The progressive development of clinical and public health nutrition has long relied on dietary clinical trials (DCTs), investigating the causal relationship between diet and multiple risk factors of non-communicable and chronic diseases. DCTs are also hallmarks for establishing dietary requirements and promoting overall nutritional health among the population. Despite their critical importance in translation into public health strategies and practices, DCTs have several limitations and challenges for study design, implementation and finding interpretation. The complex nature of nutrition interventions, collinearity between diet components, multi-target effects of the interventions, diverse dietary behaviors, and food culture are the most challenging issues. Furthermore, baseline exposure and dietary status, appropriate control groups, blinding, randomization, and poor adherence undermine the effectiveness of DCTs in translation into practices. Disruptive factors will be minimized if researchers are committed to following good clinical practice (GCP) standards available for common designs of clinical trials. Planning DCTs, however, needs careful considerations for hypothesis generation, study design development, the definition of primary and secondary outcome measures, and target population.

Development and Validation of a Mobile Phone Application Developed for Measuring Dietary Fiber Intake

We have developed a mobile phone application for measuring the intake of dietary fiber and validated the ability of the application to accurately capture this intake against measurements registered by a dietary record. We also investigated what food groups contributed most to the total, soluble, and insoluble dietary fiber intake. Twenty-six randomly selected Swedish women aged 35–85 years were included and randomized to either start to register dietary intake in the application or by a dietary record, during three consecutive days. After a washout period of at least two weeks, the participants used the other method. We found that the difference in measured mean fiber intake between the dietary record and the application was two grams independent of the total intake per day. A statistically significant correlation between fiber intake as measured by the two methods was found (rho = 0.65, p < 0.001). Vegetables and roots were the predominantly contributing foods to total and soluble fiber intake. Bread and crackers contributed most to insoluble fiber intake. In conclusion, the application may be considered as a useful and easy-to-use method to measure dietary fiber intake.

Trace elements exposure and risk in age-related eye diseases: a systematic review of epidemiological evidence

This systematic review aimed to evaluate existing evidence on the associations between trace elements exposure and age-related eye diseases. PubMed and Google scholar databases were searched for epidemiological and postmortem studies on the relationship between exposure to trace elements and Age-related eye diseases such as age-related macular degeneration (AMD), cataract, glaucoma and diabetic retinopathy (DR), in population groups aged 40 years and above. Available evidence suggests that cadmium (Cd) exposure may be positively associated with the risks of AMD and cataract. There is also evidence that exposure to lead (Pb) may be positively associated with higher risk of cataract and glaucoma. There is limited number of relevant studies and lack of prospective studies for most of the investigated associations. Evidence for other trace elements is weak and inconsistent, and the number of available studies is small. Likewise, there are very few relevant studies on the role of trace elements in DR. Chemical elements that affect the distribution and absorption of other trace elements have never been investigated. The suggestive but limited evidence motivates large and quality prospective studies to fully characterize the impact of exposure to trace (toxic and essential) elements on age-related eye diseases.

Biomarkers and Fatty Fish Intake: A Randomized Controlled Trial in Norwegian Preschool Children

BACKGROUND

Biomarkers such as omega-3 (n-3) PUFAs, urinary iodine concentration (UIC), 1-methylhistidine (1-MH), and trimethylamine N-oxide (TMAO) have been associated with fish intake in observational studies, but data from children in randomized controlled trials are limited.

OBJECTIVES

The objective of this exploratory analysis was to investigate the effects of fatty fish intake compared with meat intake on various biomarkers in preschool children.

METHODS

We randomly allocated (1:1) 232 children, aged 4 to 6 y, from 13 kindergartens. The children received lunch meals of either fatty fish (herring/mackerel) or meat (chicken/lamb/beef) 3 times a week for 16 wk. We analyzed 86 biomarkers in plasma (n = 207), serum (n = 195), RBCs (n = 211), urine (n = 200), and hair samples (n = 210). We measured the effects of the intervention on the normalized biomarker concentrations in linear mixed-effect regression models taking the clustering within the kindergartens into account. The results are presented as standardized effect sizes.

RESULTS

We found significant effects of the intervention on the following biomarkers: RBC EPA (20:5n-3), 0.61 (95% CI: 0.36, 0.86); DHA (22:6n-3), 0.43 (95% CI: 0.21, 0.66); total n-3 PUFAs, 0.41 (95% CI: 0.20, 0.64); n-3/n-6 ratio, 0.48 (95% CI: 0.24, 0.71); adrenic acid (22:4n-6, -0.65 (95% CI: -0.91, -0.40), arachidonic acid (20:4n-6), -0.54 (95% CI: -0.79, -0.28); total n-6 PUFAs, -0.31 (95% CI: -0.56, -0.06); UIC, 0.32 (95% CI: 0.052, 0.59); hair mercury, 0.83 (95% CI: 0.05, 1.05); and plasma 1-MH, -0.35 (95% CI: -0.61, -0.094).

CONCLUSIONS

Of the 86 biomarkers, the strongest effect of fatty fish intake was on n-3 PUFAs, UIC, hair mercury, and plasma 1-MH. We observed no or limited effects on biomarkers related to micronutrient status, inflammation, or essential amino acid, choline oxidation, and tryptophan pathways.The trial was registered at clinicaltrials.gov (NCT02331667).

Pre-diagnostic circulating concentrations of fat-soluble vitamins and risk of glioma in three cohort studies

Few prospective studies have evaluated the relation between fat-soluble vitamins and glioma risk. Using three cohorts-UK Biobank (UKB), Nurses' Health Study (NHS), and Health Professionals Follow-Up Study (HPFS), we investigated associations of pre-diagnostic concentrations of fat-soluble vitamins D, A, and E with incident glioma. In 346,785 participants (444 cases) in UKB, associations with vitamin D (25-hydroxyvitamin D [25(OH)D]) were evaluated by Cox proportional hazards regression. In NHS (52 cases, 104 controls) and HPFS (32 cases, 64 controls), associations with 25(OH)D, vitamin A (retinol), and vitamin E (α- and γ-tocopherol) were assessed using conditional logistic regression. Our results suggested plasma concentrations of 25(OH)D and retinol were not associated with glioma risk. Comparing the highest to lowest tertile, the multivariable hazard ratio (MVHR) for 25(OH)D was 0.87 (95% confidence interval [CI] 0.68-1.11) in UKB and the multivariable risk ratio (MVRR) was 0.97 (95% CI 0.51-1.85) in NHS and HPFS. In NHS and HPFS, the MVRR for the same comparison for retinol was 1.16 (95% CI 0.56-2.38). Nonsignificant associations were observed for α-tocopherol (MVRRtertile3vs1 = 0.61, 95% CI 0.29-1.32) and γ-tocopherol (MVRR tertile3vs1 = 1.30, 95% CI 0.63-2.69) that became stronger in 4-year lagged analyses. Further investigation is warranted on a potential association between α- and γ-tocopherol and glioma risk.

Development of Personalized Nutrition: Applications in Lactose Intolerance Diagnosis and Management

Recent discoveries in the “omics” field and the growing focus on preventive health have opened new avenues for personalized nutrition (PN), which is becoming an important theme in the strategic plans of organizations that are active in healthcare, food, and nutrition research. PN holds great potential for individual health optimization, disease management, public health interventions, and product innovation. However, there are still multiple challenges to overcome before PN can be truly embraced by the public and healthcare stakeholders. The diagnosis and management of lactose intolerance (LI), a common condition with a strong inter-individual component, is explored as an interesting example for the potential role of these technologies and the challenges of PN. From the development of genetic and metabolomic LI diagnostic tests that can be carried out in the home, to advances in the understanding of LI pathology and individualized treatment optimization, PN in LI care has shown substantial progress. However, there are still many research gaps to address, including the understanding of epigenetic regulation of lactase expression and how lactose is metabolized by the gut microbiota, in order to achieve better LI detection and effective therapeutic interventions to reverse the potential health consequences of LI.

Associations Between Maternal Nutrition in Pregnancy and Child Blood Pressure at 4-6 Years: A Prospective Study in a Community-Based Pregnancy Cohort

BACKGROUND

The intrauterine environment may influence offspring blood pressure, with effects possibly extending into adulthood. The associations between prenatal nutrition and offspring blood pressure, alone or in combination with other sociodemographic or behavioral factors, are unclear.

OBJECTIVES

To investigate the associations of maternal dietary patterns and plasma folate concentrations with blood pressure in children aged 4-6 years, and assess the potential effect modifications by child sex, maternal race, pre-pregnancy overweight or obesity, maternal smoking, and breastfeeding.

METHODS

Participants were 846 mother-child dyads from the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) study. Maternal nutrition was characterized by the Healthy Eating Index 2010 (HEI) scores and plasma folate concentrations in pregnancy. We calculated the systolic blood pressure (SBP) and diastolic blood pressure percentiles, incorporating sex, age, and height, and categorized children as either having high blood pressure (HBP; ≥90th percentile) or normal blood pressure. Linear regressions were performed to quantify the associations between maternal nutrition and continuous blood pressure percentiles, and Poisson regressions were used to estimate the incidence rate ratio (IRR) of binary HBP. We examined the effect modifications using interaction models.

RESULTS

Mean HEI scores and folate concentrations were 60.0 (SD, 11.3) and 23.1 ng/mL (SD, 11.1), respectively. Based on measurements at 1 visit, 29.6% of the children were defined as having HBP. Maternal HEI scores and plasma folate concentrations were not associated with child blood pressure percentiles or HBP in the full cohort. Among mothers self-identified as white, there was an inverse relationship between maternal HEI score and child SBP percentile (β, -0.40; 95%CI: -0.75 to -0.06). A maternal HEI score above 59 was associated with a reduced risk of HBP in girls (IRR, 0.53; 95% CI: 0.32-0.88). No modified associations by pre-pregnancy overweight or obesity, maternal smoking, or breastfeeding were indicated.

CONCLUSIONS

We found little evidence for effects of maternal nutrition during pregnancy on childhood blood pressure, but detected sex- and race-specific associations. The study contributes to the evolving scientific inquiry regarding developmental origins of disease.

Development and Relative Validity of a Semiquantitative Food Frequency Questionnaire to Estimate Dietary Intake among a Multi-Ethnic Population in the Malaysian Cohort Project

Measuring dietary intakes in a multi-ethnic and multicultural setting, such as Malaysia, remains a challenge due to its diversity. This study aims to develop and evaluate the relative validity of an interviewer-administered food frequency questionnaire (FFQ) in assessing the habitual dietary exposure of The Malaysian Cohort (TMC) participants. We developed a nutrient database (with 203 items) based on various food consumption tables, and 803 participants were involved in this study. The output of the FFQ was then validated against three-day 24-h dietary recalls (n = 64). We assessed the relative validity and its agreement using various methods, such as Spearman’s correlation, weighed Kappa, intraclass correlation coefficient (ICC), and Bland–Altman analysis. Spearman’s correlation coefficient ranged from 0.24 (vitamin C) to 0.46 (carbohydrate), and almost all nutrients had correlation coefficients above 0.3, except for vitamin C and sodium. Intraclass correlation coefficients ranged from −0.01 (calcium) to 0.59 (carbohydrates), and weighted Kappa exceeded 0.4 for 50% of nutrients. In short, TMC’s FFQ appears to have good relative validity for the assessment of nutrient intake among its participants, as compared to the three-day 24-h dietary recalls. However, estimates for iron, vitamin A, and vitamin C should be interpreted with caution.

Associations of Pre- and Postnatal Air Pollution Exposures with Child Blood Pressure and Modification by Maternal Nutrition: A Prospective Study in the CANDLE Cohort

BACKGROUND

Limited data suggest air pollution exposures may contribute to pediatric high blood pressure (HBP), a known predictor of adult cardiovascular diseases.

METHODS

We investigated this association in the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) study, a sociodemographically diverse pregnancy cohort in the southern United States with participants enrolled from 2006 to 2011. We included 822 mother-child dyads with available address histories and a valid child blood pressure measurement at 4-6 y. Systolic (SBP) and diastolic blood pressures (DBP) were converted to age-, sex-, and height-specific percentiles for normal-weight U.S. children. HBP was classified based on SBP or DBP ≥ 90 th percentile. Nitrogen dioxide (NO 2 ) and particulate matter ≤ 2.5 μ m in aerodynamic diameter (PM 2.5 ) estimates in both pre- and postnatal windows were obtained from annual national models and spatiotemporal models, respectively. We fit multivariate Linear and Poisson regressions and explored multiplicative joint effects with maternal nutrition, child sex, and maternal race using interaction terms.

RESULTS

Mean PM 2.5 and NO 2 in the prenatal period were 10.8 [standard deviation (SD): 0.9] μ g / m 3 and 10.0 (SD: 2.4) ppb, respectively, and 9.9 (SD: 0.6) μ g / m 3 and 8.8 (SD: 1.9) ppb from birth to the 4-y-old birthday. On average, SBP percentile increased by 14.6 (95% CI: 4.6, 24.6), and DBP percentile increased by 8.7 (95% CI: 1.4, 15.9) with each 2 - μ g / m 3 increase in second-trimester PM 2.5 . PM 2.5 averaged over the prenatal period was only significantly associated with higher DBP percentiles [β = 11.6 (95% CI: 2.9, 20.2)]. Positive associations of second-trimester PM 2.5 with SBP and DBP percentiles were stronger in children with maternal folate concentrations in the lowest quartile (p interaction = 0.05 and 0.07, respectively) and associations with DBP percentiles were stronger in female children (p interaction = 0.05). We did not detect significant association of NO 2 , road proximity, and postnatal PM 2.5 with any outcomes.

CONCLUSIONS

The findings suggest that higher prenatal PM 2.5 exposure, particularly in the second trimester, is associated with elevated early childhood blood pressure. This adverse association could be modified by pregnancy folate concentrations. https://doi.org/10.1289/EHP7486.

Conducting research on diet-microbiome interactions: A review of current challenges, essential methodological principles, and recommendations for best practice in study design

Diet is one of the strongest modulators of the gut microbiome. However, the complexity of the interactions between diet and the microbial community emphasises the need for a robust study design and continued methodological development. This review aims to summarise considerations for conducting high-quality diet-microbiome research, outline key challenges unique to the field, and provide advice for addressing these in a practical manner useful to dietitians, microbiologists, gastroenterologists and other diet-microbiome researchers. Searches of databases and references from relevant articles were conducted using the primary search terms 'diet', 'diet intervention', 'dietary analysis', 'microbiome' and 'microbiota', alone or in combination. Publications were considered relevant if they addressed methods for diet and/or microbiome research, or were a human study relevant to diet-microbiome interactions. Best-practice design in diet-microbiome research requires appropriate consideration of the study population and careful choice of trial design and data collection methodology. Ongoing challenges include the collection of dietary data that accurately reflects intake at a timescale relevant to microbial community structure and metabolism, measurement of nutrients in foods pertinent to microbes, improving ability to measure and understand microbial metabolic and functional properties, adequately powering studies, and the considered analysis of multivariate compositional datasets. Collaboration across the disciplines of nutrition science and microbiology is crucial for high-quality diet-microbiome research. Improvements in our understanding of the interaction between nutrient intake and microbial metabolism, as well as continued methodological innovation, will facilitate development of effective evidence-based personalised dietary treatments.

Charged metabolite biomarkers of food intake assessed via plasma metabolomics in a population-based observational study in Japan

Food intake biomarkers can be critical tools that can be used to objectively assess dietary exposure for both epidemiological and clinical nutrition studies. While an accurate estimation of food intake is essential to unravel associations between the intake and specific health conditions, random and systematic errors affect self-reported assessments. This study aimed to clarify how habitual food intake influences the circulating plasma metabolome in a free-living Japanese regional population and to identify potential food intake biomarkers. To achieve this aim, we conducted a cross-sectional analysis as part of a large cohort study. From a baseline survey of the Tsuruoka Metabolome Cohort Study, 7,012 eligible male and female participants aged 40-69 years were chosen for this study. All data on patients' health status and dietary intake were assessed via a food frequency questionnaire, and plasma samples were obtained during an annual physical examination. Ninety-four charged plasma metabolites were measured using capillary electrophoresis mass spectrometry, by a non-targeted approach. Statistical analysis was performed using partial-least-square regression. A total of 21 plasma metabolites were likely to be associated with long-term food intake of nine food groups. In particular, the influential compounds in each food group were hydroxyproline for meat, trimethylamine-N-oxide for fish, choline for eggs, galactarate for dairy, cystine and betaine for soy products, threonate and galactarate for carotenoid-rich vegetables, proline betaine for fruits, quinate and trigonelline for coffee, and pipecolate for alcohol, and these were considered as prominent food intake markers in Japanese eating habits. A set of circulating plasma metabolites was identified as potential food intake biomarkers in the Japanese community-dwelling population. These results will open the way for the application of new reliable dietary assessment tools not by self-reported measurements but through objective quantification of biofluids.

Novel standardized method for extracellular flux analysis of oxidative and glycolytic metabolism in peripheral blood mononuclear cells

Analyzing metabolism of peripheral blood mononuclear cells (PBMCs) provides key opportunities to study the pathophysiology of several diseases, such as type 2 diabetes, obesity and cancer. Extracellular flux (XF) assays provide dynamic metabolic analysis of living cells that can capture ex vivo cellular metabolic responses to biological stressors. To obtain reliable data from PBMCs from individuals, novel methods are needed that allow for standardization and take into account the non-adherent and highly dynamic nature of PBMCs. We developed a novel method for extracellular flux analysis of PBMCs, where we combined brightfield imaging with metabolic flux analysis and data integration in R. Multiple buffy coat donors were used to demonstrate assay linearity with low levels of variation. Our method allowed for accurate and precise estimation of XF assay parameters by reducing the standard score and standard score interquartile range of PBMC basal oxygen consumption rate and glycolytic rate. We applied our method to freshly isolated PBMCs from sixteen healthy subjects and demonstrated that our method reduced the coefficient of variation in group mean basal oxygen consumption rate and basal glycolytic rate, thereby decreasing the variation between PBMC donors. Our novel brightfield image procedure is a robust, sensitive and practical normalization method to reliably measure, compare and extrapolate XF assay data using PBMCs, thereby increasing the relevance for PBMCs as marker tissue in future clinical and biological studies, and enabling the use of primary blood cells instead of immortalized cell lines for immunometabolic experiments.

Vegetarian diets, circulating miRNA expression and healthspan in subjects living in the Blue Zone

A long-term vegetarian diet plays a role in the longevity and maintenance of the healthspan, but the underlying mechanisms for these observations are largely unknown. Particularly, it is not known whether a long-term vegetarian dietary pattern may affect the circulating miRNA expression in such a way as to modulate the healthspan. The Adventist Health Study-2 (AHS-2) cohort includes a large number of older adults who primarily follow vegetarian dietary patterns and reside in Loma Linda, California, one of five “Blue Zones” in the world in which a higher proportion of the population enjoys a longer than average lifespan. We performed miRNA-seq in 96 subjects selected from the AHS-2 cohort with different dietary patterns. We identified several differentially expressed miRNAs between vegetarians and non-vegetarians, which are involved in immune response and cytokine signaling, cell growth and proliferation as well as age-related diseases such as cardiovascular diseases and neurodegenerative diseases. Overall, our study showed that a vegetarian diet modulates aging-associated circulating miRNAs in a sex-dependent manner of differential expression for certain miRNAs, which may be related in a beneficial manner to the healthspan. Further investigation is needed to validate these miRNAs as potential biomarkers for diet-modulated longevity in humans.

Personalized Nutrition and -Omics

With change in global concern toward food quality over food quantity, consumer concern and choice of healthy food has become a matter of prime importance. It gave rise to concept of “personalized or precision nutrition”. The theory behind personalization of nutrition is supported by multiple factors including advances in food analytics, nutrition based diseases and public health programs, increasing use of information technology in nutrition science, concept of gene-diet interaction and growing consumer capacity or concern by better and healthy foods. The advances in “omics” tools and related analytical techniques have resulted into tremendous scope of their application in nutrition science. As a consequence, a better understanding of underlying interaction between diet and individual is expected with addressing of key challenges for successful implementation of this science. In this chapter, the above aspects are discussed to get an insight into driving factors for increasing concern in personalized nutrition.

Assessment of polyunsaturated fatty acids: A self-report and biomarker assessment with a racially and ethnically diverse sample of women

Polyunsaturated fatty acids (PUFAs) play an important role in human health, influencing chronic disease and mortality. Food Frequency Questionnaires (FFQs) are widely used to assess self-reported diet, but they can be subject to a variety of errors. Accordingly, an accurate assessment of diet is crucial in nutrition research. This study examined the association between a widely-used self-report measure of PUFAs (Diet History Questionnaire-II: DHQ-II) with the proportion of PUFA in red blood cell (RBC) membranes, and examined whether this relationship was moderated by race/ethnicity. In a racially and ethnically diverse sample of 132 female participants (M_age = 21.97±3.98, range 18 to 42 years), bivariate correlations and linear regression analyses demonstrated associations between DHQ-II and proportion of nutrients in RBCs for omega-3 fatty acids EPA (r = 0.39, ß = 0.38, p < .01), DHA (r = 0.48, ß = 0.47, p < .01), and EPA+DHA (r = 0.51, β = 0.49, p < .01). No associations were found for omega-3 fatty acid ALA or omega-6 fatty acids LA or ARA. DHQ-II and RBC associations for EPA, DHA, and EPA+DHA were moderated by race/ethnicity, controlling for age. Self-report of EPA was most consistent with RBC proportions for Caucasian individuals, and less consistent for Black/African American individuals. Self-reports of DHA and EPA+DHA were most consistent with RBC proportions for Caucasian individuals, and less consistent for Black/African American individuals and Hispanic/Latina individuals, although still statistically significant. No associations were detected for Hispanic/Latina individuals (for EPA only), Asian/Pacific Islanders or individuals of mixed/other descent. The present study found that when compared to PUFA biomarkers, the DHQ-II did not assess PUFAs consistently across all racial/ethnic groups in this sample of women. Further research is needed to determine what factors contribute to weak or lacking correlations between reported fat intake and corresponding values in RBCs, including but not limited to recall errors, underestimations of fatty acids in food composition databases, insufficient DHQ-II assessment of fatty acids in general and from particular cultures, and genetic differences in fat metabolism.

Healthy Eating Index and Nutrition Biomarkers among Army Soldiers and Civilian Control Group Indicate an Intervention Is Necessary to Raise Omega-3 Index and Vitamin D and Improve Diet Quality

Diet quality and nutrition status are important for optimal health and military performance. Few studies have simultaneously evaluated diet quality and biochemical markers of nutritional status of military service members. The Healthy Eating Index (HEI) can be used to assess dietary quality and adherence to federal nutrition guidelines. The aim of this study was to assess soldiers' diet quality and nutritional status and compare results to a civilian control group.

METHODS

A cross-sectional study was conducted with 531 soldiers. A food frequency questionnaire was used to calculate HEI scores. A blood sample was collected for analysis of select nutrition biochemical markers. Non-parametric analyses were conducted to compare the diet quality and nutritional status of soldiers and controls. Differences in non-normally distributed variables were determined by using the Wilcoxon signed-rank test.

RESULTS

Soldiers had an HEI score of 59.9 out of 100, marginally higher than the control group (55.4). Biochemical markers of interest were within normal reference values for soldiers, except for the omega-3 index and vitamin D.

CONCLUSIONS

This study identified dietary components that need improvement and deficits in biochemical markers among soldiers. Improving diet quality and nutritional status should lead to better health, performance, and readiness of the force.

Changes in human milk fatty acid composition and maternal lifestyle-related factors over a decade: a comparison between the two Ulm Birth Cohort Studies

Human milk fatty acid composition varies during lactation and is influenced by maternal diet, maternal lifestyle-related factors and genetic background. This is one of the first studies to investigate a period effect, that is, the impact of lifestyle-related changes on human milk fatty acid composition, in two different cohorts. Lactating women were recruited from the general population a decade apart in Ulm, Germany, using similar methodology. Human milk samples collected 6 weeks postpartum were analysed (Ulm Birth Cohort Study (UBCS (2000)), n 567; Ulm SPATZ Health Study (SPATZ (2012)), n 458). Centred log ratio transformation was applied to fatty acid data. Principal component analysis was used to determine study-dependent fatty acid profiles. A general linear model was used to determine the study (or period) effect on fatty acid profiles adjusting for duration of gestation, age, education, delivery mode, smoking and pre-pregnancy BMI. Two principal components were retained (PC1 and PC2). PC1 was associated with UBCS, while PC2 was associated with SPATZ. PC1 comprised high SFA, and low MUFA, n-6 and n-3 long-chain PUFA (LCPUFA). The inverse was true for PC2. Although human milk remains a source of essential fatty acids, infants could be at risk of inadequate n-3 and n-6 LCPUFA intake through human milk. The differences in the human milk fatty acid profiles also reflect changes in maternal dietary habits in the more recent cohort, which may comprise lower intakes of dietary trans-fatty acids and SFA and higher intakes of vegetable oils.

Which Method Should Be Used to Assess Protein Intake in Peritoneal Dialysis Patients? Assessment of Agreement Between Protein Equivalent of Total Nitrogen Appearance and 24-Hour Dietary Recall

OBJECTIVES

After dialysis initiation, a high protein diet is recommended due to significant nutrient losses through dialysate and increased risk of protein energy wasting. In peritoneal dialysis (PD) patients, protein intake can be assessed through different methods that have some advantages and limitations, which affect its use on routine care. The aim of this study is to evaluate the agreement between 2 different methods (24-hour dietary recall and PNA-protein equivalent of total nitrogen appearance) on estimating protein intake in PD patients.

DESIGN AND METHODS

Patients on PD for at least 3 months, aged 18 years old or more, were enrolled. To estimate protein intake, 24-hour dietary recall and PNA was used. PNA was calculated from 24-hour urine on the same day of the 24-hour dietary recall.

RESULTS

Fifty individuals on PD were included, mean age 55.7 ± 16.2 years, and body mass index 26.0 ± 4.5 kg/m². The average energy consumption was 1788.79 ± 504.40 kcal/day, which corresponds to 26.81 ± 9.11 kcal/kg current body weight (BW)/day and 29.82 ± 8.39 kcal/kg ideal body weight (IBW)/day. The median of total daily and normalized protein intake estimated using dietary recall was 61.43 (45.28-87.40) g/day, 0.90 (0.58-1.22) g/kg current BW/day, and 1.04 (0.77-1.32) g/kg IBW/day, respectively. Daily protein intake estimated by PNA was 55.75 (48.27-67.74) g/day, protein intake normalized by current BW was 0.81 (0.72-0.99) g/kg and 0.92 (0.83-1.06) g/kg IBW/day. Bland-Altman analysis indicates no systematic bias for the assessment of total protein intake and normalized protein intake for current and ideal BW. Significant proportionality bias was observed for both evaluations, showing there is a dispersion of the values.

CONCLUSIONS

Despite the absence of systematic bias in the Bland-Altman analysis, there is no agreement in the assessment of protein intake by dietary recall and PNA, due to the existence of proportionality bias. Thus, values can be influenced biased by the magnitude of the measures.

Levels of n-3 and n-6 Fatty Acids in Maternal Erythrocytes during Pregnancy and in Human Milk and Its Association with Perinatal Mental Health

Omega-3 long-chain polyunsaturated fatty acid (n-3 FA) status may be associated with mood disorders. Here, we evaluated the potential association between antenatal depression/anxiety and n-3/n-6 FA in (a) maternal erythrocytes and (b) human milk. In addition, we explored associations between n-3/n-6 FA in erythrocytes and in human milk and postpartum depression, while controlling for antenatal depression. Twenty-seven pregnant women diagnosed with a current major depressive disorder (MDD; n = 9), anxiety disorder (AD; n = 10) or a mixed anxiety-depression disorder (MADD; n = 8), and 40 healthy controls were included. n-3/n-6 FA were determined in maternal erythrocytes in gestational week 32 and in human milk in postpartum week 1. In the first week postpartum, the Edinburgh-Postnatal-Depression-Questionnaire was used to assess postpartum depression. Results show that women with M(A)DD had significantly lower erythrocyte levels of total n-3 FA, EPA, DHA and DGLA, and significantly higher n-6 DPA, and n-6:n-3, AA:EPA and n-6 DPA:DHA ratios compared to healthy controls. No significant associations between antenatal depression or anxiety and n-3/n-6 FA in human milk were found. After controlling for antenatal mental health, n-3/n-6 FA in maternal erythrocytes or in human milk were not significantly associated with postpartum depression. In conclusion, antenatal depression, alone or with an anxiety disorder, was associated with lower n-3 FA levels and higher n-6:n-3 FA ratios in maternal erythrocytes during gestation. This study provides some insights into the associations between n-3/n-6 FA levels during pregnancy and lactation and perinatal mental health.

Increased Risk of High Body Fat and Altered Lipid Metabolism Associated to Suboptimal Consumption of Vitamin A Is Modulated by Genetic Variants rs5888 (SCARB1), rs1800629 (UCP1) and rs659366 (UCP2)

Obesity is characterized by an excessive body fat percentage (BF%). Animal and cell studies have shown benefits of vitamin A (VA) on BF% and lipid metabolism, but it is still controversial in humans. Furthermore, although some genetic variants may explain heterogeneity in VA plasma levels, their role in VA metabolic response is still scarcely characterized. This study was designed as a combination of an observational study involving 158 male subjects followed by a study with a well-balanced genotype-phenotype protocol, including in the design an ex vivo intervention study performed on isolated peripheral blood mononuclear cells (PBMCs) of the 41 former males. This is a strategy to accurately identify the delivery of Precision Nutrition recommendations to targeted subjects. The study assesses the influence of rs5888 (SCARB1), rs659366 (UCP2), and rs1800629 (UCP1) variants on higher BF% associated with suboptimal VA consumption and underlines the cellular mechanisms involved by analyzing basal and retinoic acid (RA) response on PBMC gene expression. Data show that male carriers with the major allele combinations and following suboptimal-VA diet show higher BF% (adjusted ANOVA test p-value = 0.006). Genotype-BF% interaction is observed on oxidative/inflammatory gene expression and also influences lipid related gene expression in response to RA. Data indicate that under suboptimal consumption of VA, carriers of VA responsive variants and with high-BF% show a gene expression profile consistent with an impaired basal metabolic state. The results show the relevance of consuming VA within the required amounts, its impact on metabolism and energy balance, and consequently, on men's adiposity with a clear influence of genetic variants SCARB1, UCP2 and UCP1.

Ultra-Performance Liquid Chromatography-Ion Mobility Separation-Quadruple Time-of-Flight MS (UHPLC-IMS-QTOF MS) Metabolomics for Short-Term Biomarker Discovery of Orange Intake: A Randomized, Controlled Crossover Study

A major problem with dietary assessments is their subjective nature. Untargeted metabolomics and new technologies can shed light on this issue and provide a more complete picture of dietary intake by measuring the profile of metabolites in biological samples. Oranges are one of the most consumed fruits in the world, and therefore one of the most studied for their properties. The aim of this work was the application of untargeted metabolomics approach with the novel combination of ion mobility separation coupled to high resolution mass spectrometry (IMS-HRMS) and study the advantages that this technique can bring to the area of dietary biomarker discovery, with the specific case of biomarkers associated with orange consumption (Citrus reticulata) in plasma samples taken during an acute intervention study (consisting of a randomized, controlled crossover trial in healthy individuals). A total of six markers of acute orange consumption, including betonicines and conjugated flavonoids, were identified with the experimental data and previous literature, demonstrating the advantages of ion mobility in the identification of dietary biomarkers and the benefits that an additional structural descriptor, as the collision cross section value (CCS), can provide in this area.

Mass Spectrometry-Based Analysis of Urinary Biomarkers for Dietary Tomato Intake

SCOPE

In this study, the applicability of several β-carboline, imidazole, and steroidal alkaloids as biomarkers for tomato juice intake is evaluated.

METHODS AND RESULTS

Over the course of a 2-week crossover dietary intervention study, 14 volunteers were given low and high doses of tomato juice after 3 days of avoiding tomato-based products. On the day of consumption and the following days, volunteers provided urine samples that were quantitatively analyzed by high-performance liquid chromatography-tandem mass spectrometry. Herein, glucose-derived β-carboline alkaloids are determined as supporting, yet non-specific dietary biomarkers for tomato juice intake. Several imidazole alkaloids represent further biomarkers, which are shown to specifically indicate consumption of tomato juice for 24 h and partly >24 h. Additionally, steroidal alkaloids derived from esculeogenin B are determined to be specific biomarkers for tomato juice detectable for at least 48 h after consumption. The intake of low and high amounts of tomato juice is significantly distinguishable based on the urinary excretion of all determined biomarkers as well.

CONCLUSIONS

The dietary intake of tomato juice is conclusively traceable based on urinary excretion of multiple β-carboline, imidazole, and steroidal alkaloids, and can be determined for up to 48 h after consumption. Furthermore, different intake doses can clearly be distinguished based on their urinary excretion.

What Makes Nutrition Research So Difficult to Conduct and Interpret?

Conducting and interpreting nutrition research involves consideration of the research question, study design, wide variability of nutrients in foods and dietary patterns, food environment, approaches used to collect and analyze dietary data, and manner in which results are reported. This article reviews all of these considerations with regard to diabetes-related nutrition research.

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.

Detection of Early Disease Risk Factors Associated with Metabolic Syndrome: A New Era with the NMR Metabolomics Assessment

The metabolic syndrome is a multifactorial disease developed due to accumulation and chronification of several risk factors associated with disrupted metabolism. The early detection of the biomarkers by NMR spectroscopy could be helpful to prevent multifactorial diseases. The exposure of each risk factor can be detected by traditional molecular markers but the current biomarkers have not been enough precise to detect the primary stages of disease. Thus, there is a need to obtain novel molecular markers of pre-disease stages. A promising source of new molecular markers are metabolomics standing out the research of biomarkers in NMR approaches. An increasing number of nutritionists integrate metabolomics into their study design, making nutrimetabolomics one of the most promising avenues for improving personalized nutrition. This review highlight the major five risk factors associated with metabolic syndrome and related diseases including carbohydrate dysfunction, dyslipidemia, oxidative stress, inflammation, and gut microbiota dysbiosis. Together, it is proposed a profile of metabolites of each risk factor obtained from NMR approaches to target them using personalized nutrition, which will improve the quality of life for these patients.

Functional Biomarkers for the Selenium Status in a Human Nutritional Intervention Study

Soils in Germany are commonly low in selenium; consequently, a sufficient dietary supply is not always ensured. The extent of such provision adequacy is estimated by the optimal effect range of biomarkers, which often reflects the physiological requirement. Preceding epidemiological studies indicate that low selenium serum concentrations could be related to cardiovascular diseases. Inter alia, risk factors for cardiovascular diseases are physical inactivity, overweight, as well as disadvantageous eating habits. In order to assess whether these risk factors can be modulated, a cardio-protective diet comprising fixed menu plans combined with physical exercise was applied in the German MoKaRi (modulation of cardiovascular risk factors) intervention study. We analyzed serum samples of the MoKaRi cohort (51 participants) for total selenium, GPx activity, and selenoprotein P at different timepoints of the study (0, 10, 20, 40 weeks) to explore the suitability of these selenium-associated markers as indicators of selenium status. Overall, the time-dependent fluctuations in serum selenium concentration suggest a successful change in nutritional and lifestyle behavior. Compared to baseline, a pronounced increase in GPx activity and selenoprotein P was observed, while serum selenium decreased in participants with initially adequate serum selenium content. SELENOP concentration showed a moderate positive monotonic correlation (r = 0.467, p < 0.0001) to total Se concentration, while only a weak linear relationship was observed for GPx activity versus total Se concentration (r = 0.186, p = 0.021). Evidently, other factors apart from the available Se pool must have an impact on the GPx activity, leading to the conclusion that, without having identified these factors, GPx activity should not be used as a status marker for Se.

Toward the Definition of Personalized Nutrition: A Proposal by The American Nutrition Association

Personalized nutrition holds tremendous potential to improve human health. Despite exponential growth, the field has yet to be clearly delineated and a consensus definition of the term "personalized nutrition" (PN) has not been developed. Defining and delineating the field will foster standardization and scalability in research, data, training, products, services, and clinical practice; and assist in driving favorable policy. Building on the seminal work of pioneering thought leaders across disciplines, we propose that personalized nutrition be defined as: a field that leverages human individuality to drive nutrition strategies that prevent, manage, and treat disease and optimize health, and be delineated by three synergistic elements: PN science and data, PN professional education and training, and PN guidance and therapeutics. Herein we describe the application of PN in these areas and discuss challenges and solutions that the field faces as it evolves. This and future work will contribute to the continued refinement and growth of the field of PN.Teaching pointsPN approaches can be most effective when there is consensus regarding its definition and applications.PN can be delineated into three main areas of application: PN science and data, PN education and training, PN guidance and therapeutics.PN science and data foster understanding about the impact of genetic, phenotypic, biochemical and nutritional inputs on an individual's health.PN education and training equip a variety of healthcare professionals to apply PN strategies in many healthcare settings.PN professionals have greater ability to tailor interventions via PN guidance and therapeutics.Favorable policy allows PN to be more fully integrated into the healthcare system.

Urinary Metabolomic Markers of Protein Glycation, Oxidation, and Nitration in Early-Stage Decline in Metabolic, Vascular, and Renal Health

Glycation, oxidation, nitration, and crosslinking of proteins are implicated in the pathogenic mechanisms of type 2 diabetes, cardiovascular disease, and chronic kidney disease. Related modified amino acids formed by proteolysis are excreted in urine. We quantified urinary levels of these metabolites and branched-chain amino acids (BCAAs) in healthy subjects and assessed changes in early-stage decline in metabolic, vascular, and renal health and explored their diagnostic utility for a noninvasive health screen. We recruited 200 human subjects with early-stage health decline and healthy controls. Urinary amino acid metabolites were determined by stable isotopic dilution analysis liquid chromatography-tandem mass spectrometry. Machine learning was applied to optimise and validate algorithms to discriminate between study groups for potential diagnostic utility. Urinary analyte changes were as follows: impaired metabolic health-increased N ε -carboxymethyl-lysine, glucosepane, glutamic semialdehyde, and pyrraline; impaired vascular health-increased glucosepane; and impaired renal health-increased BCAAs and decreased N ε -(γ-glutamyl)lysine. Algorithms combining subject age, BMI, and BCAAs discriminated between healthy controls and impaired metabolic, vascular, and renal health study groups with accuracy of 84%, 72%, and 90%, respectively. In 2-step analysis, algorithms combining subject age, BMI, and urinary N ε -fructosyl-lysine and valine discriminated between healthy controls and impaired health (any type), accuracy of 78%, and then between types of health impairment with accuracy of 69%-78% (cf. random selection 33%). From likelihood ratios, this provided small, moderate, and conclusive evidence of early-stage cardiovascular, metabolic, and renal disease with diagnostic odds ratios of 6 - 7, 26 - 28, and 34 - 79, respectively. We conclude that measurement of urinary glycated, oxidized, crosslinked, and branched-chain amino acids provides the basis for a noninvasive health screen for early-stage health decline in metabolic, vascular, and renal health.

Coffee Silverskin Extract: Nutritional Value, Safety and Effect on Key Biological Functions

This study aimed to complete the scientific basis for the validation of a coffee silverskin extract (CSE) as a novel food ingredient according to European legislation. Nutritional value, safety, effects on biochemical biomarkers and excretion of short chain fatty acids (SCFAs) in vivo of CSE were assessed. Proteins, amino acids, fat, fatty acids, fiber, simple sugars and micronutrients were analyzed. For the first time, toxicological and physiological effects were evaluated in vivo by a repeated-dose study in healthy Wistar rats. Hormone secretion, antioxidant (enzymatic and no-enzymatic) and anti-inflammatory biomarkers, and dietary fiber fermentability of CSE (analysis of SCFAs in feces) were studied in biological samples. This unique research confirms the feasibility of CSE as a human dietary supplement with several nutrition claims: "source of proteins (16%), potassium, magnesium, calcium and vitamin C, low in fat (0.44%) and high in fiber (22%)". This is the first report demonstrating that its oral administration (1 g/kg) for 28 days is innocuous. Hormone secretion, antioxidant or anti-inflammatory biomarkers were not affected in heathy animals. Total SCFAs derived from CSE fiber fermentation were significantly higher (p < 0.05) in male treated rats compared to male control rats. All the new information pinpoints CSE as a natural, sustainable and safe food ingredient containing fermentable fiber able to produce SCFAs with beneficial effects on gut microbiota.

Breast Milk Supply of MicroRNA Associated with Leptin and Adiponectin Is Affected by Maternal Overweight/Obesity and Influences Infancy BMI

Breast milk constitutes a dietary source of leptin, adiponectin and microRNAs (miRNAs) for newborns. Expression of miRNAs previously associated with maternal obesity, leptin or adiponectin function were assessed and their impact on infant weight analyzed. Milk samples were collected (at month 1, 2, and 3) from a cohort of 59 healthy lactating mothers (38 normal-weight and 21 overweight/obese (BMI ≥ 25)), and infant growth was followed up to 2 years of age. Thirteen miRNAs, leptin and adiponectin were determined in milk. Leptin, adiponectin and miRNA showed a decrease over time of lactation in normal-weight mothers that was altered in overweight/obesity. Furthermore, negative correlations were observed in normal-weight mothers between the expression of miRNAs in milk and the concentration of leptin or adiponectin, but were absent in overweight/obesity. Moreover, miRNAs negatively correlated with infant BMI only in normal-weight mothers (miR-103, miR-17, miR-181a, miR-222, miR-let7c and miR-146b). Interestingly, target genes of milk miRNAs differently regulated in overweight/obesity could be related to neurodevelopmental processes. In conclusion, a set of miRNAs present in breast milk, in close conjunction with leptin and adiponectin, are natural bioactive compounds with the potential to modulate infant growth and brain development, an interplay that is disturbed in the case of maternal overweight/obesity.

Precision Nutrition and Metabolic Syndrome Management

The journal NUTRIENTS published some time ago a special issue about "Precision Nutrition and Metabolic Syndrome Management", which included a series of articles about the role of bioactive compounds, amino acids/proteins and fatty acids for personalized nutritional applications [...].

The Mediterranean Diet, a Rich Source of Angiopreventive Compounds in Cancer

Diet-based chemoprevention of cancer has emerged as an interesting approach to evade the disease or even target its early phases, reducing its incidence or slowing down tumor progression. In its basis in the essential role of angiogenesis for tumor growth and metastasis, angioprevention proposes the use of inhibitors of angiogenesis in cancer prevention. The anti-angiogenic potential exhibited by many natural compounds contained in many Mediterranean diet constituents makes this dietary pattern especially interesting as a source of chemopreventive agents, defined within the angioprevention strategy. In this review, we focus on natural bioactive compounds derived from the main foods included in the Mediterranean diet that display anti-angiogenic activity, as well as their possible use as angiopreventive agents.