Dietary fat and plasma total homocysteine concentrations in 2 adult age groups: the Hordaland Homocysteine Study

Involvement of tumor immune microenvironment metabolic reprogramming in colorectal cancer progression, immune escape, and response to immunotherapy

Metabolic reprogramming is a k`ey hallmark of tumors, developed in response to hypoxia and nutrient deficiency during tumor progression. In both cancer and immune cells, there is a metabolic shift from oxidative phosphorylation (OXPHOS) to aerobic glycolysis, also known as the Warburg effect, which then leads to lactate acidification, increased lipid synthesis, and glutaminolysis. This reprogramming facilitates tumor immune evasion and, within the tumor microenvironment (TME), cancer and immune cells collaborate to create a suppressive tumor immune microenvironment (TIME). The growing interest in the metabolic reprogramming of the TME, particularly its significance in colorectal cancer (CRC)-one of the most prevalent cancers-has prompted us to explore this topic. CRC exhibits abnormal glycolysis, glutaminolysis, and increased lipid synthesis. Acidosis in CRC cells hampers the activity of anti-tumor immune cells and inhibits the phagocytosis of tumor-associated macrophages (TAMs), while nutrient deficiency promotes the development of regulatory T cells (Tregs) and M2-like macrophages. In CRC cells, activation of G-protein coupled receptor 81 (GPR81) signaling leads to overexpression of programmed death-ligand 1 (PD-L1) and reduces the antigen presentation capability of dendritic cells. Moreover, the genetic and epigenetic cell phenotype, along with the microbiota, significantly influence CRC metabolic reprogramming. Activating RAS mutations and overexpression of epidermal growth factor receptor (EGFR) occur in approximately 50% and 80% of patients, respectively, stimulating glycolysis and increasing levels of hypoxia-inducible factor 1 alpha (HIF-1α) and MYC proteins. Certain bacteria produce short-chain fatty acids (SCFAs), which activate CD8+ cells and genes involved in antigen processing and presentation, while other mechanisms support pro-tumor activities. The use of immune checkpoint inhibitors (ICIs) in selected CRC patients has shown promise, and the combination of these with drugs that inhibit aerobic glycolysis is currently being intensively researched to enhance the efficacy of immunotherapy.

The Implication of a Polymorphism in the Methylenetetrahydrofolate Reductase Gene in Homocysteine Metabolism and Related Civilisation Diseases

Methylenetetrahydrofolate reductase (MTHFR) is a key regulatory enzyme in the one-carbon cycle. This enzyme is essential for the metabolism of methionine, folate, and RNA, as well as for the production of proteins, DNA, and RNA. MTHFR catalyses the irreversible conversion of 5,10-methylenetetrahydrofolate to its active form, 5-methyltetrahydrofolate, a co-substrate for homocysteine remethylation to methionine. Numerous variants of the MTHFR gene have been recognised, among which the C677T variant is the most extensively studied. The C677T polymorphism, which results in the conversion of valine to alanine at codon 222, is associated with reduced activity and an increased thermolability of the enzyme. Impaired MTHFR efficiency is associated with increased levels of homocysteine, which can contribute to increased production of reactive oxygen species and the development of oxidative stress. Homocysteine is acknowledged as an independent risk factor for cardiovascular disease, while chronic inflammation serves as the common underlying factor among these issues. Many studies have been conducted to determine whether there is an association between the C677T polymorphism and an increased risk of cardiovascular disease, hypertension, diabetes, and overweight/obesity. There is substantial evidence supporting this association, although several studies have concluded that the polymorphism cannot be reliably used for prediction. This review examines the latest research on MTHFR polymorphisms and their correlation with cardiovascular disease, obesity, and epigenetic regulation.

Methylenetetrahydrofolate Reductase Gene C677T Polymorphism-Dietary Pattern Interaction on Hyperhomocysteinemia in a Chinese Population: A Cross-Sectional Study

Background and aim: Hyperhomocysteinemia (Hhcy) has been recognized as a risk factor of several chronic diseases. There is accumulating evidence that both genetic and dietary factors had a notable impact on the risk of Hhcy. The present study aims to investigate the interaction effect on Hhcy between methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and dietary intake.

Methods: Data were collected in a cross-sectional survey conducted in China; 3,966 participants with complete information on sociodemographic characteristics, anthropometric measurements, and dietary intake were included in the analyses. Dietary patterns were identified by factor analysis combined with cluster analysis. Blood samples were collected and MTHFR C677T genotypes were tested. Both the multiplicative statistical model and the additive model were conducted to investigate the interactive effects.

Results: Proportions of MTHFR C677T genotypes among participants were 29.2% for TT, 47.4% for CT, and 23.4% for CC. Three dietary patterns were identified, namely, the balanced pattern, the snack pattern, and the high-meat pattern. Compared with the balanced pattern, the other two patterns were associated with an elevated risk of Hhcy [the snack pattern: odds ratio (OR) 1.2, 95% confidence interval (CI) 1.0–1.5; the high-meat pattern: OR 1.3, 95% CI 1.1–1.6] after adjustment for age group, gender, residential region, and MTHFR C677T genotypes. A multiplicative interaction between the high-meat pattern and MTHFR 677TT genotype was observed, and synergistic effects between both the snack pattern and the high-meat pattern with MTHFR 677TT were identified.

Conclusion: Our results indicated that MTHFR C677T polymorphism and dietary patterns had interactive effects on Hhcy among the Chinese population. Subsequent targeted and appropriate dietary guidelines should be recommended for high-risk populations or patients of Hhcy carrying specific genotypes.

Metabolic Reprogramming of Colorectal Cancer Cells and the Microenvironment: Implication for Therapy

Colorectal carcinoma (CRC) is one of the most frequently diagnosed carcinomas and one of the leading causes of cancer-related death worldwide. Metabolic reprogramming, a hallmark of cancer, is closely related to the initiation and progression of carcinomas, including CRC. Accumulating evidence shows that activation of oncogenic pathways and loss of tumor suppressor genes regulate the metabolic reprogramming that is mainly involved in glycolysis, glutaminolysis, one-carbon metabolism and lipid metabolism. The abnormal metabolic program provides tumor cells with abundant energy, nutrients and redox requirements to support their malignant growth and metastasis, which is accompanied by impaired metabolic flexibility in the tumor microenvironment (TME) and dysbiosis of the gut microbiota. The metabolic crosstalk between the tumor cells, the components of the TME and the intestinal microbiota further facilitates CRC cell proliferation, invasion and metastasis and leads to therapy resistance. Hence, to target the dysregulated tumor metabolism, the TME and the gut microbiota, novel preventive and therapeutic applications are required. In this review, the dysregulation of metabolic programs, molecular pathways, the TME and the intestinal microbiota in CRC is addressed. Possible therapeutic strategies, including metabolic inhibition and immune therapy in CRC, as well as modulation of the aberrant intestinal microbiota, are discussed.

Responsiveness of one-carbon metabolites to a high-protein diet in older men: Results from a 10-wk randomized controlled trial

OBJECTIVES

Dietary strategies to promote successful aging are divergent. Higher-protein diets are recommended to preserve skeletal muscle mass and physical function. Conversely, increased B-vitamin intake, supporting one-carbon (1C) metabolism, reduces the risk of cognitive decline and cardiovascular disease. On the hypothesis that higher protein intake through animal-based sources will benefit 1C regulation by the supply of B vitamins (folate, riboflavin, and vitamins B₆ and B₁₂) and methyl donors (choline) despite higher methionine intake, this study explored the effect of a higher-protein diet on 1C metabolite status in older men compared to current protein recommendations.

METHODS

Older men (age, 74 ± 3 y) were randomized to receive a diet for 10 wk containing either the recommended dietary allowance (RDA) of protein (0.8 g/kg body weight/d, n = 14), or double that amount (2RDA, n = 15), with differences in protein accounted for by modifying carbohydrate intake. Intervention diets were matched to each individual's energy requirements based on the Harris-Benedict equation and adjusted fortnightly as required depending on physical activity and satiety. Fasting plasma 1C metabolite concentrations were quantified by liquid chromatography coupled with mass spectrometry at baseline and after 10 wk of intervention.

RESULTS

Plasma homocysteine concentrations were reduced from baseline to follow-up with both diets. Changes in metabolite ratios reflective of betaine-dependent homocysteine remethylation were specific to the RDA diet, with an increase in the betaine-to-choline ratio and a decrease in the dimethylglycine-to-betaine ratio. Comparatively, increasing folate intake was positively associated with a change in choline concentration and inversely with the betaine-to-choline ratio for the 2RDA group.

CONCLUSIONS

Adding to the known benefits of higher protein intake in older people, this study supports a reduction of homocysteine with increased consumption of animal-based protein, although the health effects of differential response of choline metabolites to a higher-protein diet remain uncertain.

Maternal folate, one-carbon metabolism and pregnancy outcomes

Single nucleotide polymorphisms and pre- and peri-conception folic acid (FA) supplementation and dietary data were used to identify one-carbon metabolic factors associated with pregnancy outcomes in 3196 nulliparous women. In 325 participants, we also measured circulating folate, vitamin B12 and homocysteine. Pregnancy outcomes included preeclampsia (PE), gestational hypertension (GHT), small for gestational age (SGA), spontaneous preterm birth (sPTB) and gestational diabetes mellitus (GDM). Study findings show that maternal genotype MTHFR A1298C(CC) was associated with increased risk for PE, whereas TCN2 C766G(GG) had a reduced risk for sPTB. Paternal MTHFR A1298C(CC) and MTHFD1 G1958A(AA) genotypes were associated with reduced risk for sPTB, whereas MTHFR C677T(CT) genotype had an increased risk for GHT. FA supplementation was associated with higher serum folate and vitamin B12 concentrations, reduced uterine artery resistance index and increased birth weight. Women who supplemented with <800 μg daily FA at 15-week gestation had a higher incidence of PE (10.3%) compared with women who did not supplement (6.1%) or who supplemented with ≥800 μg (5.4%) (P < .0001). Higher serum folate levels were found in women who later developed GDM compared with women with uncomplicated pregnancies (Mean ± SD: 37.6 ± 8 nmol L-1 vs. 31.9 ± 11.2, P = .007). Fast food consumption was associated with increased risk for developing GDM, whereas low consumption of green leafy vegetables and fruit were independent risk factors for SGA and GDM and sPTB and SGA, respectively. In conclusion, maternal and paternal genotypes, together with maternal circulating folate and homocysteine concentrations, and pre- and early-pregnancy dietary factors, are independent risk factors for pregnancy complications.

Gene interactions observed with the HDL-c blood lipid, intakes of protein, sugar and biotin in relation to circulating homocysteine concentrations in a group of black South Africans

Background

Elevated homocysteine (Hcy) is associated with several pathologies. Gene–diet interactions related to Hcy might be used to customize dietary advice to reduce disease incidence. To explore this possibility, we investigated interactions between anthropometry, biochemical markers and diet and single-nucleotide polymorphisms (SNPs) in relation to Hcy concentrations. Five SNPs of Hcy-metabolizing enzymes were analyzed in 2010 black South Africans.

Results

Hcy was higher with each additional methylenetetrahydrofolate reductase (MTHFR) C677T minor allele copy, but was lower in methionine synthase (MTR) 2756AA homozygotes than heterozygotes. Individuals harboring cystathionine β synthase (CBS) 833 T/844ins68 had lower Hcy concentrations than others. No interactive effects were observed with any of the anthropometrical markers. MTHFR C677T and CBS T833C/844ins68 homozygote minor allele carriers presented with lower Hcy as high density lipoprotein cholesterol (HDL-c) increased. Hcy concentrations were negatively associated with dietary protein and animal protein intake in the TT and TC genotypes, but positively in the CC genotype of CBS T833C/844ins68. Hcy was markedly higher in TT homozygotes of MTHFR C677T as added sugar intake increased. In CBS T833C/844ins68 major allele carriers, biotin intake was negatively associated with Hcy; but positively in those harboring the homozygous minor allele.

Conclusions

The Hcy–SNP associations are modulated by diet and open up the possibility of invoking dietary interventions to treat hyperhomocysteinemia. Future intervention trials should further explore the observed gene–diet and gene–blood lipid interactions.

Colonic Lysine Homocysteinylation Induced by High-Fat Diet Suppresses DNA Damage Repair

Colorectal cancer (CRC) onset is profoundly affected by Western diet. Here, we report that high-fat (HF) diet-induced, organ-specific colonic lysine homocysteinylation (K-Hcy) increase might promote CRC onset by impeding DNA damage repair. HF chow induced elevated methionyl-tRNA synthetase (MARS) expression and K-Hcy levels and DNA damage accumulation in the mouse and rat colon, resulting in a phenotype identical to that of CRC tissues. Moreover, the increased copy number of MARS, whose protein product promotes K-Hcy, correlated with increased CRC risk in humans. Mechanistically, MARS preferentially bound to and modified ataxia-telangiectasia and Rad3-related protein (ATR), inhibited ATR and its downstream effectors checkpoint kinase-1 and p53, and relieved cell-cycle arrest and decreased DNA damage-induced apoptosis by disrupting the binding of ATR-interacting protein to ATR. Inhibiting K-Hcy by targeting MARS reversed these effects and suppressed oncogenic CRC cell growth. Our study reveals a mechanism of Western-diet-associated CRC and highlights an intervention approach for reversing diet-induced oncogenic effects.

Fatty Acid Profile and Cardiometabolic Markers in Relation with Diet Type and Omega-3 Supplementation in Spanish Vegetarians

Plant-based diets are becoming increasingly popular, and scientific information concerning the nutritional status in this population is needed. This study determined the fatty acid profile of Spanish lacto-ovo vegetarians (LO-vegetarians) and vegans. Participants were 104 healthy adults, LO-vegetarians (n = 49) and vegans (n = 55). Lifestyle habits and consumption of food and omega-3 supplements were estimated by questionnaires. BMI, blood pressure, and abdominal and body fat were determined. Serum was collected to analyze fatty acids, glucose, lipids, homocysteine, insulin, and leptin. Volunteers were classified according to serum omega-6 to omega-3 (n-6/n-3) ratio into three groups: n-6/n-3 < 10, n-6/n-3 ≥ 10 to 20, and n-6/n-3 > 20. Results showed low cardiovascular risk and high insulin sensitivity with negligible differences between diet types. Linoleic acid (C18:2n-6) was the major serum fatty acid, followed by oleic (C18:1n-9) and palmitic (C16:0) acids. In contrast, serum eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3) were (median, interquartile range) 0.27, 0.18% and 1.59, and 0.93%, respectively. Users of n-3 supplements (<10% of total vegetarians) had significantly higher EPA than non-users, while frequent consumption of flax-seeds was associated with increased α-linolenic acid (C18:3n-3). However, neither n-3 supplementation nor food consumption affected DHA levels in this vegetarian population.

Relationship between Homocysteine and Muscle Strength Decline: The Baltimore Longitudinal Study of Aging

Background

Decreased muscle strength is strongly associated with future mobility limitations in older adults. Homocysteine is a risk factor for vascular disease and may exacerbate muscle strength decline. The present study aimed to examine the association between homocysteine levels and muscle strength in adults aged 50 years or older.

Methods

Data were from 1,101 participants of The Baltimore Longitudinal Study of Aging between December 2004 and March 2015. Muscle strength was measured using grip strength. Mixed effects linear regression was used to estimate the association between homocysteine and muscle strength in men and women, separately.

Results

Total mean follow-up time was 4.7 ± 3.1 years, range from 0 to 10.1 years. Baseline mean grip strength was 39.9 kg for men and 25.5 kg for women. Grip strength declined over the follow-up time for both men and women. Among women, there was a significant inverse relationship between homocysteine and grip strength, where grip strength declined as a function of increasing homocysteine over time (β = -0.05, p = .031). Among men, an increase of 1 μmol/L in homocysteine was associated with -0.10 kg decrease in grip strength, though not significantly.

Conclusions

In this study of healthy older adults aged 50 years or older, higher homocysteine was related to lower muscle strength in women. This is the first study to characterize the relationship over a long follow-up period. Future research should focus on assessing homocysteine as a marker of physical function decline and translating the relationship into clinical and public health practice.

Homocysteine is a marker for metabolic syndrome and atherosclerosis

BACKGROUND

It has been documented that patients with metabolic syndrome (MS) and vascular complications have higher homocysteine levels. Hyperhomocysteinemia correlates with IR, increasing oxidative stress, which causes lesions of vascular endothelium leading to endothelial dysfunction, hypertension and atherosclerosis.

OBJECTIVE

The objectives of the study were to examine homocysteine values, along with cardiovascular risk factors (lipid and apolipoprotein status, CRP, blood pressure), indicators of renal function (microalbuminuria/24h), glucose regulation and insulin resistance (glucose and insulin level, HbA1c, HOMA-IR, uric acid) and anthropometric parameters (BMI, WC, HC, WHR) in patients with and without MS as a correlation between homocysteine and MS factors.

METHODS

The study included obese and overweight individuals, aged of 30-75 yrs. classified into two groups: with MS (n=35) and without MS (n=41).

RESULTS

Patients with MS had increased WC, BMI, BP, glycaemia, HOMA-IR, TG, CRP, microalbuminuria, homocysteine and decreased HDL-C (p<0.05). Statistically significant difference between groups was found for WC, BMI, sBP and dBP, TG, HDL-C (p<0.01) and glycaemia, CRP, Apo B, HOMA-IR (p<0.05). Significant positive correlations were found between homocysteine and sBP (p=0.036), dBP (p=0.04), Apo B (p=0.038) and hyperlipoproteinemia (type IIa, type IIb and type IV) (p=0.04).

CONCLUSION

Patients with MS had increased abdominal obesity, hypertension, hypertriglyceridemia, inflammation factors, IR, homocysteine and microalbuminuria as markers of endothelial dysfunction. A correlation between homocysteine and hypertension and hyperlipoproteinemia showed that homocysteine could be used as a potential marker for atherosclerosis progression.

Vitamin B12 and Homocysteine Associations with Gait Speed in Older Adults: The Baltimore Longitudinal Study of Aging

OBJECTIVES

This study aimed to assess the independent associations of serum levels of vitamin B12 and plasma concentrations of homocysteine with gait speed decline.

DESIGN, SETTING, PARTICIPANTS

This study utilized longitudinal analysis of participants 50 years or older from The Baltimore Longitudinal Study of Aging, N=774.

MEASUREMENTS

Gait speed (m/s) was assessed using the 6-meter usual pace test. Vitamin B12 and homocysteine concentrations were collected using standard clinical protocols. Linear mixed effects regression was stratified by baseline age category (50-69, 70-79, and ≥80 years old).

RESULTS

Mean follow-up time for the total study sample was 5.4 ± 2.0 years. No association between vitamin B12 and gait speed decline over the follow-up time for any age group was found. Elevated homocysteine concentrations were associated with decline in gait speed after adjustment for covariates (50-69: β= -0.005, p=.057; 70-79: β= -0.013, p<.001, ≥80: β= -0.007, p=.054).

CONCLUSION

Homocysteine and vitamin B12 are inversely related, yet only homocysteine was associated with gait speed decline in this population of healthy older adults. Given these results, future research should be directed towards investigating the relationship in populations with greater variation in vitamin B12 concentrations and other mechanisms influencing homocysteine concentrations.

Determinants of hyperhomocysteinemia in healthy and hypertensive subjects: A population-based study and systematic review

AIMS

Hyperhomocysteinemia (HHcy) is known to increase the risk of many diseases. Factors influencing HHcy in healthy and hypertensive subjects remain under-researched.

METHODS

A large population-based study was conducted in 60 communities from Shenzhen, China. Responses to standardized questions on lifestyle factors and blood samples were collected from all participants after a 12-h overnight fast. Multiple linear and multivariate logistic regressions were used to explore risk factors for HHcy. Results were then compared to those from a systematic review of English-language articles listed in Pubmed, EBSCOhost, Web of Science, Embase and Cochrane libraries that investigated HHcy risk factors in healthy and hypertensive subjects.

RESULTS

A total of 1586 healthy (Male/Female = 642/944) and 5935 hypertensive subjects (Male/Female = 2928/3007) participated in our population-based study. In logistic regression analyses, age, BMI and creatinine (Cr) were risk factors, while being female, fruit intake and physical activity were protective factors for HHcy in healthy subjects. In hypertensive subjects, seven [age, smoking, salt intake, systolic blood pressure (SBP), uric acid, triglycerides (TG), and Cr] and four [female, fruit intake, total cholesterol (TC), and glucose] factors were associated with higher and lower HHcy respectively. The review of 71 studies revealed that potential risk factors for Hcy included nutritional, physiologic, lifestyle habits, ethnicity, genetics, interactions between gene-environment, gene-gene, gene-nutritional, environment-environment, nutritional-nutritional.

CONCLUSION

Our study indicates the potential importance of increasing folic acid and vitamin B supplementation, daily fruit and vegetable intake, regular exercise and refraining from tobacco smoking and alcohol consumption as preventive strategies for Hcy.

Protective Effect of Folic Acid on Oxidative DNA Damage: A Randomized, Double-Blind, and Placebo Controlled Clinical Trial

Although previous reports have linked DNA damage with both transmissions across generations as well as our own survival, it is unknown how to reverse the lesion. Based on the data from a Randomized, Double-blind, Placebo Controlled Clinical Trial, this study aimed to assess the efficacy of folic acid supplementation (FAS) on DNA oxidative damage reversal.In this randomized clinical trial (RCT), a total of 450 participants were enrolled and randomly assigned to 3 groups to receive folic acid (FA) 0.4 mg/day (low-FA), 0.8 mg/day (high-FA), or placebo (control) for 8 weeks. The urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and creatinine (Cr) concentration at pre- and post-FAS were measured with modified enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC), respectively. A multivariate general linear model was applied to assess the individual effects of FAS and the joint effects between FAS and hypercholesterolemia on oxidative DNA damage improvement. This clinical trial was registered with ClinicalTrials.gov, number NCT02235948.Of the 438 subjects that received FA fortification or placebo, the median (first quartile, third quartile) of urinary 8-OHdG/Cr for placebo, low-FA, and high-FA groups were 58.19 (43.90, 82.26), 53.51 (38.97, 72.74), 54.73 (39.58, 76.63) ng/mg at baseline and 57.77 (44.35, 81.33), 51.73 (38.20, 71.30), and 50.65 (37.64, 76.17) ng/mg at the 56th day, respectively. A significant decrease of urinary 8-OHdG was observed after 56 days FA fortification (P < 0.001). Compared with the placebo, after adjusting for some potential confounding factors, including the baseline urinary 8-OHdG/Cr, the urinary 8-OHdG/Cr concentration significantly decreased after 56 days FAS [β (95% confidence interval) = -0.88 (-1.62, -0.14) and P = 0.020 for low-FA; and β (95% confidence interval) = -2.68 (-3.42, -1.94) and P < 0.001 for high-FA] in a dose-response fashion (Ptrend < 0.001). Test of interaction between hypercholesterolemia and FA supplementation on urinary 8-OHdG reduction was significant (P = 0.001).The present study demonstrates that FA fortification is independently linked to the reduction of urinary 8-OHdG/Cr in a dose-related pattern, which suggests that FA is beneficial to protect against oxidative damage to DNA. This effect is apparently stronger in those with hypercholesterolemia. The authors provide a new insight into the prevention and reversal of oxidative DNA damage.

Erythrocyte fatty acid profiles and plasma homocysteine, folate and vitamin B6 and B12 in recurrent depression: Implications for co-morbidity with cardiovascular disease

Oxidative stress induced interactions between fatty acid (FA) and one-carbon metabolism may be involved in co-occurrence of major depressive disorder (MDD) and cardiovascular disease (CVD), which have been scarcely studied together. In 137 recurrent MDD-patients vs. 73 age- and sex-matched healthy controls, we simultaneously measured key components of one-carbon metabolism in plasma (homocysteine, folate, vitamins B6 and B12), and of FA-metabolism in red blood cell membranes [main polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA) and structural FA-indices (chain length, unsaturation, peroxidation)]. Results show significant positive associations of folate with EPA, DHA, and the peroxidation index, which were similar in patients and controls. After correction for confounders, these associations were lost except for EPA. Associations between B-vitamins and FA-parameters were non-significant, but also similar in patients and controls. Homocysteine and DHA were significantly less negatively associated in patients than in controls. In conclusion, these data indicate similarities but also differences in associations between parameters of one-carbon and FA-metabolism in recurrent MDD patients vs. controls, which may reflect differences in handling of oxidative stress. Further research should test the consequences of these differences, particularly the premature development of CVD in MDD.

Vitamin B2, vitamin B12 and total homocysteine status in children and their associations with dietary intake of B-vitamins from different food groups: the Healthy Growth Study

PURPOSE

To examine the associations between the dietary intakes of certain B-vitamins from different food sources with the relevant plasma status indices in children.

METHODS

A representative subsample of 600 children aged 9-13 years from the Healthy Growth Study was selected. Dietary intakes of vitamins B₂, B₁₂, B₆ and folate derived from different food sources were estimated. Plasma levels of vitamin B₂ (or riboflavin), methylmalonic acid (MMA) and total homocysteine (tHcy) were also measured.

RESULTS

Plasma concentrations of vitamin B₂ below 3 μg/L were found in 22.8 % of the children. Children in the lower quartile of dietary vitamin B₂ intake were found to have the lowest plasma vitamin B₂ levels compared to children in the upper three quartiles (5.06 ± 7.63 vs. 6.48 ± 7.88, 6.34 ± 7.63 and 6.05 ± 4.94 μg/L respectively; P = 0.003). Regarding vitamin B₁₂ children in the lower quartile of dietary intake had higher mean plasma tHcy levels compared to children in the upper two quartiles, respectively (6.00 ± 1.79 vs. 5.41 ± 1.43 and 5.46 ± 1.64 μmol/L; P = 0.012). Positive linear associations were observed between plasma vitamin B₂ levels and dietary vitamin B₂ derived from milk and fruits (β = 0.133; P = 0.001 and β = 0.086; P = 0.037). Additionally, nonlinear associations were also observed between plasma vitamin B₂ levels and vitamin B₂ derived from red meat, as well as between tHcy levels and vitamins B₁₂ and B₆ derived from milk; vitamins B₁₂, B₆ and folate derived from cereal products and folate derived from fruits.

CONCLUSION

A considerably high prevalence of poor plasma vitamin B₂ status was observed in children. The intake of milk, fruits and cereals was associated with more favorable tHcy levels, while the intake of milk and fruits with more favorable plasma B2 levels. However, these findings need to be further confirmed from controlled dietary intervention studies examining the modulation of biomarkers of B-vitamins.

Circulating B-vitamins and smoking habits are associated with serum polyunsaturated Fatty acids in patients with suspected coronary heart disease: a cross-sectional study

The long-chain polyunsaturated fatty acids are considered to be of major health importance, and recent studies indicate that their endogenous metabolism is influenced by B-vitamin status and smoking habits. We investigated the associations of circulating B-vitamins and smoking habits with serum polyunsaturated fatty acids among 1,366 patients who underwent coronary angiography due to suspected coronary heart disease at Haukeland University Hospital, Norway. Of these, 52% provided information on dietary habits by a food frequency questionnaire. Associations were assessed using partial correlation (Spearman’s rho). In the total population, the concentrations of most circulating B-vitamins were positively associated with serum n-3 polyunsaturated fatty acids, but negatively with serum n-6 polyunsaturated fatty acids. However, the associations between B-vitamins and polyunsaturated fatty acids tended to be weaker in smokers. This could not be solely explained by differences in dietary intake. Furthermore, plasma cotinine, a marker of recent nicotine exposure, showed a negative relationship with serum n-3 polyunsaturated fatty acids, but a positive relationship with serum n-6 polyunsaturated fatty acids. In conclusion, circulating B-vitamins are, in contrast to plasma cotinine, generally positively associated with serum n-3 polyunsaturated fatty acids and negatively with serum n-6 polyunsaturated fatty acids in patients with suspected coronary heart disease. Further studies should investigate whether B-vitamin status and smoking habits may modify the clinical effects of polyunsaturated fatty acid intake.

Vitamin D intake, month the mammogram was taken and mammographic density in Norwegian women aged 50-69

BACKGROUND

The role of vitamin D in breast cancer etiology is unclear. There is some, but inconsistent, evidence that vitamin D is associated with both breast cancer risk and mammographic density (MD). We evaluated the associations of MD with month the mammogram was taken, and with vitamin D intake, in a population of women from Norway--a country with limited sunlight exposure for a large part of the year.

METHODS

3114 women aged 50-69, who participated in the Norwegian Breast Cancer Screening Program (NBCSP) in 2004 or 2006/07, completed risk factor and food frequency (FFQ) questionnaires. Dietary and total (dietary plus supplements) vitamin D, calcium and energy intakes were estimated by the FFQ. Month when the mammogram was taken was recorded on the mammogram. Percent MD was assessed using a computer assisted method (Madena, University of Southern California) after digitization of the films. Linear regression models were used to investigate percent MD associations with month the mammogram was taken, and vitamin D and calcium intakes, adjusting for age, body mass index (BMI), study year, estrogen and progestin therapy (EPT), education, parity, calcium intakes and energy intakes.

RESULTS

There was no statistical significant association between the month the mammogram was taken and percent MD. Overall, there was no association between percent MD and quartiles of total or dietary vitamin D intakes, or of calcium intake. However, analysis restricted to women aged <55 years revealed a suggestive inverse association between total vitamin D intake and percent MD (p for trend = 0.03).

CONCLUSION

Overall, we found no strong evidence that month the mammogram was taken was associated with percent MD. We found no inverse association between vitamin D intake and percent MD overall, but observed a suggestive inverse association between dietary vitamin D and MD for women less than 55 years old.

Dietary intake of saturated fat is not associated with risk of coronary events or mortality in patients with established coronary artery disease

BACKGROUND

Data from recent meta-analyses question an association between dietary intake of saturated fatty acids (SFAs) and risk of cardiovascular disease (CVD). Moreover, the prognostic effect of dietary SFA in patients with established CVD treated with modern conventional medication has not been extensively studied.

OBJECTIVE

We investigated the associations between self-reported dietary SFA intake and risk of subsequent coronary events and mortality in patients with coronary artery disease (CAD).

METHODS

This study included patients who participated in the Western Norway B-Vitamin Intervention Trial and completed a 169-item semiquantitative food-frequency questionnaire after coronary angiography. Quartiles of estimated daily intakes of SFA were related to risk of a primary composite endpoint of coronary events (unstable angina pectoris, nonfatal acute myocardial infarction, and coronary death) and separate secondary endpoints (total acute myocardial infarction, fatal coronary events, and all-cause death) with use of Cox-regression analyses.

RESULTS

This study included 2412 patients (81% men, mean age: 61.7 y). After a median follow-up of 4.8 y, a total of 292 (12%) patients experienced at least one major coronary event during follow-up. High intake of SFAs was associated with a number of risk factors at baseline. However, there were no significant associations between SFA intake and risk of coronary events [age- and sex-adjusted HR (95% CI) was 0.85 (0.61, 1.18) for the upper vs. lower SFA quartile] or any secondary endpoint. Estimates were not appreciably changed after multivariate adjustments.

CONCLUSIONS

There was no association between dietary intake of SFAs and incident coronary events or mortality in patients with established CAD.

Dietary protein and plasma total homocysteine, cysteine concentrations in coronary angiographic subjects

Background

Dietary patterns are associated with plasma total homocysteine (tHcy) concentrations in healthy populations, but the associations between dietary protein and tHcy, total cysteine (tCys) in high risk populations are unclear. We therefore examined the association between dietary protein and tHcy and tCys concentrations in coronary angiographic subjects.

Methods

We conducted a cross-sectional study of 1015 Chinese patients who underwent coronary angiography (40–85 y old). With the use of food-frequency questionnaires, we divided the total protein intakes into high animal-protein and high plant-protein diets. Circulating concentrations of tHcy and tCys were simultaneously measured by high-performance liquid chromatography with fluorescence detection.

Results

We found that high animal-protein diet was positively associated with hyperhomocysteinemia after adjustment for potential confounders, with the subjects in the highest quartile of intake having the greatest increase in risk (OR: 4.14, 95% CI: 2.67-6.43), whereas high plant-protein diet was inversely related to hyperhomocysteinemia, with a higher intake being protective. Compared with the first quartile of intake, the adjusted OR was 0.59 (95% CI: 0.38-0.91) for the fourth quartile. The total protein intake was positively associated with the risk of hypercysteinemia and the participants in highest quartile had significant OR of 1.69 (95% CI: 1.02-2.87) compared with those in lowest quartile. In multivariate linear regression analyses, high animal-protein and total-protein intakes were positively associated with plasma tHcy and tCys concentrations. The plant-protein intake was a negative determinant of plasma tHcy concentrations.

Conclusions

High animal-protein diet was positively associated with high tHcy concentrations, whereas high plant-protein diet was inversely associated with tHcy concentrations. Furthermore the total protein intake was strongly related to tCys concentrations.

Dietary intake of n-3 long-chain polyunsaturated fatty acids and risk of myocardial infarction in coronary artery disease patients with or without diabetes mellitus: a prospective cohort study

BACKGROUND

A beneficial effect of a high n-3 long-chain polyunsaturated fatty acid (LCPUFA) intake has been observed in heart failure patients, who are frequently insulin resistant. We investigated the potential influence of impaired glucose metabolism on the relation between dietary intake of n-3 LCPUFAs and risk of acute myocardial infarction (AMI) in patients with coronary artery disease.

METHODS

This prospective cohort study was based on the Western Norway B-Vitamin Intervention Trial and included 2,378 patients with coronary artery disease with available baseline glycosylated hemoglobin (HbA1c) and dietary data. Patients were sub-grouped as having no diabetes (HbA1c <5.7%), pre-diabetes (HbA1c ≥5.7%), or diabetes (previous diabetes, fasting baseline serum glucose ≥7.0, or non-fasting glucose ≥11.1 mmol/L). AMI risk was evaluated by Cox regression (age and sex adjusted), comparing the upper versus lower tertile of daily dietary n-3 LCPUFA intake.

RESULTS

The participants (80% males) had a mean age of 62 and follow-up of 4.8 years. A high n-3 LCPUFA intake was associated with reduced risk of AMI (hazard ratio 0.38, 95%CI 0.18, 0.80) in diabetes patients (median HbA1c = 7.2%), whereas no association was observed in pre-diabetes patients. In patients without diabetes a high intake tended to be associated with an increased risk (hazard ratio1.45, 95%CI 0.84, 2.53), which was significant for fatal AMI (hazard ratio 4.79, 95%CI 1.05, 21.90) and associated with lower HbA1c (mean ± standard deviation 4.55 ±0.68 versus 4.92 ±0.60, P = 0.02). No such differences in HbA1c were observed in those with pre-diabetes or diabetes.

CONCLUSIONS

A high intake of n-3 LCPUFAs was associated with a reduced risk of AMI, independent of HbA1c, in diabetic patients, but with an increased risk of fatal AMI and lower HbA1c among patients without impaired glucose metabolism. Further studies should investigate whether patients with diabetes may benefit from having a high intake of n-3 LCPUFAs and whether patients with normal glucose tolerance should be careful with a very high intake of these fatty acids.

TRIAL REGISTRATION

This trial is registered at clinicaltrials.gov as NCT00354081.

Higher intake of vitamin B-6 and dairy products and lower intake of green and oolong tea are independently associated with lower serum homocysteine concentration in young Japanese women

Little is known about the relation of modifiable dietary factors to circulating homocysteine concentrations, particularly in young adults and non-Western populations. We investigated the hypothesis that intakes of nutrients and foods are associated with serum homocysteine concentration in a group of young Japanese women. This cross-sectional study included 1050 female Japanese dietetic students aged 18 to 22 years. Dietary intake was assessed using a validated, self-administered, comprehensive diet history questionnaire. Fasting blood samples were collected, and serum homocysteine concentrations were measured. Adjustment was made for survey year, region, municipality level, current smoking, current alcohol drinking, dietary supplement use, physical activity, body mass index, energy intake, and intakes of other nutrients or foods. After adjustment for nondietary confounding factors, intakes of all B vitamins (folate, vitamin B-6, vitamin B-12, and riboflavin) were inversely associated with homocysteine concentration. However, only vitamin B-6 remained significant after further adjustment for other B vitamins. Marine-origin n-3 polyunsaturated fatty acid intake showed an inverse association, but this was not independent of intakes of B vitamins. For foods, pulses, fish and shellfish, and vegetables were independently and inversely associated with homocysteine concentration, but these associations disappeared after adjustment for intakes of other foods. Conversely, an inverse association for dairy products and a positive association for green and oolong tea remained even after adjustment for other foods. To conclude, in a group of young Japanese women, higher intake of vitamin B-6 and dairy products and lower intake of green and oolong tea were independently associated with lower serum homocysteine concentration.

Polyunsaturated fatty acids in serum and homocysteine concentrations in Japanese men and women: a cross-sectional study

Background

Supplementation studies have suggested a role of n-3 polyunsaturated fatty acids (PUFAs) in homocysteine metabolism, but the evidence is limited and inconsistent among studies that measured blood levels of n-3 and n-6 PUFAs. We examined the association between blood levels of PUFAs and homocysteine in Japanese men and women.

Methods

The subjects were 496 employees (290 men and 206 women) of 2 municipal offices in Japan. Fatty acid composition in serum phospholipids and cholesterol ester (CE) was measured using gas–liquid chromatography. Multiple regression was used to calculate means of homocysteine concentrations according to PUFA tertile with adjustment for potential confounders.

Results

Serum homocysteine concentration decreased with increasing levels of total n-3 PUFA, eicosapentaenoic acid and docosahexaenoic acid (DHA) in serum phospholipids and CE with adjustment for age, sex and workplace. However, only DHA in serum phospholipids remained statistically significant after additional adjustment for other potential confounders including serum folate (P-trend = 0.04). N-6 PUFAs were not significantly associated with homocysteine concentrations.

Conclusions

Higher proportion of DHA in serum phospholipids may be associated with lower homocysteine concentrations in Japanese men and women.

Elderly women: homocysteine reduction by short-term folic acid supplementation resulting in increased glucose concentrations and affecting lipid metabolism (C677T MTHFR polymorphism)

OBJECTIVE

Serum homocysteine levels show interindividual variation and are determined by nutritional factors, such as B-vitamin intake, and by age and genetic influences, such as the genotype of the methylenetetrahydrofolate reductase (MTHFR) gene. Recently, the relation between one-carbon and lipid metabolism has been shown. Therefore, we hypothesized that folic acid supplementation would not only decrease homocysteine concentrations but also affect lipid metabolism. The aim of the present study was to evaluate the impact of short-term folic acid supplementation on homocysteine and lipid metabolism in Polish women older than 60 y with different C677T MTHFR genotypes.

METHODS

One hundred twenty-two volunteers were supplemented with folic acid 400 μg/d for 8 wk. Folate intake was assessed using a food-frequency questionnaire. The serum homocysteine level was analyzed using high-performance liquid chromatography. Serum biomarkers were measured with a Vitalab Flexor biochemical analyzer. MTHFR genotyping was performed using the polymerase chain reaction restriction fragment length polymorphism method.

RESULTS

In the studied group, the MTHFR genotype frequencies were 0.14 for TT, 0.43 for CT, 0.43 for CC carriers. At baseline, the average folic acid and homocysteine concentrations were 12.16 ± 0.23 ng/mL and 7.94 ± 0.3 μmol/L, respectively. Folic acid supplementation lowered the serum homocysteine concentration. However, the dietary intervention also led to an increase in glucose concentrations (P < 0.01). The T-allele carriers had a larger waist circumference (P < 0.05) and a higher waist-to-hip ratio (P < 0.01).

CONCLUSIONS

In elderly women, a short-term, low-dose folic acid supplementation lowered the serum homocysteine level but also increased glucose concentrations. The C677T MTHFR polymorphism affects the waist-to-hip ratio and lipid metabolism.

Preoperative body size and composition, habitual diet, and post-operative complications in elective colorectal cancer patients in Norway

BACKGROUND

Both malnutrition and obesity are related to worsened post-operative outcomes after colorectal surgery. Obese cancer patients may be malnourished as a result of short-term weight loss. The present study aimed to evaluate preoperative nutritional status, body composition and dietary intake related to post-operative complications (POC) and post-operative hospital days (POHD) in elective colorectal cancer (CRC) patients.

METHODS

Anthropometry, body composition measured by bioelectric spectroscopy and dietary habits assessed by a validated food-frequency questionnaire were examined in 100 newly-diagnosed CRC patients. Data from 30-day POC and POHD were collected from medical records. Nonparametric and chi-squared tests and logistic regression were used to analyse associations between body and dietary variables and post-operative outcome.

RESULTS

Twenty-nine patients had at least one POC. The median POHD was six. Body size and composition measures and short-term weight loss were no different between patients with and without POC, or between patients with POHD <7 and ≥7. Dietary variables were otherwise no different between patients with and without POC, although the median intake of marine n-3 polyunsaturated fatty acids (PUFA, the sum of eicosapentaenoic and docosahexaenoic acids) was significantly lower in patients with versus without POC (0.7 versus 1.2 g day(-1) , P = 0.04).

CONCLUSIONS

We found that preoperative body size, body composition and short-term weight loss were not related to 30-day post-operative outcomes in CRC patients. A high content of marine n-3 PUFA in preoperative habitual diets may protect against POC after CRC surgery.

Diets high in palmitic acid (16:0), lauric and myristic acids (12:0 + 14:0), or oleic acid (18:1) do not alter postprandial or fasting plasma homocysteine and inflammatory markers in healthy Malaysian adults

BACKGROUND

Dietary fat type is known to modulate the plasma lipid profile, but its effects on plasma homocysteine and inflammatory markers are unclear.

OBJECTIVE

We investigated the effects of high-protein Malaysian diets prepared with palm olein, coconut oil (CO), or virgin olive oil on plasma homocysteine and selected markers of inflammation and cardiovascular disease (CVD) in healthy adults.

DESIGN

A randomized-crossover intervention with 3 dietary sequences of 5 wk each was conducted in 45 healthy subjects. The 3 test fats, namely palmitic acid (16:0)-rich palm olein (PO), lauric and myristic acid (12:0 + 14:0)-rich CO, and oleic acid (18:1)-rich virgin olive oil (OO), were incorporated at two-thirds of 30% fat calories into high-protein Malaysian diets.

RESULTS

No significant differences were observed in the effects of the 3 diets on plasma total homocysteine (tHcy) and the inflammatory markers TNF-α, IL-1β, IL-6, and IL-8, high-sensitivity C-reactive protein, and interferon-γ. Diets prepared with PO and OO had comparable nonhypercholesterolemic effects; the postprandial total cholesterol for both diets and all fasting lipid indexes for the OO diet were significantly lower (P < 0.05) than for the CO diet. Unlike the PO and OO diets, the CO diet was shown to decrease postprandial lipoprotein(a).

CONCLUSION

Diets that were rich in saturated fatty acids prepared with either PO or CO, and an OO diet that was high in oleic acid, did not alter postprandial or fasting plasma concentrations of tHcy and selected inflammatory markers. This trial was registered at clinicaltrials.gov as NCT00941837.

A maternal dietary pattern characterised by fish and seafood in association with the risk of congenital heart defects in the offspring

OBJECTIVE

To identify maternal dietary patterns related to biomarkers of methylation and to investigate associations between these dietary patterns and the risk of congenital heart defects (CHDs) in the offspring.

DESIGN

Case-control study.

SETTING

Western part of the Netherlands, 2003-08.

POPULATION

One hundred and seventy-nine mothers of children with CHD and 231 mothers of children without a congenital malformation.

METHODS

Food intake was obtained by food frequency questionnaires. The reduced rank regression method was used to identify dietary patterns related to the biomarker concentrations of methylation in blood.

MAIN OUTCOME MEASURES

Dietary patterns, vitamin B and homocysteine concentrations, biomarkers of methylation (S-adenosylmethionine [SAM] and S-adenosylhomocysteine [SAH]) and the risk of CHD estimated by odds ratios and 95% confidence intervals.

RESULTS

The one-carbon-poor dietary pattern, comprising a high intake of snacks, sugar-rich products and beverages, was associated with SAH (β = 0.92, P < 0.001). The one-carbon-rich dietary pattern with high fish and seafood intake was associated with SAM (β = 0.44, P < 0.001) and inversely with SAH (β =-0.08, P < 0.001). Strong adherence to this dietary pattern resulted in higher serum (P <0.05) and red blood cell (P < 0.01) folate and a reduced risk of CHD in offspring: odds ratio, 0.3 (95% confidence interval, 0.2-0.6).

CONCLUSIONS

The one-carbon-rich dietary pattern, characterised by the high intake of fish and seafood, is associated with a reduced risk of CHD. This finding warrants further investigation in a randomised intervention trial.

Dietary intake of n-3 long-chain polyunsaturated fatty acids and coronary events in Norwegian patients with coronary artery disease

BACKGROUND

Consumption of fish and n-3 (omega-3) long-chain polyunsaturated fatty acids (LCPUFAs) has been associated with reduced risk of coronary artery disease (CAD) mortality.

OBJECTIVE

The aim was to examine the relation between dietary intake of n-3 LCPUFAs or fish and risk of future coronary events or mortality in patients with well-characterized CAD.

DESIGN

This was a substudy of 2412 participants in the Western Norway B Vitamin Intervention Trial with a median follow-up time of 57 mo. Patients aged >18 y diagnosed with CAD (81% men) completed a food-frequency questionnaire at baseline, from which daily intakes of eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids as well as fish were estimated on the basis of diet and intakes of supplements including fish and cod liver oils. The main endpoint was a composite of coronary events, including coronary death, nonfatal acute myocardial infarction, and unstable angina pectoris.

RESULTS

The mean (+/-SD) intakes of n-3 LCPUFAs in quartiles 1-4 were 0.58 +/- 0.29, 0.83 +/- 0.30, 1.36 +/- 0.44, and 2.64 +/- 1.18 g/d, respectively. We found no dose-response relation between quartiles of n-3 LCPUFAs (based on intake as percentage of total energy) or fish and coronary events or separate endpoints. A post hoc additive proportional hazards model showed a slightly increased risk of coronary events at an intake of n-3 LCPUFAs < approximately 0.30 g/d.

CONCLUSION

Among Norwegian patients with CAD consuming relatively high amounts of n-3 LCPUFAs and fish, there were no significant trends toward a reduced risk of coronary events or mortality with increasing intakes. This trial was registered at clinicaltrials.gov as NCT00354081.

Dietary patterns are associated with hyperhomocysteinemia in an urban Pakistani population

Little attention has been given to the association of dietary patterns with plasma homocysteine. Our objective in this study was to identify major dietary patterns and investigate their association with plasma homocysteine. In a cross-sectional survey, 872 healthy adults (355 males, 517 females; aged 18-60 y) were enrolled from an urban population in Karachi. Dietary intake was assessed by a FFQ. We used factor analysis to define major dietary patterns. Fasting concentrations of plasma or serum homocysteine, folate, pyridoxal-phosphate (PLP; coenzyme form of vitamin B-6), and vitamin B-12 were measured. Three major dietary patterns were identified and labeled as "prudent diet," "high animal-protein diet," and "high plant-protein diet." We observed a protective effect of the prudent dietary pattern for the highest quartile of intake compared with the lowest quartile of hyperhomocysteinemia when the model was adjusted for age, gender, household income, BMI, tobacco chewing, and smoking [OR = 0.52 (95% CI = 0.30-0.90); P = 0.01]. The high plant-protein diet pattern was inversely related to hyperhomocysteinemia, with a higher intake being protective. Compared with the 1st quartile, the adjusted OR was 0.42 (95% CI = 0.25-0.69; P = 0.001) for the 4th quartile. The high animal-protein diet was positively associated with hyperhomocysteinemia, with participants in the highest quartile of intake having the greatest increase in risk [OR = 2.10 (95% CI = 1.22-3.60); P = 0.007]. Plasma homocysteine concentrations appeared to be correlated more with circulating folate (r = -0.25; P < 0.001) than with PLP (r = -0.02; P = 0.663) or vitamin B-12 (r = -0.16; P < 0.001). A diet rich in fruits and uncooked vegetables decreased the risk of hyperhomocysteinemia, whereas diets rich in red meat, chicken, and tea with milk were positively associated with hyperhomocysteinemia.

The efficacy of omega-3 fatty acid supplementation on plasma homocysteine and malondialdehyde levels of type 2 diabetic patients

BACKGROUND AND AIMS

Cardiovascular diseases are the major cause of mortality among diabetic patients. The concentration of malondialdehyde (MDA) and homocysteine is believed to play a role in cardiovascular diseases. Omega-3 fatty acid supplementation could be effective in some diabetes complications and in the control of the glycemic index. However, it may increase lipid peroxidation. The objective of this study was to determine the effect of omega-3 fatty acids on the concentration of homocysteine and MDA in diabetic patients.

METHODS AND RESULTS

A randomized double-blind, placebo-controlled clinical trial was conducted on 81 patients with type 2 diabetes. The patients were randomly assigned to either the treatment or control groups. Each subject received three capsules of omega-3 fatty acids or a placebo every day for a period of 2months. The two groups were similar in terms of body mass index and food intake. At the beginning of the study and after 2months of supplementation their levels of HbA(1)c, homocysteine, MDA, C-reactive protein (CRP), total cholesterol, LDL-cholesterol and fasting blood sugar (FBS) were determined. Due to omega-3 fatty acid supplementation, homocysteine was changed significantly in both treatment and control groups up to -3.10mumol/L and 0.10mumol/L respectively, and HbA(1)c decreased by 0.75% in the treatment group and increased by 0.26% in the control group. However, the changes in fasting blood sugar (FBS), malondialdehyde (MDA), C-reactive protein (CRP), total cholesterol and LDL-cholesterol levels were not significant.

CONCLUSION

The consumption of omega-3 fatty acid supplements (3g/day) for 2months decreases the levels of homocysteine in diabetic patients with no change in FBS, MDA and CRP levels.

The effects of homocysteine and MTHFR genotype on hip bone loss and fracture risk in elderly women

SUMMARY

Few studies have evaluated the effects of homocysteine and methylenetetrahydrofolate reductase (MTHFR) genotype on age-related bone loss. In our 5-year cohort study with 1,213 women aged 70-85 years, high homocysteine is associated with greater hip bone loss but not fracture risk. The effect of MTHFR genotype on bone density and fracture is weak.

INTRODUCTION

Previous studies on the effects of homocysteine and MTHFR genotype on bone mineral density (BMD) and osteoporotic fracture risk have shown inconsistent results. Few studies have evaluated their effects on age-related bone loss. We evaluated the effects of homocysteine and MTHFR genotype variation on hip BMD and fracture risk over 5 years in a cohort of 1,213 community-dwelling women aged 70-85 years.

METHODS

Nutritional intake and prevalent fracture status were assessed at baseline, plasma homocysteine was measured at year 1, and hip dual-energy X-ray absorptiometry (DXA) BMD was measured at years 1 and 5. Clinical incident osteoporotic fractures confirmed by radiographic report were collected throughout the study and the MTHFR gene C677T and A1298C polymorphisms genotyped. Data were analyzed using analysis of covariance and Cox proportional hazard regression.

RESULTS

The highest tertile of homocysteine was associated with a greater hip BMD loss over 4 years (-2.8%) compared to the middle (-1.6%) and lowest tertiles (-1.2%) (P < 0.001). This effect remained after adjustment for covariates. There was no effect of homocysteine on fracture prevalence or incidence. MTHFR gene variation was only weakly related to one of the bone outcome measures.

CONCLUSION

In this study population, high homocysteine is associated with greater hip bone loss but not fracture risk.

Homocysteine and lipids: S-adenosyl methionine as a key intermediate

An association between hyperlipidemia and hyperhomocysteinemia (HHCY) has been suggested. This link is clinically important in management of vascular risk factors especially in elderly people and patients with metabolic syndrome. Higher plasma homocysteine (Hcy) was associated with lower high-density lipoprotein (HDL)-cholesterol level. Moreover, HHCY was associated with disturbed plasma lipids or fatty liver. It seems that hypomethylation associated with HHCY is responsible for lipid accumulation in tissues. Decreased methyl group will decrease the synthesis of phosphatidylcholine, a major phospholipid required for very low-density lipoprotein (VLDL) assembly and homeostasis. The effect of Hcy on HDL-cholesterol is probably related to inhibiting enzymes or molecules participating in HDL-particle assembly.

Laying hens can convert high doses of folic acid added to the feed into natural folates in eggs providing a novel source of food folate

There are few good sources of natural food folates apart from green leafy vegetables and these may have a limited potential to increase folate status because of substantial losses that can occur during cooking. Fortified foods can overcome this but are controversial because of safety concerns regarding chronic exposure to high-dose folic acid (FA; the synthetic form). The aim of the present study was to develop eggs with an enriched natural folate content and minimal unmetabolised FA. Forty-eight, 30-week-old laying hens were randomised to receive the basal feed (formulated to provide 1 mg folate/kg feed) to which had been added one of the following FA levels (0, 2, 4, 8, 16, 32 mg/kg feed). Total folate was measured in eggs collected throughout the 12-week study period and the FA content estimated at 12 weeks. Results showed that the maximal egg folate content was achieved by adding 16 mg FA/kg feed. At this optimal dose, the total folate content per egg was 75 μg (compared with 32 μg in a regular egg) of which FA represented at most 10 %, a level which would probably be converted into natural folates by humans after ingestion. The results demonstrate that it is possible to use synthetic FA at high doses to produce novel animal foods enriched with natural folates in a cost-efficient process. Such foods may be particularly relevant to European populations without access to FA fortification and therefore dependent on natural food folate sources for the primary prevention of folate-related disease.