Effect of folic acid fortification of food on homocysteine-related mortality

Folic acid retention evaluation in preparations with wheat flour and corn submitted to different cooking methods by HPLC/DAD

Folic acid content was evaluated in food preparations containing wheat and corn flour submitted to baking, deep-frying, and steaming. Commercially fortified flours showed the absence of folic acid. Flours with laboratory folic acid fortification showed 487 and 474 μg of folic acid in 100 g of wheat and corn flours, respectively. In the corn flour preparations, the cake had the highest retention (99%) when compared to couscous (97%). Besides, the cake showed higher retention when compared to the wheat flour preparations due to the interactions of the folic acid with the hydrophobic amino acids of the Zein, a protein found in corn. In wheat flour preparations, vitamin retention was 87%, 80% and 57% in bread, cake, and White sauce respectively. These findings relate to the change of the physicochemical properties of food components that occurs during mixing and cooking of the ingredients.

Association of genetic and epigenetic variants in one-carbon metabolism gene with folate treatment response in hyperhomocysteinaemia

BACKGROUND

Folate supplementation treatment is the first-line therapy in hyperhomocysteinaemia (HHcy). Up to 40% of HHcy patients do not benefit from folate therapy. Genetic and epigenetic factors of one-carbon metabolism (1-CM) might be identified as a predictor of folate supplementation treatment response. In the present study, we attempt to identify whether genetic and epigenetic factors might predict folate treatment response.

METHODS

A total of 230 patients with HHcy were involved in this prospective cohort study. Differences between baseline concentrations and concentrations obtained at 90 days of treatment were calculated to evaluate the treatment response. General linear models and Pearson correlation was used to explore associations among single-nucleotide polymorphisms (SNPs), DNA methylation, and folate treatment response. Finally, mediation analysis was performed to investigate whether DNA methylation of MTRR mediates the association between SNPs and treatment response.

RESULTS

MTHFD rs1950902 and MTRR rs162036, rs1801394 was associated with the folate treatment response (P = 0.000, 0.048, and 0.043, respectively). CBS and CBS_2 DNA methylation was significantly associated with folate treatment response (P = 0.0009 and < 0.001). DNA methylation of MTHFR, MTR, and MTRR was also significantly associated with folate treatment response (P < 0.001). DNA methylation of MTRR and MTRR_1 mediated 40.71% and 40.47% of the effect of rs1801394 on folate treatment response, respectively.

CONCLUSIONS

Our results indicated that the 1-CM gene SNPs and DNA methylation was associated with folate treatment response and can be further evaluated relationship between SNPs and DNA methylation in 1-CM with treatment response in a larger sample.

Association between BHMT and CBS gene promoter methylation with the efficacy of folic acid therapy in patients with hyperhomocysteinemia

Both betaine homocysteine methyltransferase (BHMT) and cystathionine β-synthase (CBS) are major enzymes in the metabolism of plasma homocysteine (Hcy). Abnormal methylation levels of BHMT and CBS are positively associated with Hcy levels. The present study is performed to explore the association between the methylation levels in the promoter regions of the BHMT and CBS genes and the efficacy of folic acid therapy in patient with hyperhomocysteinemia (HHcy). A prospective cohort study recruiting HHcy (Hcy ≥ 15 μmol/L) patients was performed. The subjects were treated with oral folic acid (5 mg/d) for 90 days, and the patients were divided into the success group (Hcy < 15 μmol/L) and the failure group (Hcy ≥ 15 μmol/L) according to their Hcy levels after treatment. In the logistic regression model with adjusted covariates, the patients with lower total methylation levels in the BHMT and CBS promoter regions exhibited 1.627-fold and 1.671-fold increased risk of treatment failure compared with higher methylation individuals, respectively. Similarly, subjects who had lower methylation levels (<methylation mean) in BHMT CpG1 had 1.792 times higher risks. Stratified analysis by sex found that lower CBS methylation levels were associated with a 2.128-fold increased risk for treatment failure in males with HHcy. Lower levels of BHMT or CBS promoter total methylation might be associated with increased the risk of treatment failure. These studies suggest that lower levels of BHMT and CBS methylation are all predictors of failure in folic acid therapy for HHcy. However, due to some limitations of this study, such as the small number of the loci tested, further large-scale studies are necessary to verify our observations.

Nutritional deficiencies in the pediatric age group in a multicultural developed country, Israel

Nutrient deficiencies are prevalent worldwide. Diseases and morbid conditions have been described to result from nutritional deficiencies. It is essential to address nutrient deficiencies as these may lead to chronic long-term health problems such as rickets, iron deficiency anemia, goiter, obesity, coronary heart disease, type 2 diabetes, stroke, cancer and osteoporosis. In the present review we surveyed the extent and severity of nutritional deficiencies in Israel through a selective and comprehensive Medline review of previous reports and studies performed during the last 40 years. Israeli populations have multiple nutritional deficiencies, including iron, calcium, zinc, folic acid, and vitamins B12, C, D and E, spanning all age groups, several minorities, and specific regions. In Israel, some of the nutrients are mandatorily implemented and many of them are implemented voluntarily by local industries. We suggest ways to prevent and treat the nutritional deficiencies, as a step to promote food fortification in Israel.

Does folate therapy reduce the risk of coronary restenosis?

BACKGROUND.: A high homocysteine level is associated with an increased risk of ischaemic heart disease. Folate therapy has shown to reduce the homocysteine blood level, but does it decrease the risk of coronary restenosis in patients with coronary arterial disease? METHODS.: A systematic online literature search followed by a critical appraisal resulted in three suitable articles to provide an evidence-based evaluation of this clinical query. RESULTS.: The rate of coronary restenosis was reduced after folate therapy, except in patients who have had coronary stenting. An adverse effect of folate therapy on in-stent coronary restenosis was observed. CONCLUSION.: The effects of folate therapy on the rate of coronary restenosis after balloon angioplasty are contradicting. Until more clinical research has been preformed we recommend a conservative attitude towards folate therapy. (Neth Heart J 2007;15:12-5.).

Homocysteine lowering interventions for preventing cardiovascular events

BACKGROUND

Cardiovascular disease such as coronary artery disease, stroke and congestive heart failure, is a leading cause of death worldwide. A postulated risk factor is elevated circulating total homocysteine (tHcy) levels which is influenced mainly by blood levels of cyanocobalamin (vitamin B12), folic acid (vitamin B9) and pyridoxine (vitamin B6). There is uncertainty regarding the strength of association between tHcy and the risk of cardiovascular disease.

OBJECTIVES

To assess the clinical effectiveness of homocysteine-lowering interventions (HLI) in people with or without pre-existing cardiovascular disease.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (issue 3 2008), MEDLINE (1950 to August 2008), EMBASE (1988 to August 2008), and LILACS (1982 to September 2, 2008). We also searched in Allied and Complementary Medicine (AMED; 1985 to August 2008), ISI Web of Science (1993 to August 2008), and the Cochrane Stroke Group Specialised Register (April 2007). We hand searched pertinent journals and the reference lists of included papers. We also contacted researchers in the field. There was no language restriction in the search.

SELECTION CRITERIA

We included randomised clinical trials (RCTs) assessing the effects of HLI for preventing cardiovascular events with a follow-up period of 1 year or longer. We considered myocardial infarction and stroke as the primary outcomes. We excluded studies in patients with end-stage renal disease.

DATA COLLECTION AND ANALYSIS

We independently performed study selection, risk of bias assessment and data extraction. We estimated relative risks (RR) for dichotomous outcomes. We measured statistical heterogeneity using I(2). We used a random-effects model to synthesise the findings.

MAIN RESULTS

We included eight RCTs involving 24,210 participants with a low risk of bias in general terms. HLI did not reduce the risk of non-fatal or fatal myocardial infarction, stroke, or death by any cause (pooled RR 1.03, 95% CI 0.94 to 1.13, I(2) = 0%; pooled RR 0.89, 95% CI 0.73 to 1.08, I(2) = 15%); and pooled RR 1.00 (95% CI 0.92 to 1.09, I(2): 0%), respectively.

AUTHORS' CONCLUSIONS

Results from available published trials suggest that there is no evidence to support the use of HLI to prevent cardiovascular events.

Do dietary patterns in older men influence change in homocysteine through folate fortification? The Normative Aging Study

Objective

We aimed to describe the difference in B-vitamin intake and in plasma B-vitamin and homocysteine concentrations before and after folic acid fortification, in relation to dietary patterns.

Design

The Normative Aging Study (NAS) is a longitudinal study on ageing. Between 1961 and 1970, 2280 male volunteers aged 21–80 years (mean 42 years) were recruited. Dietary intake data have been collected since 1987 and assessment of plasma B vitamins and homocysteine was added in 1993.

Setting

Boston, Massachusetts, USA.

Subjects

In the present study, 354 men who had completed at least one FFQ and one measurement of homocysteine, both before and after the fortification period, were included.

Results

Three dietary patterns were identified by cluster analysis: (i) a prudent pattern, with relatively high intakes of fruit, vegetables, low-fat milk and breakfast cereals; (ii) an unhealthy pattern, with high intakes of baked products, sweets and added fats; and (iii) a low fruit and vegetable but relatively high alcohol intake pattern. Dietary intake and plasma concentrations of folate increased significantly (P < 0·05) among all dietary patterns after the fortification period. Homocysteine tended to decrease in supplement non-users and in subjects in the high alcohol, low fruit and vegetable dietary pattern (both P = 0·08).

Conclusions

After fortification with folic acid, folate intake and plasma folate concentration increased significantly in all dietary patterns. There was a trend towards greatest homocysteine lowering in the high alcohol, low fruit and vegetable group.

Homocysteine and vitamin B(12) concentrations and mortality rates in type 2 diabetes

OBJECTIVE

To assess the role of homocysteine as a risk factor for mortality in diabetic subjects.

METHODS

Homocysteine, vitamin B(12), and folate concentrations were measured in stored sera of 396 diabetic Pima Indians aged > or = 40 years when examined between 1982 and 1985. Vital status was assessed through 2001.

RESULTS AND CONCLUSIONS

Over a median follow-up of 15.7 years, there were 221 deaths-76 were due to cardiovascular disease (CVD), 36 to diabetes/nephropathy and 34 to infections. Homocysteine was positively associated with mortality from all causes (hazard rate ratio (HRR) for highest versus lowest tertile of homocysteine = 1.70, 95% confidence interval (CI) 1.18-2.46), from diabetes/nephropathy (HRR = 2.39, 95% CI 0.94-6.11) and from infectious diseases (HRR = 3.39, 95% CI 1.19-9.70), but not from CVD (HRR = 1.16, 95% CI 0.62-2.17) after adjustment for age, sex and diabetes duration. Homocysteine correlated with serum creatinine (r = 0.50), and the relationships with mortality rates were not significant after adjustment for creatinine. Vitamin B(12) was positively associated with all-cause mortality (HRR for 100 pg/mL difference adjusted for age, sex and diabetes duration = 1.15, 95% CI 1.08-1.22) and death from diabetes/nephropathy (HRR = 1.27, 95% CI 1.10-1.46). The association between homocysteine and mortality in type 2 diabetes is not causal, but is confounded by renal disease in Pima Indians.

Folate, vitamin B12 and total homocysteine levels in neonates from Brazil

OBJECTIVE

To determine folates, vitamin B12 and total homocysteine levels among neonates from mothers of low or high socioeconomic status.

DESIGN

We carried out a cross-sectional transversal study comprising 143 neonates from two maternity hospitals in the city of Salvador, Northeast of Brazil. Cord blood samples were obtained at the time of delivery from newborns from low (group 1, n=77) or high (group 2, n=66) socioeconomic status. The vitamin B12 and folates were analyzed by electrochemiluminescence immunoassay and by a competitive test using a natural folate-binding protein (FBP), respectively. Total homocyteine levels were measured by fluorescence polarization immunoassay. Maternal environmental risk factors for pregnancy complications were obtained from all mothers.

RESULTS

Only 2% of women from group 1 received prenatal care/vitamin supplementation, whereas almost all mothers from group 2 (96%) were properly followed. Anemia and/or infections pre- or during pregnancy was more prevalent among mothers of babies from group 1. Folate levels among newborns from group 1 and 2 were 7.38+/-2.71 and 8.83+/-4.06 ng/ml, respectively. No difference in the vitamin B12 levels was determined between groups. In addition, tHcy serum levels were higher among newborns from group 1 compared to those from group 2 (8.54+/-4.06 vs 6.35+/-1.33 micromol/l, respectively; P=0.005).

CONCLUSION

These results demonstrate that unprivileged young woman has limited accesses to prenatal care, present high-risk factors that hamper both maternal and newborn health. Maternal and newborn health status could be improved by simply reinforcing the use of folate-enriched diet. The work presented illustrates the challenges that developing countries have to face in order to provide preventive adequate health care to the population at large.

Thiol exchange: An in vitro assay that predicts the efficacy of novel homocysteine lowering therapies

Elevated plasma total homocysteine (tHcy) is a risk factor for atherosclerosis. Hcy is 70-80% bound to albumin as a disulfide. Recent trials have evaluated ability of thiol-containing drugs to exchange with protein bound Hcy and consequently increase its renal clearance. The objective of this study was to develop an in vitro assay to predict the efficacy of thiol-containing drugs to lower tHcy in the clinical setting. The assay was used to test the effects of N-acetylcysteine (NAC), mesna, captopril, dimercaptosuccinic acid (DMSA), and penicillamine. Hcy was added in vitro to plasma of healthy subjects (n = 6) and equilibrated. Concentrations of thiol exchange agent were added and incubated at 37 degrees C. Aliquots were removed at selected intervals and free Hcy determined. Mesna, captopril, and NAC caused a concentration-dependent increase in free Hcy. Three-hundred micromolar mesna and captopril had a greater effect than equimolar NAC, increasing free Hcy by 33.9 +/- 5.0% and 32.0 +/- 2.6%, respectively compared to 22.3 +/- 2.4% for NAC, p < 0.001. Our in vitro results indicate that mesna, captopril, and NAC effectively exchange with covalently bound Hcy. This assay can act as screening tool for novel tHcy lowering therapies and should spare the expense of negative trials.

The Hordaland Homocysteine Study: a community-based study of homocysteine, its determinants, and associations with disease

The Hordaland Homocysteine Study (HHS) is a population-based study of more than 18,000 men and women in the county of Hordaland in Western Norway. The first investigation (HHS-I) took place in 1992-93, when the subjects were aged 40-67 y. In 1997-99, a follow-up study (HHS-II) of 7,053 subjects was carried out. In this large population, plasma levels of total homocysteine (tHcy) are associated with several physiologic and lifestyle factors and common diseases. Increasing age, male sex, smoking, coffee consumption, high blood pressure, unfavorable lipid profile, high creatinine, and the MTHFR 677C > T polymorphism are among the factors associated with increased tHcy levels; physical activity, moderate alcohol consumption, and a good folate or vitamin B-12 status are associated with lower tHcy levels. Subjects with raised tHcy levels have increased risk of cardiovascular morbidity, cardiovascular and noncardiovascular mortality, and are more likely to suffer from depression and from cognitive deficit (elderly). Among women, raised tHcy levels are associated with decreased bone mineral density and increased risk of osteoporosis. Women with raised tHcy levels also have an increased risk of having suffered from pregnancy complications and an adverse pregnancy outcome. Significant associations between tHcy and clinical outcomes are usually observed for tHcy levels > 15 micromol/L, but for most conditions, there is a continuous concentration-response relation with no apparent threshold concentration. Overall, the findings from HHS indicate that a raised tHcy level is associated with multiple clinical conditions, whereas a low tHcy level is associated with better physical and mental health.

Folic acid, inflammation, and atherosclerosis: False hopes or the need for better trials?

An increasing body of evidence supports the existence of a strong link between inflammation, endothelial dysfunction, and the onset and progression of atherosclerosis. However, a cause-effect relationship between these phenomena has not been demonstrated yet. Although some inflammatory markers, such as C-reactive protein, have been recently shown to improve risk stratification and to strongly predict cardiovascular outcome, it is largely unknown whether modifications of these markers might provide salutary effects and reduce cardiovascular morbidity and mortality. The B-vitamin folic acid has recently gained attention because of its potential to provide beneficial effects on surrogate end-points, such as endothelial function, in patients at high cardiovascular risk. However, the role of folic acid in mitigating the pro-inflammatory state associated with atherosclerosis is controversial. Despite the theoretical arguments supporting the potential anti-atherosclerotic and anti-inflammatory effects of folic acid, the current evidence is limited, deriving from small trials on different study populations, using folic acid often in combination with other vitamins and for different treatment periods. This review will consider the current evidence supporting the role of some well-established inflammatory markers in predicting cardiovascular outcomes, the mechanisms by which folic acid might exert anti-inflammatory effects, the epidemiological data relating folic acid concentrations with inflammatory markers, the published interventional studies on the effects of folic acid supplementation on these markers, and the factors that need to be considered in designing future trials.

New approaches for designing and evaluating food fortification programs

Historically, food fortification programs were often undertaken with little attention to issues such as micronutrient bioavailability, optimal levels of addition, or efficacy or to monitoring impact on nutritional status, health, and human function. Several developments in recent years have enabled substantial progress to be made in the design and evaluation of fortification programs. The methodology for estimating the prevalence of inadequate nutrient intakes in a population and tolerable upper intake levels has been established and can be used as the basis for estimating desirable amounts of nutrient addition. More attention is being paid to assessing the bioavailability of nutrients (especially minerals) using stable and radioactive isotopes, and bioavailability of iron compounds can be estimated from changes in total body iron calculated from the ratio of transferrin receptors to serum ferritin. Procedures for quality control of the fortification process have been established. New approaches to monitoring the impact of fortification over time include assessment of liver retinol stores using retinol isotope dilution. In summary, the design and evaluation of food fortification programs now requires a series of formative research procedures on the part of nutritionists, which were not often expected or conducted in the past.

Randomized controlled trial of homocysteine-lowering vitamin treatment in elderly patients with vascular disease

BACKGROUND

Homocysteine is an independent risk factor for vascular disease and is associated with dementia in older people. Potential mechanisms include altered endothelial and hemostatic function.

OBJECTIVE

We aimed to determine the effects of folic acid plus vitamin B-12, riboflavin, and vitamin B-6 on homocysteine and cognitive function.

DESIGN

This was a factorial 2 x 2 x 2, randomized, placebo-controlled, double-blind study with 3 active treatments: folic acid (2.5 mg) plus vitamin B-12 (500 microg), vitamin B-6 (25 mg), and riboflavin (25 mg). We studied 185 patients aged >or=65 y with ischemic vascular disease. Outcome measures included plasma homocysteine, fibrinogen, and von Willebrand factor at 3 mo and cognitive change (determined with the use of the Letter Digit Coding Test and on the basis of the Telephone Interview of Cognitive Status) after 1 y.

RESULTS

The mean (+/-SD) baseline plasma homocysteine concentration was 16.5 +/- 6.4 micromol/L. This value was 5.0 (95% CI: 3.8, 6.2) micromol/L lower in patients given folic acid plus vitamin B-12 than in patients not given folic acid plus vitamin B-12 but did not change significantly with vitamin B-6 or riboflavin treatment. Homocysteine lowering with folic acid plus vitamin B-12 had no significant effect, relative to the 2 other treatments, on fibrinogen, von Willebrand factor, or cognitive performance as measured by the Letter Digit Coding Test (mean change: -1; 95% CI: -2.3, 1.4) and the Telephone Interview of Cognitive Status (-0.7; 95% CI: -1.7, 0.4).

CONCLUSION

Oral folic acid plus vitamin B-12 decreased homocysteine concentrations in elderly patients with vascular disease but was not associated with statistically significant beneficial effects on cognitive function over the short or medium term.

Vitamin B12, homocysteine and carotid plaque in the era of folic acid fortification of enriched cereal grain products

BACKGROUND

Carotid plaque area is a strong predictor of cardiovascular events. High homocysteine levels, which are associated with plaque formation, can result from inadequate intake of folate and vitamin B12. Now that folic acid fortification is widespread in North America, vitamin B12 has become an important determinant of homocysteine levels. We sought to determine the prevalence of low serum levels of vitamin B12, and their relation to homocysteine levels and carotid plaque area among patients referred for treatment of vascular disease since folic acid fortification of enriched grain products.

METHODS

We evaluated 421 consecutive new patients with complete data whom we saw in our vascular disease prevention clinics between January 1998 and January 2002. We measured total carotid plaque area by ultrasound and determined homocysteine and serum vitamin B12 levels in all patients.

RESULTS

The patients, 215 men and 206 women, ranged in age from 37 to 90 years (mean 66 years). Most were taking medications for hypertension (67%) and dyslipidemia (62%). Seventy-three patients (17%) had vitamin B12 deficiency (vitamin B12 level < 258 pmol/L with homocysteine level > 14 mumol/L or methylmalonic acid level > 271 nmol/L). The mean area of carotid plaque was significantly larger among the group of patients whose vitamin B12 level was below the median of 253 pmol/L than among those whose vitamin B12 level was above the median: 1.36 (standard deviation [SD] 1.27) cm2 v. 1.09 (SD 1.0) cm2; p = 0.016.

CONCLUSIONS

Vitamin B12 deficiency is surprisingly common among patients with vascular disease, and, in the setting of folic acid fortification, low serum vitamin B12 levels are a major determinant of elevated homocysteine levels and increased carotid plaque area.

Homocysteine and B vitamins

Homocysteine (tHcy) is an intermediate sulfur-containing amino acid which acts as a methyl group donor for methionine metabolism. Increased serum concentrations (=hyperhomocysteinemia, >10 micromol/l) have been associated with an increased cardiovascular risk. Homocystinuria, an infrequent genetic disease usually due to lack of cystathione beta-synthase, has been found with severely elevated serum homocysteine values (>150 micromol/l). Functional gene polymorphisms of key enzymes (e.g., N5,N10-methylene-tetrahydrofolate reductase) and dietary B-vitamin deficiencies in the elderly are, however, frequent in the 'Western' population. Hyperhomocysteinemia has been associated with other vascular effects such as atherothrombosis and endothelial dysfunction due to its auto-oxidative potential, thereby increasing the production of reactive oxygen species. Other effects may involve neurodegenerative diseases such as Alzheimer or dementia praecox of the elderly. Therapeutic interventions lowering tHcy may therefore offer novel tools for the prevention and treatment of atherosclerosis. B-vitamin supplementation (folic acid=vitamin B9, vitamin B6 and vitamin B12) is an efficient and safe tHcy-lowering therapy, decreases tHcy by 30%-50% and has been shown to lower cardiovascular morbidity and mortality. Furthermore, folic acid supplementation has been shown to reduce or even almost eliminate neurotubular birth defects (spina bifida) and to markedly decrease the rate of megaloblastic anemia. Thus, fortification of flour with folic acid in the USA was advocated several years ago in order to prevent these entities.

Homocysteine, B-vitamin supplementation, and stroke prevention: from observational to interventional trials

BACKGROUND

Homocysteine is an amino acid, the metabolism of which is linked to that of several vitamins-especially folic acid, B6, and B12. A high concentration of homocysteine in the plasma is linked to vascular disease, including stroke. Concentrations of homocysteine can be inexpensively and safely lowered by treatment with a combination of folate, vitamin B12, and vitamin B6. However, whether the association between high plasma concentrations of homocysteine and vascular disease is causal is unclear.

RECENT DEVELOPMENTS

Two studies have assessed the relation between dietary or supplementary B vitamin intake on the risk of stroke. In a prospective observational study of 43?732 healthy men, there was an inverse relation between dietary folate intake and the risk of ischaemic stroke. The Vitamin Intervention for Stroke Prevention study (VISP) was the first large-scale randomised interventional study that investigated the lowering of homocysteine concentrations with B vitamins in patients with ischaemic stroke. There was an association between baseline homocysteine concentrations and vascular risk in this trial. Plasma concentrations of homocysteine were only modestly reduced by high-dose versus low-dose formulation, and there was no treatment effect on recurrent stroke, coronary events, or deaths. Limitations of VISP included that only patients with mild increases in baseline homocysteine concentrations were studied, only modest reductions of homocysteine concentrations were achieved, and follow up was short. In addition, fortification of food with folate and treatment of low vitamin-B12 concentrations may have masked the effect of treatment on stroke risk. WHAT NEXT?: When exposure can be safely assigned at random, as in the case of B-vitamin therapy, randomised trials should be the standard proof to determine the effect of therapy. The results of the first randomised clinical trial of B vitamins for secondary prevention of stroke were neutral. Larger trials with longer follow-up, selection of patients with higher plasma concentrations of homocysteine, and systematic assessment of cognitive functions and dementia are needed. In the meantime, homocysteine-lowering treatment that is cheap and well-tolerated should be considered a rational approach in patients at high risk of stroke and high concentrations of homocysteine.