Folic acid fortification increases red blood cell folate concentrations in the Framingham study

Acute high folic acid treatment in SH-SY5Y cells with and without MTHFR function leads to gene expression changes in epigenetic modifying enzymes, changes in epigenetic marks, and changes in dendritic spine densities

Epigenetics are known to be involved in various disorders, including neurobiological disorders like autism. Dietary factors such as folic acid can affect epigenetic marks using methylenetetrahydrofolate reductase (MTHFR) to metabolize folic acid to a one-carbon methyl group. As MTHFR mutations are frequent, it is curious as to whether excess folic acid, with or without functioning MTHFR, could affect gene expression, epigenetics, and neuromorphology. Here, we investigated gene expression and activity of epigenetic modifying enzymes, genome-wide DNA methylation, histone 3 modifications, and dendritic spine densities in SH-SY5Y cells with or without a knockdown of MTHFR and with or without an excess of folic acid. We found alterations to gene expression of epigenetic modifying enzymes, including those associated with disorders like autism. Grouping the epigenetic modifying enzymes by function indicated that gene expression was widely affected for genes that code for enzymes affecting DNA methylation, histone acetylation, histone methylation, histone phosphorylation, and histone ubiquitination when excess folic acid treatment occurred with or without the knockdown of MTHFR. MTHFR was significantly reduced upon excess folic acid treatment whether MTHFR was knocked-down or not. Further, methyl-CpG binding protein 2 expression was significantly decreased with excess folic acid treatment with and without proper MTHFR expression. Global DNA methylation decreased due to the knockdown alone while global hydroxymethylated DNA increased due to the knockdown alone. TET2 expression significantly increased with the MTHFR knockdown alone. Excess folic acid alone induced a decrease in TET3 expression. Excess folic acid induced an increase in dendritic spines without the MTHFR knockdown, but folic acid induced a decrease in dendritic spines when MTHFR was knocked-down. The knockdown alone also increased the dendritic spines significantly. Histone 3 acetylation at lysine 18 was significantly increased when excess folic acid was applied to cells with the MTHFR knockdown, as was histone 3 phosphorylation at serine 10. Broadly, our results indicate that excess folic acid, even with functioning MTHFR, could have detrimental effects on cells.

A 2x folic acid treatment affects epigenetics and dendritic spine densities in SHSY5Y cells

Many diseases are now associated with aberrant epigenetics and gene expression changes. Epigenetics can be modified by factors like diet. One dietary factor, folic acid, is consumed in various forms including supplements, energy drinks, and fortified grains. It was hypothesized high levels of folic acid would affect gene expression and enzyme activity of chromatin modifying enzymes as well as dendritic spine densities in a commonly utilized neuron model, the SHSY5Y cell. Decreased MBD2 and MECP2 were discovered upon treatment of SHSY5Y cells with a 2x folic acid dose. Corresponding decreases in dendritic spines were apparent in the 2x folic acid treated cells as well. Activity of DNMTs and H3K4 HMTs was altered. Further, H3K4me1, H3K4me3, H3K9Ac, and global DNA methylation were decreased in the 2x folic acid treated cells. Further studies are warranted to determine if the effects of excess folic acid are detrimental to organismal physiology.

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The 2x folic acid treatment in SHSY5Y cells induces a significant decrease in MBD2 and MECP2 mRNA expression.

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The excess folic acid also causes a significant increase in dendritic spines in SHSY5Y cells.

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The 2x folic acid treatment increases DNMT activity and significantly decreases H3K4 HMT activity in SHSY5Y cells.

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These findings align with some of those seen in autism spectrum disorders.

Large -scale wheat flour folic acid fortification program increases plasma folate levels among women of reproductive age in urban Tanzania

There is widespread vitamin and mineral deficiency problem in Tanzania with known deficiencies of at least vitamin A, iron, folate and zinc, resulting in lasting negative consequences especially on maternal health, cognitive development and thus the nation's economic potential. Folate deficiency is associated with significant adverse health effects among women of reproductive age, including a higher risk of neural tube defects. Several countries, including Tanzania, have implemented mandatory fortification of wheat and maize flour but evidence on the effectiveness of these programs in developing countries remains limited. We evaluated the effectiveness of Tanzania's food fortification program by examining folate levels for women of reproductive age, 18-49 years. A prospective cohort study with 600 non-pregnant women enrolled concurrent with the initiation of food fortification and followed up for 1 year thereafter. Blood samples, dietary intake and fortified foods consumption data were collected at baseline, and at 6 and 12 months. Plasma folate levels were determined using a competitive assay with folate binding protein. Using univariate and multivariate linear regression, we compared the change in plasma folate levels at six and twelve months of the program from baseline. We also assessed the relative risk of folate deficiency during follow-up using log-binomial regression. The mean (±SE) pre-fortification plasma folate level for the women was 5.44-ng/ml (±2.30) at baseline. These levels improved significantly at six months [difference: 4.57ng/ml (±2.89)] and 12 months [difference: 4.27ng/ml (±4.18)]. Based on plasma folate cut-off level of 4 ng/ml, the prevalence of folate deficiency was 26.9% at baseline, and 5% at twelve months. One ng/ml increase in plasma folate from baseline was associated with a 25% decreased risk of folate deficiency at 12 months [(RR = 0.75; 95% CI = 0.67-0.85, P<0.001]. In a setting where folate deficiency is high, food fortification program with folic acid resulted in significant improvements in folate status among women of reproductive age.

Validation of Folate-Enriched Eggs as a Functional Food for Improving Folate Intake in Consumers

Functional foods enriched with folate may be beneficial as a means of optimizing folate status in consumers. We recently developed novel eggs enriched with folate through folic acid supplementation of the hen’s feed, but their potential to influence consumer folate status is unknown because the natural folate forms incorporated into the eggs may not necessarily be retained during storage and cooking. This study aimed to determine the stability of natural folates in folate-enriched eggs under typical conditions of storage and cooking. Total folate was determined by microbiological assay following tri-enzyme treatment in folate-enriched eggs and un-enriched (barn and free-range) on the day they were laid, after storage (up to 27 days) and after using four typical cooking methods (boiling, poaching, frying, scrambling) for different durations. On the day of laying, the folate content of enriched eggs was found to be significantly higher than that of un-enriched barn or free-range eggs (mean ± SD; 123.2 ± 12.4 vs. 41.2 ± 2.8 vs. 65.6 ± 18.5 µg/100 g; p < 0.001). Storage at refrigerator and room temperature for periods up to the Best Before date resulted in no significant losses to the folate content of folate-enriched eggs. Furthermore, folate in enriched eggs remained stable when cooked by four typical methods for periods up to the maximum cooking time (e.g., 135 ± 22.5, 133.9 ± 23.0 and 132.5 ± 35.1; p = 0.73, for raw, scrambled for 50 s and scrambled for 2 min, respectively). Thus, natural folates in folate-enriched eggs remain highly stable with little or no losses following storage and cooking. These findings are important because they demonstrate the feasibility of introducing folate-enriched eggs into the diet of consumers as functional foods with enriched folate content. Further studies will confirm their effectiveness in optimizing the biomarker folate status of consumers.

Hyperhomocysteinemia and MTHFR C677T polymorphism in patients with portal vein thrombosis complicating liver cirrhosis

BACKGROUND

Portal vein thrombosis (PVT) is serious complication of liver cirrhosis (LC), especially in the presence of hepatocellular carcinoma (HCC). The liver plays a key role in homocysteine (Hcy) metabolism: mild hyperhomocysteinemia (HHcy) has been described in LC. HHcy is a risk factor for deep vein thrombosis. Methylen-tetrahydrofolate-reductase (MTHFR) C677T polymorphism is the commonest determinant of mild HHcy and has been involved also in cancer development.

AIM

To investigate a possible relation between HHcy, MTHFR status, HCC and PVT in patients affected by LC.

MATERIALS AND METHODS

100 patients affected by LC, 38 with (PVT group, 24 with HCC) and 62 without PVT (LC group, 14 with HCC) sex-, age-, liver disease stage and etiology-matched were assessed for thrombophilia, smoking status, plasma Hcy, MTHFRC677T polymorphism and homocysteine-related vitamin status.

RESULTS

A higher prevalence of HCC, HHcy and MTHFR TT status was observed in PVT group. No significant difference in vitamin status was observed between groups. Patients with HCC showed significantly higher plasma Hcy and higher prevalence of HHcy than patients without HCC. They had also higher prevalence of MTHFR TT status. In patients with TT status (n=11) and HCC, 10 had HHcy e 9 had PVT.

CONCLUSIONS

Mild HHcy is associated to LC may have a role in PVT development and assessment of plasma Hcy may be suggested in patients with LC (especially if complicated by HCC). Association between HCC and MTHFR TT status is intriguing, due the postulated role for this polymorphism in cancer: it may represent a possible link between HCC and PVT.

Voluntary fortification of breakfast cereals with folic acid: contribution to dietary intake in Australia

Ready-to-eat breakfast cereals have been voluntarily fortified with folic acid since 1995, with the purpose of reducing the prevalence of neural tube defects in utero. Using data from the recent Australian Health Survey, this study aimed to estimate folate intake from one serving of breakfast cereals (median amount). Various commercial brands were purchased in 2002 (n = 19) and in 2014 (n = 14); folate was determined by microbiological assay and high-pressure liquid chromatography (HPLC). Total folate (μg/100 g) in 2002 and 2014 selections were 144-633 and 147-564, respectively, and mostly comparable to nutrition labels. Folic acid (2014 selection) using HPLC, ranged from 85 to 411 μg/100 g. Intake of 51 g cereals/serving by individuals ≥ 2 years could contribute 75-288 μg dietary folate equivalent. It seems that folic acid intake among children (2-3 years) exceeds the recommended dietary intake, when certain brands of breakfast cereals are consumed. Accordingly, the benefits and potential detrimental effects of the voluntary fortification need to be further explored.

Proteomic analysis identifies cytoskeleton-interacting proteins as major downstream targets of altered folate status in the aorta of adult rat

SCOPE

Mild folate deficiency and subsequently elevated plasma level of homocysteine are associated with an increased risk for vascular diseases in adults. Conversely, high intakes of folic acid (FA) may have beneficial effects on vascular function, presumably in part through homocysteine lowering. However, these effects have not yet been translated in terms of prevention or treatment of vascular pathologies. Besides, the complex biologic perturbation induced by variations of the folate supply is still not fully deciphered. We thus carried out a proteomic analysis of the aorta of adult rats after a dietary FA depletion or supplementation.

METHODS AND RESULTS

Nine month-old rats were fed a FA-depleted, FA-supplemented or control diet for 8 weeks. Total proteins from adventitia-free aortas were separated by 2DE and differentially expressed proteins were identified by MS. FA depletion or supplementation resulted in significantly changed abundance of 29 spots (p < 0.05), of which 20 proteins were identified. Bioinformatic analysis revealed that most of these proteins are involved in cytoskeleton-related processes important to cell function/maintenance, assembly/organization, and movement.

CONCLUSION

Our proteomic study supports that expression of proteins essential to vascular structure and, presumably, function is modulated by high intake as well as deprivation of FA.

Interactions between plasma concentrations of folate and markers of vitamin B(12) status with cognitive performance in elderly people not exposed to folic acid fortification: the Hordaland Health Study

A combination of high folate with low vitamin B12 plasma status has been associated with cognitive impairment in a population exposed to mandatory folic acid fortification. The objective of the present study was to examine the interactions between plasma concentrations of folate and vitamin B12 markers in relation to cognitive performance in Norwegian elderly who were unexposed to mandatory or voluntary folic acid fortification. Cognitive performance was assessed by six cognitive tests in 2203 individuals aged 72-74 years. A combined score was calculated using principal component analysis. The associations of folate concentrations, vitamin B12 markers (total vitamin B12, holotranscobalamin (holoTC) and methylmalonic acid (MMA)) and their interactions in relation to cognitive performance were evaluated by quantile regression and least-squares regression, adjusted for sex, education, apo-ɛ4 genotype, history of CVD/hypertension and creatinine. Cross-sectional analyses revealed an interaction (P= 0·009) between plasma concentrations of folate and vitamin B12 in relation to cognitive performance. Plasma vitamin B12 concentrations in the lowest quartile ( < 274 pmol/l) combined with plasma folate concentrations in the highest quartile (>18·5 nmol/l) were associated with a reduced risk of cognitive impairment compared with plasma concentrations in the middle quartiles of both vitamins (OR 0·22, 95 % CI 0·05, 0·92). The interaction between folate and holoTC or MMA in relation to cognitive performance was not significant. In conclusion, this large study population unexposed to mandatory folic acid fortification showed that plasma folate, but not plasma vitamin B12, was associated with cognitive performance. Among the elderly participants with vitamin B12 concentrations in the lower range, the association between plasma folate and cognitive performance was strongest.

Water-soluble vitamins in people with low glomerular filtration rate or on dialysis: a review

People with low glomerular filtration rate and people on dialysis are spontaneously at risk for vitamin deficiency because of the potential for problems with decreased appetite and decreased sense of smell and taste, leading to decreased intake, and because decreased energy or decreased cognitive ability results in difficulties in shopping and cooking. Imposed dietary restrictions because of their renal dysfunction and because of comorbidities such as hypertension and diabetes exacerbate this problem. Finally, particularly for water-soluble vitamins, loss may occur into the dialysate. We did not identify any randomized trials of administering daily doses close to the recommended daily allowances of these vitamins. In people who are eating at all, deficiencies of B5 and B7 seem unlikely. It is unclear whether supplements of B2 and B3 are necessary. Because of dialyzability and documented evidence of insufficiency in dialysis patients, B1 supplementation is likely to be helpful. B6, B9, and B12 are implicated in the hyperhomocysteinemia observed in patients on dialysis. These vitamins have been studied in combinations, in high doses, with the hope of reducing cardiovascular outcomes. No reductions in patient-important outcomes were seen in adequately powered randomized trials. Because of their involvement in the homocysteine pathway, however, supplementation with lower doses, close to the recommended daily allowances, may be helpful. Vitamin C deficiency is common in patients on dialysis who are not taking supplements: low-dose supplements are warranted. Vitamins for dialysis patients contain most or all of the B vitamins and low-dose vitamin C. We are not aware of any medical reasons to choose one over another.

Folate deficiency is associated with oxidative stress, increased blood pressure, and insulin resistance in spontaneously hypertensive rats

BACKGROUND

The role of folate deficiency and associated hyperhomocysteinemia in the pathogenesis of metabolic syndrome is not fully established. In the current study, we analyzed the role of folate deficiency in pathogenesis of the metabolic syndrome in the spontaneously hypertensive rat (SHR).

METHODS

Metabolic and hemodynamic traits were assessed in SHR/Ola rats fed either folate-deficient or control diet for 4 weeks starting at the age of 3 months.

RESULTS

Compared to SHRs fed a folate-replete diet, SHRs fed a folate-deficient diet showed significantly reduced serum folate (104 ± 5 vs. 11 ± 1 nmol/L, P < 0.0005) and urinary folate excretion (4.3 ± 0.6 vs. 1.2 ± 0.1 nmol/16 h, P < 0.0005) together with a near 3-fold increase in plasma total homocysteine concentration (4.5 ± 0.1 vs 13.1 ± 0.7 μmol/L, P < 0.0005), ectopic fat accumulation in liver, and impaired glucose tolerance. Folate deficiency also increased systolic blood pressure by approximately 15 mm Hg (P < 0.01). In addition, the low-folate diet was accompanied by significantly reduced activity of antioxidant enzymes and increased concentrations of lipoperoxidation products in liver, renal cortex, and heart.

CONCLUSIONS

These findings demonstrate that the SHR model is susceptible to the adverse metabolic and hemodynamic effects of low dietary intake of folate. The results are consistent with the hypothesis that folate deficiency can promote oxidative stress and multiple features of the metabolic syndrome that are associated with increased risk for diabetes and cardiovascular disease.

Estimation of trends in serum and RBC folate in the U.S. population from pre- to postfortification using assay-adjusted data from the NHANES 1988-2010

The NHANES has monitored folate status of the U.S. population from prefortification (1988-1994) to postfortification (1999-2010) by measuring serum and RBC folate concentrations. The Bio-Rad radioassay (BR) was used from 1988 to 2006, and the microbiologic assay (MBA) was used from 2007 to 2010. The MBA produces higher concentrations than the BR and is considered to be more accurate. Thus, to bridge assay differences and to examine folate trends over time, we adjusted the BR results to be comparable to the MBA results. Postfortification, assay-adjusted serum and RBC folate concentrations were 2.5 times and 1.5 times prefortification concentrations, respectively, and showed a significant linear trend (P < 0.001) to slightly lower concentrations during 1999-2010. The postfortification prevalence of low serum (<10 nmol/L) or RBC (<340 nmol/L) folate concentrations was ≤ 1%, regardless of demographic subgroup, compared with 24% for serum folate and 3.5% for RBC folate prefortification, with substantial variation among demographic subgroups. The central 95% reference intervals for serum and RBC folate varied by demographic subgroup during both pre- and postfortification periods. Age and dietary supplement use had the greatest effects on prevalence estimates of low folate concentrations during the prefortification period. In summary, the MBA-equivalent blood folate concentrations in the U.S. population showed first a sharp increase from pre- to postfortification, then showed a slight decrease (17% for serum and 12% for RBC folate) during the 12-y postfortification period. The MBA-equivalent pre- and postfortification reference concentrations will inform countries that plan folic acid fortification or that need to evaluate its impact.

Population prevalence, attributable risk, and attributable risk percentage for high methylmalonic acid concentrations in the post-folic acid fortification period in the US

BACKGROUND

Serum methylmalonic acid (MMA) is regarded as a sensitive marker of vitamin B-12 status. Elevated circulating MMA is linked to neurological abnormalities. Contribution of age, supplement use, kidney dysfunction, and vitamin B-12 deficiency to high serum MMA in post-folic acid fortification period is unknown.

METHODS

We investigated prevalence, population attributable risk (PAR), and PAR% for high MMA concentrations in the US. Data from 3 cross-sectional National Health and Nutrition Examination Surveys conducted in post-folic acid fortification period were used (n = 18569).

RESULTS

Likelihood of having high serum MMA for white relative to black was 2.5 (P < 0.0001), ≥ 60 y old persons relative to < 60 y old persons was 4.0 (P < 0.0001), non-supplement users relative to supplement users was 1.8 (P < 0.0001), persons with serum creatinine ≥ 130 μmol/L relative to those with < 130 μmol/L was 12.6 (P < 0.0001), and persons with serum vitamin B-12 < 148 pmol/L relative to those with ≥ 148 pmol/L was 13.5 (P < 0.0001). PAR% for high MMA for old age, vitamin B-12 deficiency, kidney dysfunction, and non-supplement use were 40.5, 16.2, 13.3, and 11.8, respectively. By improving serum vitamin B-12 (≥ 148 pmol/L), prevalence of high MMA would be reduced by 16-18% regardless of kidney dysfunction.

CONCLUSIONS

Old age is the strongest determinant of PAR for high MMA. About 5 cases of high serum MMA/1000 people would be reduced if vitamin B-12 deficiency (< 148 pmol/L) is eliminated. Large portion of high MMA cases are not attributable to serum vitamin B-12. Thus, caution should be used in attributing high serum MMA to vitamin B-12 deficiency.

Determination of unmetabolized folic acid in human plasma using affinity HPLC

BACKGROUND

Folic acid (FA) fortification of food created the need to determine whether fortification elevated concentrations of unmetabolized FA in plasma and whether this form of the vitamin in blood is associated with adverse health outcomes.

OBJECTIVE

The objective of this research was to devise a simple, rapid method for the measurement of unmetabolized plasma FA in epidemiologic studies.

DESIGN

We previously used the affinity/HPLC with electrochemical detection method to measure folate distribution in human plasma and red blood cells (RBCs). We modified this method with the inclusion of synthetic ethyltetrahydrofolate as an internal standard and with the use of 2 affinity columns connected in parallel to the analytic column through a switching valve to allow one column to be loaded while the other column was eluted into the analytic column.

RESULTS

We identified FA and 5-methyltetrahydrofolate (5-mTHF) by retention time and characteristic response across the channels of the electrochemical detector. Limits of detection were 0.034 pmol for 5-mTHF and 0.027 pmol for FA per injection, and the recovery was 92.2% (5-mTHF) and 98.9% (FA). CVs for samples were 8.1% (within day) and 6.8% (between day) for 5-mTHF and 3.2% (within day) and 5.9% (between day) for FA. Total folate with the use of this method correlated highly (r(2) = 0.98, P < 0.001) with values from the microbial assay. The run time for the method was 30 min per sample. Researchers can use this method with longer run times to measure the distribution of folate forms in RBCs.

CONCLUSION

This updated method allows efficient analysis of folate forms in human plasma and tissues without the loss of sensitivity or precision.

Folic acid fortification: why not vitamin B12 also?

Folic acid fortification of cereal grains was introduced in many countries to prevent neural tube defect occurrence. The metabolism of folic acid and vitamin B12 intersect during the transfer of the methyl group from 5-methyltetrahydrofolate to homocysteine catalyzed by B12-dependent methioine synthase. Regeneration of tetrahydrofolate via this reaction makes it available for synthesis of nucleotide precursors. Thus either folate or vitamin B12 deficiency can result in impaired cell division and anemia. Exposure to extra folic acid through fortification may be detrimental to those with vitamin B12 deficiency. Among participants of National Health And Nutrition Examination Survey with low vitamin B12 status, high serum folate (>59 nmol/L) was associated with higher prevalence of anemia and cognitive impairment when compared with normal serum folate. We also observed an increase in the plasma concentrations of total homocysteine and methylmalonic acid (MMA), two functional indicators of vitamin B12 status, with increase in plasma folate under low vitamin B12 status. These data strongly imply that high plasma folate is associated with the exacerbation of both the biochemical and clinical status of vitamin B12 deficiency. Hence any food fortification policy that includes folic acid should also include vitamin B12.

Blood folate status and expression of proteins involved in immune function, inflammation, and coagulation: biochemical and proteomic changes in the plasma of humans in response to long-term synthetic folic acid supplementation

We used plasma proteomics to identify human proteins responsive to folate status. Plasma was collected from subjects treated with placebo or 1.2 mg of folic acid daily for 12 weeks in a randomized controlled trial. Homocysteine and folate were measured by immunoassay and uracil misincorporation by electrophoresis. The plasma proteome was assessed by 2-D gel electrophoresis, and proteins were identified by LC MS/MS. 5-methylTHF increased 5-fold (P = 0.000003) in response to intervention. Red cell folate doubled (P = 0.013), and lymphocyte folate increased 44% (P = 0.0001). Hcy and uracil dropped 22% (P = 0.0005) and 25% (P = 0.05), respectively. ApoE A-1, alpha-1-antichymotrypsin, antithrombin, and serum amyloid P were downregulated, while albumin, IgM C, and complement C3 were upregulated (P < 0.05). More than 60 proteins were significantly associated with folate pre- and postintervention (P < 0.01). These were categorized into metabolic pathways related to complement fixation (e.g., C1, C3, C4, Factor H, Factor 1, Factor B, clusterin), coagulation (e.g., antithrombin, alpha-1-antitrypsin, kininogen) and mineral transport (e.g., transthyretin, haptoglobin, ceruloplasmin). Low folate status pre- and post-treatment were associated with lower levels of proteins involved in activation and regulation of immune function and coagulation. Supplementation with synthetic folic acid increased expression of these proteins but did not substantially disrupt the balance of these pathways.

Circulating unmetabolized folic acid and 5-methyltetrahydrofolate in relation to anemia, macrocytosis, and cognitive test performance in American seniors

BACKGROUND

Folate deficiency has serious consequences for the fetus. Folic acid fortification of food addresses this problem. However, clinical consequences of vitamin B-12 deficiency may be worsened by high folic acid intakes, perhaps as a direct result of unmetabolized folic acid, which does not occur naturally in body tissues.

OBJECTIVE

We attempted to attribute associations that we previously found between higher folate status and anemia and cognitive test performance to circulating unmetabolized folic acid or 5-methyltetrahydrofolate (5MeTHF).

DESIGN

The subjects (n = 1858) were senior participants in the US National Health and Nutrition Examination Survey (1999-2002) who had normal renal function and reported no history of stroke, recent anemia therapy, or diseases of the liver, thyroid, or coronary arteries. Subjects had undergone a phlebotomy, a complete blood count, and cognitive and dietary assessments.

RESULTS

Circulating unmetabolized folic acid was detected in approximately 33% of the subjects and was related to an increased odds of anemia in alcohol users. In seniors with a serum vitamin B-12 concentration <148 pmol/L or a plasma methylmalonic acid concentration > or =210 nmol/L, the presence compared with the absence of detectable circulating unmetabolized folic acid was related to lower cognitive test scores and lower mean cell volume. In the same subgroup, higher serum 5MeTHF was related to an increased odds of anemia and a marginally significantly decreased odds of macrocytosis. In seniors with a normal vitamin B-12 status, a higher serum 5MeTHF concentration was related to higher cognitive test scores.

CONCLUSION

Results of this epidemiologic study were somewhat consistent with reports on the folic acid treatment of patients with pernicious anemia, but some findings were unexpected.

Serum folate is a reliable indicator of hyperhomocysteinemia and borderline hyperhomocysteinemia in young adults

Serum folate has been shown to correlate well with fasting plasma homocysteine; however, erythrocyte folate concentration is a better index of tissue folate stores and probably could be a more reliable indicator for reflecting long-term supply of the vitamin and homocysteine status. The present study was undertaken to test the hypothesis that serum folate and erythrocyte folate levels had a different degree of correlation to fasting plasma homocysteine in young Taiwanese adults. This study had a cross-sectional design. Healthy young adults were divided into either a hyperhomocysteinemia (HHcy; > or =14.9 micromol/L; n = 13), borderline HHcy (BHcy; fasting homocysteine, 14.9-10.2 micromol/L; n = 52), or normohomocysteinemia (fasting homocysteine, <10.2 micromol/L; n = 65) groups based on fasting homocysteine levels. The concentrations of plasma fasting homocysteine, serum folate, erythrocyte folate, vitamin B(12), and plasma pyridoxal 5'-phosphate were measured. Fasting homocysteine was only significantly and inversely affected by serum folate (beta = -0.21, P < .05) concentration after adjusting for potential confounders. Only serum folate concentration remained to decrease the risk of fasting HHcy (odds ratio, 0.73; confidence interval, 0.56-0.95) after the other B vitamins were additionally adjusted. Serum folate also had the highest area under the receiver operating characteristic (AUC) curve to predict the risk of HHcy (AUC, 0.81) and BHcy (AUC, 0.77). Serum folate is a reliable indicator of fasting hyperhyperhomocysteinemia and BHcy in young adults.

The sex-specific role of plasma folate in mediating the association of dietary quality with depressive symptoms

Folate deficiency has been implicated in the etiology of unipolar depression. In this study, we attempted to cross-link plasma folate, depressive symptoms, and dietary quality (or dietary intake of folate) together in a comprehensive framework, while examining effect modification of those associations by sex. This was a cross-sectional, population-based study of 1681 participants aged 30-64 y (Healthy Aging in Neighborhoods of Diversity across the Lifespan Study). Participants were administered the Center for Epidemiologic Studies Depression scale (CES-D). Measures of plasma folate and dietary intakes (2 24-h recalls) from which the 2005-Healthy Eating Index (HEI) was computed were available. Multivariate logistic regression and structural equation modeling (SM) were conducted. Compared with the lowest tertile, the middle and uppermost tertiles of plasma folate were associated with a 39-40% reduced odds of elevated CES-D (> or =16) among women [adjusted odds ratio (T(3) vs. T(1)) = 0.60 (95% CI = 0.42-0.86); P = 0.006]. Confounding of this association by HEI(total) was noted among both men and women, although dietary folate did not confound this association appreciably. In SM, plasma folate completely mediated the inverse HEI(total)-CES-D association among men only, specifically for HEI(2) (higher intakes of whole fruits), HEI(3) (total vegetables), HEI(5) (total grains), HEI(6) (whole grains), HEI(7) (milk), and HEI(12) (lower discretionary energy). Among women, HEI(total) and 4 components had an inverse direct effect on CES-D score, suggesting a mechanism that is independent of plasma folate. Depressive symptoms in our study may be alleviated by improving overall dietary quality, with plasma folate playing a potential mediating role only among men.

Ordering folate assays is no longer justified for investigation of anemias, in folic acid fortified countries

Background

Since 1998, in the countries where there is mandatory fortification of grain products with folic acid, folate deficiency has become very rare. Consequently, we decided to find out whether there is any justification for ordering folate assays for investigation of anemias.

Methods

We reviewed serum folate (SF) and red cell folate (RF) data at two teaching hospitals in Canada. At the Health Sciences Centre (HSC) the folate data for the year 2001 were analyzed and the medical records of those with low SF or low RF were reviewed. At St. Boniface General Hospital(SBGH)all folate data between January 1996 and Dec 31,2004 were analyzed and the medical records of all who had low RF between January 1,1999 and December 31,2004 were reviewed.

Results

In 2001, at HSC, 11 out of 2154(0.5%)SF were low(<7.0 nmol/L) and 4 out of 560 (0.7%) RF were low (<417 nmol/L). In no subject with low SF or RF could the anemia be attributed to folate deficiency. At SBGH during the 3-year-period of 1999-2001, 19 out of 991(1.9%) had low RF (<225 nmol/L) but in only 2 patients (0.2%) the low RF was in folate deficiency anemia range; but neither of them had anemia.

Conclusion

In countries where there is mandatory fortification of grain products with folic acid, folate deficiency to the degree that could cause anemia is extremely rare. Ordering folate assays for investigation of anemias, in these countries, is waste of time and money. The result of these tests is more likely to mislead the physicians than to provide any useful information.

Metabolic evidence of vitamin B-12 deficiency, including high homocysteine and methylmalonic acid and low holotranscobalamin, is more pronounced in older adults with elevated plasma folate

BACKGROUND

An analysis of data from the National Health and Nutrition Examination Survey indicated that in older adults exposed to folic acid fortification, the combination of low serum vitamin B-12 and elevated folate is associated with higher concentrations of homocysteine and methylmalonic acid and higher odds ratios for cognitive impairment and anemia than the combination of low vitamin B-12 and nonelevated folate. These findings await confirmation in other populations.

OBJECTIVE

The purpose was to compare metabolic indicators of vitamin B-12 status, cognitive function, and depressive symptoms among elderly Latinos with elevated and nonelevated plasma folate.

DESIGN

Cross-sectional data were analyzed for 1535 subjects (age: >or=60 y) from the Sacramento Area Latino Study on Aging. Subjects were divided into 4 groups on the basis of plasma vitamin B-12 (< or >or=148 pmol/L) and folate (<or= or >45.3 nmol/L). Homocysteine, methylmalonic acid, holotranscobalamin, ratio of holotranscobalamin to vitamin B-12, Modified Mini-Mental State Examination, delayed recall, and depressive symptom scores were compared between the groups.

RESULTS

Individuals with low vitamin B-12 and elevated folate (n = 22) had the highest concentrations of homocysteine and methylmalonic acid and the lowest concentration of holotranscobalamin and ratio of holotranscobalamin to vitamin B-12 when compared with all other groups (P <or= 0.003). No differences in Modified Mini-Mental State Examination, delayed recall, and depressive symptom scores were observed between the low vitamin B-12 and elevated-folate group compared with other groups.

CONCLUSIONS

Low vitamin B-12 is associated with more pronounced metabolic evidence of vitamin B-12 deficiency when folate is elevated than when folate is not elevated. These data should be considered when assessing the potential costs, risks, and benefits of folic acid and vitamin B-12 fortification programs.

Dietary folate, vitamin B-12, vitamin B-6 and incident Alzheimer's disease: the cache county memory, health and aging study

OBJECTIVE

To examine associations between dietary and supplemental folate, vitamin B-12 and vitamin B-6 and incident Alzheimer's disease (AD) among elderly men and women.

DESIGN, SETTING AND PARTICIPANTS

Data collected were from participants of the Cache County Memory, Health and Aging Study, a longitudinal study of 5092 men and women 65 years and older who were residents of Cache County, Utah in 1995.

MEASUREMENTS

Multistage clinical assessment procedures were used to identify incident cases of AD. Dietary data were collected using a 142-item food frequency questionnaire. Cox Proportional Hazards (CPH) modeling was used to determine hazard ratios across quintiles of micronutrient intake.

RESULTS

202 participants were diagnosed with incident AD during follow-up (1995-2004). In multivariable CPH models that controlled for the effects of gender, age, education, and other covariates there were no observed differences in risk of AD or dementia by increasing quintiles of total intake of folate, vitamin B-12, or vitamin B-6. Similarly, there were no observed differences in risk of AD by regular use of either folate or B6 supplements.

CONCLUSION

Dietary intake of B-vitamins from food and supplemental sources appears unrelated to incidence of dementia and AD. Further studies examining associations between dietary intakes of B-vitamins, biomarkers of B-vitamin status and cognitive endpoints are warranted.

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.

Demographic, lifestyle, and health characteristics and serum B vitamin status are determinants of plasma total homocysteine concentration in the post-folic acid fortification period, 1999-2004

Elevated circulating total homocysteine (tHcy) concentrations are related to increased risk for cardiovascular disease. Folic acid fortification resulted in a significant decrease in circulating tHcy in the United States. In the post-folic acid fortification period, associations between plasma tHcy and demographic, health, and lifestyle factors and B vitamin status were investigated. Data from the 3 recent NHANES cycles (1999-2004) were used to study the associations among plasma tHcy and sex, race/ethnicity, age, BMI, blood pressure (BP), serum creatinine, serum cotinine, vitamin/mineral supplement use, and folate and cobalamin status in 16,254 persons (8329 men, 7925 women). Multivariate-adjusted plasma tHcy was approximately 9.7% higher in men than in women (P < 0.0001), approximately 5.3% higher in non-Hispanic whites than in non-Hispanic blacks (P < 0.0001), approximately 64.5% higher in individuals aged >or=60 y than in individuals aged <20 y (P < 0.0001), and approximately 5% higher in supplement nonusers than in supplement users (P < 0.0001). Persons in the 4th quartile for serum creatinine, serum cotinine, systolic BP, and serum methylmalonic acid (MMA) had approximately 36.1, approximately 13.4, approximately 5.6, and approximately 16.2%, respectively, higher tHcy than those in the 1st quartile (P < 0.0001). Plasma tHcy was inversely associated with serum folate (P < 0.0001), RBC folate (P < 0.0001), and serum cobalamin (P < 0.0001). In the post-folic acid fortification period, sex, race/ethnicity, age, systolic BP, supplement use, RBC folate, and serum creatinine, cotinine, folate, and cobalamin are significant determinants of plasma tHcy. Serum MMA was strongly associated with plasma tHcy.

Is it time for vitamin B-12 fortification? What are the questions?

Since the introduction of folic acid fortification of flour 10 y ago, an initiative to consider fortifying flour with vitamin B-12 has gained momentum in the United States. The impetus for this move stems from several considerations, including some evidence that a proportion of neural tube defect pregnancies may be the result of vitamin B-12 rather than folate deficiency. However, no interventional trials have taken place to show the efficacy of vitamin B-12 supplementation or fortification in the primary prevention or recurrence of neural tube defect pregnancies, as was the case with folic acid. Other reasons put forward for the institution of vitamin B-12 fortification include the high prevalence of vitamin B-12 deficiency in certain demographic groups, including the elderly and the young in some countries. Much of this deficiency, however, is subclinical and not associated with manifest morbidity. Moreover, individuals affected by the most severe cases of vitamin B-12 deficiency that are associated with morbidity would not benefit from the concentrations of vitamin B-12 fortification that are practical or that are being considered, because such individuals suffer from malabsorption of vitamin B-12 rather than from an inadequacy of intake of the vitamin. In addition to the well-recognized complications of vitamin B-12 deficiency, such as macrocytic anemia and neurological complications affecting sensory and motor function, more subtle effects have also been described, including osteopenia, neurocognitive impairment, and increased vascular disease risk associated with elevated homocysteine. This analysis focuses on the research questions that are pertinent to the consideration of whether or not to introduce mandatory vitamin B-12 fortification in the United States.

Folate-vitamin B-12 interaction in relation to cognitive impairment, anemia, and biochemical indicators of vitamin B-12 deficiency

Previous reports on pernicious anemia treatment suggested that high folic acid intake adversely influences the natural history of vitamin B-12 deficiency, which affects many elderly individuals. However, experimental investigation of this hypothesis is unethical, and the few existing observational data are inconclusive. With the use of data from the 1999-2002 National Health and Nutrition Examination Survey (NHANES), we evaluated the interaction between high serum folate and low vitamin B-12 status [ie, plasma vitamin B-12 < 148 pmol/L or methylmalonic acid (MMA) > 210 nmol/L] with respect to anemia and cognitive impairment. With subjects having both plasma folate < or = 59 nmol/L and normal vitamin B-12 status as the referent category, odds ratios for the prevalence of anemia compared with normal hemoglobin concentration and impaired compared with unimpaired cognitive function were 2.1 (95% CI: 1.1, 3.7) and 1.7 (95% CI: 1.01, 2.9), respectively, for those with low vitamin B-12 status but normal serum folate and 4.9 (95% CI: 2.3, 10.6) and 5.0 (95% CI: 2.7, 9.5), respectively, for those with low vitamin B-12 status and plasma folate >59 nmol/L. Among subjects with low vitamin B-12 status, mean circulating vitamin B-12 was 228 pmol/L for the normal-folate subgroup and 354 pmol/L for the high-folate subgroup. We subsequently showed increases in circulating homocysteine and MMA concentrations with increasing serum folate among NHANES participants with serum vitamin B-12 < 148 pmol/L, whereas the opposite trends occurred among subjects with serum vitamin B-12 > or = 148 pmol/L. These interactions, which were not seen in NHANES III before fortification, imply that, in vitamin B-12 deficiency, high folate status is associated with impaired activity of the 2 vitamin B-12-dependent enzymes, methionine synthase and MMA-coenzyme A mutase.

Long-term effects of folic acid fortification and B-vitamin supplementation on total folate, homocysteine, methylmalonic acid and cobalamin in older adults

OBJECTIVE

To investigate the long-term effects of the Canadian folic acid fortification program in older adults' whole blood cell folate (folate) and cobalamin (Cbl) status, including homocysteine (tHcy) and methylmalonic acid (MMA), with and without voluntary B-vitamin intake, from 1997 to 2004.

METHODS

Cohort of community-dwelling volunteer older adults. Clinical and biochemical data, including intake of B-vitamin supplements, were obtained at 2- to 2.5-year intervals and divided in 4 periods. Random coefficients (mixed effects) models were used to estimate the linear trend in folate and to compare levels of biochemical parameters between periods. All models were estimated by restricted maximum likelihood as implemented in PROC MIXED of SAS V8.2.

RESULTS

Folate levels increased continuously at a yearly rate of 234 ng/mL (95% CI 213-254; p < 0.001) and had not plateaued by the last period when 84% of subjects without B-vitamins had elevated folate. Homocysteine did not remain suppressed. Elevated tHcy was as prevalent in the last study period as in the first. No significant deficits of Cbl or increases of MMA were observed, but MMA levels tended to increase with time in subjects without B-vitamins. B-vitamin supplements significantly affected all results, reducing tHcy and MMA levels.

CONCLUSION

In this population, fortification with folic acid has resulted in cumulative increases of folate with no long-term reduction in tHcy or changes in Cbl or MMA. Possible deleterious effects of cumulative increases of folate, and beneficial effects of B-vitamin supplements in reducing tHcy and MMA, should be investigated.

Hemoglobin and hematocrit values are higher and prevalence of anemia is lower in the post-folic acid fortification period than in the pre-folic acid fortification period in US adults

BACKGROUND

It is not known whether the improved folate status from mandatory folic acid fortification had any impact on indexes and prevalence of anemias in the United States.

OBJECTIVE

We investigated trends in indexes and prevalence of anemia and macrocytosis with a focus on comparison of prefortification data with postfortification data.

DESIGN

Hemoglobin, hematocrit, mean corpuscular volume (MCV) and prevalences and likelihood of anemia and macrocytosis were determined for 26,596 adults examined in the National Health and Nutrition Examination Surveys, 1988-2004.

RESULTS

From 1988-1994 to 1999-2004, hemoglobin modestly but significantly improved from 15.1 to 15.4 g/dL (approximately 2.0%; P < 0.0001) and from 13.3 to 13.6 g/dL (approximately 2.3%; P < 0.0001) in men and women, respectively. There was a significant increase in MCV from 1988-1994 to 1999-2004 in men (from 90.2 to 90.7; P = 0.0123) and older (>60 y) men (from 91.6 to 92.4; P = 0.0105) and in women (from 90.7 to 91.4; P = 0.0141). Only in women was the prevalence of anemia significantly lower in 1999-2004 than in 1988-1994 (27.9% reduction; P = 0.0005). The odds of having anemia in the postfortification period relative to the prefortification period was 0.64 (95% CI: 0.54, 0.75; P < 0.0001) in women and 0.79 (95% CI: 0.62, 0.99; P < 0.0433) in men. In general, the prevalence of macrocytosis and the odds of having macrocytosis did not change significantly from 1988-1994 to 1999-2004.

CONCLUSION

The improvement in hemoglobin and the decreased prevalence of anemia from 1988-1994 to 1999-2004, especially in women, may be attributable to improved folate status, increased vitamin/mineral supplements use, and other unknown causes after the initiation of folic acid fortification. The cause of increased MCV in men, and in older persons of both sexes, warrants further investigation.

A 19-base pair deletion polymorphism in dihydrofolate reductase is associated with increased unmetabolized folic acid in plasma and decreased red blood cell folate

Dihydrofolate reductase (DHFR) catalyzes the reduction of folic acid to tetrahydrofolate (THF). A 19-bp noncoding deletion allele maps to intron 1, beginning 60 bases from the splice donor site, and has been implicated in neural tube defects and cancer, presumably by influencing folate metabolism. The functional impact of this polymorphism has not yet been demonstrated. The objective of this research was to determine the effects of the DHFR mutation with respect to folate status and assess influence of folic acid intake on these relations. The relationship between DHFR genotype and plasma concentrations of circulating folic acid, total folate, total homocysteine, and concentrations of RBC folate was determined in 1215 subjects from the Framingham Offspring Study. There was a significant interaction between DHFR genotype and folic acid intake with respect to the prevalence of high circulating unmetabolized folic acid (defined as >85th percentile). Folic acid intake of >or=500 microg/d increased the prevalence of high circulating unmetabolized folic acid in subjects with the deletion (del/del genotype (47.0%) compared with the wild type (WT)/del (21.4%) and wild type (WT)/WT genotypes (24.4%) (P for interaction = 0.03). Interaction between the DHFR polymorphism and folic acid intake was also seen with respect to RBC folate (P for interaction = 0.01). When folic acid intake was <250 microg/d, the del/del genotype was associated with significantly lower RBC folate (732.3 nmol/L) compared with the WT/WT genotype (844.4 nmol/L). Our results suggest the del/del polymorphism in DHFR is a functional polymorphism, because it limits assimilation of folic acid into cellular folate stores at high and low folic acid intakes.

Public health significance of elevated homocysteine

Homocysteine is a sulfur amino acid whose metabolism stands at the intersection of two pathways: remethylation, which requires folic acid and vitamin B12 coenzymes; and transsulfuration, which requires pyridoxal-5'-phosphate, the vitamin B6 coenzyme. Data from a number of laboratories suggest that mild elevations of homocysteine in plasma are a risk factor for occlusive vascular disease. In the Framingham studies, we have shown that plasma homocysteine concentration is inversely related to the intake and plasma levels of folate and vitamin B6 as well as vitamin B12 plasma levels. Almost two-thirds of the prevalence of high homocysteine is attributable to low vitamin status or intake. Elevated homocysteine concentrations in plasma are a risk factor for prevalence of extracranial carotid-artery stenosis > or = 25% in both men and women. Prospectively elevated plasma homocysteine is associated with increased total and cardiovascular mortality, increased incidence of stroke, increased incidence of dementia and Alzheimer's disease, increased incidence of bone fracture, and higher prevalence of chronic heart failure. It was also shown that elevated plasma homocysteine is a risk factor for preeclampsia and maybe neural tube defects (NTD). This multitude of relationships between elevated plasma homocysteine and diseases that afflict the elderly, pregnant women, and the embryo points to the existence ofa common denominator which may be responsible for these diseases. Whether this denominator is homocysteine itself or homocysteine is merely a marker, remains to be determined.

National Neural Tube Defects Prevention Program in China

Neural tube defects (NTD) are among the most common and devastating birth defects. Annually, in China, between 80,000 and 100,000 pregnancies result in children born with NTD. Northern China has the highest known rate of NTD in the world. Birth defects are becoming the leading cause of infant mortality in the urban and developed areas in China. The results of studies conducted in the early 1990s and early 2000s showed significant geographic and seasonal variations of folate status among Chinese women of childbearing age, with lower serum and red blood cell folate levels in northern China. In the north, 32% to 35% of women had low plasma folate and low red blood cell folate, and folate levels were significantly lower in spring than in fall. Since 1993, Peking University Health Science Center (formerly Beijing Medical University), collaborating with the US Centers for Disease Control and Prevention (CDC), has conducted a large-scale study to evaluate a public health campaign in China among women preparing for marriage in order to determine the effectiveness of daily supplementation of 400 microg of folic acid alone in preventing NTD in both the north and the south of China. The results showed that among the fetuses or infants of the women who took periconceptional folic acid, the reduction in risk of NTD was 85% in the northern region and 40% in the southern region. Daily intake of 400 microg of folic acid may also reduce the risk of nonsyndromic orofacial clefts. We found no evidence that daily consumption of folic acid before and during early pregnancy influenced the risk of miscarriage or twinning. In 2001, the Chinese Ministry of Health and the Chinese Disabled Person Federation released a National Action Plan for Reducing Birth Defects and Disabilities in China for 2002-2010. The Action Plan aims to improve birth outcomes, to reduce infant mortality by reducing the risk of birth defects and disabilities, and to ensure that every baby is born healthy.

Folate and unipolar depression

BACKGROUND

Although major depressive disorder (MDD) is a treatable disease, the remission rates associated with antidepressant monotherapy are still far from optimal. Folate is an inexpensive, easily tolerated natural augmenting agent, which has been reported to improve medication treatment outcomes in patients with MDD.

OBJECTIVE

The aim of this study was to review the literature on the clinical utility of folate augmentation for patients with MDD. FOLATE AND DEPRESSION: Patients with depression have consistently been found to have lower levels of serum and red blood cell folate than normal or nondepressed psychiatric patients. Decreased folate levels have been associated with lowered response rates to standard antidepressant pharmacotherapy. Recent studies have shown that augmentation with a folate supplement increases medication response in both treatment-naïve and treatment-resistant depressed patients irrespective of whether there is folate deficiency.

CONCLUSIONS

Depressed patients with both low and normal folate levels may benefit from augmenting a primary antidepressant medication either initially, at the onset of treatment, or later after some degree of treatment resistance has been recognized.

The paradox of anemia with high meat intake: a review of the multifactorial etiology of anemia in the Inuit of North America

Anemia is a serious concern among indigenous populations in North America, and it appears to be widespread among the Inuit despite abundant intakes of heme iron. It is therefore hypothesized that anemia for the Inuit involves other dietary factors not usually associated with animal foods, such as low intakes of vitamin A and/or folate, riboflavin, and vitamin C. Also, Helicobacter pylori infection and/or parasitosis may result in gastrointestinal blood loss and/or functional iron deficiency. This review aims to describe factors that may cause anemia in Inuit populations despite high meat intakes, abundant bioavailable iron, and other important hematological nutrients.

Trends in circulating concentrations of total homocysteine among US adolescents and adults: findings from the 1991-1994 and 1999-2004 National Health and Nutrition Examination Surveys

BACKGROUND

The National Health and Nutrition Examination Survey (NHANES) has monitored total homocysteine (tHcy) concentrations in a nationally-representative sample of the US population since 1991. Until recently, however, data could not be compared across survey periods because of changes in analytical methods and specimen matrices. Such an analysis of these data could supplement current knowledge regarding whether the US folic acid fortification program has modified national plasma tHcy concentrations.

METHODS

We examined tHcy data in the prefortification NHANES III survey (phase II, 1991-1994) and in 3 postfortification survey periods (1999-2000, 2001-2002, and 2003-2004). We applied method adjustment equations to the survey data based on method comparison studies of separate samples. Persons with chronic kidney disease were excluded from the analyses.

RESULTS

Mean plasma tHcy concentrations decreased by 8%, 9%, and 10% for adolescent, adult, and older men and by 6%, 3%, and 13% for women, respectively, from before to after fortification. Concentrations remained unchanged between the first and third postfortification survey periods. Prevalence estimates of increased plasma tHcy concentrations (>13 micromol/L) for older men and women decreased from prefortification (32% and 20%, respectively) to postfortification (14% and 5%, respectively) but remained unchanged thereafter (16% and 14%, respectively [males] and 5% and 9%, respectively [females]).

CONCLUSIONS

After adjusting for method changes, we quantified a prefortification to postfortification decrease in circulating tHcy concentrations of about 10% in a national sample of the US population. This change is similar to effects seen in intervention trials with folic acid and in smaller observational studies.

Hematologic problems in psychosomatic medicine

Vitamin B12 deficiency is associated with problems in cognition, mood, psychosis, and less commonly, anxiety. Folate deficiency primarily is associated with problems in mood. Patients who have sickle cell disease, a disease of chronic pain, experience difficulties with depression, anxiety, stigma, and are at risk for substance abuse and dependence. Patients with hemophilia have benefited from advances in treatment; however, their morbidity and mortality were compounded in those who received blood products contaminated with HIV, or hepatitis B and C. Psychiatrists who practice psychosomatic medicine should expect to encounter patients with the above problems, as they are frequently seen in medical settings. Finally, most of the commonly used psychotropic medications have uncommon but potentially important hematologic side effects or may interact with the anticoagulants used in medically ill patients.

Effect of a voluntary food fortification policy on folate, related B vitamin status, and homocysteine in healthy adults

BACKGROUND

Mandatory folic acid fortification of food is effective in reducing neural tube defects and may even reduce stroke-related mortality, but it remains controversial because of concerns about potential adverse effects. Thus, it is virtually nonexistent in Europe, albeit many countries allow food fortification on a voluntary basis.

OBJECTIVE

The objective of the study was to examine the effect of a voluntary but liberal food fortification policy on dietary intake and biomarker status of folate and other homocysteine-related B vitamins in a healthy population.

DESIGN

The study was a cross-sectional study. From a convenience sample of 662 adults in Northern Ireland, those who provided a fasting blood sample and dietary intake data were examined (n = 441, aged 18-92 y). Intakes of both natural food folate and folic acid from fortified foods were estimated; we used the latter to categorize participants by fortified food intake.

RESULTS

Fortified foods were associated with significantly higher dietary intakes and biomarker status of folate, vitamin B-12, vitamin B-6, and riboflavin than were unfortified foods. There was no difference in natural food folate intake (range: 179-197 microg/d) between the fortified food categories. Red blood cell folate concentrations were 387 nmol/L higher and plasma total homocysteine concentrations were 2 micromol/L lower in the group with the highest fortified food intake (median intake: 208 microg/d folic acid) than in the nonconsumers of fortified foods (0 microg/d folic acid).

CONCLUSIONS

These results show that voluntary food fortification is associated with a substantial increase in dietary intake and biomarker status of folate and metabolically related B vitamins with potential beneficial effects on health. However, those who do not consume fortified foods regularly may have insufficient B vitamin status to achieve the known and potential health benefits.

Proportion of individuals with low serum vitamin B-12 concentrations without macrocytosis is higher in the post folic acid fortification period than in the pre folic acid fortification period

BACKGROUND

Large intakes of folic acid may delay the diagnosis of vitamin B-12 deficiency, which could lead to irreversible neuropathy.

OBJECTIVE

The objective of this study was to determine whether the proportion of individuals with low serum vitamin B-12 without macrocytosis (undiagnosed vitamin B-12 deficiency) has increased in the post-folic acid fortification period.

DESIGN

Individuals aged >or=19 y with low serum vitamin B-12 (<258 pmol/L) and mean corpuscular volume (MCV) measured between 1995 and 2004 were identified from medical records. The proportion and odds ratios of individuals with low serum vitamin B-12 without macrocytosis by sex, race, and age according to prefortification (n = 86), perifortification (n = 138), and postfortification (n = 409) periods were determined.

RESULTS

MCV was significantly lower in the postfortification period (88.6 fL) than in the prefortification (94.4 fL; P < 0.001) and perifortification (90.6 fL; P = 0.007) periods. The proportion of subjects with low serum vitamin B-12 without macrocytosis was significantly higher in the postfortification (approximately 87%) and perifortification (approximately 85%) periods than in the prefortification period (approximately 70%; P < 0.001). In a sex-, race-, and age-adjusted analysis, the odds ratio for having low serum vitamin B-12 without macrocytosis was 3.0 (95% CI: 1.7, 5.2) in the postfortification period relative to the prefortification period.

CONCLUSIONS

Subjects with low serum vitamin B-12 were likely to be without macrocytosis in the postfortification period. MCV should not be used as a marker for vitamin B-12 insufficiency. It is possible that folic acid fortification may have led to a correction of macrocytosis associated with vitamin B-12 insufficiency.

Folate during reproduction: the Canadian experience with folic acid fortification

Folate has received international attention regarding its role in the risk-reduction of birth defects, specifically neural tube defects (NTDs). In 1998, health officials in Canada, like the United States, mandated the addition of folic acid to white flour and select grain products to increase the folate intake of reproductive-aged women. Subsequent to this initiative there has been an increase in blood folate concentrations in Canada and a 50% reduction in NTDs. Many countries, including Korea, have not mandated folic acid fortification of their food supply. Reasons vary but often include concern over the masking of vitamin B₁₂ deficiency, a belief that folate intakes among womenare adequate, low priority relative to other domestic issues, and the philosophy that individuals have the right not to consume supplemental folic acid if they so choose. Prior to folic acid fortification of the food supply in Canada, the folate intakes of women were low, and their blood folate concentrations while not sufficiently low to produce overt signs of folate deficiency (eg. anemia) were inconsistent with a level known to reduce the risk of an NTD-affected pregnancy. The purpose of this article is to describe the role of folate during the periconceptional period, pregnancy, and during lactation. The rationale for, and history of recommending folic acid-containing supplements during the periconceptional period and pregnancy is described as is folic acid fortification of the food supply. The impact of folic acid fortification in Canada is discussed, and unresolved issues associated with this policy described. While the incidence of NTDs in Canada pre-folic acid fortification were seemingly higherthan that of Korea today, blood folate levels of Korean women are strikingly similar. We will briefly explore these parallels in an attempt to understand whether folic acid fortification of the food supply in Korea might be worth consideration

Trends in blood folate and vitamin B-12 concentrations in the United States, 1988 2004

BACKGROUND

Monitoring the folate status of US population groups over time has been a public health priority for the past 2 decades, and the focus has been enhanced since the implementation of a folic acid fortification program in the mid-1990s.

OBJECTIVE

We aimed to determine how population concentrations of serum and red blood cell (RBC) folate and serum vitamin B-12 have changed over the past 2 decades.

DESIGN

Measurement of blood indicators of folate and vitamin B-12 status was conducted in approximately 23,000 participants in the prefortification third National Health and Nutrition Examination Survey (NHANES III; 1988-1994) and in approximately 8000 participants in 3 postfortification NHANES periods (together covering 1999-2004).

RESULTS

Serum and RBC folate concentrations increased substantially (by 119-161% and 44-64%, respectively) in each age group in the first postfortification survey period and then declined slightly (by 5-13% and 6-9%, respectively) in most age groups between the first and third postfortification survey periods. Serum vitamin B-12 concentrations did not change appreciably. Prevalence estimates of low serum and RBC folate concentrations declined in women of childbearing age from before to after fortification (from 21% to <1% and from 38% to 5%, respectively) but remained unchanged thereafter. Prevalence estimates of high serum folate concentrations increased in children and older persons from before to after fortification (from 5% to 42% and from 7% to 38%, respectively) but decreased later after fortification.

CONCLUSIONS

The decrease in folate concentrations observed longer after fortification is small compared with the increase soon after the introduction of fortification. The decrease is not at the low end of concentrations and therefore does not raise concerns about inadequate status.

Comparison of blood folate levels among pregnant Chinese women in areas with high and low prevalence of neural tube defects

Objective

To characterise plasma and red-blood-cell (RBC) folate status among pregnant women in an area with an extremely high prevalence of neural tube defects, and to compare them with those of women from a low prevalence area.

Design

A cross-sectional survey conducted in 2003.

Setting

One county and one city from each of the high prevalence area and the low prevalence area in China.

Subjects

Five hundred and sixty-two women in their first trimester of pregnancy in the high prevalence area and 695 pregnant women in the low prevalence area.

Results

Women in the high prevalence area had less than half the plasma and RBC folate concentrations (12.2 and 440.0 nmol l− 1, respectively) of women in the low prevalence area (33.5 and 910.4 nmol l− 1, respectively). In the high prevalence area, 40% of rural women were deficient in RBC folate and 50% were deficient in plasma folate; 20% of urban women were deficient in RBC folate and 30% deficient in plasma folate. In contrast, only 4% (RBC folate) and 6% (plasma folate) of rural women, and 2% (RBC folate) and 1% (plasma folate) of urban women, were folate-deficient in the low prevalence area. Less than 10% of rural and about 26% of urban women in the high prevalence area took folic acid periconceptionally, compared with 70% and 60% of women in the low prevalence area.

Conclusions

Blood folate deficiency is highly prevalent among pregnant women in an area of China with a very high prevalence of neural tube defects.

Folate and colorectal cancer: an evidence-based critical review

Currently available evidence from epidemiologic, animal, and intervention studies does not unequivocally support the role of folate, a water-soluble B vitamin and important cofactor in one-carbon transfer, in the development and progression of colorectal cancer (CRC). However, when the portfolio of evidence from these studies is analyzed critically, the overall conclusion supports the inverse association between folate status and CRC risk. It is becoming increasingly evident that folate possesses dual modulatory effects on colorectal carcinogenesis depending on the timing and dose of folate intervention. Folate deficiency has an inhibitory effect whereas folate supplementation has a promoting effect on the progression of established colorectal neoplasms. In contrast, folate deficiency in normal colorectal mucosa appears to predispose it to neoplastic transformation, and modest levels of folic acid supplementation suppress, whereas supraphysiologic supplemental doses enhance, the development of cancer in normal colorectal mucosa. Several potential mechanisms relating to the disruption of one-carbon transfer reactions exist to support the dual modulatory role of folate in colorectal carcinogenesis. Based on the lack of compelling supportive evidence and on the potential tumor-promoting effect, routine folic acid supplementation should not be recommended as a chemopreventive measure against CRC at present.