Fortification of foods with folic acid--how much is enough?

Antioxidant, anti-inflammatory and immunomodulatory roles of vitamins in COVID-19 therapy

oxidative stress is caused by an abundant generation of reactive oxygen species, associated to a diminished capacity of the endogenous systems of the organism to counteract them. Activation of pro-oxidative pathways and boosting of inflammatory cytokines are always encountered in viral infections, including SARS-CoV-2. So, the importance of counteracting cytokine storm in COVID-19 pathology is highly important, to hamper the immunogenic damage of the endothelium and alveolar membranes. Antioxidants prevent oxidative processes, by impeding radical species generation. It has been proved that vitamin intake lowers oxidative stress markers, alleviates cytokine storm and has a potential role in reducing disease severity, by lowering pro-inflammatory cytokines, hampering hyperinflammation and organ failure. For the approached compounds, direct antiviral roles are also discussed in this review, as these activities encompass secretion of antiviral peptides, modulation of angiotensin-converting enzyme 2 receptor expression and interaction with spike protein, inactivation of furin protease, or inhibition of pathogen replication by nucleic acid impairment induction. Vitamin administration results in beneficial effects. Nevertheless, timing, dosage and mutual influences of these micronutrients should be carefullly regarded.

Adequate or elevated dietary folate does not ameliorate the reduced antioxidant capacity induced by vitamin B12 deficiency in aged rats

Folate could have an antioxidant role but also may be detrimental under vitamin B₁₂ deficiency. The aim was to investigate the effect of different dietary folic acid (FA) levels, on oxidative stress in B₁₂ induced deficient aged rats. Thirty-five male aged Sprague-Dawley rats, were fed either a vitamin B₁₂ deficient (n = 27) or a control diet (n = 8) during eight weeks. Then, animals were divided into four groups: B₁₂ and FA deficient diet (DBDF), B₁₂ deficient diet and FA control diet (DBCF), B₁₂ deficient diet and FA supplemented diet (DBSF), and control diet (CBCF) for a 30 days period. Methionine metabolism and antioxidant status were evaluated. Both vitamins deficiencies elevated serum homocysteine (Hcy) (7.7 vs. 4.3 μmol/L, p < 0.05) and reduced S-adenosylmethionine hepatic content (283.7 vs. 581.9 μg/g protein, p < 0.05), the total antioxidant capacity (155.7 vs. 189.3 μmol/L, p < 0.05), glutathione (GSH) (120.5 vs. 419.9 μg/mg protein, p < 0.05) and oxidized glutathione (0.9 vs. 2.6 μg/mg protein, p < 0.05) compared to control. Activities of glutathione peroxidase and glutathione reductase enzymes or damage to macromolecules were unaffected. Adequate or elevated dietary FA in B₁₂ deficiency rats decreased Hcy (5.7 and 6.3 μmol/L, respectively) and increased total antioxidant capacity (189.8 and 192.6 μmol/L, respectively) to values similar to control group, whereas GSH concentration was significantly lower than control (209.1 and 208.0 μg/mg protein respectively, p < 0.05). In conclusion, in a vitamin B₁₂ deficiency status, adequate or elevated FA prevented impairment in one-carbon metabolism, but does not fully reverse the decrease in antioxidant capacity.

Dietary sources and intakes of folates and vitamin B12 in the Spanish population: Findings from the ANIBES study

Background

Folates and vitamin B₁₂ are key nutrients in one-carbon metabolism and related diseases. Updated and plausible information on population intakes and their major dietary sources is scarce and urgently needed in Spain in order to increase the knowledge that can lead as previous step to prevention by fortification and supplementation policies.

Aims

The present study aims to evaluate main dietary folate and vitamin B₁₂ sources and intakes in the Spanish population.

Materials and methods

Results were derived from the ANIBES cross-sectional study using a nationally representative sample of the Spanish population (9–75 years, n = 2,009).

Results

Food groups with the highest mean proportional contribution to total folate intakes in both males and females were vegetables (21.7–24.9%) and cereals (10.7–11.2%), while meat and meat products (26.4%) and milk and dairy products (27.3%) were for B₁₂. Total median folate and B₁₂ intakes amongst women were 156.3 μg/d and 4.0 μg/d while for men were 163.6 μg/d and 4.5 μg/d, respectively. In all age groups, vitamin intakes were significantly higher in plausible than in non-plausible energy reporters.

Conclusion

A limited number of participants had adequate folate intakes, whereas vitamin B₁₂ intakes were adequate for practically the entire population. There is a clear need for improving folates intake in the Spanish population.

Low and high dietary folic acid levels perturb postnatal cerebellar morphology in growing rats

The brain is particularly sensitive to folate metabolic disturbances, because methyl groups are critical for brain functions. This study aimed to investigate the effects of different dietary levels of folic acid (FA) on postnatal cerebellar morphology, including the architecture and organisation of the various layers. A total of forty male OFA rats (a Sprague-Dawley strain), 5 weeks old, were classified into the following four dietary groups: FA deficient (0 mg/kg FA); FA supplemented (8 mg/kg FA); FA supra-supplemented (40 mg/kg FA); and control (2 mg/kg FA) (all n 10 per group). Rats were fed ad libitum for 30 d. The cerebellum was quickly removed and processed for histological and immunohistochemical analysis. Slides were immunostained for glial fibrillary acidic protein (to label Bergmann glia), calbindin (to label Purkinje cells) and NeuN (to label post-mitotic neurons). Microscopic analysis revealed two types of defect: partial disappearance of fissures and/or neuronal ectopia, primarily in supra-supplemented animals (incidence of 80 %, P≤0·01), but also in deficient and supplemented groups (incidence of 40 %, P≤0·05), compared with control animals. The primary fissure was predominantly affected, sometimes accompanied by defects in the secondary fissure. Our findings show that growing rats fed an FA-modified diet, including both deficient and supplemented diets, have an increased risk of disturbances in cerebellar corticogenesis. Defects caused by these diets may have functional consequences in later life. The present study is the first to demonstrate that cerebellar morphological defects can arise from deficient, as well as high, FA levels in the diet.

Two Cases of Craniospinal Rachischisis Totalis: Role of Magnetic Resonance Imaging in Diagnosis and Review of Neural Tube Defects in the Indian Context with Implications for Folate Fortification

Craniospinal rachischisis is a rare and severe form of neural tube defects (NTDs), which is always fatal. It is characterized by anencephaly accompanied by a bony defect of the spine and exposure of neural tissue. We describe the two patients with ultrasonographic and magnetic resonance imaging appearance of craniospinal rachischisis totalis, detected antenatally at 22 and 25 weeks of gestation, and confirmed after termination of pregnancy. The multifactorial etiology of NTDs, with specific reference to folate deficiency, is discussed with possible role of folate fortification in the Indian context.

Establishing Safe and Potentially Efficacious Fortification Contents for Folic Acid and Vitamin B12

Determining the micronutrient contents in fortified foods depends not only on the health goal (additional intake to complement the diet), but also on ensuring that fortification does not raise micronutrient intakes beyond the Tolerable Upper Intake Level (UL), i.e., the safe limit. Technological incompatibility and cost may also restrict the fortification contents. For folic acid, the limiting factor is safety, while for vitamin B12, it is cost. However, adequate fortification contents that are both safe and efficacious can be estimated for both nutrients. In order to obtain the maximum benefit from the fortification programs, three different formulas responding to three categories of consumption, as specified by the median and 95th percentile of consumption, are proposed.

The model presented is based on the estimation of a Feasible Fortification Level (FFL), which then is used to determine the average, minimum, and maximum contents of the nutrients during production, taking into consideration the acceptable variation of the fortification process. Finally, the regulatory parameters, which support standards and enforcement, are calculated by reducing the proportion of the nutrient that is degraded during the usual marketing process of the fortified food. It is expected that this model will establish a common standard for food fortification, and improve the reliability and enforcement procedures of these programs.

The model was applied to flours as vehicles for folic acid in the United States, Guatemala, and Chile. Analysis of the data revealed that, with the exception of Chile, where wheat flour consumption is very high and probably within a narrow range, supplementation with folic acid is still needed to cover individuals at the low end of consumption. This is especially true when the difference in flour consumption is too wide, as in the case of Guatemala, where the proportional difference between consumption at the 95th percentile of the nonpoor group is as high as 100 times the consumption at the 5th percentile of the extremely poor group. Adoption of fortification content for staple foods near the safe limit brings together the need of restricting the voluntary addition of the specific nutrient to other foods and to dietary supplements.

Changes in knowledge and attitudes of folate, and use of dietary supplements among women of reproductive age in Norway 1998 - 2000

Aims: From March 1998, Norwegian nutrition authorities have recommended that women consume a folic acid supplement before and early in pregnancy to prevent neural tube defects. The authors wished to establish Norwegian data on knowledge of, use of, and attitudes to folic acid supplement and dietary supplements before and after implementing national information campaigns on folate and pregnancy. Methods: Telephone surveys were carried out in late 1998 and in late 2000 among, respectively, 1,146 and 1,218 Norwegian women of reproductive age. Results: Overall, 50% of the women in 1998 and 60% of the women in 2000 had heard about folate, 33% and 46% knew about its role in pregnancy, and 9.5% and 21% knew that it may prevent a congenital malformation. Only 4.0% and 8.5% of the women, respectively, knew that the critical period for folic acid supplement to reduce the risk of neural tube defect is before and early in pregnancy. Knowledge and increase in knowledge between the two surveys were highest among women close to pregnancy (woman planning pregnancy, pregnant women, or women who had given birth within the last 12 months), and among women with high education. Among the 54 women in 1998 and the 55 women in 2000 whose last birth was within the previous year, use of a folic acid supplement before or early in the last pregnancy was reported by 10% (95% confidence interval (CI) 5 - 21%) and by 47% (95% CI 35 - 60%), respectively. Among women close to pregnancy, 76% in 1998 and 87% in 2000 stated that they would use a folic acid supplement in a future pregnancy. Conclusions: Knowledge and use of folate among Norwegian women increased from 1998 to 2000. Future information strategies on folate and pregnancy should in particular aim at increasing women's knowledge on the critical period for folic acid supplementation, as well as reducing socio-demographic differences in use and knowledge of folate.

Vitamin B(12) and folic acid imbalance modifies NK cytotoxicity, lymphocytes B and lymphoprolipheration in aged rats

Different vitamin B₁₂ and folic acid concentrations could exacerbate the immune response. The aim was to evaluate different dietary folic acid and vitamin B₁₂ levels on the immune response in aged rats. Male Sprague Dawley aged rats were assigned to three folic acid groups (deficient, control, supplemented) each in absence of vitamin B₁₂ for 30 days. Several parameters of innate and acquired immune responses were measured. Serum and hepatic folate levels increased according to folic acid dietary level, while vitamin B₁₂ levels decreased. There was a significant decrease in natural killer cell-mediated cytotoxicity in the spleen for the vitamin B₁₂ deficient diet and folic acid control diet groups. Significant changes in CD45 lymphocyte subsets were also observed according to dietary imbalance. Lymphoproliferative response to concanavalin A and phytohemagglutinin did not differ significantly between groups. The spleen response to lipopolysaccharide increased significantly, but was unmodified for the other organs. An imbalance between dietary vitamin B₁₂ and folic acid concentrations alters some immunological parameters in aged rats. Therefore, the ratio between folate and vitamin B₁₂ could be as important as their absolute dietary concentrations.

Neural tube defects, folic acid and methylation

Neural tube defects (NTDs) are common complex congenital malformations resulting from failure of the neural tube closure during embryogenesis. It is established that folic acid supplementation decreases the prevalence of NTDs, which has led to national public health policies regarding folic acid. To date, animal studies have not provided sufficient information to establish the metabolic and/or genomic mechanism(s) underlying human folic acid responsiveness in NTDs. However, several lines of evidence suggest that not only folates but also choline, B12 and methylation metabolisms are involved in NTDs. Decreased B12 vitamin and increased total choline or homocysteine in maternal blood have been shown to be associated with increased NTDs risk. Several polymorphisms of genes involved in these pathways have also been implicated in risk of development of NTDs. This raises the question whether supplementation with B12 vitamin, betaine or other methylation donors in addition to folic acid periconceptional supplementation will further reduce NTD risk. The objective of this article is to review the role of methylation metabolism in the onset of neural tube defects.

Significant impact of the MTHFR polymorphisms and haplotypes on male infertility risk

Background

Methylenetetrahydrofolate reductase (MTHFR) converts 5,10-methylene tetrahydrofolate to 5-methyl tetrahydrofolate and affects the activity of cellular cycles participating in nucleotide synthesis, DNA repair, genome stability, maintenance of methyl pool, and gene regulation. Genetically compromised MTHFR activity has been suggested to affect male fertility. The objective of the present study was to find the impact on infertility risk of c.203G>A, c.1298A>C, and c.1793G>A polymorphisms in the MTHFR gene.

Methods

PCR-RFLP and DNA sequencing were used to genotype the common SNPs in the MTHFR gene in 630 infertile and 250 fertile males. Chi-square test was applied for statistical comparison of genotype data. Linkage disequilibrium between the SNPs and the frequency of common haplotypes were assessed using Haploview software. Biochemical levels of total homocysteine (tHcy) and folic acid were measured. Meta-analysis on c.1298A>C polymorphism was performed using data from ten studies, comprising 2734 cases and 2737 controls.

Results

c.203G>A and c.1298A>C were found to be unrelated to infertility risk. c.1793G>A was protective against infertility (P = 0.0008). c.677C>T and c.1793G>A were in significant LD (D’ = 0.9). Folic acid and tHcy level did not correlate with male infertility. Pooled estimate on c.1298A>C data from all published studies including our data showed no association of this polymorphism with male infertility (Odds ratio = 1.035, P = 0.56), azoospermia (Odds ratio = 0.97, P = 0.74), or oligoasthenoteratozoospermia (Odds ratio = 0.92, p = 0.29). Eight haplotypes with more than 1% frequency were detected, of which CCGA was protective against infertility (p = 0.02), but the significance of the latter was not seen after applying Bonferroni correction.

Conclusion

Among MTHFR polymorphisms, c.203G>A and c.1298A>C do not affect infertility risk and c.1793G>A is protective against infertility. Haplotype analysis suggested that risk factors on the MTHFR locus do not extend too long on the DNA string.

Recommendations for folate intake in women: implications for public health strategies

Folate deficiency has been associated with anemia and other adverse outcomes in pregnancy such as neural tube defects. The current recommendations for prevention of such outcomes are difficult to achieve through diet only, and folic acid supplementation and food fortification are feasible public health strategies. However, it is necessary to determine the usual diet and supplement use among women of reproductive age, including an accurate assessment of other dietary micronutrients. In addition to the beneficial effects observed in randomized clinical trials, health risks to the population have also been widely evaluated and discussed in the scientific community: for a minority to benefit from fortification programs, many are exposed to high folic acid intake levels.

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.

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.

Folate status and homocysteine response to folic acid doses and withdrawal among young Chinese women in a large-scale randomized double-blind trial

BACKGROUND

There are no large randomized trials of the effect of folic acid dosing regimens on blood folate and homocysteine concentrations.

OBJECTIVE

We aimed to evaluate the changes in folate and homocysteine concentrations in response to different folic acid doses and to withdrawal in young women not exposed to other sources of folic acid.

DESIGN

Women (n = 1108) were randomly assigned to 1 of 6 intervention groups for which daily intakes of folic acid for 6 mo were 100 microg 1 time/d, 25 microg 4 times/d, 400 microg 1 time/d, 100 microg 4 times/d, 4000 microg 1 time/d, or 4000 microg 1 time/wk. Plasma and red blood cell folate and homocysteine concentrations were measured at baseline; at 1, 3, and 6 mo; and 3 mo after the discontinuation of folic acid.

RESULTS

Folate and homocysteine concentrations were not different at baseline between the groups who had the same daily intake of folic acid as a single dose or multiple doses (P = 0.058). Plasma folate concentrations plateaued at 3 mo with 108% (95% CI: 97.7%, 120%), 259% (95% CI: 240%, 279%), 460% (95% CI: 417%, 503%), and 142% (95% CI: 123%, 162%) observed increases for the folic acid groups receiving 100, 400, and 4000 microg/d and 4000 microg/wk, respectively. The rate of reduction in folate concentrations during the 3 mo after cessation of folic acid was dose-dependent-higher intakes were associated with faster reductions.

CONCLUSIONS

Changes in folate and homocysteine concentrations were unaffected by different dosing schedules. After folic acid cessation, blood folate declined rapidly, which indicated that the intervention-enhanced folate status was rapidly diminished.

Spontaneous abortion and the prophylactic effect of folic acid supplementation in epileptic women undergoing antiepileptic therapy

BACKGROUND

Antiepileptic drugs (AEDs) like phenytoin (PHE), carbamazepine (CBZ), barbiturates and valproic acid (VPA) interfere with folic acid absorption and metabolism, which in turn can be the cause of adverse pregnancy outcome.

OBJECTIVE

To study the prophylactic effect of folic acid supplementation with regard to spontaneous abortion and preterm delivery (fetal demise after week 20 of gestational age) in pregnant women receiving AED therapy, as well as benefits of most common dosage and preconceptional commencement.

METHODS

Prospective examination of 104 patients, registered in EURAP from 1999-2004 at a single center and a retrospective analysis of data from our epilepsy databank completed with medical records and patients interviews of the Department of Neurology of Innsbruck University Hospital from 1971 to 1999.

RESULTS

388 pregnancies in 244 patients were analyzed. Pregnancies with folic acid supplementation showed significant reduction of spontaneous abortion. With regard to monotherapies, in the group of women taking VPA, supplementation of folic acid had significant benefit. Other examined monotherapies (CBZ, PHE, and PB) known to interfere with folic acid showed no significant results.

CONCLUSIONS

This study confirms the prophylactic effect of folic acid supplementation on spontaneous abortion. For AED therapy, folic acid supplementation should be part of the therapy of every pregnant epileptic woman, especially for those treated with VPA.

Changes in predictors and status of homocysteine in young male adults after a dietary intervention with vegetables, fruits and bread

BACKGROUND

Elevated plasma total homocysteine (p-tHcy) is associated with increased risk of cardiovascular disease, and an inverse association has been shown between the dietary intake of B-vitamins, B-vitamin profile and the concentration of p-tHcy.

AIM OF THE STUDY

The main objective of this investigation was to study the effect of a dietary intervention focusing on an increased intake of vegetables, fruits and bread. The effect of the dietary intervention was determined by the changes in plasma concentrations of tHcy, cysteine (cys), riboflavin, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) and serum concentrations of folate and vitamin B(12).

METHOD

An intervention study with duration of 5 months, including 541 male recruits from the Norwegian National Guard, Vaernes and a control group, including 209 male recruits from the Norwegian Army, Heggelia.

RESULTS

The dietary intervention resulted in decreased concentration of p-tHcy (-10%, P = 0.002), p-cys (-6%, P < 0.001) and FMN (-11%, P = 0.310) and increased concentration of riboflavin (+23%, P < 0.001) and FAD (+10%, P = 0.008) in the intervention group compared with the control group. The change in p-tHcy concentration was positively related to the change in the concentration of p-cys (P < 0.001) and FMN (P = 0.035) and inversely related to the change in concentration of folate (P = 0.021).

CONCLUSIONS

A dietary intervention program focusing on an increased intake of vegetables, fruits and bread showed a favourable effect on the concentration of p-tHcy and its metabolites. Our findings suggest that the changes in the concentration of p-cys, folate and FMN seem to be predictors of changes in the p-tHcy concentration.

Folate Intake of Older Adults Before and After Fortification of Grain Products

Purpose: To determine whether fortification allowed older adults in the Kingston, Frontenac, and Lennox & Addington (KFL&A) Public Health area to obtain adequate amounts of food folate, and the proportion at risk of consuming more than the upper limit (UL) of folic acid (1,000 mcg).

Methods: Dietary intake of a convenience sample of 103 healthy, active older adults (age range: 65 to 95 years) was measured using three 24-hour recalls. Dietary folate preand post-fortification was estimated.

Results: Mean dietary folate increased from pre- to postfortification, but 43.4% of women and 20% of men still consumed less than the Estimated Average Requirement of 320 mcg dietary folate equivalent. No intakes exceeded the UL. Participants whose diet met grain products and vegetable and fruit recommendations of Canada's Food Guide to Healthy Eating consumed significantly more folate.

Conclusions: Despite fortification, some older adults in the KFL&A area may not be obtaining enough folate to meet their nutritional needs, and may be at risk for health problems associated with folate deficiency. However, without concomitant serum folate measurements, the proportion is not known. Dietitians need to continue promoting foods naturally rich in folate, along with folic acid-fortified foods. While none of the older adults consumed more than the UL, some could exceed this amount if folic acid supplements were added to a folic acid-rich diet.

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.

Low compliance with recommendations on folic acid use in relation to pregnancy: is there a need for fortification?

Objective:

As a means to prevent neural tube defects (NTDs), women planning pregnancy in Denmark are recommended to take a dietary supplement of 400 μg folic acid daily during the periconceptional period. We examined compliance with this recommendation in a national survey.

Design:

Cohort study on pregnant women in Denmark.

Setting:

The Danish National Birth Cohort (DNBC).

Subjects:

From November 2000 to February 2002, 22 000 pregnant women were recruited for DNBC. Use of dietary supplements was recorded at enrolment. Compliance with the recommendation was related to an information campaign that took place during the second half of 2001, and to lifestyle factors provided in a telephone interview by the end of the first trimester of pregnancy.

Results:

An increase was seen in the proportion of women complying with the recommendation in the study period and this coincided with the information campaign events. However, even at the end of the period, only 22.3% of the women who had planned their pregnancy fully complied with the recommendation. No increase at all was seen in periconceptional folic acid use among women with unplanned pregnancies. Young age, low education and smoking were identified as factors that determined non-compliance.

Conclusions:

Alternative and more effective strategies are needed if the Danish population is to benefit fully from the knowledge that folic acid prevents NTDs. Future strategies should not only target vulnerable groups, such as the less educated and the young, but also women who get pregnant without planning this. The only possible way to reach the last group may be through fortification of foods with folic acid.

Challenges in translating scientific evidence into mandatory food fortification policy: an antipodean case study of the folate–neural tube defect relationship

Objective

To identify challenges in translating scientific evidence of a nutrient and health relationship into mandatory food fortification policy.

Design

A case study approach was used in which available evidence associated with the folate–neural tube defect relationship was reviewed against the Australia New Zealand Food Regulation Ministerial Council's Policy Guideline for mandatory food fortification.

Results

Three particular challenges were identified. The first is knowing when and how to act in the face of scientific uncertainty. The second is knowing how to address the special needs of at-risk individuals without compromising the health and safety of the population as a whole. The third is to ensure that a policy is sufficiently monitored and evaluated.

Conclusions

Despite the availability of compelling evidence of a relationship between a particular nutrient and a health outcome, a definitive policy response may not be apparent. Judgement and interpretation inevitably play significant roles in influencing whether and how authorities translate scientific evidence into mandatory food fortification policy. In relation to the case study, it would be prudent to undertake a risk–benefit analysis of policy alternatives and to implement nutrition education activities to promote folic acid supplement use among the target group. Should mandatory folate fortification be implemented, comprehensive monitoring and evaluation of this policy will be essential to know that it is implemented as planned and does more good than harm. In relation to mandatory food fortification policy-making around the world, ongoing national nutrition surveys are required to complement national policy guidelines.

Folate and vitamin B-12 status in relation to anemia, macrocytosis, and cognitive impairment in older Americans in the age of folic acid fortification

BACKGROUND

Historic reports on the treatment of pernicious anemia with folic acid suggest that high-level folic acid fortification delays the diagnosis of or exacerbates the effects of vitamin B-12 deficiency, which affects many seniors. This idea is controversial, however, because observational data are few and inconclusive. Furthermore, experimental investigation is unethical.

OBJECTIVE

We examined the relations between serum folate and vitamin B-12 status relative to anemia, macrocytosis, and cognitive impairment (ie, Digit Symbol-Coding score < 34) in senior participants in the 1999-2002 US National Health and Nutrition Examination Survey.

DESIGN

The subjects had normal serum creatinine concentrations and reported no history of stroke, alcoholism, recent anemia therapy, or diseases of the liver, thyroid, or coronary arteries (n = 1459). We defined low vitamin B-12 status as a serum vitamin B-12 concentration < 148 pmol/L or a serum methylmalonic acid concentration > 210 nmol/L-the maximum of the reference range for serum vitamin B-12-replete participants with normal creatinine.

RESULTS

After control for demographic characteristics, cancer, smoking, alcohol intake, serum ferritin, and serum creatinine, low versus normal vitamin B-12 status was associated with anemia [odds ratio (OR): 2.7; 95% CI: 1.7, 4.2], macrocytosis (OR: 1.8; 95% CI: 1.01, 3.3), and cognitive impairment (OR: 2.5; 95% CI: 1.6, 3.8). In the group with a low vitamin B-12 status, serum folate > 59 nmol/L (80th percentile), as opposed to < or = 59 nmol/L, was associated with anemia (OR: 3.1; 95% CI: 1.5, 6.6) and cognitive impairment (OR: 2.6; 95% CI: 1.1, 6.1). In the normal vitamin B-12 group, ORs relating high versus normal serum folate to these outcomes were < 1.0 (P(interaction) < 0.05), but significantly < 1.0 only for cognitive impairment (0.4; 95% CI: 0.2, 0.9).

CONCLUSION

In seniors with low vitamin B-12 status, high serum folate was associated with anemia and cognitive impairment. When vitamin B-12 status was normal, however, high serum folate was associated with protection against cognitive impairment.

Hospitalizations of newborns with folate-sensitive birth defects before and after fortification of foods with folic acid

CONTEXT

The prevalence of neural tube defects is reduced in populations of women who receive folic acid supplementation. Since 1998, grain products in the United States have been fortified with folic acid. Fortification may have additional benefits by reducing the national prevalence of newborn hospitalizations for other folate-sensitive birth defects.

OBJECTIVE

Our purpose with this work was to compare rates of hospitalizations of newborns with folate-sensitive birth defects before and after implementation of fortification of grains.

METHOD

National hospital discharge data from the Healthcare Cost and Utilization Project were used to compute rates of newborn hospitalizations for selected birth defects per 10,000 live births in the United States. Newborn hospitalization rates involving congenital anomalies recognizable at birth were analyzed for 5 years before fortification of grains and 5 years after fortification. Additional analyses compared changes in newborn hospitalization rates for birth defects by race/ethnicity, income, insurance status, and region of the country.

RESULTS

Newborn hospitalization rates for spina bifida decreased 21% from 1993-1997 to 1998-2002. Newborn hospitalization rates also decreased for anencephaly (20%) and limb-reduction defects (4%). Decline in hospitalizations for spina bifida occurred more often among Hispanic newborns (33%) than among white (13%) or black (21%) newborns. Decline in limb-reduction defects was seen primarily among blacks (11%). Findings using hospitalization data were similar to recent reports using birth defect surveillance systems with the exception of findings for orofacial clefts and conotruncal heart defects. No reductions were noted in newborn hospitalizations for these anomalies.

CONCLUSIONS

Results from this ecological study fail to demonstrate substantial declines in newborn hospitalizations beyond those anticipated from a reduction in neural tube defects. The society-wide impact of the fortification program on birth defects and other health conditions should continue to be monitored.

Fortification of industrialized foods with vitamins

Vitamins are essential to life. Inadequate eating habits, high caloric intake and metabolic defects lead to micronutrient deficiencies, affecting more than two billion people worldwide. The increasing intake of industrialized foods, combined with low vitamin stability has led to the common practice of adding these nutrients to processed foods. This review discusses the terminology, availability, intake and risk of hypervitaminosis, due to the intake and nutritional importance of foods fortified with vitamins. The addition of nutrients should occur in foods that are effectively consumed by the target population and must meet the real needs of a significant segment of the population. In Brazil, a total of 166 products available in supermarkets are vitamin-enriched. A 10-year study involving children and adolescents in Germany showed that 90% of those surveyed used at least one fortified food. During this 10-year period, 472 fortified products were consumed. The enrichment of foods should be based on the needs of each country and, if possible, regional needs. For instance, in order to increase its intake, Vitamin D is added to foods in Denmark during the winter, mainly for the elderly. However, in Brazil, there is no evidence of the need to fortify food with this vitamin. A survey showed that of the 76 enriched dairy products, 37 contained vitamin D. Food-fortification is a very important strategy to solve nutritional deficiency problems, but it can also cause many health problems.

Trends in serum folate, RBC folate, and circulating total homocysteine concentrations in the United States: analysis of data from National Health and Nutrition Examination Surveys, 1988-1994, 1999-2000, and 2001-2002

Folate intakes increased dramatically after folic acid fortification. We investigated the changes in serum folate, RBC folate, and total homocysteine (tHcy) concentrations utilizing data from National Health and Nutrition Examination Surveys (NHANES) 1988-2002. NHANES 1988-2002 were based on a stratified, multistage, probability sampling design conducted among civilian U.S. residents. The current study included 17,144, 17,213, and 11,415 measurements for serum folate, RBC folate, and tHcy, respectively. Overall, geometric mean serum folate concentrations were 149.6 and 129.8% higher in 1999-2000 and 2001-2002, respectively, than in 1988-1994 (P < 0.0001). Sex-, age-, and race-ethnicity-adjusted serum folate was significantly lower in 2001-2002 than in 1999-2000 (10.4%, P < 0.0002). The prevalence of low serum folate decreased from 18.4% in 1988-1994 to 0.8% in 1999-2000 and to 0.2% in 2001-2002 (P < 0.0001). RBC folate increased from 391 nmol/L in 1988-1994 to 618 nmol/L in 1999-2000, and to 611 nmol/L in 2001-2002. Consequently, the prevalence of low RBC folate decreased from 45.8% in 1988-1994 to 7.3% in 1999-2000 and to 7.1% in 2001-2002 (P < 0.0001). Although, RBC folate status improved after folic acid fortification in all race-ethnicities, the prevalence of low RBC folate ( approximately 20.5%) continues to be high in non-Hispanic blacks. Age-, sex-, and race-ethnicity-adjusted tHcy declined from 9.5 micromol/L in 1988-1994 to 7.6 mumol/L in 1999-2000 and to 7.9 micromol/L in 2001-2002. Although folic acid fortification contributed to significant improvement in folate status, serum folate concentrations have declined recently. This may be attributable to lower folic acid intakes.

A comparison of the dietary and total intake of micronutrients in a group of pregnant Greek women with the Dietary Reference Intakes

OBJECTIVE

We compared the dietary and total (diet and supplement) intake of micronutrients with the Dietary Reference Intakes (DRIs) from the USA in a population of pregnant Greek women.

METHODS

Two hundred pregnant women participated in a nutritional survey, 98 in the second trimester and 102 in the third trimester in a random sampling. To examine dietary intake we used two questionnaires, the nutritional questionnaire for pregnant women from the California Department of Health Services, and a semi-quantitative questionnaire (Walter Willet) with modifications for use in Greece. Dietary intake analysis was performed using the Diet Analysis Plus software, Version 3, ESHA Research. Statistical analysis was performed with Minitab for Windows, Release 12. A simple complementary questionnaire concerning demographic and socio-economic features was also completed.

RESULTS

The average total intake of vitamins A, B(1), B(2), B(3), B(6), B(12) and C, calcium and phosphorus was higher than the respective DRIs. Folic acid and iron intake exceed the highest values specified for pregnancy. Vitamin E and zinc was lower than the DRIs, while vitamin D, magnesium and thiamin did not differ.

CONCLUSIONS

The results of our study suggest that in a Greek population, sufficient micronutrients appear to be received in adequate amount from diet, except for folic acid and iron, which also had to be taken in the form of nutritional supplements.

Reevaluating the benefits of folic acid fortification in the United States: economic analysis, regulation, and public health

Before a 1996 US regulation requiring fortification of enriched cereal-grain products with folic acid, 3 economic evaluations projected net economic benefits or cost savings of folic acid fortification resulting from the prevention of pregnancies affected by a neural tube defect. Because the observed decline in neural tube defect rates is greater than was forecast before fortification, the economic gains are correspondingly larger. Applying both cost-benefit and cost-effectiveness analytic techniques, we estimated that folic acid fortification is associated with annual economic benefit of 312 million dollars to 425 million dollars. The cost savings (net reduction in direct costs) were estimated to be in the range of 88 million dollars to 145 million dollars per year.

Folate Supplementation and Twin Pregnancies

BACKGROUND

Women in many countries are advised to increase their folate intake to lower the risk of neural tube defects. For this purpose several countries add folate to the flour. Therefore, it is important to monitor possible adverse effects of this B vitamin. We have assessed the effect of folate on twin pregnancies.

METHODS

We conducted a retrospective, population-register based study of 176,042 women who gave birth from December 1998 through the end of 2001. Use of folate and multivitamin supplements was recorded on the mandatory birth notification form of the Medical Birth Registry of Norway. Pregnancies after in vitro fertilization (IVF) were reported separately.

RESULTS

With adjustment for maternal age and parity, we observed an increased risk of twin pregnancies associated with preconceptional use of folate (odds ratio = 1.59; 95% confidence interval = 1.41-1.78). This association was largely explained by confounding with IVF pregnancies, which were strongly associated both with twin pregnancies and folate use. After exclusion of known IVF pregnancies, and accounting for underreporting of both IVF pregnancies and folate use, the risk was no longer elevated (1.02; 0.85-1.24). Weak associations with twin pregnancies were observed for use of multivitamins and folate during pregnancy, but could be due to increased use of vitamins after a recognized twin pregnancy.

CONCLUSIONS

The association between preconceptional folate use and twin pregnancies was strongly confounded by IVF. After accounting for IVF pregnancies and underreporting, we found no evidence for an association between preconceptional folate supplements and twinning.

An Exploration of Health Effects of Folic Acid in Pregnancy Beyond Reducing Neural Tube Defects

OBJECTIVES

First, to examine the biological basis of why folic acid may have health effects beyond its proven effect of reducing neural tube defects; and second, to explore current controversial policies of folic acid supplementation and food fortification.

METHODS

We searched MEDLINE for English-language papers published from 1991 to 2003, using the key words "folic acid" and "folate." The literature search was restricted to human studies. Of 8986 publications identified, 65 were relevant to the objectives of this paper.

RESULTS

Analysis of the literature revealed that a major mechanism of folic acid in improving infant health may be related to its effect in correcting maternal folate-homocysteine-methylenetetrahydrofolate reductase metabolic defects. Conversely, exposure to high levels of folic acid may have such adverse health effects as increased risk of neurologic disorders in the general population.

CONCLUSIONS

Randomized trials or well-designed prospective cohort studies are needed to assess the effects of folic acid on various pregnancy outcomes. To enable an examination of the association between folic acid and rare outcomes, such as a specific category of birth defects and fetal and neonatal deaths, it is necessary to recruit a large number of pregnant women to participate in such studies.

Impact of folic acid fortification in the United States: markedly diminished high maternal serum alpha-fetoprotein values

OBJECTIVE

Folic acid fortification of breads and grains was implemented in the United States in 1998 in an attempt to reduce the incidence of neural tube defects. Outcome data from birth registries have shown a 20% drop-less than originally predicted. In this study, we ascertain if the impact of folic acid fortification is better seen at the time of midtrimester prenatal diagnosis by looking at incidence of high maternal serum alpha-fetoprotein (MSAFP) values.

METHODS

Data regarding MSAFP levels in 61,119 patients undergoing maternal serum screening at a large commercial laboratory were categorized by multiples of the median (MoM). The data were compared between 2 groups: before mandatory supplementation in the United States in 1997 and after mandatory supplementation in 2000. High MSAFP values were further categorized as high (2.75-4.00 MoM) or very high (more than 4.00 MoM). Data were analyzed by chi(2) analysis.

RESULTS

Comparative data showed a 32% decrease of patients with MoM greater than 2.75 + (2.5% -1.7%). Further categorizations revealed similar decreases.

CONCLUSION

The introduction of folic acid fortification has produced a profound decrease in the number of high MSAFP values, reflective of a decreased incidence of neural tube defects. Our results help to validate the decision to fortify food with folic acid, which represents a highly successful public health policy for primary prevention of birth defects.

LEVEL OF EVIDENCE

II-2

Effects of folic acid fortification and multivitamin therapy on homocysteine and vitamin b12 status in cardiac transplant recipients

BACKGROUND

Hyperhomocysteinemia is a frequent finding after cardiac transplantation, but increased folate intake induces a decrease in total homocysteine concentrations. In 1998, food in Canada was fortified nationwide with folic acid. We assessed the impact of routine folate fortification on homocysteine concentrations in our cardiac transplant population.

METHODS

In 18 subjects, we measured total homocysteine (tHcy), serum folate, and cobalamin concentrations in 1997 (before folate fortification) and in 1998 (after fortification). We repeated the analysis after specific multivitamin supplementation for 10 weeks.

RESULTS

We found a significant decrease in baseline tHcy concentrations and in folate concentrations between 1997 and 1998. However, we also found a decrease in serum cobalamin concentrations. We found a correlation between decreased cobalamin concentrations and the methionine synthase A2756G genotype, but not with other common polymorphisms associated with homocysteine metabolism. After multivitamin supplementation, we observed a trend toward further decrease in tHcy concentrations and a significant increase in serum folate and cobalamin concentrations. Finally, we measured serum methylmalonic acid concentrations, an index of tissue cobalamin status. We did not find a correlation between increased methylmalonic acid concentrations and decreased serum cobalamin, perhaps related to the confounding effect of altered renal status on methylmalonic acid excretion.

CONCLUSIONS

National folate fortification was associated with decreased tHcy and increased folate concentrations in our cardiac transplant population. Additional administration of vitamin supplements induced a further decrease in tHcy and an increase in folate. Finally, folate fortification unveiled cobalamin deficiency in some patients, associated with the methionine synthase A2756G mutation.

Effects of once-a-week or daily folic acid supplementation on red blood cell folate concentrations in women

OBJECTIVE

Our aim was to determine if a once-a-week folic acid supplement increases women's red blood cell folate to concentrations (>905 nmol/l) that are associated with a low risk of bearing a child with a neural tube defect.

DESIGN

Randomized control trial.

SETTING

General community.

SUBJECTS

In total, 114 nonpregnant women (18-40 y) volunteers, with red blood cell folate concentrations between 295 and 905 nmol/l at screening.

INTERVENTION

Women were randomized to receive a once-a-week 2800 microg folic acid supplement, a daily 400 microg folic acid supplement or a daily placebo for 12 weeks.

RESULTS

The mean (95% CI) red blood cell folate concentrations increased during the 12-week intervention from 608 (553-668) to 900 (828-978) in the weekly folic acid group (P<0.05) and from 615 (560-677) to 1053 (957-1158) nmol/l in the daily group (P<0.05) during the trial. At week 12, 49% of women ingesting the weekly folic acid supplement had red blood cell folate concentrations greater than 905 nmol/l compared to 74% of women ingesting the daily supplement.

CONCLUSION

A once-a-week 2800 microg folic acid supplement can increase women's red blood cell folate to concentrations associated with a reduced risk of bearing a child with a neural tube defect, but is less effective than a 400 microg daily supplement. Use of a weekly folic acid supplement over at least 12 weeks before conception by women of child-bearing age may prevent neural tube defects.

FUNDING

The Otago Medical Research Foundation (Laurenson Award). Healtheries (New Zealand) provided the supplements.

Folate intake assessment: validation of a new approach

OBJECTIVE

To describe the performance characteristics and validate a folate-specific focused recall approach to estimating folate intake.

DESIGN

In a cross-sectional study, folate-specific recalls were used to estimate subjects' average daily folate intake from seven days of dietary recall over a one-month period. This estimate was compared to an estimate of the average daily folate intake obtained using the Fred Hutchinson Cancer Research Center Food Frequency Questionnaire (FFQ) and to plasma folate and homocysteine concentrations.

SUBJECTS

Subjects were women aged 21 to 47 years and were recruited from the university community. Thirty-three subjects were recruited, and 28 subjects completed the study.

INTERVENTION

After an initial clinic visit, during which a baseline blood sample was collected for measurement of plasma folate and total homocysteine concentrations, subjects participated in focused dietary recall interviews by telephone and/or Internet (e-mail). At the end of the month, subjects completed the FFQ. Main outcome measures The main outcome measures were to describe how well the focused recalls were able to describe relative dietary folate intake as compared to the FFQ and if the focused recall method estimate correlated with plasma folate and homocysteine concentrations. Statistical analyses Estimated folate intakes were ranked by tertiles using the two dietary assessment approaches and the rankings were compared. The Spearman correlation test was used to compare the focused recall and the FFQ dietary data to plasma folate and homocysteine concentrations.

RESULTS

Estimated folate intake inclusive of supplements was 411.4+/-192.8 (mean+/-SD) microg/day based on focused recalls and 458.5+/-221.5 microg/day based on the FFQ. Exclusive of supplements, estimated folate intake from the diet was 327.8+/-30.2 microg/day based on focused recalls and 373.5+/-155.6 microg/day based on the FFQ. The ranking comparison of focused recalls vs the FFQ demonstrated a concordance of 44% without supplements and 67% with supplements for the highest tertile, and 56% without supplements and 67% with supplements for the lowest tertile. Estimated folate intake based on focused recalls was correlated significantly with plasma homocysteine (r=-0.443, P<.02) and was marginally significantly correlated with plasma folate (r=0.354; P=.06) concentrations.

APPLICATIONS

A focused dietary recall approach is a useful method for collecting information on folate intake in women. Estimated folate intake based on the focused recall approach is reasonably correlated with plasma folate and total homocysteine concentrations even in this small sample of women. Accurate data on folate intake can form the basis of dietary counseling to increase intake of this important micronutrient in the target population of young women.

Low vitamin B-12 concentrations in patients without anemia: the effect of folic acid fortification of grain

BACKGROUND

In some patients with vitamin B-12 deficiency mistakenly treated with folic acid, anemia resolved but neurologic complications became worse (masking). Fortification of enriched cereal grains with folic acid has raised concerns that people who consume large quantities of cereal grains, particularly the elderly, may be at increased risk of masking. It is unclear, however, what proportion of people with low vitamin B-12 concentrations do not have anemia and whether the proportion is increasing.

OBJECTIVE

We investigated whether fortification has increased the proportion of patients with low vitamin B-12 but without anemia.

DESIGN

We reviewed the laboratory results of every patient for whom a vitamin B-12 concentration was measured at the Veterans Affairs Medical Center in Washington, DC, between 1992 and 2000. Those with a low vitamin B-12 concentration (< 258 pmol/L) had their hematocrits and mean cell volumes checked. The proportion without anemia was examined by year before, during, and after folic acid fortification began.

RESULTS

There were 1573 subjects with a low vitamin B-12 concentration. The proportion without anemia did not increase significantly from the prefortification period (39.2%) to the period of optional fortification (45.5%) and the postfortification period (37.6%). These findings did not change when the analysis was limited to patients aged > 60 y or when a more conservative definition of low vitamin B-12 (< 150 pmol/L) was used.

CONCLUSIONS

Despite evidence that folic acid exposure has increased dramatically since food fortification began, this population showed no evidence of an increase in low vitamin B-12 concentrations without anemia. If confirmed, these results would indicate that food fortification has not caused a major increase in masking of vitamin B-12 deficiency.

Risk analysis applied to food fortification

OBJECTIVE

To describe how a risk analysis can be applied to food fortification, with emphasis on voluntary fortification and intake levels that might exceed usual dietary levels.

DESIGN

Use of the risk analysis model as a frame to classify nutrients according to the risk of exceeding upper safe intake levels. Furthermore, to apply the model when discussing possible consequences of liberal fortification practices on eating behaviour and disease patterns.

SETTING

The discussion on food fortification presently going on internationally.

RESULTS

Micronutrients can be classified according to their safety margin, i.e. the size of the interval between the recommended intake and the upper safe level of intake. We suggest that nutrients with a small safety margin, i.e. for which the upper safe level is less than five times the recommended intake, be placed in a category A and should be handled with care (retinol, vitamin D, niacin, folate and all minerals). Category B comprises nutrients with an intermediate safety margin (vitamins E, B6, B12 and C), while nutrients that according to present knowledge are harmless even at 100 times the recommendation (vitamin K, thiamin, riboflavin, pantothenic acid and biotin) are categorised as C.

DISCUSSION

The risk analysis model is a useful tool when assessing the risk of both too low and excess intakes of single micronutrients, but can also be applied to analyse the consequences of fortification practices on eating behaviour and disease patterns. Liberal fortification regulations may, for example, distort the conception of what is healthy food, and drive consumption towards a more unhealthy diet, contributing to the plague of overweight and concomitant increased risk of degenerative diseases.

CONCLUSION

The impact of fortification practices on the total eating pattern of a population should become an integrated part of the discussions and regulations connected to the issue.

The interaction between MTHFR 677 C-->T genotype and folate status is a determinant of coronary atherosclerosis risk

The 677 C-->T polymorphism in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene interacts with folate status in determining elevated total plasma levels of homocysteine, a risk factor for coronary atherosclerotic disease (CAD). The present study had the following goals: 1) to define the 677 C-->T genotype-specific threshold values of both plasma and RBC folate, associated with hyperhomocysteinemia (>15 micro mol/L); and 2) to determine the risk of CAD among subjects with levels of folate below the genotype-specific threshold considered at risk for hyperhomocysteinemia. We examined 655 subjects, with (433) or without (222) angiographically documented CAD. The MTHFR 677 C-->T genotype-specific threshold values of plasma folate corresponded to the 40th, 30th and 10th percentile in the TT, CT and CC genotype, respectively. A multivariate logistic regression analysis showed that the risk of CAD among subjects with plasma folate levels below the genotype-specific thresholds was 1.6 (95% CI, 1.04-2.46). Similar results were obtained when RBC folate was considered as a measure of folate status (odds ratio = 1.8, 95% CI, 1.03-3.15). A gene-nutrient interaction that defines a higher risk for CAD is determined by folate levels below specific thresholds, which differ depending on the MTHFR 677 C-->T genotype.

Screening for vitamin B-12 and folate deficiency in older persons

BACKGROUND

Vitamin B-12 deficiency is usually accompanied by elevated concentrations of serum total homocysteine (tHcy) and methylmalonic acid (MMA). Folate deficiency also results in elevated tHcy. Measurement of these metabolites can be used to screen for functional vitamin B-12 or folate deficiency.

OBJECTIVE

We assessed the prevalence of vitamin B-12 and folate deficiency in a population-based study (n = 1562) of older persons living in Oxford City, United Kingdom.

DESIGN

We postulated that, as vitamin B-12 or folate concentrations declined from adequate to impaired levels, tHcy (or MMA) concentrations would increase. Individuals were classified as being at high risk of vitamin B-12 deficiency if they had low vitamin B-12 (< 150 pmol/L) or borderline vitamin B-12 (150-200 pmol/L) accompanied by elevated MMA (> 0.35 micromol/L) or tHcy (> 15.0 micromol/L). Individuals were classified as being at high risk of folate deficiency if they had low folate (< 5 nmol/L) or borderline folate (5-7 nmol/L) accompanied by elevated tHcy (> 15 micromol/L).

RESULTS

Cutoffs of 15.0 micro mol/L for tHcy and 0.35 micro mol/L for MMA identified persons with normal or elevated concentrations. Among persons aged 65-74 and >or= 75 y, respectively, approximately 10% and 20% were at high risk of vitamin B-12 deficiency. About 10% and 20%, respectively, were also at high risk of folate deficiency. About 10% of persons with vitamin B-12 deficiency also had folate deficiency.

CONCLUSION

Use of tHcy or MMA among older persons with borderline vitamin concentrations may identify those at high risk of vitamin B-12 deficiency who should be considered for treatment.

Folate intake and the risk of neural tube defects: an estimation of dose-response

BACKGROUND

Studies have shown that folic acid supplementation in early pregnancy markedly reduces the risk of neural tube defects (NTDs). Investigation of the relation between relative dose of supplemental folic acid or total folate intake and NTD risk is limited.

METHODS

We used data from 23,228 women, predominantly from the northeastern United States, enrolled between October 1984 and June 1987 in a prospective study of early prenatal exposures and pregnancy outcomes. Diet and vitamin intake data were gathered in the early second trimester. NTDs were ascertained through prenatal testing and by report of the delivering physician. Data analyses included multiple logistic regression and restricted spline regression modeling.

RESULTS

For each additional 500 dietary folate equivalents consumed per day, the prevalence of NTDs decreased by 0.78 cases (95% confidence interval [CI] = 0.47-1.09) per 1,000 pregnancies. Compared with women having the lowest total folate intakes (0-149 folate equivalents per day), the prevalence of NTDs declined by 34%, 30%, 56% and 77% among the offspring of those women consuming 150-399, 400-799, 800-1199 and > or = 1200 folate equivalents per day, respectively (P-value for linear trend = 0.016).

CONCLUSIONS

Our results suggest that NTD risk declines markedly with modest increases of total folate in early pregnancy. Total folate dose, rather than supplemental folate alone, should be considered in formulating public health guidelines for NTD prevention.

Folate: a key to optimizing health and reducing disease risk in the elderly

Inadequate folate status is associated with an increased risk for chronic diseases that may have a negative impact on the health of the aging population. Folate, a water-soluble vitamin, includes naturally occurring food folate and synthetic folic acid in supplements and fortified foods. Inadequate folate status may result in hyperhomocysteinemia, a significant risk factor for atherosclerotic vascular disease, changes in DNA that may result in pro-carcinogenic effects and increased risk for cognitive dysfunction. Folate status may be negatively influenced by inadequate intake, genetic polymorphisms and interactions with various drugs. In the US, folic acid is now added to enriched grain products and continues to be included in the majority of ready-to-eat breakfast cereals. Recent data indicate that the folate status in the US population has improved significantly, presumably due to the effects of fortification. Folic acid (not food folate) intake in excess of the Tolerable Upper Intake Level may mask the diagnosis of a vitamin B(12) deficiency, which is more prevalent in the elderly than younger individuals. When folic acid supplements are recommended, a multivitamin that includes vitamin B(12) should also be advised. To safely and effectively increase folate intake in the elderly, naturally occurring folate-rich food sources should be promoted. Folate-rich foods include orange juice, dark green leafy vegetables, asparagus, strawberries and legumes. These foods are also excellent sources of other health-promoting nutrients associated with chronic disease risk reduction.

Folate intakes and awareness of folate to prevent neural tube defects: a survey of women living in Vancouver, Canada

OBJECTIVE

To estimate folate intake and knowledge in women of childbearing age, in relation to risk of neural tube defects.

SUBJECTS/SETTING

One hundred forty-eight women (aged 18 to 45 years) in the Vancouver area of British Columbia, Canada.

DESIGN

Using an interviewer-administered survey, we examined women for folate knowledge and the relation of folate knowledge to intake in a random sample. Contribution of folate from food, fortified grain products, and supplements was assessed by validated semiquantitative food frequency questionnaire.

STATISTICAL ANALYSIS PERFORMED

Descriptive statistics, t tests, Chi;(2), Pearson correlation analysis.

RESULTS

Mean daily folate intake from food, fortified foods, and supplementation was 812+/-710 Dietary Folate Equivalents (DFE)/day. Fortification of bread and grain products contributed 104+/-68 microg synthetic folic acid (SFA)/day (equal to 174+/-114 DFE), and supplements contributed 205+/-388 microg SFA/day. Although 86% of women met the Estimated Average Requirement (320 DFE/day) for folate, only 26% met the recommendation (400 microg SFA/day) for women capable of becoming pregnant. Most (95%) of the women had heard of folate, but only 25% knew that it could prevent birth defects. One-fourth of the women had good or very good knowledge of folate-rich foods. However, folate knowledge was not related to its intake. The most common sources of folate information were magazines/newspapers, doctors, and television/radio. Lack of awareness of the importance of folate was the most common reason given for choosing not to use folic acid supplements before pregnancy. However, 78% of the women indicated that, with knowledge of the benefits of folate, they would use supplemental folic acid daily to reduce the risk of birth defects.

APPLICATIONS/CONCLUSIONS

Educational strategies are required to increase folate awareness among women and to promote the benefits of periconceptional folic acid supplementation. Targeting physicians to educate women on the importance of folate could be a potentially successful route. J

Dietary counseling to increase natural folate intake: a randomized, placebo-controlled trial in free-living subjects to assess effects on serum folate and plasma total homocysteine

BACKGROUND

The association between vascular disease and elevated plasma total homocysteine (tHcy) concentrations is caused, in part, by inadequate intakes of dietary folate. Increasing folate intake either through supplements or foods naturally rich in folates has been shown to decrease tHcy concentrations.

OBJECTIVE

The aim of this study was to determine whether a similar reduction in tHcy was possible in free-living persons receiving dietary counseling.

DESIGN

The study included a 4-wk placebo-controlled dietary intervention trial in which participants consumed either unfortified breakfast cereal (control group) or an extra 350 micro g folate derived from food/d (dietary group). Serum folate and tHcy concentrations in both groups were measured before and after the intervention period, and the concentrations in the dietary group were also measured 17 wk after the intervention period.

RESULTS

During the 4-wk intervention, mean dietary folate intake in the dietary group increased from 263 (95% CI: 225, 307) to 618 micro g/d (535, 714), resulting in a mean increase in serum folate of 37% (15%, 63%) and a decrease in tHcy from 12.0 (10.9, 13.3) to 11.3 micro mol/L (10.2, 12.5). A further decrease in tHcy occurred in the dietary group during follow-up, with a final tHcy concentration of 9.7 micro mol/L (8.8, 10.8).

CONCLUSIONS

Increasing natural folate intake improved folate status and decreased tHcy concentrations to an extent that may significantly reduce the risk of vascular disease. Dietary modification may have advantages over folic acid fortification because the altered food-consumption patterns lead to increased intakes of several vitamins and minerals and decreased intakes of saturated fatty acids.

Potential prevention of neural tube defects by assessment of women of childbearing age through monitoring of folate

BACKGROUND

Three quarters of neural tube defects (NTD) can be prevented by sufficient dietary folate supplementation. Despite this knowledge, most women do not supplement their diet effectively. Red cell folate concentrations correlate with the risk of NTD, and levels of less than 900 nM are associated with an increased risk of these serious congenital anomalies.

OBJECTIVE

Laboratory tests to assess anemia include testing for folate. This study was conducted to estimate the potential benefits of informing women of reproductive age who are unaware of their low folate levels, uncovered in their anemia tests.

METHODS

The number of Ontario women of reproductive age who undergo folate tests and are at an increased risk of NTD was calculated. In addition, the authors calculated the number of NTD cases that could have been prevented if these women were informed of the possible consequences of their low folate levels should they become pregnant.

RESULTS

In 1998, red cell folate concentrations were measured in 23,109 women of childbearing age (15-45 y). Approximately half of the women [n = 11,392 (49.3%)] had folate levels below 900 nM and thus were at an increased risk of giving birth to a child with NTD should they have become pregnant. Their overall mean relative risk (RR) of NTD was 1.95, or 1:512 births. If they would have been informed of this risk and subsequently increased their consumption of folate before becoming pregnant, 22.3 cases of NTD per year could have possibly been prevented at no extra cost, since the folic acid results were a part of investigational blood tests performed for another reason (anemia).

CONCLUSIONS

Women of reproductive age who are being evaluated for the cause of anemia and have low red cell folate results constitute a high-risk group for NTD in their children. These women should be informed of the increased risk and of methods of dietary folate supplementation.