Sources of folate and serum folate levels in older adults

This study examined dietary folate intake in 173 older adults. A subsample (n=128) also provided data about folic acid from vitamin/mineral supplements and serum folate. Subjects were community-dwelling men and women 60 years of age and older. Overall, this sample had healthful dietary patterns with adequate dietary folate. Mean dietary intake converted to dietary folate equivalents (DFE) was 464 microg DFE/day. However, 20% (n=36) had inadequate and 2% (n=3) had high dietary DFE (>1,000 microg DFE/day). A subsample (n=128) completed a dietary supplement questionnaire and biochemical assessment of folate. Adding folic acid from vitamin/mineral supplements to dietary folate (total DFE), intake increased to 766 microg DFE/day; 13% (n=16) had inadequate, 75% (n=95) had adequate, and 13% (n=13) had high total DFE. No subject with low total DFE reported supplement use, but 94% (n=39) with high total DFE intake did so. In the subsample, all subjects had acceptable serum folate levels (mean serum folate=28.0+/-13.8 ng/mL [63.5+/-31.3 nmol/L]). In conclusion, vitamin/mineral supplements should be included in nutrition assessment of older adults. Older adults may be at risk for inadequate folate intake if their energy intake is low, they do not take a vitamin/mineral supplement, or are not consuming fortified cereals. However, older adults may be at risk for excess folic acid intake if they consume both a supplement and fortified cereals.     

Folate fortification: potential impact on folate intake in an older population

OBJECTIVE: To examine the potential impact of different models of folate fortification of Australian foods on the folate intakes of older Australians. DESIGN: Dietary data were collected using a food frequency questionnaire from people attending a population-based health study. SETTING: Two postcode areas west of Sydney, Australia. SUBJECTS: A total of 2895 people aged over 49 y, obtained from a door knock census (79% of 3654 subjects examined). MAIN OUTCOME MEASURES: The folate intake in this population was estimated using four different models: (1) pre-fortification folate values; (2) current voluntary folate fortification in Australia; (3) universal fortification of all foods permitted to add folate, at 25% recommended dietary intake (RDI) per reference serve; and (4) universal fortification of all foods permitted to add folate, at 50% RDI per reference serve. The increased bioavailability of synthetic folic acid (SFA) was included in the analysis. RESULTS: At current voluntary folate fortification, approximately 65% of this population consume 320 microg dietary folate equivalents (DFE) or more per day from diet and supplements, and 0.4% (n=10) consume greater than the recommended upper safety level of 1000 microg from SFA. More than 95% of this older population would be expected to consume more than 320 microg DFE from diet and supplements with universal fortification at 50% of the RDI, and 0.5% (n=14) may consume greater than 1000 microg/day of SFA. CONCLUSIONS: There is unlikely to be a large increase in the proportion of older persons who are likely to consume more than the upper safety level of intake with universal folate fortification. As most of those who currently or are predicted to consume over 1000 microg SFA take supplements containing folic acid, it is highly recommended that vitamin B12 be included in any vitamin supplements containing folate. SPONSORSHIP: This study was supported by the Australian National Health and Medical Research Council (NHMRC).     

Race-ethnicity differences in folic acid intake in women of childbearing age in the United States after folic acid fortification: findings from the National Health and Nutrition Examination Survey, 2001-2002

BACKGROUND: Neural tube defects are serious birth defects of the brain and spinal cord. Up to 70% of neural tube defects can be prevented by the consumption of folic acid by women before and early during pregnancy. OBJECTIVE: The objective was to examine folic acid intake in women of childbearing age in the United States. DESIGN: We analyzed nutrient intake data reported by 1685 nonpregnant women aged 15-49 y who participated in the National Health and Nutritional Examination Survey, 2001-2002. RESULTS: The adjusted geometric mean consumption of folic acid from fortified foods was 128 microg/d (95% CI: 123, 134 microg/d) in nonpregnant women. Eight percent (95% CI: 5.8%, 11.0%) of nonpregnant women reported consuming >or=400 microg folic acid/d from fortified foods. This proportion was lower among non-Hispanic black women (5.0%) than among non-Hispanic white (8.9%) or Hispanic (6.8%) women. A smaller percentage of non-Hispanic black (19.1%) and Hispanic (21%) women than of non-Hispanic white women (40.5%) consumed >or=400 microg folic acid from supplements, fortified foods, or both, in addition to food folate, as recommended by the Institute of Medicine to reduce the frequency of neural tube defects. CONCLUSIONS: Most nonpregnant women of childbearing age in the United States reported consuming less than the recommended amount of folic acid. The proportion with low daily folic acid intake was significantly higher in non-Hispanic black and Hispanic women than in non-Hispanic white women. At the present level of folic acid fortification, most women need to take a folic acid-containing dietary supplement to achieve the Institute of Medicine recommendation.     

Folate promotion in Western Australia and the prevention of neural tube defects

OBJECTIVES: We conducted a case-control study to investigate the effectiveness of efforts to increase folate intake in Western Australia (WA) for the prevention of neural tube defects (NTD). METHODS: Case (36) and control (578) mothers completed questionnaires, from which their intake of folate from supplements and food (including fortified foods) was estimated. RESULTS: Almost one-third of women took folic acid supplements periconceptionally. Supplement use was associated with a non-significant 4% reduction in risk. For women not taking supplements, dietary sources of folate were protective, and most women obtained at least some folate from fortified food. CONCLUSIONS: For the two-thirds of WA women not taking supplements, fortified food is an important source of folate for the prevention of NTD. IMPLICATIONS: Greater promotion of foods currently allowed to be fortified with folate, or mandatory fortification, is needed to maximise prevention of NTD in Australia.     

Acculturation factors are associated with folate intakes among Mexican American women

Folic acid can prevent neural tube defects (NTD). Hispanic women have a higher prevalence of NTD than non-Hispanic white (NHW) women and consume less folic acid. Among Hispanics, acculturation has been associated with lower intakes of natural folate. It is unknown if this same relationship is seen for fortified foods. This article describes the associations of acculturation factors with usual folate intakes from foods and supplements and compares the proportion that meets recommended intakes of folic acid of US Mexican American (MA) women with those of NHW women. For US NHW and MA women aged 15-44 y (n = 3167), usual folate intakes (i.e., natural food folate, folic acid from food, total folic acid [fortified foods plus supplements], and total folate) were estimated using measurement error models from NHANES 2001-2008. Compared with NHW women, MA women did not differ in their intake of natural food folate or folic acid from food. Similarly, compared with NHW women (332 ± 17.3 μg/d), the mean total usual folic acid intakes were lower among MA women who reported speaking Spanish (224 ± 24.9 μg/d) but not for MA women who reported speaking English (283 ± 36.2 μg/d). MA women were more likely than NHW women to consume a total folic acid intake <400 μg/d. MA women with lower acculturation factors were the most likely to have an intake <400 μg/d compared to NHW women. Public health efforts should focus on increasing total folic acid intake among MA women, emphasizing those with lower acculturation factors (e.g., MA women who report speaking Spanish).     

A comparison of the effect of advice to eat either '5-a-day' fruit and vegetables or folic acid-fortified foods on plasma folate and homocysteine

OBJECTIVE: To assess and compare the effects of natural folate (100 micro g) with those of folic acid from fortified sources (100 micro g/day) on plasma folate and homocysteine. DESIGN: Randomized controlled trial (parallel groups). SETTING: Men and women living in South Wales, UK. SUBJECTS: A total of 135 healthy individuals recruited from the local workforce and blood donor sessions. All subjects possessed the 'wild-type' CC genotype for C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR). INTERVENTIONS: Subjects underwent one of the following dietary interventions for 4 months: (1) fortified diet-usual diet plus 100 microg/day folic acid from fortified foods; (2) natural folate diet-usual diet plus 100 microg/day folate from natural sources; (3) control-usual diet. RESULTS: The fortified group increased reported intake of folic acid from fortified foods compared to other groups (P<0.001) achieving an extra 98 microg/day (95% CI 88-108). The natural folate group increased reported intake of natural source folates compared with the other two groups (P<0.001), but achieved a mean increase of only 50 microg/day (95% CI 34-66). Plasma folate increased (P<0.01) by a similar amount in both intervention groups compared to controls (fortified group 2.97, 95% CI 0.8-5.1; natural group 2.76, 95% CI 0.6-4.9. Plasma homocysteine, vitamins B(6) and B(12) were not significantly changed. CONCLUSIONS: Subjects achieved increases in folate intake using fortified foods more easily than by folate-rich foods, however both sources increased plasma folate by a similar amount. These levels of intake were insufficient to reduce homocysteine concentrations in MTHFR CC homozygotes, but may be more effective in other genotypes.     

Folate Status of Young Canadian Women after Folic Acid Fortification of Grain Products

Women of childbearing age are advised to consume folic acid–containing supplements. Whether this remains necessary after folic acid fortification of the food supply in North America has yet to be determined. The objectives of this study were to assess folate intakes and the contribution of folic acid to the diets of women of childbearing age in the post–folic acid fortification era. Using a cross-sectional study design, fasting blood samples were obtained from 95 women (aged 18 to 25 years), and the samples were analyzed for serum and red blood cell folate, as well for total homocysteine. Dietary and supplemental folate intakes were assessed. The biochemical evidence showed that no women were folate deficient, but only 14% reached red blood cell folate concentrations associated with significant reductions in neural tube defect risk. Mean dietary intake of food folic acid was 96±64 μg/day, supplemental folic acid was 94±189 μg/day, natural folate was 314±134 μg/day, and the total intake, as dietary folate equivalents, was 646±368 μg dietary folate equivalents/day. Therefore, intakes of folic acid from fortified foods are within the level originally predicted for the fortification efforts; however, only 17% of participants met the special recommendation for women capable of becoming pregnant (400 μg folic acid daily from supplements, fortified foods, or both in addition to consuming food folate from a varied diet). These data suggest that women of childbearing age are achieving positive folate status in the postfortification era, but it may not be sufficient to achieve red blood cell folate concentrations associated with a significant reduction in neural tube defect risk. Even with food fortification, women of childbearing age should be advised to take a folic acid–containing supplement on a daily basis.     

Promotion of folate for the prevention of neural tube defects: who benefits?

Since the publication of randomised trials showing firm evidence of prevention of neural tube defects with periconceptional folic acid, there have been population health promotion programmes to encourage women to take folic acid supplements, and the introduction of voluntary fortification of some foods with folic acid in Australia. In order to evaluate these two strategies, we collected data by self-administered questionnaire from a random sample of recently pregnant women in Western Australia between September 1997 and March 2000. Response to health promotion was measured in three ways: (1) knowledge of the association between periconceptional folate and prevention of spina bifida (the 'correct message'); (2) use of periconceptional vitamin supplements of folic acid daily in the periconceptional period; and (3) daily folate intake from fortified foods in the 6 months before pregnancy. We examined the relationship of maternal demographic and behavioural characteristics with these three measures. Overall, 62.3% of women were aware of the correct message before pregnancy, 28.5% reported taking 200 microg or more of folic acid from supplements daily in the periconceptional period and 56.6% of women obtained 100 microg or more of folic acid from fortified foods. Women who first became aware of the correct message during pregnancy or who were unaware of the correct message before or during pregnancy were more likely than women aware before pregnancy to be younger, having their first pregnancy, be single or in a de facto relationship, have no tertiary education, and be a public patient. Similar associations were seen for women taking either no folic acid or < 200 microg of folic acid in supplements daily in the periconceptional period. There were no significant associations between these demographic variables and amount of folate obtained from fortified foods. Women who were unaware of the correct message and did not take folic acid supplements were more likely to have smoked, not to have engaged in exercise, and not to have planned their pregnancy, whereas there was no association with these behavioural characteristics and intake of folate from fortified foods. These results indicate that health promotion strategies have not reached all segments of the target population equally, but there is no such disparity with folate-fortified foods, and they suggest that mandatory fortification of a staple food is likely to reach all women regardless of demographic and behavioural characteristics, and hence provide improved opportunity for prevention of neural tube defects in Australia.     

Assessing the Association between Natural Food Folate Intake and Blood Folate Concentrations: A Systematic Review and Bayesian Meta-Analysis of Trials and Observational Studies

Folate is found naturally in foods or as synthetic folic acid in dietary supplements and fortified foods. Adequate periconceptional folic acid intake can prevent neural tube defects. Folate intake impacts blood folate concentration; however, the dose-response between natural food folate and blood folate concentrations has not been well described. We estimated this association among healthy females. A systematic literature review identified studies (1 1992–3 2014) with both natural food folate intake alone and blood folate concentration among females aged 12–49 years. Bayesian methods were used to estimate regression model parameters describing the association between natural food folate intake and subsequent blood folate concentration. Seven controlled trials and 29 observational studies met the inclusion criteria. For the six studies using microbiologic assay (MA) included in the meta-analysis, we estimate that a 6% (95% Credible Interval (CrI): 4%, 9%) increase in red blood cell (RBC) folate concentration and a 7% (95% CrI: 1%, 12%) increase in serum/plasma folate concentration can occur for every 10% increase in natural food folate intake. Using modeled results, we estimate that a natural food folate intake of ≥450 μg dietary folate equivalents (DFE)/day could achieve the lower bound of an RBC folate concentration (~1050 nmol/L) associated with the lowest risk of a neural tube defect. Natural food folate intake affects blood folate concentration and adequate intakes could help women achieve a RBC folate concentration associated with a risk of 6 neural tube defects/10,000 live births.     

A long-term controlled folate feeding study in young women supports the validity of the 1.7 multiplier in the dietary folate equivalency equation

The presence of folic acid in enriched cereal grain products and the higher bioavailability of folic acid than food folate led to the expression of the 1998 folate RDA, 400 microg/d, as dietary folate equivalents (DFE). DFE are defined as: mug natural food folate + 1.7 x microg synthetic folic acid. The 1.7 multiplier was based on assumptions that added folic acid was 85% available and food folate was 50% available. The 85/50 ratio also inferred that the bioavailability of food folate was approximately 60% relative to added folic acid. The objective of this long-term controlled feeding study was to assess the dietary folate equivalency of folic acid. After a 2-wk period of folate restriction, women (n = 42, 18-45 y old) consumed either 400 or 800 microg DFE/d derived from various combinations of food folate and folic acid for 12 wk. Folic acid was converted to DFE using the 1.7 multiplier from the DFE calculation and was consumed with a meal throughout the treatment period. Folate status response to the various treatments was assessed during wk 12-14. Serum folate, RBC folate, and plasma total homocysteine did not differ among the 400 microg DFE/d groups or among the 800 microg DFE/d groups. In contrast, consumption of 800 microg DFE/d led to higher (P 相似文献   

Fortifying food with folic acid improves folate intake in German infants, children, and adolescents

Folate is a critical nutrient and programs to enhance folate intake have been established or are under consideration. We investigated to what extent consumers (C) profit from folic acid-fortified food and dietary supplements compared to nonconsumers (NC) of these products. A total of 6135 weighed records from 861 subjects (47% males, 53% females, age 6 mo to 18 y) from the Dortmund Nutritional and Anthropometric Longitudinally Designed Study between 1990 and 2001 were evaluated. In 61% of the records, at least 1 item fortified with folic acid was reported, and in total 644 different items with a wide range of fortification levels were found. These were primarily commercial infant food (i.e., infant formula, weaning food) (44%), breakfast cereals (20%), and soft drinks (11%). Median dietary folate equivalents (DFEs) in NC increased from 65 and 62 microg/d in boys and girls at 6-12 mo of age, respectively, to 184 and 143 microg/d in adolescents 15-18 y of age. In C, DFEs increased from 109 and 100 microg/d in boys and girls at 6-12 mo of age, respectively, to 370 and 276 microg/d in adolescents 15-18 y of age. Irrespective of gender, NC had 50-70% the DFE intakes of C with a tendency for higher percentages in younger than in older children and adolescents. Folate intakes by male and female consumers of fortified food or supplements exceeded the upper levels in 1.7 and 1.2% of subjects, respectively. Currently, a fortification program for staple foods (e.g., grain products) does not seem necessary in Germany if children and adolescents consume food already fortified with folic acid.     

Fortification with low amounts of folic acid makes a significant difference in folate status in young women: implications for the prevention of neural tube defects.

BACKGROUND: Mandatory fortification of grain products with folic acid was introduced recently in the United States, a policy expected to result in a mean additional intake of 100 microgram/d. One way of predicting the effectiveness of this measure is to determine the effect of removing a similar amount of folic acid as fortified food from the diets of young women who had been electively exposed to chronic fortification. OBJECTIVE: The objective was to examine the effect on folate status of foods fortified with low amounts of folic acid. DESIGN: We investigated the changes in dietary intakes and in red blood cell and serum concentrations of folate in response to removing folic acid-fortified foods for 12 wk from the diets of women who reportedly consumed such foods at least once weekly (consumers). RESULTS: Consumers (n = 21) had higher total folate intakes (P = 0.002) and red blood cell folate concentrations (P = 0.023) than nonconsumers (women who consumed folic acid-fortified foods less than once weekly; n = 30). Of greater interest, a 12-wk intervention involving the exclusion of these foods resulted in a decrease in folate intake of 78 +/- 56 microgram/d (P < 0.001), which was reflected in a significant reduction in red blood cell folate concentrations (P < 0.05). CONCLUSIONS: Cessation of eating folic acid-fortified foods resulted in removing 78 microgram folic acid/d from the diet. Over 12 wk this resulted in a lowering of red blood cell folate concentrations by 111 nmol/L (49 microgram/L). This magnitude of change in folate status in women can be anticipated as a result of the new US fortification legislation and is predicted to have a significant, although not optimal, effect in preventing neural tube defects.     

Folic acid intake from fortification in United States exceeds predictions

In 1996, the U.S. Food and Drug Administration issued a regulation requiring that all enriched cereal-grain products be fortified with folic acid by January 1998. An average increase in folic acid intake of 100 micro g/d was projected as a result of this fortification. The objective of the present study was to estimate the effect of this fortification on the intake of folic acid and total folate, and on the prevalence of individuals with inadequate folate intake and with high folic acid intake. We used data on food and nutrient intake from 1480 individuals who participated in the 5th and 6th examinations of the Framingham Offspring Cohort Study. Fortification was instituted during the 6th examination so that 931 participants were examined before its implementation (nonexposed) and 549 after implementation (exposed). Published data on total folate in enriched cereal-grain products were used to correct folate content in these foods to reflect fortification. Among nonsupplement users, folic acid intake increased by a mean of 190 [95% confidence interval (CI): 176, 204] micro g/d (P < 0.001) and total folate intake increased by a mean of 323 (95% CI: 296-350) micro g dietary folate equivalents (DFE)/d (P < 0.001) in the exposed participants. Similar increases were seen among supplement users exposed to fortification. The prevalence of exposed individuals with total folate intake below the estimated average requirement (320 micro g DFE/d) decreased from 48.6% (95% CI: 44.2-53.1%) before fortification to 7.0% (95% CI: 3.1-10.9%) after fortification in individuals who did not use folic acid supplements. This prevalence was approximately 1% or less for users of supplements both before and after fortification. Prevalence of individuals with folic acid intake above the upper tolerable intake level (1000 micro g folic acid/d) increased only among supplement users exposed to fortification (from 1.3 to 11.3%, P < 0.001). No changes in folic acid intake were observed over time in the nonexposed participants. By these estimations, folic acid fortification resulted in a mean increase in folic acid intake that was approximately twice as large as previously projected.     

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.     

Folate intakes and folate biomarker profiles of pregnant Japanese women in the first trimester

OBJECTIVE: To assess the status of dietary folate intake, serum and red blood cell (RBC) folate, and related nutritional biomarkers in healthy Japanese women in early pregnancy. DESIGN: A cross-sectional, observational study. SUBJECTS: Pregnant women in the first trimester, at 7-15 weeks gestation (n=70), who were not consuming any folate supplements or folate fortified foods. METHODS: Three-day dietary records were obtained from each subject to assess dietary folate intake. Blood samples were collected for measurement of biomarkers. Biomarkers and nutrient intake were analyzed in two groups defined by their serum folate concentrations: the low folate group (serum folate < 9 ng/ml) and the high folate group (serum folate > or = 9 ng/ml). RESULT: Mean serum and RBC folate concentrations in all subjects were 10.3 and 519 ng/ml, respectively. These levels were remarkably higher than the reported values from many other countries despite our subjects receiving no folic acids supplements. However, mean folate intake by our subjects from natural foods was 289 microg/day, which is thought to be low according to the Japanese dietary recommendation specified for pregnant women. The intake of spinach and fruits was significantly greater in the high folate group than in the low folate group. CONCLUSION: Folate intake was thought to be adequate to maintain a desirable level of serum folate concentration in Japanese pregnant women in the first trimester, although the intake of folate from natural food was not high enough to meet the recommended daily intake.     

Folic acid fortified milk increases blood folate and lowers homocysteine concentration in women of childbearing age

Daily consumption of 400 microg folic acid prior to conception and during early pregnancy is recommended for the prevention of neural tube defects (NTD). Strategies to increase folic acid consumption include supplements and fortified foods. Milk is consumed by women and can be fortified with folic acid but little is known about the effect of fortified milk on blood folate concentration in women of childbearing age. The objective of this study was to determine whether daily consumption of milk fortified with 375 microg folic acid increases blood folate and lowers homocysteine concentrations in women of childbearing age. Seventy-three non-pregnant women (aged 18-47 y) were randomized to receive either 75 g/d of a fortified or unfortified (control) milk powder for 12 weeks. Women who consumed the folic acid fortified milk had mean (95% CI) red blood cell and plasma folate concentrations that were 539 nmol/L (436, 641) and 35 nmol/L (30, 41) higher, respectively, than in the control group. Women drinking fortified milk had a 14% lower mean plasma homocysteine concentration at week 12 than women consuming the control milk. Daily consumption of fortified milk powder providing 375 microg folic acid increases blood folate and lowers homocysteine concentrations over 12 weeks in women of childbearing age. Daily consumption of fortified milk would be expected to reduce NTD risk.     

Folate status in Germany 1997-2000

Data about folate intake and blood values of the German population, published between 1997 and 2000, have been reviewed. Median folate intake is about 250 micrograms/day in the adult population, which indicates a high likelihood of inadequate intake when compared to the Estimated Average Requirement (EAR) of 320 micrograms/day. Only a few studies have evaluated serum and erythrocyte folate or plasma homocysteine as a marker of folate status. The most representative data show that 25% of German women of childbearing age have an inadequate recent folate intake. Only 13.3% of the women have red blood cell folate values above the critical value of 400 micrograms/day established by Daly et al (1995). Folic acid fortification of food is shown to be responsible for about 25% of folate intake in the German child and adolescent population in one study. If we extrapolate these data to the general population, folic acid fortification could be the explanation for the differences observed between folate intake and blood values. The discrepancy might also be explained by slight inaccuracies in food composition tables. Folate intake from fortified food or from supplements is not taken into account in most of the studies, which is a variable that can lead to confusion. Nutrition surveys should adapt official composition tables for local food patterns, and include fortified commercial foods, in order to make folate intake data more accurate. However, representative serum and erythrocyte folate values are lacking for most age groups. Before taking public health measures concerning folate fortification of food, the real folate status of the German population should be established.     

One-third of pregnant and lactating women may not be meeting their folate requirements from diet alone based on mandated levels of folic acid fortification

Many women are advised to consume a folic acid-containing prenatal supplement for the duration of pregnancy and lactation. Whether this remains necessary after folic acid fortification of the food supply in North America has yet to be determined. Our objective was to assess the dietary folate intake of a sample of pregnant and lactating women at mandated and predicted folic acid-fortification levels and determine the prevalence of inadequate and excessive intakes. Weighed food records (for 3 d) were collected from predominantly university-educated women (32 +/- 4 y of age) at 36 wk of pregnancy (n = 61) and at 4 and 16 wk of lactation (n = 60). Dietary folate intakes during pregnancy and lactation, assuming fortification at mandated levels (140-150 micro g/100 g), were 562 +/- 106 and 498 +/- 99 micro g/d dietary folate equivalents (DFE), respectively. The prevalence of inadequacy for folate, or the proportion of individuals with usual folate intakes less than their nutrient requirement, was 36% for women during pregnancy (estimated average requirement of 520 micro g/d DFE), and 32% during lactation (estimated average requirement of 450 micro g/d DFE). Assuming fortification at twice the mandated level, mean dietary intakes during pregnancy and lactation were 786 +/- 132 and 716 +/- 150 micro g/d DFE, respectively, producing only a 3% prevalence of folate inadequacy. Grains contributed approximately 41% of total folate intake followed by fruits and vegetables (approximately 21%). To conclude, at mandated levels of fortification many pregnant and lactating women are unlikely to meet their folate requirements from dietary sources alone; however, the actual level of inadequacy cannot be determined until the level of folic acid in the food supply is known with greater precision.     

Women Taking a Folic Acid Supplement in Countries with Mandatory Food Fortification Programs May Be Exceeding the Upper Tolerable Limit of Folic Acid: A Systematic Review

Background: In preconception and pregnancy, women are encouraged to take folic acid-based supplements over and above food intake. The upper tolerable limit of folic acid is 1000 mcg per day; however, this level was determined to avoid masking a vitamin B12 deficiency and not based on folic acid bioavailability and metabolism. This review’s aim is to assess the total all-source intake of folate in women of childbearing age and in pregnancy in high-income countries with folate food fortification programs. Methods: A systematic search was conducted in five databases to find studies published since 1998 that reported folate and folic acid intake in countries with a mandatory fortification policy. Results: Women of childbearing age do not receive sufficient folate intake from food sources alone even when consuming fortified food products; however, almost all women taking a folic acid-based supplement exceed the upper tolerable limit of folic acid intake. Conclusions: Folic acid supplement recommendations and the upper tolerable limit of 1000 mcg set by policy makers warrant careful review in light of potential adverse effects of exceeding the upper tolerable limit on folic acid absorption and metabolism, and subsequent impacts on women’s health during their childbearing years.     

The impact of folic acid fortification of enriched grains on an elderly population: the New Mexico Aging Process Study

Fortification of enriched grains with synthetic folic acid is a potential concern for the elderly population who is at higher risk for Vitamin B12 deficiency. Consuming excess amounts of naturally occurring folate or synthetic folic acid can precipitate a deficiency of Vitamin B12, resulting in neurological damage. The purpose of this study was to determine the increase in folate intake in an elderly population due to the fortification of enriched grains. Three-day diet records of 320 participants (average age 76.8 years) were evaluated for total folate intake from food and supplements before and after the fortification of enriched grains. There was a significant mean daily folate intake increase of 63.8 microg due to fortification (p < 0.0001), raising the intake of total folate to 359 microg (89.8% of RDA). Supplements containing folic acid were consumed by 66% of the participants, raising the average total folate intake of supplement users to 793 microg per day. Only 5 participants exceeded the UL of 1,000 microg folic acid per day, with all 5 of these individuals consuming more than 1,000 microg folic acid per day from supplements alone. Folic acid fortification of grains does not appear to have increased the risk of excess folic acid in this population.