Prevalence and Disparities in Folate and Vitamin B12 Deficiency Among Preschool Children in Guatemala.

BACKGROUND AND OBJECTIVE: Folate and vitamin B12 deficiencies can impair proper growth and brain development in children. Data on the folate and vitamin B12 status of children aged 6-59 months in Guatemala are scarce. Identification of factors associated with higher prevalence of these micronutrient deficiencies within the population is needed for national and regional policymakers. OBJECTIVE: To describe national and regional post-fortification folate and vitamin B12 status of children aged 6-59 months in Guatemala. METHODS: A multistage, cluster probability study was carried out with national and regional representation of children aged 6-59 months. Demographic and health information was collected for 1246 preschool children, but blood samples for red blood cell (RBC) folate and vitamin B12 were collected and analyzed for 1,245 and 1143 preschool children, respectively. We used the following deficiency criteria as cutoff points for the analyses: < 305 nmol/L for RBC folate, < 148 pmol/L for vitamin B12 deficiency, and 148-221 pmol/L for marginal vitamin B12 deficiency. Prevalence of RBC folate deficiency and vitamin B12 deficiency and marginal deficiency were estimated. Prevalence risk ratios of RBC folate and vitamin B12 deficiency were estimated comparing subpopulations of interest. RESULTS: The national prevalence estimates of RBC folate deficiency among children was 33.5% [95% CI 29.1, 38.3]. The prevalence of RBC folate deficiency showed wide variation by age (20.3-46.6%) and was significantly higher among children 6-11 months and 12-23 months (46.6 and 37.0%, respectively), compared to older children aged 48-59 months (20.3%). RBC folate deficiency also varied widely by household wealth index (22.6-42.0%) and geographic region (27.2-46.7%) though the differences were not statistically significant. The national geometric mean for RBC folate concentrations was 354.2 nmol/L. The national prevalences of vitamin B12 deficiency and marginal deficiency among children were 22.5% [95% CI 18.2, 27.5] and 27.5% [95% CI 23.7, 31.7], respectively. The prevalence of vitamin B12 deficiency was significantly higher among indigenous children than among non-indigenous children (34.5% vs. 13.1%, aPRR 2.1 95% CI 1.4, 3.0). The prevalence of vitamin B12 deficiency also significantly varied between the highest and lowest household wealth index (34.3 and 6.0%, respectively). The national geometric mean for vitamin B12 concentrations was 235.1 pmol/L. The geometric means of folate and B12 concentrations were significantly lower among children who were younger, had a lower household wealth index, and were indigenous (for vitamin B12 only). Folate and vitamin B12 concentrations showed wide variation by region (not statistically significant), and the Petén and Norte regions showed the lowest RBC folate and vitamin B12 concentrations, respectively. CONCLUSIONS: In this study, a third of all children had RBC folate deficiency and half were vitamin B12 deficient. Folate deficiency was more common in younger children and vitamin B12 deficiency was more common in indigenous children and those from the poorest families. These findings suggest gaps in the coverage of fortification and the need for additional implementation strategies to address these gaps in coverage to help safeguard the health of Guatemalan children.

Obesity affects short-term folate pharmacokinetics in women of childbearing age.

Maternal folate status and body mass index (BMI) are independent risk factors for neural tube defects (NTD). Population-based studies have identified an inverse association between serum folate and BMI, after adjusting for intake. The objective of this intervention study was to compare the relationship between BMI and the short-term pharmacokinetic response to an oral dose of folic acid. Healthy obese (BMI 30.0 kg m(-2); n=16) and normal-weight (BMI 18.5-24.9 kg m(-2); n=16) women of childbearing age (18-35 years) were administered a single oral dose of folic acid (400 µg). Blood samples were collected over a 10-h period to evaluate the serum folate response. Fasting baseline serum folate was lower in the obese group (P=0.005); in contrast, red blood cell folate was higher (P=0.05). Area-under-the-curve for the absorption phase (0-3 h) and peak serum folate concentrations were lower in obese versus normal-weight women (P<0.005). Overall serum folate response (0-10 h) was lower in obese versus normal-weight women (repeated-measures ANOVA, P=0.001). Data suggest body distribution of folate is significantly affected by obesity, and, should pregnancy occur, may reduce the amount of folate available to the developing embryo. These findings provide additional support for a BMI-adjusted folic acid intake recommendation for NTD risk reduction.

Methylenetetrahydrofolate reductase mutation (677C-->T) negatively influences plasma homocysteine response to marginal folate intake in elderly women.

Individuals who are homozygous for the methylenetetrahydrofolate reductase (MTHFR) 677C --> T mutation have depressed serum folate (SF) and elevated plasma total homocysteine (tHcy) concentrations, which may affect folate requirements and increase the risk for coronary artery disease. A controlled metabolic study (14 weeks) using a depletion/repletion protocol was performed in women (aged 60 to 85 years, N = 33) to provide age-specific data on the effects of the MTHFR mutation on SF and tHcy status. Subjects consumed a moderately folate-deplete diet (118 microg/d) for 7 weeks, followed by 7 weeks of folate repletion with 200 or 415 microg/d provided as two different treatments. Following folate depletion, the mean SF concentration was lower for homozygous (P = .017) versus heterozygous subjects. Homozygotes for the 677C --> T mutation showed a higher (P = .015) percent increase in plasma tHcy (44%) than heterozygous (20%) or normal (15%) subjects. At week 7, the mean plasma tHcy concentration was higher in homozygous subjects (12.5 +/- 5.3 micromol/L, mean +/- SD) versus the heterozygous (10.8 +/- 3.8 micromol/L, P = .008) or normal (11.3 +/- 2.7 micromol/L, P = .001) genotype groups. Following folate repletion, plasma tHcy concentrations were not different between genotype groups, despite a higher (P < .016) SF concentration in subjects with the homozygous genotype. These data suggest that older women who are homozygous for the MTHFR 677C --> T mutation may be at risk for greater elevations in plasma tHcy in response to moderately low folate intake as compared with individuals with the normal or heterozygous genotypes.

Genomic DNA methylation decreases in response to moderate folate depletion in elderly women.

BACKGROUND: Methylation of genomic DNA is dependent on an adequate supply of folate coenzymes. Previous data support the hypothesis that abnormal DNA methylation plays an integral role in carcinogenesis. To date, no studies assessing the effect of inadequate folate status on DNA methylation in older women (aged >63 y) have been reported. OBJECTIVE: The effect of moderate folate depletion followed by folate repletion on leukocyte genomic DNA methylation was investigated in elderly women (aged 60-85 y) to evaluate whether DNA methylation could be used as a functional indicator of folate status. DESIGN: Healthy, postmenopausal women (n = 33) consumed a moderately folate-depleted diet (118 microg folate/d) for 7 wk, followed by 7 wk of folate repletion with 200 or 415 microg/d, each provided as 2 different dietary treatments for a total of 4 treatment groups (n = 30). Leukocyte DNA methylation was determined on the basis of the ability of DNA to incorporate [(3)H]methyl groups from labeled S:-adenosylmethionine in an in vitro assay. RESULTS: Incorporation of [(3)H]methyl groups increased significantly (P: = 0.0025) in response to folate depletion, suggesting undermethylation of DNA. No significant changes were detected in [(3)H]methyl incorporation in any group over the 7-wk repletion period compared with postdepletion values. CONCLUSIONS: DNA methylation status may be used as a functional indicator of moderately depleted folate status. The slow response to the repletion diets observed suggests that normalization of DNA methylation after moderate folate depletion may be delayed in older women.

Folate absorption in women with a history of neural tube defect-affected pregnancy.

BACKGROUND: The risk of neural tube defects (NTDs) is significantly reduced by supplemental folic acid. NTD risk may be associated with impaired absorption of polyglutamyl folate, the primary form of naturally occurring food folate, and of folic acid in supplements or fortified food. Stable-isotope methods provide the specificity needed to test this hypothesis. OBJECTIVE: We determined whether women who had an NTD-affected pregnancy had a reduced ability compared with control women to absorb polyglutamyl folate relative to folic acid. DESIGN: Healthy, nonpregnant women with a history of an NTD-affected pregnancy (cases; n = 11) and control women (n = 11) were administered an oral dose containing a mixture of [(2)H]pteroylpentaglutamate ([(2)H(2)]PteGlu(5); 233 nmol) and [(13)C]pteroylmonoglutamate ([(13)C(5)]PteGlu(1); 567 nmol) after a 30-d saturation protocol (2 mg unlabeled folic acid/d). Relative extents of absorption were evaluated by urinary excretion of (2)H(2)- and (13)C(5)-labeled folates 48 h postdose. RESULTS: During the first 24 h postdose, cases excreted less (f1.gif" BORDER="0"> +/- SD) [(2)H(2)]PteGlu(5) (21 +/- 12% compared with 37 +/- 19%; P = 0.01) and [(13)C(5)]PteGlu(1) (17 +/- 8% compared with 31 +/- 14%; P = 0.007) than did controls. No significant differences between cases and controls were detected in the percentage of [(2)H(2)]PteGlu(5) or [(13)C(5)]PteGlu(1) excreted during the second 24 h postdose or when the data were averaged over 48 h. However, excretion of the [(2)H(2)]folates tended to be lower in cases than in controls over the 48-h period (33 +/- 13% compared with 45 +/- 26%; P = 0.21). A similar trend (P = 0.29) for lower excretion of [(13)C(5)]folates in cases was also observed (31 +/- 16% compared with 39 +/- 17%). The ratio of urinary [(2)H(2)]folates to [(13)C(5)]folates did not differ significantly between cases and controls. CONCLUSION: These data suggest the need for a larger-scale study using stable-isotope methods to further investigate this hypothesis.

Folate status of elderly women following moderate folate depletion responds only to a higher folate intake.

Dietary Reference Intakes (DRI) for folate for elderly women have been based primarily on data extrapolated from studies in younger women. This study was conducted to provide the first age-specific data in elderly women (60-85 y) from a controlled metabolic study on which to base folate intake recommendations. Subjects (n = 33) consumed a moderately folate-deplete (118 microg/d) diet for 7 wk, followed by repletion diets providing either 200 or 415 microg folate/d as diet plus folic acid (FA) or a combination of FA and orange juice (OJ) for 7 wk (n = 30). Comparisons among and within groups were made for serum folate (SF), RBC folate and plasma total homocysteine (tHcy) concentrations. SF concentrations decreased significantly (P < 0.001) during depletion (65 +/- 15%). Postrepletion, the adjusted SF concentration for subjects consuming 415 microg folate/d was significantly greater (P = 0.003) than for subjects consuming 200 microg folate/d. RBC folate concentrations decreased (P < 0.001) during depletion (21 +/- 10%) and further (P < 0.001) during repletion (5 +/- 14%). During depletion, plasma tHcy concentrations increased significantly (P < 0.001) and an inverse relationship between SF and plasma tHcy concentrations was observed in 94% of subjects (P < 0.001). Reversal of this inverse relationship was significant only for subjects consuming 415 microg folate/d (P < 0.001). Postrepletion, subjects consuming 200 microg folate/d had a significantly higher (P = 0.009) adjusted plasma tHcy concentration than subjects consuming 415 microg folate/d. These data in elderly women indicate that 415 microg/d folate, provided as a combination of diet, FA and OJ, or diet and FA, normalizes folate status more effectively than does 200 microg/d, thus providing age-specific data for future folate intake recommendations.

Altered copper status in adult men with cystic fibrosis.

OBJECTIVES: To measure indices of copper status in adult men with cystic fibrosis (CF). A previous study in children showed changes in copper homeostasis compared to controls. This study was designed to investigate whether this observation persisted into adulthood. METHODS: This was a case-control age-matched study using seven men with CF and six healthy men. Blood samples were drawn into metal free tubes and fractionated into plasma, polymorphonuclear cells, mononuclear cells and erythrocytes. Cell fractions were assayed for copper and CuZn-superoxide dismutase; plasma was assayed for ceruloplasmin. RESULTS: The men with cystic fibrosis had significantly greater plasma copper and ceruloplasmin activity, yet had significantly lower copper-zinc superoxide dismutase activity in mononuclear and polymorphonuclear cells. Furthermore, the mononuclear cells of the cystic fibrosis subjects had about 45% percent less copper-zinc superoxide dismutase protein. Cellular copper levels were not statistically different between the two groups. A significant correlation was found between lung function and copper-zinc superoxide dismutase activity in the polymorphonuclear cells. Iron status was normal. CONCLUSIONS: The results indicate that individuals with cystic fibrosis have altered copper distribution compared to control individuals. Some aspects are characteristic of an inflammatory response; however, other measures suggest that copper homeostasis may be abnormal. It is not known whether the deviation in copper homeostasis in these individuals is a result of poor copper absorption, inadequate dietary intake, a result of their chronic inflammation or a direct effect due to the defect in ion transport caused by the disease. However, this research suggests that the severity of the disease and the activity of a copper dependent enzyme may be related. Further work will be necessary to determine the cause of the abnormal copper homeostasis and whether correcting it has any bearing on the course of the disease.

Practitioners' guide to meeting the vitamin B-12 recommended dietary allowance for people aged 51 years and older.

In response to research findings that 10% to 30% of people aged 51 years and older may have protein-bound vitamin B-12 malabsorption, the National Academy of Sciences' Institute of Medicine recommends that these people consume a majority of the new Recommended Dietary Allowance (RDA) of 2.4 micrograms/day in its synthetic form rather than in its food form. Protein-bound vitamin B-12 malabsorption in older adults has been attributed to reduced pepsin activity and gastric acid secretion, which interfere with cleavage of vitamin B-12 from dietary protein before absorption. Unlike patients with pernicious anemia, most people with protein-bound vitamin B-12 malabsorption produce intrinsic factor and have the ability to absorb synthetic vitamin B-12 normally. Early diagnosis is necessary to prevent the untoward effects of vitamin B-12 deficiency. A thorough assessment of vitamin B-12 status entails measurement of multiple biochemical assessment indexes, including serum vitamin B-12, methylmalonic acid, and homocysteine concentrations. Dietitians and other health care professionals should be aware of the prevalence of vitamin B-12 deficiency in older adults and be familiar with sources of synthetic vitamin B-12 to facilitate implementation of the new RDA.

Plasma homocyst(e)ine concentrations in pregnant and nonpregnant women with controlled folate intake.

OBJECTIVE: To assess the effects of folate intake and pregnancy on plasma total homocyst(e)ine concentrations in women during the second trimester of pregnancy compared with young, healthy nonpregnant women. METHODS: The diet provided either 450 or 850 microg of folate per day. These levels are approximately the current (400 microg/day) and previous (800 microg/day) Recommended Dietary Allowances for folate in pregnant women. Folate was provided as both food folate (120 microg/day) and supplemental folic acid (either 330 or 730 microg/day) for a period of 12 weeks. Plasma homocyst(e)ine (sum of free and protein-bound homocysteine), serum folate, and erythrocyte folate concentrations were determined weekly. RESULTS: Homocyst(e)ine concentrations were lower in pregnant women during the second trimester of normal pregnancy than in nonpregnant controls, independent of dietary folate intake. The overall mean (+/- standard deviation) homocyst(e)ine concentration of the pregnant subjects (5.4 +/- 1.4 micromol/L) was significantly lower than that observed in the nonpregnant control group (8.7 +/- 1.7 micromol/L) (P < .0001). This difference in homocyst(e)ine concentrations remained constant throughout the 12 weeks of the investigation. CONCLUSION: The folate intakes in this investigation were adequate to maintain constant homocyst(e)ine concentrations in pregnant and nonpregnant women. The lower homocyst(e)ine concentrations observed in pregnant subjects compared with nonpregnant controls may be a physiologic response to pregnancy.

Zinc status is not adversely affected by folic acid supplementation and zinc intake does not impair folate utilization in human subjects.

Changes in zinc status in response to folic acid supplementation and the effect of zinc intake on folate utilization were evaluated in 12 men (20-34 y old) consuming a diet containing 3.5 or 14.5 mg zinc/d for two 25-d intervals. Deuterium-labeled folic acid (800 micrograms/d) or a placebo was administered orally during each phase. No differences in plasma zinc, erythrocyte zinc, urinary zinc, erythrocyte metallothionein or serum alkaline phosphatase, due to supplemental folic acid, were detected at either level of zinc intake. Differences in the response to folic acid supplementation, due to the level of zinc intake, were not detected for serum, erythrocyte or urinary (labeled and unlabeled) folate. Within the constraints of this short-term folic acid supplementation study, adverse effects on zinc status were not observed and our data suggest that folic acid utilization was not influenced by level of zinc intake.

Continuous assistive-passive exercise and cycle ergometer training in sedentary women.

Continuous assistive-passive exercise (CAPE) is a new exercise modality that has become popular with older females. To evaluate the efficacy of CAPE, 43 sedentary, postmenopausal women (PMW) were randomly divided into three groups: CAPE training (N = 15), cycle ergometer training (N = 14), and control (N = 14). The CAPE training consisted of 10 min bouts on six CAPE tables, twice per week. The cycle ergometer group trained twice per week for 30 min per session, at 70-85% of maximal heart rate. The cycle ergometer and CAPE groups trained for 12 wk, while the control group remained sedentary for the duration of the study. Groups were similar with respect to age, height, weight, girths, skinfolds, and aerobic power (VO2max) upon entering the study (P greater than 0.05). The groups were tested pre- and post-training on the sum of seven body girths (sigma 7G), sum of four skinfolds (sigma 4SF), weight, and VO2max. A 3 d dietary recall was recorded pre and post and analyzed for total caloric intake. Following training, changes in caloric intake, sigma 7G, and sigma 4SF were not significantly different among groups. The cycle group lost 1.1 kg (P less than 0.05) and increased VO2max (l.min-1) by 9.2% (P less than 0.05), while the CAPE group significantly decreased VO2max (P = 0.04). Our results indicate that CAPE does not alter sigma 7G or sigma 4SF in sedentary PMW and that two 30 min sessions of cycle training per week at 70-85% of maximal heart rate can result in moderate but significant increases in VO2max in sedentary PMW.