[ Preparation of folic acid supplements].
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Folic Acid↗
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Preventing birth defects with folic acid supplementation.
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Folic Acid↗
Effects of change in dietary folic acid content on pentylenetetrazol seizure threshold in rat.
Pentylenetetrazol (PT) eeg thresholds were measured in rats on a folic acid (FA) deficient diet, normal diet, and a diet supplemented with large amounts of folic acid. The intraperitoneal dose per kilogram body weight of PT is significantly higher in the FA deficient group and significantly lower in the FA supplemented group than in rats on a normal diet. This indicates an effect of FA metabolism on PT epilepsy. The Lactobacillus casei minus Streptococcus faecalis activity of the brain is decreased in the FA deficient and increased in the FA supplemented group. The relation between brain folate metabolism and epilepsy is discussed.
Animals↗
Epileptogenic properties of folic acid and N5 methyltetrahydrofolate in cat.
The epileptogenic properties of folic acid and N5-methyltetrahydrofolate applied locally on the cortex were compared in cats. Neither substance was epileptogenic except in very high concentration, on the order of 10(-3) M. N5-Methyltetrahydrofolate, the folate derivative most widely distributed in the central nervous system and CSF of mammals, was not more epileptogenic than folic acid. Because the level of N5-methyltetrahydrofolate is only slightly diminished in patients treated with anticonvulsants, the change cannot account for the therapeutic effect of the drugs.
Animals↗
Effects of short-term folic acid and/or riboflavin supplementation on serum folate and plasma total homocysteine concentrations in young Japanese male subjects.
OBJECTIVE: To investigate the effects of short-term folic acid and/or riboflavin supplementation on serum folate and plasma plasma total homocysteine (tHcy) concentrations in young Japanese male subjects. DESIGN: In a double blind, randomized controlled trial. INTERVENTION: Subjects were randomly assigned to one of four groups and received a placebo (control group), 800 microg/day folic acid (FA group), 8.4 mg/day riboflavin (R group), or both (FAR group) for 2 weeks. SETTING: Tokyo, Japan. SUBJECTS: In total, 32 healthy male volunteers aged 20-29 years. RESULTS: At the end of the 2 week supplementation period, the tHcy concentration decreased significantly in the FA group. Serum folate concentrations had increased between 2.7 and 2.0-fold in the FA and FAR groups, respectively, but the mean within-group changes in serum folate and plasma tHcy concentrations did not differ between these two groups. At the end of the study, alanine amino transferase was decreased in the R and FAR groups, while alanine amino transferase was increased in the FA group. CONCLUSION: Supplementation with folic acid, 800 microg/day, for 2 weeks, increased the serum and red blood cell folate concentrations and decreased the plasma tHcy concentrations in healthy young male subjects. Riboflavin supplementation may have blunted the effect of folic acid, which resulted in a diminished reduction of tHcy in our subjects.
Adult↗
Plasma total homocysteine response to oral doses of folic acid and pyridoxine hydrochloride (vitamin B6) in healthy individuals. Oral doses of vitamin B6 reduce concentrations of serum folate.
Plasma total homocysteine response was compared in four groups of healthy individuals given orally divided doses of vitamin supplementations for a duration of 5 weeks. The vitamin supplements; A, 0.3 mg folic acid; B, 120 mg vitamin B6; C, combination of 0.3 mg folic acid and 120 mg vitamin B6 or D, 0.6 mg folic acid reduced the concentrations of plasma total homocysteine 20, 17, 32 and 24%, respectively. However, the intergroup comparisons did not show a significant difference in the effects of vitamin supplements. Multivariate analysis with correction for differences in pre-supplement values indicated a significant effect of vitamin B6 supplementation on plasma total homocysteine and serum folate. Our data show that plasma total homocysteine concentrations are reduced with low to medium divided doses of folic acid alone or in combination with vitamin B6.
Administration, Oral↗
Surveillance of neural tube defects in Israel: the effect of the recommendation for periconceptional folic acid.
BACKGROUND: Open neural tube defects are among the most common severely disabling birth defects. Secondary prevention by early diagnosis during pregnancy and abortion of affected fetuses lead to a marked reduction of NTD incidence at birth. For primary prevention of these defects, in August 2000 the Israel Ministry of Health issued guidelines recommending a daily 0.4 mg folic acid supplement for all women in their childbearing years with special emphasis on the 3 months preceding conception and the first trimester of pregnancy. OBJECTIVES: To compare the epidemiologic characteristics of NTD in Israel before and after the guidelines for folic acid supplementation. METHODS: A national registry of NTD was begun in 1999. Since the Ministry of Health published the recommendation for folic acid supplementation in mid-2000, the years 1999-2000 represent the status prior to the recommendation and the years 2002-2004 the status after. RESULTS: A marked decline in the rate of spina bifida was observed in the last 3 years (from 4.9 to 2.7 per 10,000 live births among Jews and 9.5 to 6.2 among Arabs and Druze). There was no apparent reduction for anencephaly. CONCLUSIONS: Following the Ministry of Health guidelines on folic acid supplementation for women in the reproductive age, a marked reduction in the rates of NTD was observed. In light of this apparent success, continuous efforts should be made to increase the percentage of women taking the supplementation and, especially, to introduce folic acid fortification.
Dietary Supplements↗
Treatment of vitiligo vulgaris with narrow band UVB (311 nm) for one year and the effect of addition of folic acid and vitamin B12.
Narrow band UVB is succeeding psoralen and UVA irradiation as the main treatment of vitiligo vulgaris in several European countries. Vitamin B12 and folic acid deficiency in some vitiligo patients has prompted researchers to investigate the efficacy of these vitamins in the treatment of vitiligo. In the present controlled study we investigated the value of narrow band UVB phototherapy in the treatment of vitiligo and the possible additive effect of vitamin B12 and folic acid. Twenty-seven patients with long-term stable vitiligo were included and randomized in a "UVB only" (UVB) or "UVB combined with vitamin B12 and folic acid" (UVB+) group. Patients were irradiated thrice weekly for one year, whilst repigmentation was carefully monitored. In 92% (25/27) of the patients up to 100% repigmentation was seen. Repigmentation was notable in lesions on the face, neck and throat, lower arm, chest, back and lower legs, whilst repigmentation on the hands, wrists, feet and ankles proved to be minimal. Maximum repigmentation rates did not differ significantly between the UVB group and the UVB+ group. Our study reconfirms that narrow band UVB phototherapy is an effective treatment for vitiligo and shows that co-treatment with vitamin B12 and folic acid does not improve the outcome of treatment of vitiligo with narrow band UVB phototherapy.
Analysis of Variance↗
Intermediates in the folic acid biosynthetic pathway are incorporated into molybdopterin the yeast, Pichia canadensis.
Biosynthesis of molybdopterin was followed in the yeast, Pichia canadensis, using labeled precursors. High performance liquid chromatography analysis of extracts from cells labeled with [U-14C]guanosine showed that the label was incorporated into the molybdopterin oxidation product, dephospho Form A. Dephospho Form A isolated from cells labeled with [U-14C,5'-3H]guanosine was devoid of tritium, indicating partial loss of the ribose moiety of guanosine during the synthesis of molybdopterin. In vivo labeling of P. canadensis using [7-14C]neopterin and [6,7,1-14C]hydroxymethylpterin led to label from both compounds appearing in dephospho Form A as well as in folic acid in wild type cells. When these labeled precursors were incubated with P. canadensis mutants blocked in molybdopterin synthesis, only folic acid was labeled. These results suggest a shared pathway in the biosyntheses of molybdopterin and folic acid. [6-14C]Glucose labeling experiments led to exclusive incorporation into the 4'-position of dephospho Form A but not in folic acid. It is proposed that molybdopterin synthesis branches from the folic acid biosynthetic pathway at dihydrohydroxymethylpterin and that a 3-carbon phosphorylated compound such as glyceraldehyde 3-phosphate may condense with dihydrohydroxymethylpterin to form the 4-carbon side chain precursor to molybdopterin.
Coenzymes↗
The effect of folic acid on the development of stomach and other gastrointestinal cancers.
OBJECTIVE: To evaluate the roles of folic acid and beta-carotene in the chemoprevention of gastric and other gastrointestinal (GI) cancers. METHODS: In a randomized, double-blind, placebo-controlled trial, a total of 216 patients with atrophic gastritis were randomly assigned to one of the four groups: (1) folate (FA, 20 mg per day plus vitamin B(12) 1 mg, intramuscularly, per month for one year, then 20 mg two times a week plus 1 mg per three months for the next year); (2) natural beta-carotene (N-betaC, 30 mg per day for first year, then 30 mg two times a week for the next); (3) synthetic beta-carotene (S-betaC, administered as in N-betaC); and (4) placebo. Follow-ups continued from 1994 to 2001. RESULTS: A total of 7 new cases of gastrointestinal cancers were diagnosed with 3 stomach, 1 colon and 1 esophageal cancers occurring in the placebo group; 1 stomach cancer in both of the N-betaC and S-betaC groups, and no cancer occurring in FA group. In terms of GI cancers, there was a significant reduction in the FA group, compared with the placebo group (P = 0.04). A similar trend was observed in both N-betaC and S-betaC groups (P = 0.07 - 0.08). Taken together, the three intervention groups displayed a highly significant decrease in occurrence (P = 0.004, vs placebo), and a lower risk for GI cancers (OR = 0.12; 95% confidence interval, 0.03 - 0.51). For development of gastric cancer, any one of the three active-treated groups did not reach statistically significant reduction. The FA group showed obvious improvement of the gastric mucosal lesions with more patients displaying lesions reversed or stable atrophy and inflammation (P = 0.04), reversed intestinal metaplasia (P = 0.06) at the end of follow-up, and reversed displasia (P = 0.017) at 12 months. Two cases of false jaundice were found in beta-carotene groups with no influence on administration, and no side-effects were reported in FA group. CONCLUSIONS: This trial revealed the interventional effect of folic acid on the development of GI cancers, a similar effect of beta-carotene was also detected. Also, folic acid may be of use to treat atrophic gastritis by preventing or reversing the precancerous lesions.
Adult↗
Synthesis and biological activity of novel folic acid analogues: pteroyl-S-alkylhomocysteine sulfoximines.
The synthesis of a novel series of gamma-substituted folic acid analogues, pteroyl-S-alkyl-DL-homocysteine (RS)-sulfoximines, and the corresponding S-methylhomocysteine sulfone is described. Side reactions of the sulfoximine groups of the amino acid ester reactants were considered. The correct structures of the isolated target compounds were confirmed by NMR and FAB/MS excluding other alternatives. The replacement of the gamma-COOH of the glutamate moiety of folic acid with S-alkylsulfoximine groups or S-methylsulfone did not affect the substrate activity of the vitamin for dihydrofolate reductase. The resulting tetrahydrofolate analogues could serve as cofactors for the thymidylate synthase cycle of murine leukemia L1210 cells in situ. The analogues inhibited the growth of these cells in culture with 2 orders of magnitude lower IC50 values [(2-4) x 10(-4) M] than the parent folic acid.
Animals↗
A phase I clinical study of the antipurine antifolate lometrexol (DDATHF) given with oral folic acid.
Lometrexol is an antifolate which inhibits glycinamide ribonucleotide formyltransferase (GARFT), an enzyme essential for de novo purine synthesis. Extensive experimental and limited clinical data have shown that lometrexol has activity against tumours which are refractory to other drugs, notably methotrexate. However, the initial clinical development of lometrexol was curtailed because of severe and cumulative antiproliferative toxicities. Preclinical murine studies demonstrated that the toxicity of lometrexol can be prevented by low dose folic acid administration, i.e. for 7 days prior to and 7 days following a single bolus dose. This observation prompted a Phase I clinical study of lometrexol given with folic acid supplementation which has confirmed that the toxicity of lometrexol can be markedly reduced by folic acid supplementation. Thrombocytopenia and mucositis were the major toxicities. There was no clear relationship between clinical toxicity and the extent of plasma folate elevation. Associated studies demonstrated that lometrexol plasma pharmacokinetics were not altered by folic acid administration indicating that supplementation is unlikely to reduce toxicity by enhancing lometrexol plasma clearance. The work described in this report has identified for the first time a clinically acceptable schedule for the administration of a GARFT inhibitor. This information will facilitate the future evaluation of this class of compounds in cancer therapy.
Acyltransferases↗
Low-dose folic acid supplementation reduces plasma levels of the cardiovascular risk factor homocysteine in postmenopausal women.
OBJECTIVE: The aim of our randomized, controlled trial was to verify the effect of folic acid supplementation on homocysteine levels in postmenopausal women. STUDY DESIGN: Thirty-six women were divided randomly into 2 groups as follows: a placebo group (n = 18) and a group receiving 500 microg folic acid per day for 4 weeks (n = 18). To assess concentrations of plasma homocysteine, venous blood samples were taken on enrollment and after 4 weeks of treatment. RESULTS: Mean plasma homocysteine levels were 10.9 +/- 2.7 micromol/L in the placebo group and 7.8 +/- 2.35 micromol/L (P <.01) in the group receiving 500 microg folic acid per day for 4 weeks. The thirds (referred to as tertiles) of women with the highest baseline homocysteine plasma levels showed the greatest reduction in homocysteine, with a mean decrease of 4.35 micromol/L (32%; P <.01), in comparison with a decrease of 3.35 micromol/L (29%; P <.01) in the middle tertile and 1.3 micromol/L (22.4%; P =.09) in the lower tertile. CONCLUSIONS: The results show that low doses of folic acid are associated with a significant reduction in plasma concentrations of homocysteine. The highest initial levels of homocysteine showed the most important reduction after therapy.
Cardiovascular Diseases↗
Folic acid knowledge and use in a multi-ethnic pregnancy cohort: the role of language proficiency.
OBJECTIVE: To investigate the role of language proficiency as determinant of folic acid knowledge and use in a multi-ethnic pregnancy cohort. DESIGN: Prospective cohort study. SETTING AND POPULATION: Pregnant women from Amsterdam attending obstetric care for their first antenatal visit. Number approached: 12,373 women, response rate: 67% (8266 women aged 14-49 years). Ethnicity was based on the country of birth: the Netherlands, Surinam, Antilles, Turkey, Morocco, Ghana, other non-Western and other Western countries. MAIN OUTCOME MEASURES: Knowledge about and use of folic acid supplements in pregnancy as elicited in a multilingual questionnaire, as well as determinants of these in ethnic groups separately. RESULTS: Both periconceptional folic acid use and knowledge were significantly lower among Ghanaian, Moroccan, Turkish, and other non-Western women than among women born in the Netherlands or other Western countries. Language proficiency in Dutch was a major determinant of knowledge in all the ethnic groups with a mother tongue other than Dutch [adjusted odds ratios (OR): Western 3.2, non-Western (all countries combined) 7.5], while educational attainment was of secondary importance. Knowledge in turn was the strongest determinant of use (adjusted OR: Western 17.4, non-Western 27.0). CONCLUSIONS: Periconceptional folic acid supplement use among women born in non-Dutch-speaking non-Western countries is low, reflecting a lack of knowledge that is determined by the inability to speak and understand the language of the country of residence. Measures to tackle this problem include the provision of linguistically appropriate information via ethnic health advisors, and language courses integrating health education for immigrants.
Adolescent↗
Effect of folic acid supplementation on aluminum accumulation in rats.
OBJECTIVE: Exposure to many xenobiotics may cause depletion of folic acid (folate), which is an essential vitamin for humans. Replacement of folate can be effective in protection against some diseases and in partial or total prevention of adverse effects related to xenobiotics. Aluminum (Al) is the most widely distributed metal in the outer crust of the earth. Its toxicity in humans is well known. However, there is no evidence that folate can decrease accumulation of Al to which humans can be exposed in many ways. The aim of the present study was to quantify organ Al accumulation and to evaluate whether there is any protective (or reductive) effect of folic acid on Al accumulation. METHODS: Male Wistar rats were assigned oral Al chloride (200 mg x kg(-1) x d(-1), n = 10, group 1) alone or in combination with folic acid (20 mg x kg(-1) x d(-1), n = 10, group 2) for 8 wk. At the end of the period, bone, kidney, brain, and blood samples were collected, and Al concentrations were determined by electrothermal atomic absorption spectrophotometry. RESULTS: Mean values of Al in the tissue samples from group 1 were higher than those from group 2 (all P < 0.05). No difference was observed in serum Al levels between groups (P > 0.05). CONCLUSION: These results suggest that folate supplementation might be useful to decrease Al accumulation in its main target organs, i.e., bone, kidney, and brain.
Aluminum↗
Multicentric study of efficacy of periconceptional folic acid containing vitamin supplementation in prevention of open neural tube defects from India.
BACKGROUND & OBJECTIVES: A folic acid containing multivitamin preparation was evaluated for its efficacy in preventing recurrence of open neural tube defect (NTD) in a blind, placebo-controlled randomized trial. The trial was carried out at the five centres in India, viz., Bangalore, Mumbai, Lucknow, New Delhi and Pune. METHODS: The preparation contained 4 mg of folic acid besides calcium, iron, zinc and vitamins A, B1, B2, B6, C, D and nicotinamide. The placebo contained calcium and iron only. A total of 466 women with previous history of giving birth to a child with open NTD were included in the trial (231 in the vitamin group and 235 in the placebo group). The supplementation was given for at least one month prior to conception and up to three months after conception. All women were offered antenatal diagnosis with screening of maternal serum alpha foetoprotein (AFP) and ultrasound. RESULTS: Pregnancy outcome with reference to recurrence of NTD was unknown in 137 women in the vitamin group and 142 in the placebo group. The recurrence of open NTD in the vitamin group was 2.92 per cent compared to 7.04 per cent in the placebo group, a reduction by about 60 per cent. The difference, however, was not statistically significant (P = 0.06). INTERPRETATION & CONCLUSIONS: The study seems to support the role of periconceptional folic acid supplementation in prevention of recurrence of NTDs in the Indian population. The reason for high recurrence rate observed in the placebo group requires further investigation.
Female↗
Effect of short-term folic acid supplementation on insulin sensitivity and inflammatory markers in overweight subjects.
OBJECTIVE: Inflammation plays a pivotal role in the atherosclerotic process, and some chemokines seem to be crucial in the pathogenesis of vascular damage. High-serum homocysteine, recently recognized as an independent risk factor for vascular disease might increase cytokine and chemokine levels, thus amplifying endothelial damage; moreover, it might worse insulin resistance, thus further contributing to enhance cardiovascular risk. The effect of folic acid supplementation in improving in vivo endothelial function is still debated. In this study, we investigated the effect of folic acid supplementation on insulin sensitivity and peripheral markers of inflammation in overweight healthy subjects. DESIGN: The study was performed as an unmasked randomized placebo-controlled trial of 12 weeks duration. SUBJECTS: Sixty healthy volunteers with normal glucose tolerance and BMI between 25 and 29 kg/m2 were enrolled. MEASUREMENTS: Biochemical parameters and plasma concentrations of homocysteine and of some inflammatory molecules were measured at baseline and at the end of the study, together with an estimation of insulin sensitivity. RESULTS: Subjects receiving folic acid supplementation showed a decrement of homocysteine and an amelioration of insulin sensitivity; this treatment was also associated with a significant drop in the circulating concentration of monocyte chemoattractant protein-1, interleukin-8 and C-reactive protein, in the absence of any significant variation of BMI or fat mass. CONCLUSIONS: In healthy overweight subjects a short-term folic acid supplementation reduces the circulating level of some inflammatory mediators independently of weight change, thus suggesting a potential therapeutic role for folic acid in the protection from atherogenesis and cardiovascular diseases.
Adult↗
Hyperhomocysteinemia, and low intakes of folic acid and vitamin B12 in urban North India.
BACKGROUND AND AIM: An adverse coronary risk profile has been reported amongst rural-to-urban migrant population living in urban slums undergoing stressful socio-economic transition. These individuals are likely to have low intakes of folic acid and vitamin B12, which may have an adverse impact on serum levels of homocysteine (Hcy). To test this hypothesis, we studied serum levels of Hcy in subjects living in an urban slum of North India and healthy subjects from urban nonslum area. METHODS: Group I consisted of 46 subjects (22 males and 24 females) living in an urban slum, while group II consisted of healthy subjects (n = 26, 13 males and 13 females) living in the adjacent non-slum area. Anthropometric measurements, biochemical profile (fasting blood glucose, total cholesterol, serum triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol) and fasting serum levels of Hcy were measured. Dietary intakes of folic acid, vitamin B12, vitamin B1, and iron were calculated by the 24-hour dietary recall method. Serum levels of Hcy were correlated with dietary intakes of nutrients, anthropometry, and metabolic variables. RESULTS: Sex-adjusted serum levels of Hcy in micromol/L (Mean +/- SD) were high, though statistically comparable, in both the groups (group I: 20.8 +/- 5.9 and group II: 23.2 +/- 5.9). Overall, higher than normal serum levels of Hcy (> 15 micromol/L) were recorded in 84% of the subjects. A substantial proportion of subjects in both groups had daily nutrient intakes below that recommended for the Asian Indian population (folic acid: 93.4% in group I and 96.7% in group II, vitamin B12: 76.1 % in group I and 88.4% in group II). However, between the two groups, average daily dietary intakes of both the nutrients were statistically comparable. As compared to non-vegetarians, vegetarians showed lower intakes of folic acid (p < 0.01) and vitamin B12 (p < 0.01) in both groups. On multivariate linear regression analysis with serum Hcy as the response variable and vegetarian/non-vegetarian status and sex (male/female) as predictor variables, higher serum levels of Hcy were observed in vegetarians vs non-vegetarians (1 = 4.6, p < 0.05) and males vs females (beta = 5.3, p < 0.01). CONCLUSIONS: Low intakes of folic acid and vitamin B12, and hyperhomocysteinemia, in both the healthy population living in urban slums and adjacent urban non-slum areas, are important observations for the prevention of nutritional and cardiovascular diseases in the Indian subcontinent.
Adult↗