Bioavailability of lutein from vegetables is 5 times higher than that of beta-carotene

BACKGROUND

To gain more insight into the relation between vegetable consumption and the risk of chronic diseases, it is important to determine the bioavailability of carotenoids from vegetables and the effect of vegetable consumption on selected biomarkers of chronic diseases.

OBJECTIVE

To assess the bioavailability of beta-carotene and lutein from vegetables and the effect of increased vegetable consumption on the ex vivo oxidizability of LDL.

DESIGN

Over 4 wk, 22 healthy adult subjects consumed a high-vegetable diet (490 g/d), 22 consumed a low-vegetable diet (130 g/d), and 10 consumed a low-vegetable diet supplemented with pure beta-carotene (6 mg/d) and lutein (9 mg/d).

RESULTS

Plasma concentrations of vitamin C and carotenoids (ie, alpha-carotene, beta-carotene, lutein, zeaxanthin, and beta-cryptoxanthin) were significantly higher after the high-vegetable diet than after the low-vegetable diet. In addition to an increase in plasma beta-carotene and lutein, the pure carotenoid-supplemented diet induced a significant decrease in plasma lycopene concentration of -0.11 micromol/L (95% CI: -0.21, -0.0061). The responses of plasma beta-carotene and lutein to the high-vegetable diet were 14% and 67%, respectively, of those to the pure carotenoid- supplemented diet. Conversion of beta-carotene to retinol may have attenuated its plasma response compared with that of lutein. There was no significant effect on the resistance of LDL to oxidation ex vivo.

CONCLUSIONS

Increased vegetable consumption enhances plasma vitamin C and carotenoid concentrations, but not resistance of LDL to oxidation. The relative bioavailability of lutein from vegetables is higher than that of beta-carotene.

Low-dose folic acid supplementation does not influence plasma methionine concentrations in young non-pregnant women

An elevated plasma total homocysteine (tHcy) concentration is a risk factor for cardiovascular disease and for having offspring with a neural-tube defect. Folate is a methyl donor in the remethylation of homocysteine into methionine. Although folic acid supplementation decreases tHcy concentrations, effects of folic acid supplementation on plasma methionine concentrations are unclear. There is also concern that folic acid supplementation negatively affects vitamin B12 status. We studied effects of low-dose folic acid supplementation on methionine and vitamin B12 concentrations in plasma. We also investigated whether baseline plasma methionine and tHcy concentrations correlated with the baseline folate and vitamin B12 status. For a period of 4 weeks, 144 young women received either 500 micrograms folic acid each day, or 500 micrograms folic acid and placebo tablets on alternate days, or a placebo tablet each day. Plasma methionine, tHcy and plasma vitamin B12 concentrations were measured at start and end of the intervention period. Folic acid supplementation had no effect on plasma methionine or plasma vitamin B12 concentrations although it significantly decreased tHcy concentrations. Plasma methionine concentrations showed no correlation with either tHcy concentrations (Spearman rs-0.01, P = 0.89), or any of the blood vitamin variables at baseline. Baseline tHcy concentrations showed a slight inverse correlation with baseline concentrations of plasma vitamin B12 (rs-0.25, P < 0.001), plasma folate (rs-0.24, P < 0.01) and erythrocyte folate (rs-0.19, P < 0.05). In conclusion, low-dose folic acid supplementation did not influence plasma methionine or plasma vitamin B12 concentrations. Furthermore, no correlation between plasma methionine concentrations and the blood folate and vitamin B12 status was shown.

Dietary folate from vegetables and citrus fruit decreases plasma homocysteine concentrations in humans in a dietary controlled trial

Elevated total plasma homocysteine (tHcy) concentrations are considered a risk factor for neural tube defects (NTD) and cardiovascular disease. Supplementation with folic acid decreases the risk of women having children with NTD. In both sexes, it decreases tHcy levels. We investigated the efficacy of natural dietary folate in improving folate and homocysteine status. We performed a 4-wk dietary controlled, parallel design intervention trial with 66 healthy subjects (18-45 y) divided into 3 treatment groups: the dietary folate group, the folic acid group and the placebo group. Each day each group was fed a different diet. The dietary folate group received a diet high in vegetables and citrus fruit (total folate content approximately 560 microgram) plus a placebo tablet. The folic acid group received a diet naturally low in folate (approximately 210 microgram) plus 500 microgram folic acid and placebo tablet on alternate days, i.e., 250 microgram folic acid/d. And the placebo group received the same low-folate diet as the folic acid group plus a placebo tablet. After 4 wk of intervention, folate status improved, and tHcy concentrations decreased in both the dietary folate and the folic acid groups. From the amount of additional folate (350 microgram/d) and folic acid (250 microgram/d) consumed, the relative bioavailability of dietary folate compared to folic acid was calculated to be 60-98%, depending on the endpoint used. In conclusion, increasing the consumption of vegetables and citrus fruit, both good sources of folate, will improve folate status and decrease tHcy concentrations. This may contribute to the prevention of cardiovascular disease and NTD in the general population

Low-dose folic acid supplementation decreases plasma homocysteine concentrations: a randomized trial

BACKGROUND

An elevated plasma total homocysteine concentration is a risk factor for cardiovascular disease and neural tube defects. A high daily intake of supplemental folic acid is known to decrease total homocysteine concentrations.

OBJECTIVE

We studied the effect of low-dose folic acid administration (250 or 500 (microgram/d) for 4 wk on plasma total homocysteine concentrations and folate status. We also investigated whether total homocysteine concentrations and blood folate concentrations returned to baseline after an 8-wk washout period.

DESIGN

In this placebo-controlled study, 144 healthy women aged 18-40 y received 500 microgram folic acid/d, 500 microgram folic acid every second day (250 microgram/d), or a placebo tablet with their habitual diet (mean dietary folate intake: 280 microgram/d).

RESULTS

Administration of 250 and 500 microgram folic acid/d for 4 wk significantly increased folate concentrations in plasma (P < 0.001) and red blood cells (P < 0.01). Total homocysteine concentrations decreased significantly (P < 0.001) in women (n = 50) who took 250 microgram folic acid/d [mean (+/-SEM) deviation from baseline: - 11.4 +/- 198%] and in women (n = 45) who took 500 microgram folic acid/d (-21.8 + 1.49%). Eight weeks after the end of the intervention period (week 12), plasma total homocysteine concentrations in the folic acid-supplemented groups had not returned to baseline (week 0).

CONCLUSIONS

Doses of folic acid as low as 250 microgram/d, on average, in addition to usual dietary intakes of folate significantly decreased plasma total homocysteine concentrations in healthy, young women. An 8-wk washout period was not sufficient for blood folate and plasma total homocysteine concentrations to return to baseline concentrations.

[Multiples births: a continuing problem with assisted reproductive techniques]

Assisted reproductive techniques (ART) such as in vitro fertilisation (IVF), ovulation induction and superovulation followed by insemination have caused a sharp increase in multiple birth prevalence rates. The perinatal morbidity of multiple birth infants is high because of the high incidence of premature birth. The social and psychological problems of multiple birth families are also considerable. In 1990 high-order multiple births were mainly the result of IVF. Although the number of IVF treatments has increased more than the number of other ART treatments, nowadays high-order multiple births are predominantly caused by superovulation. Since 1990 the number of high-order multiple births has stabilised, but the recent sharp increase in ART twins results in a further rise in births of severely preterm ART infants. More restraint should be practised in superovulation treatments to bring down the number of (high-order) multiple births.

Multiple birth prevalence in The Netherlands. Impact of maternal age and assisted reproductive techniques

OBJECTIVE

To evaluate the impact of maternal age and use of fertility drugs on multiple birth prevalence from 1970 to 1995 in the Netherlands.

STUDY DESIGN

A population-based survey was carried out in which data were collected from the Centraal Bureau voor Statistiek, the Institute of Medical Statistics and from all clinics for in vitro fertilization.

RESULTS

In the last two decades, the prevalence of multiple births, especially of twin and triplet births, has increased significantly. Three possible explanations for this phenomenon are: (1) introduction of assisted reproductive techniques in combination with fertility drugs; (2) increasing maternal age; and (3) decreasing fecundity with increasing maternal age, resulting in more fertility treatments. A surplus of 1,366 twins was born in 1995 as compared to 1975. The expected excess of twins was 1,368, of which 104 (7.6%) were a result of the increase in total births in 1995, 583 (42.6%) were due to maternal age > 29 years, and, respectively, 330 (24.1%) and 351 (25.7%) twins were due to in vitro fertilization treatment and intrauterine insemination.

CONCLUSION

The delay in achieving pregnancy and the use of fertility-promoting therapies profoundly affect the prevalence of multiple pregnancies in a given country. The general population should be informed of this risk.

Folate intake in Europe: recommended, actual and desired intake

OBJECTIVES

To evaluate possible inconsistencies between recommended, actual and desired folate intake in European adult populations.

DESIGN

Review of dietary recommendations, of food consumption surveys, and of intervention and observational studies relating folate intake to the risk of neural tube defects and plasma homocysteine levels.

RESULTS

In Europe, mean dietary folate intake in adults is 291 micrograms/d (range 197-326) for men and 247 micrograms/d (range 168-320) for women. The recommended intakes vary between 200-300 micrograms/d (men) and 170-300 micrograms/d (women). However, women with a previous pregnancy affected by a neural tube defect (NTD), are recommended to take 4000 micrograms/d of supplemental folic acid when planning a subsequent pregnancy. For those without a history of NTD, the use of 400 micrograms/d of supplemental folic acid is the best option to prevent the occurrence of NTDs. A daily dose of 650 micrograms supplemental folic acid normalises elevated plasma homocysteine levels, which is a risk factor for cardiovascular diseases. A dietary folate intake of at least 350 micrograms/d is desired to prevent an increase in plasma homocysteine levels of the adult population in general.

CONCLUSIONS

Mean dietary folate intake in Europe is in line with recommendations, but the desired dietary intake of > 350 micrograms/d is only reached by a small part of studied European populations. It is considered unethical to investigate whether supplements with a dose lower than 400 micrograms/d of folic acid are also protective against NTDs. However, research to establish the lowest effective dose of dietary folate/supplemental folic acid to optimise homocysteine levels and research on the bioavailability of folate is required. This will enable the choice of a strategy to achieve desired folate intakes in the general population. In the meantime, consumption of plant foods like vegetables, fruits, and cereals should be stimulated to reach the desired level of 350 micrograms of dietary folate per day.

Altered folate and vitamin B12 metabolism in families with spina bifida offspring

Folic acid intake reduces the risk of neural tube defects (NTDs). Although the 677C-->T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene is a risk factor for NTDs, it only partly explains the elevated homocysteine levels in mothers of children with NTDs. We measured vitamin B12, folate and homocysteine in patients with spina bifida (SB), their parents, and in controls, to investigate which other enzymes of homocysteine metabolism might be defective. Because homozygosity for the 677C-->T mutation causes decreased plasma folate and increased red-cell folate (RCF) and plasma homocysteine levels, we excluded individuals homozygous for that mutation. The remaining SB patients and their parents still had lowered plasma folate and elevated total homocysteine levels, and a small subset had decreased vitamin B12 levels. Red-cell folate was the same in all groups, suggesting that dietary folate intake and its uptake was normal. Risk of SB was increased at the 25th percentile of plasma folate and at the 75th percentile of homocysteine values in SB patients and their parents, and at the 5th and 25th percentiles of vitamin B12 in mothers with SB-affected offspring. This underlines the functional importance of homocysteine remethylation to methionine. There was no correlation between vitamin B12 and homocysteine or RCF. In combination with the lowered plasma folate (80-90% 5-methyltetrahydrofolate), our data do not support a major involvement of methionine synthase in the aetiology of SB. Our data rather favour the involvement of genetic variation at loci coding for the formation of 5-methyltetrahydrofolate, such as MTHFR, methylenetetrahydrofolate dehydrogenase or serine hydroxymethyltransferase.

Maternal and fetal levels of methionine and homocysteine in early human pregnancy

OBJECTIVE

To investigate methionine metabolism during normal human embryonic development by measuring levels of methionine and total homocysteine in samples of maternal serum, extra-embryonic coelomic fluid, and amniotic fluid.

DESIGN

Cross-sectional observational study.

SETTING

Collaboration between St Bartholomew's Hospital, London, and the University Hospital of Nijmegen in The Netherlands.

PARTICIPANTS

Twenty-three women with uncomplicated pregnancies between 8 and 12 weeks of gestation before surgical termination of an ultrasonographically normal fetus.

METHODS

Maternal serum samples were collected prior to surgery. Samples of extra-embryonic fluid and amniotic fluids were obtained by transvaginal ultrasound-guided coelocentesis and amniocentesis. Methionine was measured using an amino acid analyser and total homocysteine by high performance liquid chromatography.

RESULTS

Levels of methionine were four times higher in extra-embryonic coelomic fluid and twice as high in amniotic fluid compared with maternal serum. In contrast, the total homocysteine concentrations were much lower in both extra-embryonic coelomic fluid and amniotic fluid than in maternal serum. All differences were significant (P < or = 0.01).

CONCLUSIONS

The comparatively high concentrations of methionine in extra-embryonic coelomic fluid and amniotic fluid, and the concomitant low levels of total homocysteine in these fluids, suggest a role for methionine metabolism during early human pregnancy.

Decreased methylene tetrahydrofolate reductase activity due to the 677C-->T mutation in families with spina bifida offspring

Periconceptional folate intake reduces both the occurrence and recurrence risk of neural tube defects. Plasma homocysteine levels can be elevated in mothers of a child with a neural tube defect, suggesting a dysfunctional folate metabolism. Very recently we showed that a common 677C-->T mutation in the 5,10-methylene tetrahydrofolate reductase gene, causing thermolability of the enzyme, is a risk factor for spina bifida offspring. Restriction enzyme analysis of the genomic 5,10-methylene tetrahydrofolate reductase polymerase chain reaction fragment revealed a significantly higher prevalence of a +/+ genotype among spina bifida patients and their mothers. The risk for spina bifida offspring is the strongest if both the mother and her child have the mutation in the homozygous state. Enzymatic analysis showed that homozygosity for the 677C-->T mutation causes a decreased 5,10-methylene tetrahydrofolate reductase activity, resulting in elevated plasma homocysteine and red blood cell folate levels and lowered plasma folate and cysteine values. This extended study demonstrates that a nucleotide substitution in the coding region of 5,10-methylene tetrahydrofolate reductase, resulting in reduced activity and an impaired homocysteine and folate metabolism, is a genetic risk factor for spina bifida.

Hyperhomocysteinemia: a risk factor for placental abruption or infarction

OBJECTIVE

To establish the prevalence of hyperhomocysteinemia in women with placental abruption or infarction.

DESIGN

Forty-six women with normal pregnancy outcome (controls) and 84 women with placental abruption or infarction (study group) were selected, and studied in the non-pregnant state. Homocysteine metabolism was investigated by a standardized oral methionine loading test. Hyperhomocysteinemia was defined as a concentration of fasting and/or postmethionine plasma homocysteine exceeding the estimated 97.5 percentile level of the controls. In the fasting state, the vitamin status was investigated by the measurement of serum and red cell folate, serum vitamin B12, and whole blood pyridoxal-5'-phosphate (PLP, an active form of vitamin B6).

RESULTS

Hyperhomocysteinemia was diagnosed in four controls (9%) and 26 women of the study group (31%, P < 0.05). The median concentrations of the vitamins studied were significantly lower in women of the study group as compared to the controls, except for red cell folate, where the median concentration was comparable in both groups. The median concentration of fasting plasma homocysteine, unlike post-methionine plasma homocysteine, was significantly higher in women who experienced placental abruption or infarction in their first pregnancy than in women who had the same event after one or more uncomplicated pregnancies.

CONCLUSION

Hyperhomocysteinemia is associated with placental abruption or infarction.

Mutated methylenetetrahydrofolate reductase as a risk factor for spina bifida

Periconceptional folate supplementation reduces the risk of neural-tube defects. We studied the frequency of the 677C-->T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene in 55 patients with spina bifida and parents of such patients (70 mothers, 60 fathers). 5% of 207 controls were homozygous for the 677C-->T mutation compared with 16% of mothers, 10% of fathers, and 13% of patients. The mutation was associated with decreased MTHFR activity, low plasma folate, and high plasma homocysteine and red-cell folate concentrations. The 677C-->T mutation should be regarded as a genetic risk factor for spina bifida.

Folate metabolism and neural tube defects: a review

The importance of folate in normal fetal development and wellbeing has been recognized only during the past three decades and knowledge concerned is still far from complete. In man, folate acts as a substrate in the transfer of one-carbon moieties and thereby, plays an essential role in the synthesis of several amino acids such as methionine and nucleic acids. Consequently, folate requirements are related to the amount of tissue growth. Epidemiological, clinical and teratological research showed that this B-vitamin is particularly involved in the prevention and pathogenesis of neural tube defects. Therefore, in this review the metabolism of folate has been outlined. Furthermore, the characteristics of the various genically determined folate 'deficiencies' as well as a possible biochemical explanation of the relationship between folate and neural tube defects are being discussed. Finally, the new recommendations launched in November 1993 by the Dutch Health Council as well as the Food and Nutrition Council with regard to folate supplementation in the prevention of neural tube defects are presented.

Neural tube defects and elevated homocysteine levels in amniotic fluid

OBJECTIVE

Our purpose was to study maternal blood and amniotic fluid concentrations of homocysteine and relevant vitamins in relation to neural tube defects.

STUDY DESIGN

Concentrations of total homocysteine, folate, and vitamins B12 and B6 were measured in maternal blood and amniotic fluid of 27 women carrying a fetus with a neural tube defect and 31 control women carrying a healthy fetus.

RESULTS

The mean total homocysteine concentration in amniotic fluid of the study group was significantly higher than that of the control group. The mean concentrations of total homocysteine in blood and the vitamins folate, B12, and B6 in, respectively, blood and amniotic fluid were not significantly different between the groups. The mean concentrations of homocysteine and vitamin B6 were significantly lower in amniotic fluid than in blood in both groups, whereas vitamin B12 in amniotic fluid was higher than in blood.

CONCLUSION

These results support the hypothesis that at least the cause of a subset of neural tube defects could reside in a primary or secondary maternal or fetal derangement of homocysteine metabolism.

Maternal hyperhomocysteinemia: a risk factor for neural-tube defects?

The maternal vitamin status, especially of folate, is involved in the pathogenesis of neural-tube defects (NTDs). Maternal folate administration can prevent these malformations. The precise metabolic mechanism of the beneficial effect of folate is unclear. In this study we focus on homocysteine accumulation, which may derive from abnormalities of metabolism of folate, vitamin B12, and vitamin B6. We studied nonpregnant women, 41 of whom had given birth to infants with NTDs and 50 control women who previously had normal offspring. The determinations included the plasma total homocysteine both in the fasting state and 6 hours after the ingestion of a methionine load. In addition, we measured the fasting blood levels of folate, vitamin B12, and vitamin B6. The mean values for both basal homocysteine and homocysteine following a methionine load were significantly increased in the group of women who previously had infants with NTDs. In nine of these subjects and two controls, the values after methionine ingestion exceeded the mean control by more than 2 standard deviations. Cystathionine synthase levels in skin fibroblasts derived from these methionine-intolerant women were within the normal range. Our findings suggest a disorder in the remethylation of homocysteine to methionine due to an acquired (ie, nutritional) or inherited derangement of folate or vitamin B12 metabolism. Increased homocysteine levels can be normalized by administration of vitamin B6 or folate. Therefore, we suggest that the prevention of NTDs by periconceptional folate administration may effectively correct a mild to moderate hyperhomocysteinemia.

Factors influencing the risk of abnormal pregnancy outcome in epileptic women: a multi-centre prospective study

We studied pregnancy outcome in preconceptionally recruited epileptic and control women in a multi-centre prospective non-intervention study at two university hospitals and three general hospitals. We evaluated 225 singleton pregnancies: 119 pregnancies of epileptic women who received either antiepileptic drugs (AEDs) (n = 99) or not (n = 20), and 106 pregnancies of controls. The main outcome measures were abnormal pregnancy outcome: major and minor congenital malformations, ectopic pregnancies, abortions; neonatal headcircumference; birth weight and birth length. Epileptic women had a two-fold risk of having an abnormal pregnancy outcome or an infant with minor malformations compared to healthy controls (odds ratio, with 95% confidence interval, respectively 2.1 (1.1, 4.0) and 2.0 (1.0, 4.0)). A significant correlation between the prevalence of abnormal pregnancy outcome and duration of epilepsy and AED treatment was found (risk increased by 9% (6%, 16%) per annum). No significant effect in terms of the type, the number or the serum level of the AEDs could be established. The head circumference of infants of epileptic mothers was significantly smaller (0.7 (1.2, 0.28 cm) compared to controls. An effect on the outcome of pregnancy of maternal folate supplementation or of folate blood concentrations during the periconceptional period and first trimester of pregnancy could not be determined. The severity of maternal epilepsy and/or AED treatment influences pregnancy outcome.

Primary prevention of neural-tube defects with folic acid

This symposium dealt with the trilogic, epidemiologic, occupational, genetic and nutritional aspects of neural tube defects (NTD). Homocysteine could be involved in the pathogenesis of NTD. Folic acid is highly recommended for prevention.

Study on the presence of homocysteine in ovarian follicular fluid

OBJECTIVE

To study the presence of homocysteine, methionine and the vitamins folate, B12, and B6 in human ovarian follicular fluid (FF).

DESIGN

Measurement of homocysteine, methionine, folate, and vitamins B12 and B6 in ovarian FF and blood.

SETTING

Academic Department of Obstetrics and Gynecology at St. Radboud Hospital, Nijmegen, The Netherlands.

PARTICIPANTS

Fourteen healthy women undergoing an IVF program.

RESULTS

Detectable amounts of homocysteine and methionine were found in FF. Homocysteine concentrations were similar to those in serum. Methionine concentrations proved to be slightly but significantly lower than in corresponding serum samples. Concentrations of vitamins B12 and B6 were significantly lower in FF than in serum, whereas folate concentrations were not significantly different. A statistically significant correlation between corresponding serum and FF concentrations of homocysteine, folate, and vitamin B12 could be established.

CONCLUSIONS

These data support the hypothesis that the ovum might be exposed to high homocysteine or low methionine concentrations, or both, and a lack of vitamins, which might be important in fertilization and early embryogenesis.

Hyperhomocysteinemia: a risk factor in women with unexplained recurrent early pregnancy loss

OBJECTIVE

To establish the prevalence of hyperhomocysteinemia in women with unexplained recurrent early pregnancy loss.

DESIGN

In a patient-control study, the methionine-homocysteine metabolism was investigated by a standardized oral methionine-loading test.

SETTING

Gynecologic outpatient department of university hospital.

PATIENTS

One-hundred and two women who had been referred to the hospital because they suffered from at least two consecutive unexplained spontaneous abortions (study group) as well as 41 controls who were recruited by public advertisement were selected.

INTERVENTIONS

Blood samples were collected just before and 6 hours after oral methionine administration to determine plasma total homocysteine concentrations.

MAIN OUTCOME MEASURE

Plasma total homocysteine concentrations 6 hours after methionine loading. Hyperhomocysteinemia was defined as total homocysteine concentration at 6 hours exceeding the 97.5 percentile level of the controls.

RESULTS

Hyperhomocysteinemia was diagnosed in 21 women of the study group (21%). In the parous women of the study group, the prevalence of hyperhomocysteinemia was more than two times greater compared with the nulliparous subjects (33% and 14%, respectively).

CONCLUSION

Hyperhomocysteinemia is a risk factor in women with unexplained recurrent early pregnancy loss.

Periconceptional vitamin profiles are not suitable for identifying women at risk for neural tube defects

Folic acid and other vitamin deficiencies may play a role in the etiology of neural tube defects. The Medical Research Council Vitamin Study confirmed the beneficial effect of folic acid supplementation on the prevention of neural tube defects. However, the concentrations of vitamins other than folate were not a common feature of any of the former studies. We measured the concentrations of vitamin A, riboflavin, riboflavine-5'-monophosphate, flavine-adenine-dinucleotide, vitamin B-6, vitamin B-12, vitamin C, vitamin E, folate and ferritin in the serum of women who had previously had a child with a neural tube defect and were planning a further pregnancy. Vitamin and folic acid supplements were supplied before conception to 44 high risk women before conception. Eighteen other high risk women not given supplements were the control group. We concluded that vitamin profiles do not form a suitable means for identifying women at risk for neural tube defects before pregnancy. This endorses the hypothesis that the beneficial effect of folic acid supplementation on the prevention of neural tube defects is possibly at least partly due to the fact that it overrides a relative folic acid shortage caused by a metabolic disorder.

Sub-50 oral contraceptives affect folate kinetics

The effects of long-term use of oral contraceptives containing less than 50 micrograms of estrogen (sub-50 OCs) on the kinetics of folic acid monoglutamate, vitamin B12 levels, and iron status have been studied in 29 OC users (Marvelon) and in 13 women without OC use serving as controls. At 210 min after oral folate loading the median serum folate concentration was significantly lower in OC users when compared to the control group. OC users showed significantly higher total iron binding capacity and significantly lower serum vitamin B12 concentrations. This data demonstrates that sub-50 OCs significantly affect folate kinetics and vitamin B12 levels. However, the folate and vitamin B12 status does not seem to be at risk.