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The level of plasma total homocysteine (tHcy), long known to be B vitamin dependent, has recently been shown to be inversely associated with plasma selenium (Se) concentration in human subjects. We therefore, chose to investigate the interaction between Se, tHcy and B vitamins in a double-blind, placebo-controlled trial where 501 healthy UK elderly volunteers were randomly allocated to receive 100, 200, or 300 microg Se/day as high-Se-yeast, or placebo-yeast for 6 months. Plasma Se, tHcy, folate, vitamin B-12, pyridoxal-5'-phosphate (PLP) and its catabolite, 4-pyridoxic acid, were measured in all participants at baseline and in samples from the placebo, 100 and 300 microg Se/day groups, at follow-up. At baseline, Se was inversely correlated with tHcy but only in males (p < 0.001). Before supplementation, tHcy concentration was significantly lower in the highest compared to the lowest Se tertile in males (p < 0.05), and in females when folate concentrations were also in the top tertile (p < 0.05). The effect of folate, PLP and vitamin B-12 concentrations on plasma tHcy correlated with Se concentration at baseline. After 6 months of Se supplementation, only Se concentration had changed significantly. Supplementation with Se does not affect tHcy concentration in the UK elderly population.

Background. In view of plans for dietary fortification with folic acid, there is a need to reassess the advice being given in primary care. Patients and professionals may assume that fortification will make preconceptional folic acid supplementation unnecessary, but this is unlikely to be correct. Aim. To calculate the intake of total folic acid and folate at conception and to estimate the impact of fortification on the incidence of neural tube defect (NTD) conceptions. Design. An in-depth investigation of dietary folate intake of 18 women and a survey of preconception supplementation in a group of 130 women, including an assessment of the probable impact of mandatory fortification. Method. Dietary folate intake of six infertile women and 12 age-matched fertile controls was assessed using a 7-day weighed diet diary. Mean values for this group were used as an estimate of local dietary folate intake. Questionnaires about periconceptional intake of supplements that included folic acid in their formulation were given to newly pregnant women attending district midwife clinics, a series of women attending an assisted conception unit and a self-help group of lesbians who were either pregnant or planning a pregnancy. Results. Of the 18 women in the dietary study there was suboptimal dietary folate intake in all infertile subjects and in eight of 12 controls. An approximate value for the combined intake of dietary folate and folic acid in the larger survey (n = 130) was calculated. We estimated that UK dietary fortification will double the number of pregnancies with adequate total folate intake. From previous data on folic acid intake and NTD births we estimate that this will prevent 226-343 conceptions per year in the UK from developing NTD malformations. Conclusions. Fortification should prevent approximately 226-343 conceptions a year from developing NTDs, but 45% of women will still have an inadequate total folate intake, unless supplementation levels improve. [ABSTRACT FROM AUTHOR]

Purpose. To compare the nutritional status of infertile women with non-pregnant fertile age-matched controls and to assess the periconceptional intake of nutritional supplements in pregnancy with an estimation of total micronutrient (diet and supplementary) intake. Design. An assessment of the nutritional status of infertile women and fertile, age-matched non-pregnant controls and a survey of the periconceptional intake of folic acid and other nutritional supplements. Materials and methods. Group 1: a 7-day weighed diet diary and blood tests for magnesium, mineral and pyridoxine status were used to assess the nutritional status of six infertile women and 12 non-pregnant, healthy, age-matched controls. Group 2: the periconceptional dietary intake of folic acid and other nutritional supplements was estimated in 87 pregnant women attending midwife clinics, 36 women attending an assisted conception clinic and 7 women attending a self help group for lesbian pregnancy. Results. In the group of six infertile subjects and 12 fertile controls, there was a non-significant trend for micronutrient intake in the controls to be higher than for the infertile subjects. Comparisons with the UK reference nutrient intake confirmed suboptimal nutrition in all subjects and some controls. Twenty-five per cent of controls and 33% of infertile subjects had subnormal serum selenium consistent with reduced antioxidant defence. There was also a non-significant trend for non-caeruloplasmin copper and cadmium to be higher in the infertile subjects. The combined mean dietary intake for all subjects and controls was similar to the values from the National Diet and Nutrition Survey. Therefore, an approximate value for the total intake of nutrients (diet and supplementation) of the 130 women in the larger survey was calculated using the mean dietary intake of the smaller group as an estimate of the dietary component. This analysis suggested suboptimal total intake for >50% of the subjects for selenium, zinc, magnesium and iodine and borderline total intake for >50% of subjects for vitamins B12, C and E, betacarotene, iron, folate + folic acid and essential fatty acids. Conclusions. Current levels of supplementation with folic acid and other nutrients are failing to compensate for poor mean dietary intake of these nutrients at the time of conception. These nutritional deficiencies are probably important contributory factors in infertility, spontaneous abortion, pregnancy complications and post-partum health problems in the mother and infant (including congenital malformations and postnatal depression). [ABSTRACT FROM AUTHOR]