Lowering blood homocysteine with folic acid-based supplements: meta-analysis of randomised trials.

The objective of this study was to determine the size of reduction in homocysteine concentrations produced by dietary supplementation with folic acid and with vitamins B12 or B6. Meta-analysis of individual data on 1114 people in 12 randomised controlled trials assessed the effects of folic acid-based supplements on blood homocysteine concentrations. Multivariate regression analysis was used to determine the effects on homocysteine concentration of different doses of folic acid and of the addition of vitamin B12 or B6. The results showed that the proportional and absolute reductions in blood homocysteine produced by folic acid supplements were greater at higher pre-treatment blood homocysteine concentrations (p<0.001) and at lower pre-treatment blood folate concentrations (p<0.001). After standardisation to pre-treatment blood concentrations of homocysteine of 12 micromol/L and of folate of 12 nmol/L (approximate average concentrations for Western populations), dietary folic acid reduced blood homocysteine concentrations by 25 percent (95% confidence interval 23%-28%; p<0.001), with similar effects in the range of 0.5-5 mg folic acid daily. Vitamin B12 (mean 0.5 mg daily) produced an additional 7 percent (3%-10%) reduction in blood homocysteine. Vitamin B6 (mean 16.5 mg daily) did not have a significant additional effect. In conclusion, typically in Western populations, daily supplementation with both 0.5-5 mg folic acid and about 0.5 mg vitamin B12 would be expected to reduce blood homocysteine concentrations by about a quarter to a third (for example, from about 12 micromol/L to 8-9 micromol/L). Large scale randomised trials of such regimens in high risk populations are now needed to determine whether lowering blood homocysteine concentration reduces the risk of vascular disease.

Riboflavin and pyridoxine status in a group of pregnant Mexican women

In order to assess the nutritional status of riboflavin and pyridoxine during pregnancy, 24 Mexican women were studied during the second trimester and 17 during the third trimester of gestation. The biochemical evaluation of the riboflavin and pyridoxine status was performed by measuring the activation coefficients (AC) of the erythrocyte glutathione reductase (eGR) and aspartate aminotranferase (eAAT), respectively. Dietary protein, riboflavin, thiamin, and calcium intake decreased significantly in the last trimester of gestation. The women presented biochemical deficiency of pyridoxine in the second and third trimester of pregnancy, but they developed biochemical deficiency of riboflavin and pyridoxine deficiency. None showed clincial signg of vitamin deficiency. No significant correlation was found between individual serum concentrations of estradiol or progesterone and eGR-AC or eAAT-AC in both trimesters of pregnancy. Six newborns studied showed normal eGR-AC and eAAT-AC

Carpal tunnel syndrome during pregnancy: prevalence and blood level of pyridoxine.

The prevalence of CTS in third trimester pregnant women in the study in 28 per cent. With the use of NCS it was able to detect nearly 80 per cent of them who had no symptoms or signs. There was no association between the level of vitamin B6 or B6 deficiency and CTS. Since CTS may result in a permanent disability if undiagnosed or left untreated it is essential to make an early diagnosis and treat it especially older women and those who are edematous.

The vitamin B1, B2 and B6 status of school children in two resettlement areas in Northeast Thailand.

The vitamin B1, B2 and B6 status of school children were studied in the Khon Kaen resettlement and irrigation area and in the Lam-takong settlement in northease Thailand using the in vitro tests based on the erythrocyte transketolase, glutathione reductase and glutamate-oxaloacetate transaminase activities. Healthy school children from the Khon Kaen University School were selected as a reference group. The results demonstrate that the vitamin B1 status in the resettlement area is sufficient, but about 20% to 35% of all the children show evidence of vitamin B2 and B6 deficiencies. It is noticed that besides a high prevalence of parasitic infections and poor hygienic conditions the protein and vitamin intake is low and improvement of the situation is necessary.