No abstract

This study evaluates the effects of vitamin B-6 supplementation (20 mg pyridoxine HCL daily for 3 months) on mood and performance in 38 self-supporting healthy men, aged between 70-79 years. Effects were compared with 38 controls who received placebo and were matched for age, plasma pyridoxal-5'-phosphate (PLP) concentration and intelligence score. Before and after drug intervention vitamin B-6 status was determined, and mood and performance were measured by means of a computerized testing system. In addition, the phasic pupil response was measured in order to assess mental effort. Positive effects of vitamin B-6 supplementation were only found with respect to memory, especially concerning long-term memory. In view of the finding that mental performance improvement and delta PLP values were most strongly correlated within an intermediate range of delta PLP, it is suggested that cognitive effects are primarily associated with a certain range of vitamin B-6 status increment. The general conclusion is that vitamin B-6 supplementation improves storage of information modestly but significantly.

Vitamins, just as minerals and trace elements, meet with great interest in the world of sports because of their supposed role in enhancing physical performance. Of the 13 compounds now considered as vitamins, most water-soluble vitamins and vitamin E are involved in mitochondrial energy metabolism. The influence of vitamin supplementation on mitochondrial metabolism is largely unknown. The principal argument for vitamin supplementation is the assumed increased vitamin requirement of athletes. Theoretically, an increased requirement can be caused by decreased absorption by the gastrointestinal tract, increased excretion in sweat, urine and faeces, increased turnover, as well as biochemical adaptation to training. Of course, a marginal low vitamin status can simply be the consequence of a long-term inadequate intake. However, considering the RDAs there are no indications that long-term vitamin intake among athletes is insufficient. Neither are there indications that vitamin excretion or turnover is increased in athletes. However, it is very likely that the (apparently) increased requirement is the consequence of biochemical adaptation to training and does not indicate a decreased intake. Although a marginal vitamin status, induced by inadequate vitamin intake, may have a negative effect on performance, there is no evidence to support the view that this occurs in trained athletes. Moreover, vitamin supplementation in athletes with an adequate vitamin status has no effect on physical working capacity. Possibly, exceptions have to be made for the use of vitamin E at high altitudes and for the use of vitamin C and multiple B-vitamin supplements in hot climates.

The absence of vitamin-specific effects on performance decrements due to thiamin, riboflavin and vitamin B6 restriction suggests quantitatively similar but non-additive effects of these B-vitamins on mitochondrial metabolism.

Orlistat is a potent and selective inhibitor of gastrointestinal lipases. The drug is designed for the treatment of obesity. The effect on dietary fat absorption of orlistat after administration of divided doses spread over 2 hours from mid-meal, in comparison with that after administration of a full dose mid-meal, was investigated in a randomized, single-blind study including 16 hospitalized healthy males. After a 5-day run-in, to accustom the subjects to a diet of 2350 kcal and 76 g fat per day and to establish baseline fecal fat excretion, subjects received, in two parallel groups of eight over 8 days, three times a day 80 mg orlistat at mid-meal, and placebo at mid-meal and 0.5, 1, and 2 hr after mid-meal (group A), or placebo at mid-meal, and 20 mg orlistat at mid-meal and 0.5, 1, and 2 hr after mid-meal (group B). Feces were collected to measure total fat excretion. The mean (SD) of fecal fat in percent of dietary fat, after deduction of pretreatment fecal fat, was (%) 36.1 (4.2) and 37.0 (9.3) in groups A and B, respectively. Changing the mode of administration of orlistat, within the dose regimens investigated, does not affect its pharmacologic efficacy.