Vitamin C megadosage the airways as a result of vigorous exercise. EIB seems to be caused by the loss of water caused by increased ventilation, which may lead to the release of mediators such as histamine, prostaglandins and leukotrienes, all of which cause bronchoconstriction. Vitamin C participates in the metabolism of these mediators and might thereby influence EIB. A meta-analysis showed that 0.5 to 2 g/day of vitamin C before exercise decreased EIB by half. A meta-analysis showed a significant positive effect of vitamin C on endothelial function. Benefit was found of vitamin C in doses in the range from 0.5 to 4
Vitamin E E versus placebo. Subset analysis for ischaemic stroke, haemorrhagic stroke, fatal stroke, non-fatal stroke - all no significant difference in risk. Likewise for subset analysis of natural or synthetic vitamin E, or only above or below 300 IU/day, or whether the enrolled people were healthy or considered to be at higher than normal risk. The authors concluded that there was a lack of clinically important benefit of vitamin E supplementation in the prevention of stroke. One large, multi-year study in which post-menopausal women consumed either placebo or 600 IU of natural-sourced vitamin E on alternate days reported no effect on