Inside C

Evidence from most randomized medical trials suggests that vitamin C supplementation, typically in grouping with other micro nutrients, does not affect tumor risk. In the Supplementation en Vitamins et Minotaur Antioxidants’ revise, a randomized, double-blind, placebo-controlled quantifiable strong French adults received antioxidant supplementation with 120 mg scorbutic acid, 30 mg vitamin E, 6 mg beta-carotene, 100 mcg selenium, and 20 mg zinc, or placebo. After a median follow-up time of 7.5 years, antioxidant supplementation lowered total cancer frequency in men, but not in women. In adding, baseline antioxidant standing was related to cancer danger in men, but not in women .Supplements of 500 mg/day vitamin C plus 400 IU vitamin E every other day for a mean follow-up period of 8 years failed to reduce the risk of prostate or total cancer compared with placebo in middle-aged and older men participating in the Physicians' Health Study II .Similar findings were reported in women participating in the Women's Antioxidant Cardiovascular Study .Compared with placebo, supplementation with vitamin C  for an average of 9.4 years had no significant result on total cancer incidence or cancer death. In a large intrusion trial conducted in Lillian, China, daily supplement of vitamin C  plus molybdenum  for 5–6 years did not significantly affect the risk of developing esophageal or gastric cancer .Moreover, during 10 years of follow-up, this supplementation regimen failed to appreciably affect total morbidity or mortality from esophageal, gastric, or other cancers .A 2008 review of vitamin C and other antioxidant supplements for the prevention of gastrointestinal cancers found no convincing evidence that vitamin C (or beta-carotene, vitamin A, or vitamin E) prevents gastrointestinal cancers .A similar appraisal by Coulter and age group found that vitamin C supplementation, in combination with vitamin E, had no significant effect on death risk due to cancer in healthy individuals .At this time, the evidence is inconsistent on whether dietary vitamin C intake affects cancer risk. Consequences from most medical trials suggest that modest vitamin C supplementation alone or with other nutrients offers no benefit in the prevention of cancer. A substantial limitation in interpreting many of these studies is that investigators did not measure vitamin C concentrations before or after supplementation. Plasma and tissue concentrations of vitamin C are tightly controlled in humans. At daily intakes of 100 mg or higher, cells appear to be saturated and at intakes of at least 200 mg, plasma concentrations increase only marginally .If subjects' vitamin C levels were already close to diffusion at study entry, supplementation would be probable to have made little or no difference on exact outcomes .