Even in the recent past, vitamins were looked at as an essential weapon to prevent illness, however, a large study by the Cochrane Hepato-Biliary Group at the Centre for Clinical Intervention Research at Copenhagen University has come up with disappointing evidence.
A large evidence-based analysis was performed involving a population of 170,525 persons who were enrolled in randomized trials. They received a regimen of antioxidant supplementation that included beta-carotene, vitamin A, vitamin C, and vitamin E daily or on alternate days for 1 to 12 years, along with selenium every year for 2 to 4 years.
All trials reported the separate or combined incidence of cancer of the esophagus, colon, pancreas, stomach or the liver.
Results showed that beta-carotene alone, the most widely tested antioxidant for cancer prevention, did not have substantial cancer-fighting properties in gastrointestinal cancers. The devastating blow is the fact that beta-carotene in combination with vitamin A and vitamin C significantly increased mortality! Recent studies examining vitamin C show, that it can be an antioxidant, but it also can be a pro-oxidant (the less desirable quality). Trials involving selenium very clearly showed that it might have beneficial effects on the incidence of gastrointestinal cancers.
Following these news it would be a grave mistake to assume, that fruit and vegetables with their built-in antioxidants, micronutrients, dietary fiber and beneficial plant-chemicals have fallen off grace.
The truth is, that fruit and vegetables typically contain safe levels of vitamins. Most studies have reported that adequate intake of fruit and vegetables are indeed associated with a low incidence of cancer.
The study, however, clearly points out the pitfalls of vitamin supplementation.
-“The more the better” does not apply when it comes to taking vitamins.
-Antioxidants according to this study are not as beneficial for cancer prevention as was thought of in the past.
– Only vitamin C and selenium held up to the scrutiny of the evidence-based researchers with regard to having preventative effects regarding the above named gastrointestinal cancers.
Reference: The Lancet, Vol. 364, Number 9441, pg.1219-28, October 2, 2004
Last edited December 7, 2012