Are vitamins harmful to health?

This old chestnut, the claim made today in the Daily Mail that vitamin supplements increase cancer risk, is based on some spurious research, published in 1996, that happened to find that smokers during a beta-carotene study, had a higher rate of cancer. The non-smokers didn’t. A follow up of the participants, in 2004, found that there was no statistically significant risk associated with beta-carotene once a person stopped their drugs. Last week a very important 20 year study has conclusively shown that the higher one’s blood carotene levels the lower is the risk for breast cancer. Not only that, but those who developed cancer, and had higher carotene levels reduced their risk of a recurrence or death by 68%! (see

The other anti-supplement claim made is about folic acid and colo-rectal cancer. it is a well known fact that floats protect cells from becoming cancerous. However, if a person has pre-cancerous cells in the gut, often found in those with colorectal polyps, supplementing large amounts of folic acid can make those pre-cancerous cells grow faster, thus increase colorectal cancer risk. That is why I am not in favour of fortifying all food with folic acid, and caution against supplementing large amounts, e.g. 800mcg, unless you have good reason to, such as a high homocysteine level.

The guy referred to as making these claims at the recent American Association for Cancer research meeting, which is of course largely funded by big pharma, has not one paper published that I could find, and there are no details of any of new research as such, so I must assume it is just regurgitating old myths.

Have a look at for dissection of the antioxidant myths.