In a five year study carried out by the National Cancer Institute and involving nearly 300,000 men it was found that men who were regularly taking more than the recommended daily dose of one multi-vitamin tablet a day increased their risk from advanced prostate cancer by about thirty percent. In addition, the risk of death from advanced prostate cancer was doubled. The study also noted that there was an increased risk in a sub-group of men who also had a family history of prostate cancer or who also took selenium, beta-carotene and zinc supplements.

One important finding of this study was that there was no apparent increase in the overall rate of prostate cancer within the study group and so there is no suggestion that the excessive use of vitamins actually causes prostate cancer.

However, in the case of those members of the study group who were taking multi-vitamins in excessive quantities the risk of developing advanced prostate cancer was increased by nearly one-third and their risk of dying from advanced prostate cancer was doubled.

Vitamin and mineral supplements have been shown over many hundreds of years to have considerable health benefits and today a multi-million dollar industry has been established to meet our growing demand from an ever widening range of supplements. Indeed several, such as green tea extract (EGCG), have been developed specifically for men suffering from prostate problems. So does this study mean that we should stop taking supplements?

No. First, the study clearly shows that the problem only arises in men who exceed the normal daily dose of multi-vitamins and there is no evidence to suggest any risk as long as you keep your intake within recommended levels. Second, because the study looked only at multi-vitamins it is not possible at this point to say just which component (or components) causes the problem. At this point further study will clearly be necessary to isolate the true root of the problem.

On balance, if you need to supplement your diet with vitamins, then the benefits will almost certainly outweigh any risks. Just be careful and take no more than you need and which your doctor recommends.