A disappointing end to an otherwise promising clinical trial. It was known as the SELECT (Selenium and Vitamin E Cancer Prevention Trial) and it evaluated whether supplementation with selenium and Vitamin E can prevent prostate cancer. The large-scale long-term study of the National Cancer Institute (NCI) included more than 35,000 male participants in the US, Puerto Rico and Canada. They were randomly assigned to one of 3 groups: group 1 took vitamin E only, group 2 took selenium only, group 3 took both, and group 4 took placebos only.
After, on the average, 5 years of follow up, the NCI decided to cut short the study because of “concerning” findings, namely:
- The analysis found no lower risk of prostate cancer in men taking the supplements, either alone or together.
- Men who were taking only vitamin E actually had a slightly higher risk of developing prostate cancer.
- Men taking only selenium seemed to have a slightly higher risk of developing diabetes.
The “slight increased risks” observed were not statistically significant, and could therefore be due to pure chance. However, with such major health risks, there are no taking chances. One thing remains clear: that supplementation with vitamin E and selenium do not prevent prostate cancer.
This is not the first indication that supplementation with vitamins and minerals may actually have adverse effects to our health. In 2007, Danish researchers conducted a meta-analysis of studies on the antioxidant supplementation with beta-carotene, selenium, vitamins A, C, and E. The results of the study suggest that antioxidant supplements do not prevent cancer or cardiovascular disease but may even increase the risk of overall mortality.
Several studies evaluated whether antioxidant supplements can prevent other types of cancer, with negative results. In one study, the authors concluded that “we could not find convincing evidence that antioxidant supplements prevent gastrointestinal cancers.”
Does this mean to say we don’t actually need all these supposedly essential vitamins and minerals? Actually we do. It is just we are probably using the wrong sources. Millions of people are swallowing vitamin pills each day as part of their “healthy lifestyles.” The multivitamin manufacturing has been a multi-billion industry because most of these “health supplements” are available over the counter without the need of any prescription. Vitamin pills are convenient and easy, can be taken on the go, can fit in the smallest of handbags, don’t spoil, and no need to wash, peel, slice or puree. But are they really the best for us? The abovementioned studies indicate that the answer is “No.”
These are no substitutes for the vitamins and minerals we get from fresh fruits, vegetables and nuts. Nature is still the best source of our nutritional needs.