Food supplements: more harm than good?

Should we add vitamins to foods in order to prevent cancer or cardiovascular disease? A new Norwegian study reinforces the opponents of these practices. Folic acid and vitamin B12 may increase the risk of malicious tumors development, including lung cancer.

These findings call into question the enrichment of many foods with these vitamins. However, countries like the United States and Canada make many products fortified with folic acid (vitamin B9) in order to reduce the risk of abnormal neural tube closure in the fetus.

The folic acid and vitamin B12 or B6 have been evaluated in several studies for the purpose of preventing cardiovascular unsuccessfully. But two Norwegian studies on this subject have shown a slight rise in cancer cases.

The authors followed the patients for over three years to assess this particular risk. Around 7000 people, suffering from coronary disease received either folic acid and vitamins B6 and B12 or folic acid and vitamin B12 alone or vitamin B6 alone or placebo.

Researchers have shown a 21% increase in cancer risk with folic acid and vitamin B12. The risk of death from cancer was increased by 38% and overall mortality by 18%. Vitamin B6 had however no effect on cancer risk.

Certainly, there is a contradiction between their results and the results of other studies on folic acid and vitamin B12, which found no increase in cancers. But the Norwegians explained that by the fact that studies were conducted primarily in the United States, where, due to the enrichment of the diet, the effect of supplements added to an already high basic level, could have been minimized. The debate is far from over.

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