Risk of cancer in men increased by use of vitamin B6 and B12 supplements

The cobalt-based compounds sold as B12 supplements have been propelled into the hearts of Americans as The Dr. Oz Show has recommended to “end your energy crisis with Vitamin B12”, but they might pose a serious health risk.

The marketing claims B12 benefited from were born from the fact that B12 deficiency causes anemia and correcting that deficiency will alleviate fatigue symptoms. However, as the National Institutes of Health notes, “Vitamin B12 supplementation appears to have no beneficial effect on performance in the absence of a nutritional deficit.”

Around 50% of people in the US take dietary supplements – and the most common are B vitamins, according to the Atlantic. This usage might be really dangerous, as stated in a study published in the Journal of Clinical Oncology. Taking high doses of vitamin B6 and B12 supplements (like the ones sold in stores) seems to triple and even quadruple some people’s risk of developing lung cancer.

This is not the first time concerns about B-vitamin supplements and their connection to cancer emerge. The first time they appeared was in a large trial in Norway that was concluded ten years ago. In 1998, researchers assigned 6,837 people with heart disease to take either B vitamins or a placebo. Afterwards, the researchers observed as people died and contracted diseases in the years that followed.

As it turns out, the group that was given vitamins raised concerns. In 2009, the researchers reported in the Journal of the American Medical Association that taking high doses of vitamin B12 along with folic acid (vitamin B9) was linked to a greater risk of cancer and all-cause mortality.

Using over 55 micrograms daily seemed to quadruple cancer risk. The largest increase in cancer risk was in the lung. However, the number of lung cancer cases among the 6,837 Norwegians involved in the study was quit small, which made the quantification of the risk difficult.

The study inspired Theodore Brasky and Emily White, two researchers at the Fred Hutchinson Cancer Research Center in Seattle, to make a study that involved ten times as many people as the Norwegian trial – around 77,000 people across Washington state. Their supplement intake is being tracked at the moment and followed for cancers by the National Cancer Registry.

The findings of Brasky and White’s study were more significant than those of the previous Norwegian study. Lung-cancer risk among men who took 20 milligrams of B6 a day for years was twice that of men who didn’t. The effect seemed to be synergistic among smokers, as B6 usage increased risk threefold. The risk was far worsefor smokers taking B12. Only 55 micrograms daily appeared to quadruple the risk of lung cancer. For women, there was no apparent risk.

It is advisable to consider these vitamins as pharmaceuticals. The research team noted that the doses of B vitamins in question are high. The US Recommended Dietary Allowance for B6 is 1.7 milligrams per day, and for B12 it’s 2.4 micrograms. The high-risk group in the study was taking almost 20 times these amounts. These doses are sold at places considered healthy, such as Whole Foods and GNC. Many sellers offer daily 100-milligram B6 pills and 5,000-microgram B12 pills.

A 1994 law called the Dietary Supplement Health and Education Act (DSHEA) absolve supplements of certain requirements – such as being sold in reasonable doses and revealing the risks associated with ingesting them. “The law was created by industry lobbying to keep the FDA away from regulation, so the industry self-regulates,” said Brasky.

The current law doesn’t give consumers a reason to expect the risks of certain products or the accuracy of their health claims. Products like high-dose B6 and B12 supplements hit shelves often, but only decades later the long-term health effects are being revealed.