It is common knowledge that Vitamins and minerals promise a wealth of health benefits, but very few have scientifically proven attributes. In fact, even their safety has been thrown into question since a number of studies highlighted potential cancer risks. Four supplements, in particular, may increase the odds of the disease unless taken at the correct dose.
The researcher, who led a meta-analysis of 12 trials involving more than 300,000, probed the relationship between cancer and several vitamins to assess their protective effect.
The analysis revealed that taking high doses of beta carotene, selenium, vitamin E, and folic acid were all linked with an increased risk of cancer.
The lead researcher said it remained unclear why supplements had these adverse effects, as other supplements included in the analysis didn’t.
Selenium supplements
Studies suggest that taken at higher doses, selenium supplements can cause serious side effects.
While the supplement’s association with cancer remains unclear, some research suggests it may increase the risk of aggressive and secondary tumours.
In the study led by the University of Colorado Cancer Centre, the supplement appeared to be linked to a higher risk of skin.
A statement on the Government’s website suggests that at high doses, vitamin E may act as a pro-oxidant, instead of an antioxidant.
The National Cancer Institute points out, however, that no link has been found between dietary sources of vitamin E and prostate cancer risk.
Conversely, high levels of alpha-tocopherol in the blood may be linked with a lower risk of developing advanced prostate cancer.
Folic acid, B vitamin
There is mixed evidence supporting the link between folic acid use and an increased risk of colon cancer.
But studies suggest the supplement could be a double-edged sword for the disease.
In 2009, research published in the journal of the American Medical Association showed that heart patients who took folic acid and vitamin B12 supplements had a significantly higher risk of cancer.
Folic acid and B12 supplements were associated with a 21 percent increased risk for cancer, and a 38 percent increased risk of dying from the disease.
Beta carotene
Beta-carotene supplements have been associated with an increased risk of lung cancer in people who smoke, or have been exposed to asbestos.
In one study of 29,000, researchers found an 18 percent increased risk of lung cancer among individuals taking 20 mg of beta-carotene a day for five to eight years.
Foods that are rich in beta-carotene, however, are appeared safe and appear to lower the risk of cancer, according to the Mayo Clinic.
Cover Photo: 12 Vitamins. Photo credit: 123rf
(Express)
