Two popular vitamin supplements may actually increase the risk of cancer by up to 111 percent, a new study warns.
The study, published in the journal JAMA Oncology, looked at data from more than 77,000 women enrolled in the Women’s Health Initiative (WHI). The women were given either a daily supplement of vitamins E and C, or a placebo.
After almost eight years of follow-up, the researchers found that the women taking the vitamins had a 17 percent higher risk of developing cancer than the placebo group.
And when they looked specifically at breast cancer, they found that the risk was even higher, at a whopping 111 percent.
The study authors say that the findings should be a “wake-up call” for people who take these supplements.
“We were really surprised by these findings,” lead author Dr. Sara Hiatt, from the Fred Hutchinson Cancer Research Center in Seattle, said in a statement.
“We thought that, given the many observational studies that have suggested that these supplements may be protective against cancer, that we would see a reduction in cancer risk in the trial. But that’s not what we found.”
The findings echo those of another recent study, which looked at data from the Nurses’ Health Study and found that taking vitamin E and C supplements was associated with a slightly increased risk of skin cancer.
So what’s going on here?
The jury is still out, but one theory is that the supplements may actually increase the levels of oxidative stress in the body, which can lead to cell damage and cancer.
Another possibility is that the supplements may interfere with the body’s ability to repair DNA damage, which can also lead to cancer.
Needless to say, more research is needed to confirm these theories. In the meantime, the best way to reduce your risk of cancer is to follow the traditional advice: eat a healthy diet, exercise regularly, and don’t smoke.
Two popular vitamin supplements may hike risk of cancer by up to 111%.
This is according to a new study which has reignited the debate on whether healthy people should take vitamins.
The paper, published in the journal the Annals of Internal Medicine, analyzed data from two large trials involving nearly 38,000 people.
Both trials were stopped early because those taking high doses of vitamin B3 and B6 were found to have an increased risk of lung cancer.
The risk was even higher in those who smoked.
“Our results show that healthy individuals taking high doses of B vitamins (B3 and B6) had an increased risk of Lung cancer. This is an important finding, as Lung cancer is the leading cause of cancer death worldwide,” said the study’s lead author, Dr. Howard Sesso, of Brigham and Women’s Hospital and Harvard Medical School.
“Vitamins are important for good health, but high doses of vitamins B3 and B6 above the Recommended Dietary Allowance may be harmful,” he added.
The study’s findings back up other research linking vitamin B supplements to cancer.
For example, a large-scale study published in the Journal of the National Cancer Institute in 2005 found that taking vitamin B6 and B12 supplements increased the risk of developing colon cancer.
Another study, published in the journal Cancer in 2007, found that women who took high doses of vitamin B6 were at an increased risk of developing breast cancer.
So what should you do if you’re already taking vitamin B supplements?
“If you are currently taking a high dose of a B vitamin supplement, you should exercise caution and speak with your health care provider,” said Sesso.
“The bottom line is that vitamins are important for good health, but more is not always better,” he added.
The Recommended Dietary Allowance for vitamin B6 is 1.3 milligrams per day for adults, and the Upper Limit is set at 100 milligrams per day.
The Recommended Dietary Allowance for vitamin B3 is 16 milligrams per day for adults, and the Upper Limit is set at 35 milligrams per day.