Dietary supplements increase cancer risk

May 15, 2012

Beta-carotene, selenium and folic acid – taken up to three times their recommended daily allowance, these supplements are probably harmless. But taken at much higher levels as some supplement manufacturers suggest, these three supplements have now been proven to increase the risk of developing a host of cancers.

"It's not that these nutrients are toxic – they're essential and we need them, but we need them in a certain balance," says Tim Byers, MD, MPH, professor of epidemiology at the Colorado School of Public Health and associate director for prevention and control at the University of Colorado Cancer Center.

Byers is senior author of a commentary recently published in the Journal of the National Cancer Institute that discusses the clinical and policy implications of the increased cancer risk from high dose dietary supplements.

"We have a window into less than half of the biology of what these nutrients are doing," Byers says. "We say generalized things about them, calling them an antioxidant or an essential mineral, but true biology turns out to be more complex than that. The effects of these supplements are certainly not limited to the label we give them. And, as we've seen, sometimes the unintended effects include increased risk."

Currently the FDA regulates dietary supplements as food, but, as Byers and colleagues suggest, supplements, especially at high doses, are more accurately described as inhabiting a mid-ground between food and drugs. Like drugs, supplement ingredients are biologically active – sometimes for better and sometimes for worse.

"We need to do a better job as a society in ensuring that the messages people get about value versus risk is accurate for nutritional ," Byers says. "My conclusion is that taking high doses of any particular nutrient is more likely to be a bad thing than a good thing."

Explore further: Supplements and cancer prevention: A cautionary tale

Related Stories

Supplements and cancer prevention: A cautionary tale

April 25, 2012
Government regulators and the scientific community should work to ensure that they give clear guidance to the public about dietary supplements and cancer risk, according to a commentary published April 25 in the Journal of ...

Expert advises against high doses of supplements

May 4, 2012
(Medical Xpress) -- That vitamin D and calcium you're taking could be causing more harm than good, a new article in the Journal of the National Cancer Institute says.

Certain dietary supplements associated with increased risk of death in older women

October 10, 2011
Consuming dietary supplements, including multivitamins, folic acid, iron and copper, among others, appears to be associated with an increased risk of death in older women, according to a report in the October 10 issue of ...

Monitoring the population's food and supplement intakes

March 8, 2012
Collecting data on what the U.S. population actually consumes is a key nutrition monitoring step. Nutritionists then translate "foods eaten" into "nutrients consumed." This snapshot of the population's food-nutrient intakes ...

Recommended for you

Shooting the achilles heel of nervous system cancers

July 20, 2017
Virtually all cancer treatments used today also damage normal cells, causing the toxic side effects associated with cancer treatment. A cooperative research team led by researchers at Dartmouth's Norris Cotton Cancer Center ...

Molecular changes with age in normal breast tissue are linked to cancer-related changes

July 20, 2017
Several known factors are associated with a higher risk of breast cancer including increasing age, being overweight after menopause, alcohol intake, and family history. However, the underlying biologic mechanisms through ...

Immune-cell numbers predict response to combination immunotherapy in melanoma

July 20, 2017
Whether a melanoma patient will better respond to a single immunotherapy drug or two in combination depends on the abundance of certain white blood cells within their tumors, according to a new study conducted by UC San Francisco ...

Discovery could lead to better results for patients undergoing radiation

July 19, 2017
More than half of cancer patients undergo radiotherapy, in which high doses of radiation are aimed at diseased tissue to kill cancer cells. But due to a phenomenon known as radiation-induced bystander effect (RIBE), in which ...

Definitive genomic study reveals alterations driving most medulloblastoma brain tumors

July 19, 2017
The most comprehensive analysis yet of medulloblastoma has identified genomic changes responsible for more than 75 percent of the brain tumors, including two new suspected cancer genes that were found exclusively in the least ...

Novel CRISPR-Cas9 screening enables discovery of new targets to aid cancer immunotherapy

July 19, 2017
A novel screening method developed by a team at Dana-Farber/Boston Children's Cancer and Blood Disorders Center—using CRISPR-Cas9 genome editing technology to test the function of thousands of tumor genes in mice—has ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.