Is it risky to take vitamin A every day?

Long-term use of supplements might increase the risk of lung cancer, especially if you’re a smoker, according to researchers from the University of North Carolina at Chapel Hill.

Here are the results from the VITamins And Lifestyle (VITAL) Study.

First, the details.

  • 77,126 older adults completed a questionnaire about their use of multivitamins and individual supplements/mixtures during the previous 10 years.
  • Associations between the risk of getting lung cancer and the use of supplemental β-carotene, retinol, vitamin A, lutein, and lycopene were made.

And, the results.

  • In smokers, longer duration of taking β-carotene, retinol, and lutein supplements was associated with a significantly higher risk of lung cancer.
  • For example, taking retinol and lutein supplements for 4 years or longer was associated with increases in lung cancer risk of 53% and 102%, respectively.
  • There was no association between the average dose taken over 10 years and lung cancer risk.
  • There were too few non-smokers with cancer to permit any conclusions about this group.

The bottom line?
“Long-term use of individual β-carotene, retinol, and lutein supplements should not be recommended for lung cancer prevention, particularly among smokers,” warn the authors.

In a Medical News Today article, Dr. Jessie Satia summarized the contradictory evidence that has appeared since the 1980s.

Theoretically, higher doses of antioxidants such as vitamin A should help protect against cancer, but other factors appear to prevent this from being clearly demonstrated in studies.

The New York State Osteoporosis Prevention and Education Website advises, “You can get all of the vitamin A that you need by consuming foods rich in beta-carotene. Beta-carotene is found in plant foods, especially in dark green leafy vegetables and deep yellow or orange fruits.”

4/1/09 11:29 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.