Should You Take Beta-Carotene Supplements?

The link between beta-carotene and cancer

Beta-carotene has been studied as a potential cancer disruptor for some time, and that’s because research suggests that people who eat a lot of foods containing vitamin A or beta-carotene have a lower risk of certain types of cancers.

Beta-carotene is an antioxidant, which is a substance that can prevent or slow cell damage. “So the thought was that if oxidative stress [a process that can trigger cell damage] leads to cancer, then maybe supplementing large doses of beta-carotene and a lot of other vitamins that have antioxidant properties may help prevent cancer,” Shepherd explains.

The theory hasn’t panned out, though, despite ongoing research. And some studies have even shown a counterproductive effect, where high doses of beta-carotene supplements are linked to an increased risk of lung cancer and death in smokers and people who have been exposed to asbestos. Supplementation with the nutrient has also been associated with an increased risk for cardiovascular disease.

This is why, after reviewing the latest data, the panel concluded “with moderate certainty” that the harms of beta-carotene supplements outweigh the benefits for the prevention of cancer or cardiovascular disease.

Who should take a beta-carotene supplement?

One sign that you could need more beta-carotene is if you start experiencing difficulty seeing well in the dark but still see just fine in the light. “That might be a time to go visit with your physician,” who can check your vitamin A levels, Shepherd says. If they’re low, your doctor might prescribe a beta-carotene or vitamin A supplement.

Other warning signs that you are lacking in vitamin A include dry eyes, eye infections, skin problems and slowed growth, according to Mayo Clinic.

If you don’t have symptoms of a deficiency but are worried about your beta-carotene intake, switch up your diet before reaching for a supplement. There is no recommended daily allowance for beta-carotene, but adults should eat five or more servings of fruits and vegetables every day to get about 3 to 6 milligrams (mg) of beta-carotene, the experts at Mount Sinai say. One sweet potato contains about 11 mg of beta-carotene; so does a cup of raw chopped carrots. 

And you don’t have to just stick to orange foods. Leafy greens (kale, spinach, broccoli) are also a great source of beta-carotene, says Candy Tsourounis, a pharmacist, professor and supplements expert at the University of California San Francisco School of Pharmacy.

One reason it’s better to start with food is because “diet is, by definition, more balanced,” says Emanuela Taioli, M.D., director of the Institute for Translational Epidemiology at the Icahn School of Medicine at Mount Sinai in New York City. Fruits and vegetables contain a whole host of nutrients that “probably act synergistically to deliver health benefits,” the authors of an editorial accompanying the task force recommendations write. And the feeling of being full will kick in before you can consume too much of any one vitamin or mineral, Taioli adds.

Small supplements, on the other hand, can be particularly potent. Amounts of vitamin A crammed into pill form vary widely, but 3,000 micrograms — that’s 333 percent of the recommended daily value — is common, according to the National Institutes of Health’s Office of Dietary Supplements. And if you take that alongside other supplements, like a multivitamin, it’s easy to overdo it.

Tsourounis sees this all the time, especially among older adults. “When I have them bring in all the supplements that they’re taking, it is so common to see that they may be taking three different supplements. And they may be unrelated — maybe one they’re taking for overall health, one could be for knee pain, one could be for sleep — but yet they may share similar vitamins or similar ingredients. And when taken together, it may exceed what they should be ingesting on a daily basis,” she says. One study published in The Journal of Nutrition found that almost 30 percent of older adults in the U.S. take four or more supplements.

High doses of certain supplements, including vitamin A, can be downright dangerous because they’re not soluble in water and the body can’t flush the excess away. But since the body converts only as much vitamin A from beta-carotene as it needs, beta-carotene supplementation comes with fewer potential side effects, like yellowing of the skin, dizziness, diarrhea and joint pain. Still, it’s important to be cautious.

Beta-carotene supplements can also interact with a few medications, including some statins and some cholesterol-lowering drugs, as well as the weight-loss drug orlistat (Alli, Xenical). “And again, if [someone] has a history of smoking or asbestos exposure, I might be a little more cautious now,” Shepherd says.

Before starting any supplement, it’s always a good idea to talk to a doctor to discuss the benefits and potential harms, says Taioli, who adds that “there is no harm to a healthy diet.”

And if you’re interested in lowering your risks for heart disease and cancer, don’t neglect the everyday actions that experts say can help: Exercise regularly, limit your alcohol intake, avoid smoking and eat plenty of healthy foods.

“If somebody was on a tight budget, I think they could make better choices about spending their money on things that are going to be much more helpful for them than a supplement, unless their physician prescribed it for some reason,” Shepherd says.