Beta Carotene and Smoking: Can the Combination Cause Cancer? (2025)

Beta carotene is a type of naturally occurring pigment called a carotenoid. It’s found in a variety of plants, fungi, and algae and helps give them a yellow, orange, or red color.

Your body can convert the beta carotene you get from your diet to vitamin A. Both vitamin A and beta carotene are antioxidants, which are substances that help reduce oxidative stress.

Oxidative stress plays a role in a variety of health conditions, including cardiovascular disease, neurological diseases, and cancer. Some people may take beta carotene as a supplement.

However, research has found that beta carotene supplements are linked with an increased risk of lung cancer in people who smoke or used to smoke.

Lung cancer is the second most common type of cancer in both men and women, according to the American Cancer Society. It’s also the leading cause of cancer death in the United States.

Researchers have long been interested in ways to prevent lung cancer. One area of focus has been whether antioxidant intake lowers cancer risk. Because antioxidants fight oxidative stress, they may lower cancer risk.

Beta carotene supplements may increase lung cancer risk in people who smoke

Two clinical trials done in the 1990s, called the ATBC and CARET trials, found that beta carotene supplementation increased lung cancer risk in people who smoked.

In 2022, an analysis of another clinical trial supported these findings. Over a 10-year follow-up, researchers found that beta carotene supplementation was linked with a higher risk of lung cancer in participants with a prior history of smoking.

Overall lung cancer risk

In 2022, the U.S. Preventive Services Task Force analyzed prior research into vitamin and mineral supplements for cancer prevention. For beta carotene, this involved an analysis of six clinical trials, including the ATBC and CARET trials.

Researchers found that beta carotene supplements were associated with a 20% increased risk of lung cancer in participants in both the larger population as well as people with a higher risk of lung cancer.

However, researchers did note that the evidence was strongest for people with a higher risk of lung cancer, such as those with a history of smoking.

Results of their analysis led the task force to recommend against taking beta carotene supplements for cancer prevention.

Why it happens

It’s not known why beta carotene supplements increases the risk of lung cancer in people who smoke or used to smoke. However, experts have suggested some ideas.

For example, heavy smoking could impair the different pathways that beta carotene is associated with in the body. This could, in turn, promote the development of cancer.

It’s also possible that components of cigarette smoke, such as nicotine or tar, may be involved. However, one 2018 study found that beta carotene supplements increased the risk of lung cancer regardless of nicotine or tar intake.

If you vape, you may be wondering if you’re also at a higher risk of lung cancer from beta carotene supplements. At this time, there’s little to no research into this topic.

The CDC also notes that the flavors used in some vaping products, specifically a flavoring called diacetyl, can cause potentially serious lung disease.

Further analysis of the ATBC trial has found that beta carotene supplements are associated with a higher risk of pneumonia and death in people who smoke.

But what about the risks of beta carotene supplements in people who don’t smoke?

The most common side effect of excess beta carotene is carotenodermia, a harmless condition where your skin takes on a yellow-orange hue.

It’s also possible that beta carotene supplements may interact with other medications or supplements you’re taking. Because of this, it’s important to consult a healthcare professional before starting any new supplement.

As with other types of supplements and vitamins, taking too much beta carotene may lead to toxicity. This is a potentially serious effect.

The Food and Nutrition Board of the National Academy of Medicine has not set safe upper limits for beta carotene intake.

However, it recommends against taking beta carotene supplements unless you have a known vitamin A deficiency.

Generally, you should be able to receive all the beta carotene you need from your diet. Good sources of beta carotene include:

In addition to beta carotene, there may be other vitamin supplements to avoid if you smoke. One of these is vitamin A. This makes some sense since vitamin A can be made from beta carotene.

Some research has also associated long-term supplementation with certain B vitamins, specifically vitamins B6 and B12, with a higher risk of lung cancer in men who smoke.

When it comes to which supplements to take and which to avoid, it’s important to speak with a healthcare professional. They can help make recommendations that are tailored to you.

Is beta carotene good for the lungs?

As an antioxidant, beta carotene can have many beneficial effects throughout the body, including in the lungs. However, most people should be able to get the beta carotene they need from their diet without taking supplements.

Can you eat carrots if you smoke?

Yes, you can still eat carrots if you smoke. Research has found a higher risk of lung cancer from beta carotene supplements, not from dietary sources.

Beta carotene supplements have been found to increase the risk of lung cancer in people who currently or used to smoke. The exact reason is unknown.

If you smoke or used to smoke, speak with a doctor about your lung cancer risk and which supplements are safe for you.