10 Foods Linked to Lower Lung Cancer Risk, and Why Experts Warn Smokers Against Beta-Carotene Supplements

Smoking remains by far the leading cause of lung cancer, and quitting is the most effective way to lower risk. But research suggests that what people eat may also play a role, with diets rich in fruits and vegetables linked to modestly lower risk.

Experts stress that diet is not a substitute for avoiding tobacco. A meta-analysis that found an 8% to 18% decreased risk of lung cancer with higher intakes of fruits and vegetables also emphasized the importance of quitting smoking as a preventive measure.

The American Lung Association says there is some evidence that a plant-based diet high in fruits and vegetables can lower the risk of lung cancer, but more research is needed.

Here are 10 foods linked to lower risk in research.

1. Broccoli, cabbage and other cruciferous vegetables

Inverse associations between cruciferous vegetable intake and lung cancer risk have been consistently reported, and one study concluded that a diet rich in cruciferous vegetables may reduce lung cancer risk among smokers.

2. Oranges and other citrus fruits

Citrus provides vitamin C. AICR says foods with vitamin C may reduce lung cancer risk among people who smoke.

3. Tomatoes

Red vegetables such as tomatoes are among the foods AICR highlights. One study found intakes of lycopene, the pigment in tomatoes, were linked to lower risk in male heavy smokers.

4. Sweet red peppers

AICR also lists sweet red peppers among red vegetables of interest.

5. Carrots

Carrots are rich in beta-carotene. Foods with carotenoids, including beta-carotene, seem to lower risk of lung cancer, even after adjusting for smoking.

6. Sweet potatoes and squash

These orange vegetables are other strong carotenoid sources. Fruits and foods containing carotenoids probably decrease the risk of lung cancer, according to an expert panel.

7. Leafy greens

Non-starchy vegetables and fruits may reduce lung cancer risk in people who smoke or used to smoke.

8. Fruits rich in beta-cryptoxanthin

A pooled study suggested high beta-cryptoxanthin intake may decrease lung cancer risk, though which compounds are responsible remains unclear. Common sources include oranges, tangerines and papaya.

9. Fruit overall

An earlier pooled analysis found a statistically significant 23% reduction in lung cancer risk with high fruit consumption.

10. Beans and whole grains

A plant-based eating pattern also supports healthy weight and blood sugar. The American Lung Association recommends a varied diet high in fruits and vegetables and low in red and processed meats and processed sugar.

How much is enough?

Studies show little additional drop in lung cancer risk beyond about five modest servings of vegetables and fruits a day and vitamin C beyond 100 mg a day.

Warning: avoid beta-carotene supplements if you smoke

Getting nutrients from food is very different from taking pills. Beta-carotene in high-dose supplements increases lung cancer risk when taken by people who smoke or used to smoke, according to evidence rated convincing by AICR.

These high-dose supplements often provide 20 to 30 milligrams a day, comparable to eating 15 to 20 cups of cooked broccoli.

There is no evidence of a link between lung cancer and beta-carotene that occurs naturally in the diet.

What to limit

Some studies have suggested eating red meat, processed meat and drinking alcohol could raise lung cancer risk, though more research is needed.

People currently being treated for lung cancer should talk to their care team before taking any supplements, since some can interfere with treatment. This article is for informational purposes only and is not medical advice. Anyone who smokes can get help quitting from their doctor or a quitline.