November 17, 2020 | 6 minute read

Do you take your lungs for granted? Amidst images you see of the thousands of people facing a devastating attack on their lungs due to COVID-19, don’t forget about the ongoing threat of lung cancer. Recent estimates show incidence of lung cancer to be 228, 820 and mortality to be 135, 720.

What is the most powerful step you can take to reduce your risk of developing lung cancer? Don’t smoke. But it’s not only people who smoke who develop this disease. Read on for answers to some common questions about how you can also protect yourself.

Can People Who Don’t Smoke Get Lung Cancer?

Tobacco smoking is by far the major cause of lung cancer. It causes about 85 percent of lung cancer cases. But 15 percent – about 34,000 – of cases of lung cancer each year are in US adults who have never smoked.

Several other factors also put people at risk:

Second-hand smoke

Second-hand smoke contains the same hazardous chemicals someone gets by smoking, just at a lower concentration. People who live with a smoker or face second-hand smoke in the workplace have higher risk of lung cancer. Second-hand smoke increases risk 20% compared to non-smokers not exposed.

Radon and air pollution

Radon and air pollution increase risk of lung cancer. (Radon is a gas that forms as uranium breaks down in soil, and can leak into air or water supply, entering homes through leaks in the foundation.)

Workplace exposures

Workplace exposures to asbestos, arsenic, diesel exhaust and certain other chemicals increases lung cancer occurrence and deaths, depending on the level of exposure. Lung cancer risk especially increases in people who also smoke.

Could Diet Affect Risk of Lung Cancer?

Evidence of how eating choices could reduce your risk of lung cancer is limited. Yet based on research about how nutrients and natural plant compounds (phytochemicals) seem to act throughout the process of cancer development, it’s reasonable that plant-forward eating habits might help reduce risk.

According to analysis in AICR’s Third Expert Report, limited evidence shows:

• Non-starchy vegetables and fruits may reduce lung cancer risk in people who smoke or used to smoke.
• Foods with vitamin C may reduce lung cancer risk among people who smoke.
• Foods with carotenoids, including beta-carotene, seem to lower risk of lung cancer, even after adjusting for smoking.

Antioxidant defense support could be an important role for these foods to reduce lung cancer risk. Highly reactive compounds known as free radicals create DNA damage and promote chronic inflammation that can lead to cancer development. Exposure can come from tobacco smoke and environmental hazards, as well as from free radicals that form during normal metabolic processes.

Vitamin C and at least some carotenoids are antioxidants that can inactivate these free radicals or prevent their damage. And carotenoids, as well as other phytochemicals in fruits and vegetables, seem to turn on the body’s antioxidant defense system of enzymes and protective compounds.

Cell signaling between neighboring cells helps keep them healthy and inhibits reproduction of abnormal cells. Laboratory studies suggest that carotenoids may stimulate this cell-to-cell communication, and perhaps influence gene expression that controls cell growth. In addition, your body can use certain carotenoids to create vitamin A. Since this vitamin supports the immune system and helps regulate cell growth in lab studies, this could provide yet another layer of protection.

Should I Be Eating A Lot of Carrots Then?

Carrots are nutrition powerhouses…and super-delicious! But look at the broader picture.

Aim for variety rather than focusing on beta-carotene alone. Boost carotenoids with green, yellow, orange and red vegetables and fruits. Of the hundreds identified, six account for most of the carotenoids in our food. Check how often throughout a typical week you eat choices like these:

• Dark green leafy vegetables – including spinach, kale, bok choy, collard and mustard greens
• Green and yellow vegetables that aren’t “leafy” – such as broccoli, Brussels sprouts, summer squash, peas, corn
• Deep orange vegetables – carrots, pumpkin, sweet potatoes, winter squash
• Deep yellow-orange fruits – apricots, cantaloupe, oranges, papaya, mango, tangerines
• Red vegetables – tomatoes, sweet red peppers
• Red fruit that’s carotenoid-rich – red (or pink) grapefruit, guava, watermelon

Don’t stop at carotenoids. Even though some human studies link higher reported consumption of carotenoids and higher blood levels of circulating carotenoids with lower risk of lung cancer, it may not be the carotenoids themselves that are the key to protection. Blood levels of carotenoids are proven indicators of overall vegetable and fruit consumption. So an association with lower lung cancer risk could reflect effects of the multiple nutrients and phytochemicals you get by making vegetables and fruits the center of your meals.

Why Not Rely on Supplements for Protection?

It’s easy to assume that if these nutrients and compounds show potential for decreasing risk of lung cancer, then more would provide extra protection. But that’s clearly not what research shows.

• Perfect eating isn’t required. Whether looking at vegetables and fruits overall, or at increasing vitamin C and carotenoids, compared to low consumption, eating more is linked with a drop in risk of lung cancer in the limited studies currently available. But studies show little additional drop in lung cancer risk linked with vegetables and fruits beyond about five modest servings a day and vitamin C beyond 100 mg per day.
• High-dose supplements pose risk to people who’ve smoked. You might think that people at greater risk of lung cancer would benefit from higher amounts of potential protectors. But among people who smoke or used to smoke, beta-carotene supplements increase risk of lung cancer. These high-dose supplements often provide 20 to 30 milligrams (mg) per day, which is comparable to eating 15 to 20 cups of cooked broccoli each day.

What if You’ve Already Tried to Quit Smoking?

For someone who smokes, avoiding tobacco is the most powerful step to reduce lung cancer risk.

• Smoking-related cancer risk gradually decreases with time after quitting. So does risk of heart disease. Cancer risk will never be as low as in someone who never smoked, but the sooner you quit, the better.
• Most people need several tries at quitting before they succeed. Studies suggest that it typically takes four to ten attempts at quitting before people succeed. And success is possible. According to the CDC, almost two-thirds of adults who once smoked have now quit. You can learn something each time you try to quit, and experiment with new strategies to find the ones that work best for you.
• Exercise and healthy eating reduce cancer risk and can support your plan to quit. Don’t ignore physical activity and healthy eating choices while you work on quitting! For example, see how yoga and other kinds of exercise can help you handle stress. You can choose strategies and create a personalized quit plan.

In Conclusion

When it comes to lung cancer – diet and physical activity take a back seat to avoiding tobacco as the top strategy to lower risk. Though much less often, people who don’t smoke can develop lung cancer. So avoiding hazards and creating a healthy lifestyle is a smart move for us all. And remember, all these choices come together as important steps to reduce overall cancer risk.