Former President Joe Biden has been diagnosed with prostate cancer—one of the 300,000 new cases diagnosed in the U.S. each year. Prostate cancer is the second-most common cancer among men behind skin cancer, with about 1 in 8 men diagnosed during their lifetime, according to the American Cancer Society (ACS).
Every man’s risk is different, depending on their lifestyle, race/ethnicity, family history, and age. Prostate cancer is more likely to develop in older men, the ACS says. (The average age of men first diagnosed is 67; Biden is 82).
The American Association for Cancer Research claims that one of the most controllable factors in lowering overall cancer risk is your eating habits: Of the American Institute for Cancer Research’s 10 cancer prevention recommendations, six are based on diet.
“Whether someone is concerned about reducing their risk of prostate cancer or improving their survival after a diagnosis, we recommend a combined healthy diet, weight management and physical activity as the most effective evidence-based approach,” says Dr. Nigel Brockton, Vice President of Research at the American Institute for Cancer Research (AICR).
“The strongest modifiable risk factor for prostate cancer risk is obesity rather than diet or individual components of diet, directly,” Brockton says. “We recommend avoiding foods that are linked to increased risk for obesity, including sugar-sweetened beverages and fast and ultra-processed foods.”
Consider limiting these foods
Research indicates that certain foods—specifically meat and dairy—could increase the risk of prostate cancer, says Martha Silva, RD, LDN, oncology dietitian at Mass General Brigham.
Men who consume a lot of dairy may have a slightly higher risk of developing prostate cancer, research shows. One study of nearly 48,000 men found that those with diets high in calcium had a greater risk of developing prostate cancer, and more aggressive forms of the cancer. A systematic review revealed that some studies have found a correlation between milk consumption—especially full-fat—and increased prostate cancer risk.
Brockton is skeptical of limiting dairy and calcium too much, because the research is limited.
“Higher intakes of dairy or dietary calcium may increase prostate cancer risk but we do not have a specific recommendation to avoid these foods because they are linked to a reduced risk of other types of cancer (breast and colorectal cancer),” he tells Fortune.
Another systematic review from 2022—which included 1.9 million men across 25 studies—found that higher total meal consumption and a diet high in processed meats (deli meat, sausages, hot dogs, etc.) was linked with higher risk of prostate cancer. And a 2014 study found that habitual consumption of a diet high in saturated fat, well-done meats, and calcium was associated with an increased risk of advanced prostate cancer.
Additionally, Silva advises limiting alcohol because it could cause DNA mutations that lead to cancer growth, Silva says.
Focus on fruits and veggies
Silva likes to encourage people to “bump up those plant foods as much as possible” and focus on what you’re adding into your diet, rather than taking away.
A 2024 study from the University of California, San Francisco (UCSF) found that men with localized prostate cancer who ate a primarily plant-based diet had a 47% lower risk that their cancer would progress compared to those who consumed the most animal products.
In that study, of 2,000 men with a median age of 65, the researchers found that eating just one or two more servings per day of fruits, vegetables, and whole grains and less dairy and meat had the best health outcomes. Another study found that men who consumed at least 28 servings of vegetables per week had a reduced risk of prostate cancer compared with those who ate fewer than 14 servings per week.
The UCSF study also promotes eating fruits and vegetables to lower the risk of prostate cancer because of the vitamins, minerals, and cancer-fighting phytochemicals like carotenoids, lycopene, indoles, and flavonols.
Experts have previously pointed out that fiber and plant-based eating are key components of a diet that can help lower overall cancer risk, but there are certain fruits and veggies that may be even more powerful in the fight against prostate cancer, Silva says.
There is evidence that cruciferous vegetables—like broccoli, cauliflower, cabbage, kale, bok choy, arugula, Brussels sprouts, and radishes—could play a unique role in preventing prostate cancer as well. That’s because of a phytochemical called sulforaphane found in these veggies, which is known to help prevent numerous types of cancer in addition to prostate.
Silva adds that tomatoes and watermelon have one compound that has been found to be particularly protective against prostate cancer: lycopene. Research shows that lycopene can not only slow the progression and growth of prostate cancer cells, but it also could provoke the death of prostate cancer cells. However, Brockton cautions that research is still limited on lycopene, and a strong link has not been established yet.
Silva recommends eating at least five servings of whole fruits and vegetables daily to reap their cancer-protective effects—but the more you can eat, the better, she says. She advises keeping frozen fruits and vegetables—which are just as nutritious as fresh—stocked in your freezer to add into smoothies, oatmeal, or dinners.
Fill up on fiber
There’s another nutrient that fruits and vegetables have in common that has protective qualities against cancer: fiber.
Fiber can help prevent cancer in numerous ways, experts say. Eating high-fiber foods—like whole grains, fruits, vegetables, beans, nuts, and seeds—can boost your gut health, which in turn strengthens your immune system, according to Brockton. A stronger immune system will give your body the tools to fight off potentially cancerous cells, he told Fortune.
One study also found that eating high-fiber whole grains was able to lower risk of aggressive prostate cancer via the production of the sex-hormone binding globulin, which helps regulate androgen levels that influence prostate cancer growth.
The U.S. Dietary Guidelines recommend that men consume about 28 to 34 grams of fiber per day, but Silva advises shooting for 35 grams. She recommends making easy swaps like brown rice for white rice or whole grain bread for white bread to boost your fiber intake.
“Small changes like that can certainly help to move the needle,” Silva tells Fortune.
You can also reach for high-fiber foods like:
- Oats, barley, quinoa, amaranth, bulgur, and millet
- Beans and lentils
- Nuts and seeds
- Berries
- Avocados
- Leafy greens like kale, spinach, bok choy, and arugula
- Apples and pears
- Sweet potatoes
- Popcorn
Add in omega-3s
Some research also indicates that foods rich in omega-3 fatty acids could also help slow the progression of prostate cancer. A recent study from UCLA showed that a diet low in omega-6 fatty acids—like those found in vegetable oil and some packaged or fast foods—and high in omega-3s, significantly reduced the growth rate of prostate cancer cells in men with early-stage disease.
You can get omega-3s from fish oil supplements, along with foods such as:
- Salmon
- Sardines
- Trout
- Walnuts
- Flaxseeds
- Chia seeds
For more on diet and cancer risk:
- How much ultraprocessed food is too much? The exact amount that raises your risk of heart disease and cancer
- This is the best nut to eat if you want to lower your colorectal cancer risk, study finds
- RFK Jr. warns seed oils are poisoning Americans, and a new study shows a possible link to cancer
