Mayo Clinic Cancer Doctor: 5 Foods That Heal the Body, Starve Cancer, & Prevent Disease

KEYPOINTS

• 01

  Dr. Mussallem treats food, movement, sleep and love as part of cancer care, alongside standard treatment.

  She's a double board-certified Mayo Clinic physician, an integrative oncologist and a stage 4 cancer survivor. She stresses she followed her doctors' medical advice. What she added was 'tripling down' on the healthy parts of her life instead of fixating on the diagnosis. Her message isn't 'go vegan' or skip treatment. She wants people eating whole foods, mostly plants.

• 02

  Most people, including cancer patients, aren't eating nearly enough vegetables and fruit.

  She says about 90% of Americans miss the recommended servings. When she studied her own Mayo cancer center, 95% of patients fell short. She checked for food insecurity and says it wasn't driving the gap. Busy lives and not making time were. In the research she cites, people eating five servings a day had a 10% lower risk of dying from cancer and 12% lower from heart disease.

• 03

  Exercise is her 'number one' for cancer patients, even during chemo.

  She kept exercising through chemotherapy and felt better as the tumor shrank. She says exercise burns off stress hormones (her caveman versus saber-tooth tiger comparison), lifts mood and may improve how well treatment works. She cites breast cancer research showing outcomes improved by 'almost 50%'. You don't need a gym: 'five minutes counts,' even walking around the kitchen or dancing.

• 04

  Berries are an easy, cheap cancer-fighting food.

  She cites the Nurses' Health Study: for breast cancer survivors, every two servings of berries a week was linked to a 25% lower risk of dying from breast cancer. Mel double-checks it's two servings a week, not a day. Frozen berries count, which keeps it affordable.

• 05

  Eat at least some cruciferous vegetables raw to get more benefit.

  Broccoli, cauliflower, Brussels sprouts, arugula and cabbage contain an enzyme, myrosinase, that she says helps you absorb their protective compounds. Cooking cuts it back. Her fixes: nibble a little raw before cooking, add a raw arugula salad alongside cooked broccoli, or sprinkle dry mustard seed on top. If your gut can't handle one (some people can't tolerate broccoli), pick another from the family.

• 06

  Fiber is 'magic,' and protein hype is crowding it out.

  She cites a recent umbrella review covering 17 million person-years. She calls it 'class one' evidence that fiber lowers the risk of dying from any cause, from heart disease and from pancreatic cancer. Another review linked fiber to a 22% lower cancer risk. Over 90% of people don't get enough, and fiber only comes from plants. To limit gas, start beans slowly and use simple swaps rather than adding beans to every meal.

• 07

  Soy is protective for breast cancer survivors, not dangerous.

  Many survivors avoid soy. She points to the American Cancer Society's 2022 nutrition update, which covered soy safety, and a meta-analysis showing a 25% drop in breast cancer coming back. The benefit was strongest in estrogen receptor-negative cancer, but receptor-positive patients benefited too. She also uses edamame for menopausal hot flashes, citing Neal Barnard's research with half a cup a day plus a plant-based diet.

• 08

  Ultra-processed food is the first thing she'd cut, and the label tells you what you need to know.

  She says processed meat (pepperoni, sausage, bacon, chicken nuggets, lunch meat) is a class one carcinogen. In the aisles, read the ingredient list. If there are words you don't recognize, put it back. 'Vegan' doesn't mean healthy. She told one patient to swap her weekly vegan ice cream for regular ice cream rather than eat 'the fake stuff.'

• 09

  Skip artificial sweeteners and go easy on sugar alcohols.

  She describes a study in which sucralose (found in sugar-free drinks) seemed to reduce how well immunotherapy worked, possibly by disrupting the gut microbiome. She calls this suggestive. She thinks fears about erythritol are exaggerated but still on the watch list for making platelets stickier. Ingredients ending in '-ol' often cause bloating. Her green lights: dates, honey, maple syrup, stevia or monk fruit without additives.

• 10

  Sleep is medicine: 7–9 hours lets the brain 'take a bath.'

  She says the brain clears toxins during sleep and the body regenerates. She links shift work to higher cancer risk and blames blue light after sundown for trouble staying asleep. Her 'three things' for every cancer patient are love (yourself and others), move and food. She notes that without self-love you won't show up for the other two.

• 11

  It's never too late, and perfect isn't required.

  She cites research suggesting that eating better from age 20 could add about 11 healthy years for women and 13 for men. Starting at 60 adds about eight, and starting at 80 about 3.4. About 75% of healthy aging is modifiable. Nurses' Health Study data showed women who improved their diet after a breast cancer diagnosis also did better. Her 'speed limit' comparison: going 67 in a 65 zone won't get you a ticket if you're doing everything else right.