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

Personal Journey

Dr. Mussallem's story begins with a harrowing cancer diagnosis during her first months of medical school. At only 26 years old, she was confronted with stage four cancer wrapped around her heart, causing cardiogenic shock. Despite doctors giving her a prognosis of just a few months to live without treatment, she committed to chemotherapy and a bone marrow transplant, embodying an extraordinary resolve to not only survive but thrive.

Her personal narrative profoundly shapes her medical practice. The stark contrast between her early vitality—climbing mountains twice daily—and her unexpected illness highlights how cancer can strike even those living healthy lives. Importantly, she emphasizes that receiving a difficult diagnosis does not imply personal failure; rather, it reveals the complexities of disease. Through acceptance rather than resistance, she discovered a path to vitality, mental clarity, and empowerment, teaching her patients to do the same.

The Top Foods to Avoid

Dr. Mussallem highlights ultrarocessed foods as the foremost dietary culprits contributing to cancer risk. These foods, often laden with artificial ingredients and chemical additives, account for approximately 60% of the American diet and are linked with increased mortality from cancers such as breast and ovarian cancer. She urges careful scrutiny of ingredient lists when shopping, recommending avoidance of obscure additives like mono- and diglycerides, which have been associated with significantly heightened cancer risks in large population studies.

Processed meats are identified as class one carcinogens in the World Health Organization's classification, strongly linked to colorectal and other cancers. This category includes pepperoni, sausage, bacon, lunch meats, and even chicken nuggets. Dr. Mussallem advocates for moderation—occasional consumption likely does not pose great harm—but stresses that daily or heavy intake is detrimental and should be replaced with whole, minimally processed foods.

Cancer-Fighting Foods

Central to Dr. Mussallem's message is the power of food to prevent and even heal cancer at the cellular level. Among her "five cancer-fighting foods," frozen berries are championed for their high anthocyanin content, phytonutrients with potent antioxidant and anti-inflammatory properties. As part of her clinical research, consuming just two servings of berries per week was linked to a remarkable 25% reduction in breast cancer recurrence risk for survivors, emphasizing accessibility by encouraging the use of affordable frozen varieties.

Purple sweet potatoes emerge as another nutritional superstar with 150% more anthocyanins than berries. These vegetables, revered in longevity hotspots like Okinawa, Japan, help regulate gene expression by activating tumor suppressor genes and silencing genes that promote cancer growth. Dr. Mussallem underscores that the synergy of these whole foods bolsters the body's own defenses, contributing to reduced cancer incidence and improved overall health.

Fiber-Rich Beans

Beans, particularly lentils, split peas, and black beans, provide not only plant-based protein but also critical dietary fiber, an overlooked nutrient in the typical American diet. Dr. Mussallem draws attention to fiber's class one evidence-supported role in lowering mortality across diseases—including a 22% decrease in cancer risk—and its positive impact on pancreatic cancer outcomes.

She offers practical advice on cooking and preparing beans to reduce common side effects like gas, explaining enzymes like rafinose and the importance of soaking and rinsing dry beans before cooking. This guidance reflects her broader philosophy of actionable, science-based steps anyone can implement to enhance gut health, support immunity, and influence metabolic processes tied to cancer prevention.

Soy and Edamame

Challenging widespread misconceptions, Dr. Mussallem affirms that soy products—including edamame, tofu, and tempeh—do not increase cancer risk but are protective, especially in breast and prostate cancers. The early rodent studies that sowed fear about soy's estrogen-like effects do not translate to humans due to significant metabolic differences, and robust meta-analyses support soy's association with a 25% reduction in breast cancer recurrence.

She also notes the multiple benefits soy provides beyond cancer control, such as significant reductions in moderate to severe hot flashes among breast cancer survivors on anti-estrogen therapy, accompanied by improvements in mood and libido. This evidence reframes soy from a cultural taboo into a valuable component of a cancer-protective diet.

Kiwi

Dr. Mussallem highlights kiwi fruit for its multifaceted health benefits, particularly its ability to alleviate constipation—a common and distressing issue for many cancer patients—and its rich vitamin C content. She explains that kiwi aids in reducing oxidative stress at the DNA level, an important factor in the prevention of cancer and other chronic diseases.

The fruit's diverse fibers and antioxidants support a balanced gut microbiome and promote the body's natural detoxification processes. Eating kiwis with the skin maximizes fiber intake, and consuming them raw helps preserve delicate phytonutrients, aligning with her overall emphasis on whole, minimally processed foods for cancer prevention and health maintenance.

Exercise as Medicine in Cancer Care

Exercise emerges as a critical element of cancer prevention and survivorship, with Dr. Mussallem describing it as possibly as effective as chemotherapy for certain cancer types. She highlights studies showing exercise can improve breast cancer outcomes by nearly 50%, reduce fatigue during chemotherapy, support metabolic health by improving blood sugar regulation, and maintain muscle mass, which is essential for resilience and recovery.

Even gentle movement—walking, light resistance training, or dancing—can mitigate the physiological effects of stress, improve mood, and assist in clearing metabolic waste. Dr. Mussallem emphasizes listening to one's body while maintaining consistency, framing exercise not as punishment but as a joyful means of honoring and energizing one's body through the cancer journey.

Acceptance and Mental Attitude

Rejecting the traditional notion of "battling" cancer, Dr. Mussallem stresses acceptance as the emotional cornerstone for thriving after a diagnosis. She explains that prolonged resistance fuels stress and diminishes well-being, whereas acceptance fosters peace and opens the door to living purposefully.

Her personal reflections remind listeners that fear, grief, and vulnerability are natural, but channeling those feelings towards loving oneself, embracing life's preciousness, and seeking joy can dramatically influence outcomes. Positive mindset, love—both for self and others—and intentional living form the triad of emotional resilience that supports physical healing.

The Role of Sleep in Cancer Prevention

Sleep's restorative power is not only metaphorical but biological, as Dr. Mussallem reveals. She describes the brain's nightly cleansing through cerebrospinal fluid flow, akin to a "brain bath," crucial for clearing toxins and maintaining cognitive function. Seven to nine hours of high-quality sleep regulate hormonal balance, support immune function, and improve metabolic health, all contributing to reduced cancer risk.

Modern disruptors like blue light from screens impair melatonin production, the natural hormone governing sleep-wake cycles, and shift work has been linked to increased cancer rates. Dr. Mussallem advises morning sunlight exposure to reset circadian rhythms and minimizing screen exposure before bedtime to optimize sleep quality, reaffirming the role of rest in comprehensive cancer care.

Muscle Strength

Muscle's vital role transcends aesthetics; it is a key player in metabolic regulation. Dr. Mussallem points out that muscle tissue is the primary consumer of blood sugar, thus critical in preventing insulin resistance—a known risk factor for cancer and other chronic diseases. Maintaining muscle mass through resistance training not only improves metabolic health but also supports bone density, reducing risks of fractures common among cancer survivors, especially those on anti-estrogen therapies.

For many patients, preserving muscle strength translates into better treatment tolerance, enhanced mobility, and improved quality of life. Dr. Mussallem urges integrating manageable strength-building exercises alongside aerobic activity, underscoring the holistic benefits of a physically engaged lifestyle.

Conventional Treatments

While Dr. Mussallem champions lifestyle medicine's role in cancer prevention and survivorship, she underscores the indispensable value of conventional medical therapies such as chemotherapy, radiation, and surgery. She candidly addresses the increased mortality risk—up to 2.5 times—for patients who eschew standard treatments in favor of solely natural approaches.

Her approach is one of integration: combining evidence-based conventional oncology with supportive lifestyle interventions and natural therapies that mitigate side effects and enhance efficacy. She encourages patients to find oncology teams that listen and support individualized care plans that honor patient concerns while emphasizing the proven benefits of combined modalities.