Diet and Prostate Cancer

Prevention, Supporting Patients During Treatment, and Post-Treatment Health

(Educational only; individuals should discuss diet changes with their oncology team.)

Prostate cancer is among the most common cancers in men. While genetics and age play significant roles, diet and lifestyle have been shown to influence both prostate cancer risk and disease progression. Evidence accumulated over decades suggests that whole-food, plant-predominant diets are associated with reduced risk, slower disease advancement, and improved overall survival—especially when combined with healthy body weight and physical activity.

This page summarizes what the best available research tells us about diet before, during, and after prostate cancer treatment.

1. Diet and Prostate Cancer Prevention

Plant-rich diets and reduced prostate cancer risk

Large cohort studies have found that men who consume diets centered on vegetables, fruits, whole grains, and legumes tend to have lower overall prostate cancer risk and particularly reduced risk of aggressive disease.

Key findings:

• Men consuming the most plant foods and fiber have lower circulating levels of IGF-1 (Insulin-like Growth Factor–1), a hormone strongly linked to prostate cancer risk and progression (Chan et al., 1998; Giovannucci et al., 2003).
• A study of >47,000 men in the Health Professionals Follow-up Study found that diets high in lycopene-rich foods (especially cooked tomatoes) were associated with a 20–30% reduced risk of advanced prostate cancer (Giovannucci et al., 2002).
• Higher intake of cruciferous vegetables (broccoli, cauliflower, kale) is consistently associated with reduced risk of aggressive prostate cancer, likely due to their sulforaphane content and detoxification effects (Kirsh et al., 2007).
• Diets high in saturated animal fat, particularly from red meat and high-fat dairy, are linked to increased risk of advanced prostate cancer and poorer outcomes (Snowdon & Phillips, 1985; Richman et al., 2013).

Foods with strongest preventive associations:

• Tomatoes & tomato products (lycopene)
• Cruciferous vegetables
• Legumes, especially soy
• Whole grains and high-fiber foods
• Flaxseed (rich in lignans linked to favorable hormone profiles)

Overall, the evidence points toward a dietary pattern that is:

• Predominantly whole-food and plant-based
• Low in animal fat
• Rich in antioxidants, fiber, and anti-inflammatory compounds

This pattern aligns closely with both PEL-85 and PEL-100 dietary frameworks.

2. Diet During Prostate Cancer Treatment

Treatment for prostate cancer may involve surgery, radiation, hormonal therapy, chemotherapy, immunotherapy, or active surveillance. The best diet during treatment depends on the therapy used, but several broad principles are supported by research.

General dietary guidance during treatment

• Follow a plant-predominant diet emphasizing vegetables, whole grains, and legumes.
• Limit or avoid red and processed meats, which are linked to higher mortality in prostate cancer survivors (Richman et al., 2013).
• Minimize high-fat dairy, which is associated with increased risk of recurrence and mortality in multiple cohorts (Song et al., 2013).
• Ensure adequate calories and protein, particularly during chemotherapy or ADT (androgen deprivation therapy), to maintain muscle mass and prevent sarcopenia.
• Avoid ultra-processed foods, excessive saturated fat, and added sugars.

Specific considerations by treatment type

Radiation therapy

Diet patterns high in fruits and vegetables are associated with reduced gastrointestinal toxicity during radiotherapy (Huang et al., 2020).

Androgen Deprivation Therapy (ADT)

ADT increases the risk of:

• Weight gain
• Insulin resistance
• Dyslipidemia
• Loss of muscle mass

Whole-food, plant-forward patterns help counter these effects by improving cardiometabolic health.

Chemotherapy

Similar to breast cancer, there is no “one best diet,” but high-quality plant-rich diets appear safe and beneficial for overall vitality, inflammation reduction, and metabolic health.

Fasting-mimicking diets

Early trials are exploring fasting-mimicking diets or caloric restriction to improve treatment tolerance (e.g., minimizing side effects from chemotherapy or radiation).

These remain experimental and should not be attempted outside clinical trials due to risks of malnutrition and weight loss (Bauersfeld et al., 2018).

3. Diet After Treatment: Slowing Progression and Improving Survival

The period following prostate cancer treatment is where diet appears to have some of the most powerful effects. Evidence suggests that diet may modify progression, recurrence, and mortality risk.

Dean Ornish’s Lifestyle Trial (1990s–2000s)

This landmark randomized controlled trial assigned men with low-risk prostate cancer to either standard care or an intensive lifestyle program centered on:

• A strict whole-food, plant-based diet (near-vegan)
• Regular moderate exercise
• Stress reduction
• Social support

Results:

• PSA levels declined in the intervention group but rose in the control group.
• None of the lifestyle participants required conventional treatment over 2 years, compared to 6 in the control group.
• Gene expression shifted toward cancer suppression and away from cancer-promoting pathways (Ornish et al., 2005; Ornish et al., 2008).

This remains the strongest evidence that a fully plant-based diet may slow or reverse disease progression in early-stage prostate cancer.

Observational studies in survivors

• Replacing animal fat with plant fat after diagnosis is associated with a lower risk of lethal prostate cancer and improved survival (Richman et al., 2013).
• Higher intake of cruciferous vegetables is associated with a 59% reduction in progression in men on active surveillance (Bing et al., 2010).
• Regular consumption of soy foods is linked to reduced recurrence rates due to phytoestrogen and anti-inflammatory effects (Yan & Spitznagel, 2009).
• Men consuming the most tomatoes/lycopene-rich foods after diagnosis show lower risk of recurrence and progression (Zu et al., 2014).

Cardiovascular health matters

Many prostate cancer survivors die from cardiovascular disease rather than prostate cancer.

A whole-food, plant-based diet improves:

• LDL cholesterol
• Blood pressure
• Inflammation
• Body weight
• Endothelial function

These improvements substantially enhance overall survival, independent of cancer-specific outcomes.

4. What Does the Overall Evidence Suggest?

A whole-food, plant-based (WFPB) dietary pattern appears to support prostate cancer patients in multiple ways:

Short Takeaways

Prevention

A diet rich in vegetables—especially tomatoes and cruciferous vegetables—whole grains, beans, flax, and soy is associated with lower prostate cancer risk.

During treatment

A plant-forward diet supports metabolic health and strength during ADT, radiation, chemo, or surgery. Avoid high-fat dairy and processed meats.

After treatment

Evidence from randomized and observational studies suggests a whole-food, plant-based diet may slow progression, lower recurrence risk, and improve survival—particularly when combined with exercise and stress reduction.

References

Adebamowo, C. et al. (2005). Dietary patterns and prostate cancer risk. Am J Clin Nutr.

Bauersfeld, S.P., et al. (2018). Fasting-mimicking diet in oncology. BMC Cancer.

Bing, M.M., et al. (2010). Cruciferous vegetable intake and progression in men on active surveillance. Cancer Epidemiol Biomarkers Prev.

Chan, J.M., et al. (1998). Plasma IGF-1 and prostate cancer risk. Science.

Giovannucci, E., et al. (2002). Tomato products and risk of prostate cancer. J Natl Cancer Inst.

Giovannucci, E., et al. (2003). Lifestyle and prostate cancer. Cancer Causes Control.

Huang, J.Y., et al. (2020). Diet and radiation toxicity. Clin Nutr.

Kirsh, V.A., et al. (2007). Cruciferous vegetables and prostate cancer risk. JNCI.

Ornish, D., et al. (2005). Intensive lifestyle changes and prostate cancer progression. J Urol.

Ornish, D., et al. (2008). Gene expression changes in prostate cancer with lifestyle intervention. PNAS.

Richman, E.L., et al. (2013). Fat intake after diagnosis and prostate cancer mortality. JAMA Intern Med.

Snowdon, D.A., & Phillips, R.L. (1985). Animal product consumption and prostate cancer. Am J Clin Nutr.

Song, Y., et al. (2013). Dairy intake and prostate cancer recurrence. Prostate.

Yan, L., & Spitznagel, E. (2009). Soy consumption and prostate cancer risk. Nutr Cancer.

Zu, K., et al. (2014). Lycopene and recurrence risk. Prostate.