SupplementsSelenium
Minerals
A trace mineral that is part of the body's antioxidant defense (glutathione peroxidase). Adequate selenium from food supports normal cell protection — but more is not better, and supplements have not been proven to prevent cancer.
Relevant for
- Essential cofactor for antioxidant enzymes that help protect cells from oxidative damage.
- Adequate selenium status supports normal immune and thyroid function.
- Easily obtained from food — just 1-2 Brazil nuts a day meets typical needs.
Get selenium from food: Brazil nuts, seafood, eggs, whole grains. Only supplement if a deficiency is confirmed.
The large SELECT trial found selenium supplements did NOT prevent cancer, and excess selenium may raise the risk of some cancers and diabetes. Don't over-supplement — food sources are safest. Confirm any supplement with your care team.
Learn more from trusted sources
- American Cancer Society — NutritionEating well during and after cancer treatment.
- American Institute for Cancer Research (AICR)Evidence-based cancer-prevention diet and lifestyle guidance.
- National Cancer Institute — NutritionNutrition in cancer care (U.S. NIH).
- World Cancer Research Fund (WCRF)Global research on diet, activity and cancer.
- Cancer Research UK — Diet & CancerManaging diet and eating problems during treatment.
This information is educational and may support wellbeing — it is not medical advice and never a promise of a cure. Always consult your oncology care team before changing diet, supplements, or medication.