Wide release: June 11, 2026. Not medical advice.
Nick speaks with Dr. Isaac Harris about the biology of antioxidants and oxidative stress. Harris shares his lab’s recent work showing that breast cancer tumors catabolize extracellular glutathione to acquire cysteine and support growth. The conversation explores how reactive oxygen species (ROS) arise in metabolism, the central role of glutathione as a natural antioxidant, why high-dose antioxidant supplements can backfire, and emerging strategies that target cancer’s reliance on antioxidant systems.
TOPICS DISCUSSED:
Oxidative Stress: Reactive oxygen species (ROS) generated by mitochondrial metabolism cause damage; context determines whether they promote or suppress cancer.
Glutathione Biology: Primary cellular antioxidant made from cysteine, glycine, and glutamate; works with peroxidase enzymes to protect against ROS.
Antioxidant Paradox: Clinical trials (SELECT vitamin E, beta-carotene) showed supplements increased cancer rather than preventing it.
Cancer Antioxidant Hijacking: Tumors ramp up antioxidant systems to handle high metabolic rates and survive stress including metastasis.
Extracellular Glutathione Catabolism: Cancer cells break down external glutathione into amino acids, particularly cysteine, to fuel growth (new findings).
Therapeutic Window: Blocking glutathione breakdown slows tumors in models while sparing normal cells.
Diet vs Supplements: Balanced diets support glutathione needs; excess isolated antioxidants may enrich the tumor microenvironment.
ABOUT THE GUEST: Isaac Harris, PhD is a biologist working on the role of antioxidants in health, disease, and cancer metabolism.
RELATED CONTENT:
M&M 229: Linoleic Acid, Seed Oils, mTOR & Breast Cancer | Nikos Koundouros & John Blenis
KNOW YOURSELF:
Visit the SUPPORT PAGE if you find value in this content. Includes discount codes + links to affiliate partners, including products to help you measure and manage your health.
Listen or watch on your favorite platform:
PRACTICAL TAKEAWAYS:
Obtain amino acids like cysteine through whole-food protein sources rather than isolated antioxidant supplements.
Exercise caution with high-dose vitamin E, NAC, or glutathione supplements, especially with a cancer history.
Prioritize evidence-based metabolic approaches over blind antioxidant megadosing.
SUBSCRIBER CONTENT BELOW: Reference paper + episode transcript.
Listen to this episode with a 7-day free trial
Subscribe to Mind & Matter to listen to this post and get 7 days of free access to the full post archives.
