1357: Dr. William Li | Working with Your Body to Beat Disease Naturally

What It Covers

Physician-scientist William Li explains how the human body continuously forms and destroys microscopic cancers through five defense systems — angiogenesis, stem cells, the microbiome, DNA repair, and immunity. The conversation covers how food directly activates or suppresses these systems, why cancer immunotherapy is producing stage-four-to-zero reversals, and what everyday dietary choices do to cellular-level defenses.

Key Questions Answered

• •Cancer Formation Is Continuous: The body's 40 trillion cells copy their DNA constantly, generating errors that produce microscopic cancers in everyone, including children. These abnormal cell clusters remain harmless — capped at roughly pencil-tip size — because they cannot recruit a blood supply. The immune system routinely finds and eliminates them. Disease occurs not when cancer appears, but when the body's defense systems weaken enough to lose control of that ongoing process.
• •Personalized Cancer Vaccines: A treatment already used in glioblastoma patients sequences the full genome of a tumor biopsy alongside healthy blood cells, then uses AI to isolate cancer-only mutations. Up to 20 of those mutations are linked into a synthetic protein and injected under the skin, training the immune system to target that specific cancer. Some patients — including one documented case now eight years cancer-free — achieve complete remission through this approach.
• •Angiogenesis as a Two-Way Switch: Blood vessels must stay in a precise "Goldilocks zone" — too few causes organ death via heart attack or stroke, while excess growth causes macular degeneration, psoriasis, and tumor expansion. Tumors hijack angiogenesis to grow 16,000 times in two weeks once they access a blood supply. Certain foods cut off tumor blood supply the same way anti-VEGF drugs do, making dietary choices a practical lever for this defense system.
• •Gut Bacteria Produce Natural GLP-1: When fed plant-based foods rich in polyphenols and dietary fiber, the gut's 39 trillion bacteria convert those inputs into short-chain fatty acids, particularly butyrate, which suppress systemic inflammation. Butyrate also signals the gut lining to release the body's own GLP-1 — the same hormone targeted by Ozempic and Wegovy — without injection. Ultra-processed foods, artificial sweeteners, and diet sodas measurably damage this bacterial ecosystem and reduce that output.
• •Microbiome Determines Immunotherapy Outcomes: Checkpoint inhibitor immunotherapy — one of the most advanced cancer treatments available — can fail entirely if a patient lacks specific gut bacteria. Research shows that a single bacterial species can determine whether the immune system responds to treatment. Since 70% of the immune system resides in the gut wall and communicates directly with gut bacteria, maintaining microbiome diversity through diet is a prerequisite for immunotherapy effectiveness, not a secondary consideration.
• •Food Activates Tumor Suppressor Genes: Cruciferous vegetables — broccoli, kale, cabbage, Brussels sprouts — contain sulforaphane, a compound that removes epigenetic blocks on dormant tumor suppressor genes, including those specific to breast cancer. Berries containing ellagic acid produce similar effects. These foods function as a form of dietary gene therapy, unmasking functional cancer-fighting genes that were previously silenced. Conversely, ultra-processed meats and artificial food dyes accelerate telomere shortening, speeding cellular aging.
• •Cancer Stem Cells Explain Recurrence: Standard cancer treatment — surgery, chemotherapy, radiation — can eliminate detectable tumors while leaving behind cancer stem cells, which later regenerate the disease. This explains why cancers return in year six or eight after apparent five-year remission. No approved drug currently kills cancer stem cells, but matcha tea polyphenols have demonstrated the ability to eliminate breast cancer stem cells in laboratory research, and purple potatoes show the same effect on colon cancer stem cells.