How To OPTIMIZE Your Immune System & FIGHT VIRUSES! (Including COVID) | Roger Seheult

Seheult's Swiss cheese model holds that each measure has holes, so vitamin D, sleep, food and other habits together protect better than any one alone. He says vitamin D is where you start, not where you stop.

Seheult calls it a very tolerable fat-soluble vitamin, cites a US study linking levels below 50 to more SARS-CoV-2 infection, and suggests up to 4,000 IU daily for at-risk people. He takes 5,000 units a day after testing his levels, and both doctors recommend testing.

Spanish calcifediol studies showed a drop in ICU admission from 50% to 1% but weren't replicated, the Indian SHADE study showed benefits, and a Brazilian single-dose study showed none. Seheult still puts his COVID patients on vitamin D.

Seheult calls sleep probably the most important thing for immunity, linking early-night slow-wave sleep to growth hormone. He advises dimming lights in the evening, turning screens off, and getting bright light in the morning to shift the circadian rhythm earlier.

Seheult points to processed foods, a red meat link via sialic acids, and a study associating high-protein low-carb diets with higher COVID risk, and recommends eating less food and more plants such as berries. He takes NAC at 600 mg twice daily in winter because a 1990s study found it reduced flu severity, though not infection.