I was reading How Not to Die by Michael Greger, M.D and the book highlights studies showing athletes, particularly marathon runners, face increased risks of respiratory infections due to compromised immunity after intense exertion. Apparently, brewer's and nutritional yeasts can significantly reduce these risks.

Both come from Saccharomyces cerevisiae, but they differ in processing methods and nutritional profiles. Nutritional yeast is deactivated and often fortified (particularly with vitamin B12), brewer's yeast is naturally rich in nutrients, notably selenium, which is essential for immune health.

Key points from research

  • β-Glucans: These are complex sugars in Saccharomyces cerevisiae activate white blood cells, boosting immune response against pathogens.
  • Selenium: Brewer's yeast has higher selenium levels, essential for the enzyme glutathione peroxidase, reducing oxidative stress and inflammation.
  • Probiotic Benefits: The strain S. cerevisiae var. boulardii has been clinically proven to enhance gut immunity and combat gastrointestinal infections, indirectly supporting overall immunity.

Here's a quick comparison of their nutrient profiles:

Yeast Type Protein B-vitamins Selenium Fiber
Nutritional yeast 8-14g high 10-20µg 4-6g
Brewer's yeast 16-20g high 60-100µg 3-5g

Since I'm training for a marathon, I found it especially interesting that marathon runners who consumed about a spoonful of nutritional yeast daily after their race reported half the rates of upper respiratory infections compared to placebo.

His practical usage tips:

  • Add brewer's yeast to soups, smoothies, or savory oatmeal. Note that its flavor is somewhat bitter compared to nutritional yeast's cheesy taste.
  • Consider introducing brewer's yeast gradually, as it can cause bloating or gas.

Key takeaways:

  • Brewer's yeast provides similar immune benefits to nutritional yeast but with significantly more selenium.
  • Selenium in brewer's yeast supports antioxidant enzymes, helping to manage inflammation effectively.
  • Yeast supplementation is beneficial for athletes or anyone engaged in intensive physical activities, helping to maintain immune function and reduce infection risk.