Yeast

Animal and lab studies only

• Open question

  Immune cell response⁹

  In lab studies, yeast from fermented milk made immune cells less able to trigger other immune cells.

• Open question

  Immune cell activity¹¹

  In lab studies, yeast plasmolysate changed how immune cells switched on, but it also cut their growth.

• Benefit

  Memory and brain health¹²

  In animal studies, selenium-enriched yeast improved memory and brain changes in mice with Alzheimer's-like disease.

Study type not stated

• Benefit

  Bread flavour and rising⁴

  Yeast in sourdough makes bread rise and gives it flavour, and some kinds may add vitamins too.

How it’s made and used

• What's still unknown³

  Yeast extract is used in animal feed, food flavoring, cosmetics and fermentation, but its full potential is not yet realized.

• Selenium in the diet⁵

  Finnish diets often lack selenium, so yeast can be grown to carry this mineral.

• Cooked ham texture⁶

  Adding spent yeast extract to cooked ham made it firmer and chewier, and it stayed that way during storage.

• Savoury taste⁷

  Yeast protein can be broken down into peptides that taste savoury and may boost saltiness, though this was tested in lab studies.

• Digestive tract tolerance⁸

  In lab studies, some yeasts survived the trip through a simulated gut better than others.

• Stomach acid tolerance¹⁰

  Some yeast strains from infant faeces and Feta cheese survived stomach acid and bile in lab tests.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.