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Study · Nature communications · 2026Conflicts declared

Chili pepper compound and Alzheimer's-like changes in mice

Li Y, Wang H, Zhang D, et al · Free full text

What it found

In people, eating more chili was linked to better thinking scores and higher blood levels of a cholesterol-related molecule.

In mice, capsaicin improved memory and reduced Alzheimer's-like brain changes, apparently through gut bacteria.

What they found

Studies in people

Thinking scores in people

People who ate moderate to high amounts of chili had higher scores on thinking tests than those who ate little or none. This was seen in people with mild memory problems and those with Alzheimer's disease.

24-HC in people

People with mild memory problems or Alzheimer's who ate more chili had higher levels of 24-HC in their blood. Higher 24-HC levels went with better thinking scores and lower levels of Alzheimer's-related proteins.

Animal and lab studies

Memory in mice

Mice with Alzheimer's-like disease that received capsaicin for a month did better on memory tests than untreated mice. They also had fewer amyloid plaques and less brain inflammation.

Gut bacteria's role

When gut bacteria from capsaicin-treated mice were transferred to other mice with Alzheimer's-like disease, those mice also showed fewer plaques and better memory. This suggests the effects depend on gut bacteria.

24-HC and brain cells

In lab tests, 24-HC helped microglia (brain immune cells) clear amyloid and reduced inflammatory signals. Mice given 24-HC directly also had fewer plaques and less inflammation.

Tau pathology in mice

In a different mouse model that develops tau tangles, capsaicin reduced abnormal tau and improved memory. This suggests capsaicin may help with both major brain changes seen in Alzheimer's.

What the authors conclude

“These findings suggest the potential of capsaicin or capsaicin-rich diets in the prevention or treatment of AD and related diseases.”
Li Y, Wang H, Zhang D, et al, 2026

Also in their conclusions

  • They say their findings suggest that capsaicin or capsaicin-rich diets have potential for the prevention or treatment of Alzheimer's disease and related diseases.
  • They note that the exact effect of capsaicin on cognitive function is still controversial and that more research is needed.
  • They advise that future studies should investigate whether higher doses of capsaicin might be more beneficial or could worsen the disease.

How it was done

The authors wanted to understand how capsaicin from chili peppers might affect Alzheimer's disease, since previous studies suggested a link but the mechanism was unclear.

They studied two groups of people in China (151 and 95 people) and gave capsaicin to mice with Alzheimer's-like disease for a month. They also transferred gut bacteria from treated mice to untreated mice and tested a cholesterol-related molecule called 24-HC.

What it can’t tell you

  • The human part of this study looked at people at one point in time, so it can show a link between chili intake and better thinking, but not that chili caused the improvement.
  • The mouse experiments used only male mice, so the results might not apply to females.
  • The findings in mice may not be the same in people.

The paper

Title
Gut microbiota-dependent 24-hydroxycholesterol metabolism contributes to capsaicin-induced amelioration of Alzheimer's disease-like pathology in mice
Type
Study
Evidence
Studies in people · animals · lab
Summarised from
Full text
Cite
Li Y, Wang H, Zhang D, et al (2026). Gut microbiota-dependent 24-hydroxycholesterol metabolism contributes to capsaicin-induced amelioration of Alzheimer's disease-like pathology in mice. Nature communications. doi:10.1038/s41467-026-68937-9Free full textPubMed 41634017DOI

Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error