Thiamin and its link to memory loss and dementia
What it found
Low thiamin levels are linked to memory problems and brain changes seen in Alzheimer's disease in both people and animals.
Giving extra thiamin or related compounds improved memory and reduced brain damage markers in animal tests.
What they found
Studies in people
Brain energy use drops
In people with Alzheimer's disease, the brain uses 20 to 30% less sugar for energy. The same drop happens in people who are very low in thiamin.
Lower thiamin in patients
Blood tests showed that people with Alzheimer's disease had about one-third less thiamin than healthy people. Their brains also had much lower activity of enzymes that need thiamin to work.
Small trials in people
Past trials giving thiamin or related compounds to people with Alzheimer's disease were very small and short. Some showed mild improvements in memory scores, but the results were not strong enough to be certain.
Animal and lab studies
Memory loss in animals
Rats and mice fed too little thiamin performed poorly on memory tasks like mazes. Giving them thiamin again reversed the memory problems if done early enough.
Brain plaques in mice
Mice bred to develop Alzheimer-like brain plaques got many more plaques after just ten days without enough thiamin. A thiamin-related compound called benfotiamine reduced these plaques by 75% over eight weeks.
Other findings
Sources and absorption issues
Foods like pork, fish, nuts, seeds, beans, and enriched flour provide thiamin. However, gut problems, weight-loss surgery, alcohol, and many common medicines can stop the body from absorbing it properly.
What the authors conclude
- They note that thiamin has long been linked to brain problems, delirium, and dementia, but scientists do not yet know all the ways it works in the brain.
- They point out that thiamin and its related compounds have a good safety record in people.
- The authors advise that large, well-designed trials should test these compounds in people with Alzheimer's disease.
How it was done
Scientists have known for decades that a lack of thiamin causes severe brain and memory problems. They wanted to explore whether low thiamin might also play a role in Alzheimer's disease, since both conditions share similar brain changes.
The authors gathered and examined past research on thiamin, brain energy use, and memory loss. They looked at studies in people with Alzheimer's disease, people with severe thiamin deficiency, and lab animals given low or high amounts of thiamin.
What it can’t tell you
- This is a summary of past research, so it cannot prove that low thiamin directly causes Alzheimer's disease in people.
- The animal studies show that thiamin shortage creates brain plaques, but this does not guarantee the same process happens in human brains.
- The past trials in people were too small and too short to show whether taking extra thiamin prevents or treats dementia.
Who paid
- Funding
- Funded by NIA NIH HHS (from the PubMed record).
- Conflicts
- Conflicts of interest . The authors declare no conflicts of interest.
- Authors work at
- Brain and Mind Research Institute, New York; Burke Rehabilitation Hospital, New York
The paper
- Title
- Vitamin B1 (thiamine) and dementia
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Gibson GE, Hirsch JA, Fonzetti P, Jordan BD, Cirio RT, Elder J (2016). Vitamin B1 (thiamine) and dementia. Annals of the New York Academy of Sciences. doi:10.1111/nyas.13031Free full textPubMed 26971083DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error