Vitamin B12

Normal levels of Vitamin B12 has been associated with a reduced incidence of dementia in large population-based surveys. While this does not prove that B12 prevents dementia, it should encourage us to keep our B12 levels in the normal range. Currently, research does not support taking more Vitamin B12 if your levels are normal.

If you meet one of the following criteria, ask your doctor about getting a Vitamin B12 test to check your levels.

• Are older than 75 years,

• Are a vegan or strict vegetarian,

• Have had gastric or small intestine resections or inflammatory bowel disease,

• Have been taking metformin for more than four months or have used of proton pump inhibitors or histamine H₂ blockers for a year or more.

If you do not met one of these criteria, routine testing is not recommended, as your doctor will be on the lookout for any signs of a possible deficiency.

Vitamin D

Vitamin D deficiency (<12ng/mL) has been associated with an increased risk of dementia in several population studies. These studies show that keeping your Vitamin D levels in the recommended range reduces your risk of dementia. However, research does not support taking Vitamin D if your levels are presumed to be normal or taking more than the recommended amount, as too much Vitamin D can be dangerous. Foods which are high in Vitamin D include salmon and other fish, egg yolks, and mushrooms.

Other Vitamins

Currently, there is no evidence to support the use of Vitamin E, multivitamins, or fish oil to reduce your risk of dementia. As mentioned above, some vitamins may reduce the risk of dementia, but only those with a known deficiency. If you do not have a deficiency of these vitamins, you should focus on eating a varied and healthy diet which will provide you with the vitamins you need.

Sources:

Vitamin B12 Levels and Dementia, JAMA, https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2738056

Recommendations on Testing B12, American Family Physician, https://www.aafp.org/afp/2017/0915/p384.html

Vitamin D and the Risk of Dementia and Alzheimer Disease, Neurology, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4153851/

Recommendations on Testing Vitamin D, American Family Physician, https://www.aafp.org/afp/2018/0215/p254.html

Skip Vitamins, Focus on Lifestyle, Harvard Medicine, https://www.health.harvard.edu/staying-healthy/skip-vitamins-focus-on-lifestyle-to-avoid-dementia