RESEARCHERS PINPOINT HOW A LACK OF VITAMIN D MAY INCREASE THE RISK OF ALZHEIMER'S AND VASCULAR DEMENTIA

Researchers have found that low blood levels of vitamin D are associated with an increased risk for a host of health problems ranging from cardiovascular disease, susceptibility to infections, and diabetes, to osteoporosis, dental cavities and periodontal disease.  Vitamin D deficiency is also known to be linked to an increased risk of Alzheimer’s and vascular dementia.   For example, recently, a study from the large Third National Health and Nutrition Survey (NHANES III) in the U.S. showed a marked association between vitamin D deficiency and risk of dementia.   According to the latest estimates, 5.3 million Americans have Alzheimer's disease and it is the seventh-leading cause of death in the U.S

In 2009 it was reported that vitamin D3 appears to stimulate the immune system to clear harmful amyloid beta proteins, the main component of plaques associated with Alzheimer's disease.  But, the researchers didn't know how it worked.  Now researchers have identified the cellular mechanisms regulated by vitamin D3 that help the body clear the brain of amyloid proteins.

For the study, scientists drew blood samples from Alzheimer's patients and healthy controls and then isolated critical immune cells from the blood called macrophages, which are responsible for gobbling up amyloid beta and other waste products in the brain and body.  The team incubated the immune cells overnight with amyloid beta. An active form of vitamin D3 which is made in the body was added to some of the cells to gauge the effect it had on amyloid beta absorption.  They found that vitamin D3 activates key genes and cellular signaling networks to help stimulate the immune system to clear the amyloid protein. 

To determine whether vitamin D supplementation may help to treat dementia, clinical trials are still needed.  It is too early to know whether supplementation with vitamin D can reverse or slow the course of dementia.

What to do:  To reduce your risk of inflammatory diseases such as Alzheimer’s and heart disease, aim to maintain a healthy weight and lifestyle as well as adequate vitamin D.  For vitamin D, consume food sources rich in vitamin D such as lowfat/nonfat milk and oily fish such as salmon.  Also, next time you get blood work with your regular doctor, you can request your vitamin D level be checked.   This way you can know if you are deficient or not and how much to supplement with.  Vitamin D3 is widely available in supplements.  To maximize uptake of vitamin D, it is best to take it along with calcium.  Persons with some conditions should not supplement with vitamin D so check with your doctor before starting supplementation.  

Adapted from content in:   Journal of Alzheimer's Disease, 2009 17:1 & 2012;29:51-62, Science Daily at http://www.sciencedaily.com/releases/2009/05/090526140747.htm and Medscape at  http://www.medscape.com/viewarticle/760305.