Cognitive Decline

For Your Health: Can Low Levels of Key Vitamins Lead to Cognitive Decline?
By David N. Ilfeld, M.D. Board Certified Internal Medicine, Rheumatology, Allergy & Immunology 7/29/2010
With the population of adults over 65 rapidly expanding, there has been an increased focus on cognitive and neurological health. New research has revealed an interesting prospect - a potential link between blood levels or oral intake of vitamins D and E and the risk of cognitive decline and other neurological disorders.

One recent study involved approximately 850 adults aged 65 and older. Researchers conducted interviews, blood tests and cognitive assessments on each participant three times during a six-year period1. The authors found that after six years, those with the lowest blood levels of vitamin D (measured as 25-hydroxyvitamin D) were 60 percent more likely to display general symptoms of cognitive decline and 31 percent more likely to experience declines in specific cognitive abilities, such as planning, organizing and prioritizing.

Another study analyzed the correlation between vitamin D levels and the risk of developing Parkinson's disease2. Nearly 3,200 Finnish men and women underwent medical evaluation and blood tests. After 29 years, researchers found that participants who initially had the highest blood levels of vitamin D were 67 percent less likely to develop Parkinson's disease than those with the lowest blood levels of vitamin D.

A study published this month in the Archives of Neurology looked at the link between vitamin E, dementia and Alzheimer's disease3. Approximately 5,400 men and women over the age of 55 who showed no signs of dementia provided detailed information about their dietary patterns. After nine years, researchers found that those with the highest dietary intake of vitamin E (mostly from sunflower oil, margarine and soybean oil) were 25 percent less likely to develop dementia. After adjusting for major risk factors, a similar reduced risk was also discovered for Alzheimer's disease.

I do not suggest consuming sunflower oil, margarine and soybean oil as these contain an overabundance of omega-6 fatty acids. Please remember that most omega-6 fatty acids (other than GLA) are pro-inflammatory and often harmful. A healthy and effective way to get vitamin E is to eat nuts and seeds.

It should be noted that the vitamin E in food is predominantly in the form of gamma-tocopherol and delta-tocopherol. In contrast, vitamin E in dry powder capsules is commonly found in the form of alpha-tocopherol. If you want to supplement with vitamin E, you should look for gamma-tocopherol and delta-tocopherol in softgels. More potent forms of vitamin E (tocotrienols) can also be taken as softgels.

In the case of vitamin D, supplementation may be crucial. In fact, the latest National Health and Nutrition Examination Survey reported that 77 percent of nearly 19,000 U.S. teens and adults were shown to have vitamin D deficiency (blood levels of less than 30 ng/ml). Vitamin D blood levels have declined over the past decade as people experience less skin exposure to ultraviolet-B sunlight, our body's main method of obtaining vitamin D. I recommend that adults supplement with 4,000 to 5,000 IU of vitamin D3 per day, taken with a meal that contains fat to maximize absorption of this fat-soluble vitamin.

As always, to your good health,
David N. Ilfeld, M.D.