Why should we care? What's the consequence on brain function? Vit D is important for maintaining the health of the brain's vasculature. This is particularly critical for many elderly who are at risk of Vascular Dementia. Recent evidence also suggests that Vit D may enhance the clearance amyloid from the brain. Amyloid is a protein that condenses into plaques in the brain of patients with Alzheimer's disease. Some researchers speculate that enhancing the removal of amyloid from the brain might reduce the symptoms of dementia. Thus Vit D may offer at least two ways to protect the brain from the changes often associated with pathological aging.

What is the consequence on brain function of not having enough Vit D? A recent study measured the level of Vit D in the blood of a large population of elderly adults in the US (see July 12 issue of Archives of Internal Medicine). A whopping fifty percent of those people who were vit D deficient demonstrated significant cognitive impairments. Overall, this study suggests that having severely low levels of Vit D in the body makes one four times more likely to develop an age-associated cognitive impairment that might be the harbinger of a more severe dementia. Vit D deficiency may have other consequences upon brain health as we age; low levels of this vitamin have been recently associated with an increased risk of Parkinson's disease. So if you're truly concerned your brain's health, have some mackerel, salmon or eel for dinner tonight.