Low Vitamin D Linked to Cognitive Decline, Dementia

Vitamin D’s beneficial effects are well known with respect to preventing falls in the elderly, certain cancers, and cardiovascular disease. New research now has linked low vitamin D levels with an increased risk of cognitive decline and dementia in older adults.

The current issue of the Archives of Internal Medicine reports on a study of 858 adults at or over the age of 65, who were surveyed for seven years. At the start of the study, these volunteers underwent extensive evaluation of their cognitive function. All patients also underwent testing of their blood for vitamin D levels. The testing was repeated every three years.

The results indicated that participants with low vitamin D levels in the blood (less than 25 nmol/liter), when compared with volunteers with normal levels (75 nmol/liter, or higher), experienced significant declines in their intellectual function. Indeed, those with decreased vitamin D levels were as much as 60 percent more likely to exhibit progressive cognitive decline or dementia over the relatively brief duration of this study.

These findings are very similar to those of a similar study that has just been published in the journal Neurology. The latter study showed that an inadequate level of vitamin D in the blood of elderly men and women was associated with a significantly increased risk of cognitive decline and dementia from all causes, including Alzheimer’s disease and stroke.

Moreover, abnormalities of the brain, as detected by MRI scans, were also more commonly observed in patients who were deficient in vitamin D.

Vitamin D deficiency is very common in older men and women. An estimated 80 percent of people over the age of 65 have inadequate levels of vitamin D in their blood; for as many as 45 percent, the deficiency is characterized as severe.

The results of these two studies strongly suggest that adequate blood levels of vitamin D may significantly reduce the risk of aging-associated cognitive decline and dementia in older men and women. That’s in addition to improving muscle strength, decreasing the risk of certain cancers, and decreasing the risk of cardiovascular disease.

Not everyone should take large doses of vitamin D, however, as the unmonitored use of this potent hormone-like vitamin can cause dangerous elevations in the level of calcium in the blood. It can also cause calcifications in the soft tissues, kidney failure, pancreatitis, and gastrointestinal ulcers. Prior to starting Vitamin D supplements, you should certainly discuss the risks and benefits with your physician.

(To learn more about vitamin D and the risk of cancer, look for my new book, A Cancer Prevention Guide for the Human Race, which will be published in August.)