Vitamin D appears to play an integral role in the cognitive health of women as they age, two new studies suggest.

Vitamin D is known to be necessary for good bone health. Sunshine is the primary source of this vitamin, with the body producing it as a result of the action of sunlight on the skin. It can also be found in supplements and foods, such as oily fish, egg yolks and fortified foods like milk and cereal.

However, recent research has indicated that the vitamin may be necessary for more than just bone health.

In the first new study, US scientists looked at more than 6,200 older women and found that those with lower levels of vitamin D in their bodies were more likely to display cognitive impairment and cognitive decline.

Meanwhile, the second study, which involved almost 500 women, found that those who had a higher intake of vitamin D in their diets had a reduced risk of developing Alzheimer's disease.

In fact, among the women who took part, those who developed Alzheimer's had lower vitamin D intake than those who developed other types of dementia or no dementia at all.

The two studies are published in the Journals of Gerontology Series A: Biological Sciences and Medical Sciences.

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