Vitamin D is important for bone health, but according to two new studies, it has other benefits as well, at least for women. Research suggests that women who are at risk for cognitive decline and neurodegenerative conditions such as Alzheimer’s disease can slow or even prevent these conditions.
One study, in Minnesota, measured the vitamin levels and cognitive functioning of more than 6,000 older women. In this study, researchers found that low levels of the vitamin went hand in hand with cognitive impairment. Forty nanograms of vitamin D per milliliter of blood serum is a normal level; less than 20 ng/mL is considered low.
Another study, in France, found that vitamin D from a woman’s diet is associated with a lower risk of her developing Alzheimer’s disease. The research did not indicate whether solar derived vitamin D had the same benefit. Both of these studies built on earlier research suggesting that vitamin D may reduce the risk of dementia, especially Alzheimer’s disease, in men and women.
There are two forms of vitamin D used by people, which are called D2 and D3. The D2 type comes from food, and is found in eggs, dairy, fish, and certain plant-based foods, as well as being available in supplements. People can actually make D3 on their own, from sunlight. As little as ten minutes a day of sun exposure is usually enough to meet someone’s need for Vitamin D3.
Vitamin D—both types—is necessary for helping the body grow normally. It’s particularly important for the development of healthy bones, but the vitamin is closely involved in protecting against and recovering from a number of diseases. In particular, there is some indication that it protects against the spread of most forms of cancer.
In addition to cognitive difficulties, vitamin D deficiency is linked with cancer and with fatal cardiovascular illness. In children, it can lead to rickets—a condition characterized by soft bones and skeletal deformity—as well as severe asthma. Osteomalacia, a disease similar to rickets that causes muscle weakness, can be associated with vitamin D deficiency in adults.