April 16, 2010 (Toronto) -- Two new studies add to evidence that older people with low levels of vitamin D may be more likely to suffer from cognitive impairment.

The hope is that vitamin D supplements may be able to slow mental decline -- an intervention that one research team plans to put to the test this summer.

Vitamin D is best known for helping the body absorb calcium, which restores and strengthens bone, protecting against fracture.

But vitamin D also seems to have anti-inflammatory effects that may help keep blood vessels healthy, ensuring nutrient- and oxygen-rich blood flow to brain cells, says Amie Peterson, MD, of Oregon Health & Science University in Portland.

In addition, the presence of vitamin D receptors throughout the brain suggests that it may directly affect brain tissue, she tells WebMD.