Higher intake of vitamin D seems to protect mental health among women, besides keeping Alzheimer's at bay, say two new studies in France and the US.

The group led by Yelena Slinin, at the VA Medical Centre in Minneapolis, found that low vitamin D levels among older women are tied with higher odds of global cognitive impairment and cognitive decline.

The group based its analysis on 6,257 community-dwelling older women who had vitamin D levels measured during the Study of Osteopathic Fractures and whose cognitive function was tested by the Mini-Mental State Examination, the Journals of Gerontology Series A: Biological Sciences and Medical Sciences reported.

The team led by Cedric Annweiler, at the Angers University Hospital in France, based its findings on data from 498 community-dwelling women.

Among this population, women who developed Alzheimer's disease had lower baseline vitamin D intakes (50.3 micrograms per week) than those who developed other dementias (63.6 micrograms per week) or no dementia at all (59.0 micrograms per week).

These reports follow an article published in the Journals of Gerontology Series A earlier this year that found that both men and women who don't get enough vitamin D - either from diet, supplements, or sun exposure - may be at increased risk of developing mobility limitations and disability.