Vitamin-D-free regimen intensifies the spatial learning deficit in Alzheimer's disease.

Evidences support a link between nutrition and risk of neurodegenerative Alzheimer's disease (AD). This work was designed to find out if food regimens lacking vitamin D or with a supplement of vitamin D could affect spatial performances in the Alzheimeric animals. The experiment was done on the control and Alzheimeric (ALZ) animals on a normal regimen of food, as well as the Alzheimeric rats fed with regimens lacking vitamin D (ALZ-D) or supplemented with 1,25(OH)2D3 (ALZ+D). For learning the spatial task the animals were trained to locate a hidden platform in the Morris water maze. We found that the ALZ rats had an obvious lower performance compared with the control ones. Generally, the ALZ-D rats displayed a poorer spatial learning compared with either the ALZ or the ALZ+D rats. Vitamin D supplement did not significantly influence the spatial performance. We conclude that although vitamin D deficiency strengthens the spatial learning deficit in AD, a supplement of 1,25(OH)2D3 does not effectively underlie the maze performance. It can be concluded that subjects with AD must be protected from vitamin D inadequacy.