PHOTO CAPTION: Higher intakes of calcium and vitamin D have been promoted in recent years as a way to prevent bone loss with aging – but there may be a downside.
In one of the first studies to examine the relationship between diet and brain lesions, researchers observed that elderly people who reported higher calcium and vitamin D intake were much more likely to have greater volumes of brain lesions – regions of damage that can increase risk of cognitive impairment. Our finding of a relationship between brain lesions and consumption of both calcium and vitamin D raises the question about a possible down side to high intakes of these nutrients, Dr. Martha E. Payne of Duke University, Durham, North Carolina, told Reuters Health. Higher intakes of calcium and vitamin D have been promoted in recent years as a way to prevent bone loss with aging. We are concerned that some of this extra calcium may end up in the blood vessel walls rather than the bone. This may be a particular problem for individuals with renal disease since calcium excretion may be impaired, Payne said. The research team assessed calcium and vitamin D intakes and magnetic resonance imaging (MRI) brain scans in 232 elderly men and women. All of the subjects displayed some brain lesions of varying sizes but those reporting the highest intakes of calcium and vitamin D were significantly more likely to have higher total volume of brain lesions as measured across several MRI scans. These positive associations remained significant in two separate multivariable models controlling for age, high blood pressure, diabetes, heart disease, and depression. In one model containing both calcium and vitamin D, only vitamin D remained significantly positively associated with brain lesion volume. We cannot conclude that calcium or vitamin D caused the brain lesions that we found, Payne said. However, we hypothesize that our findings may be due to vascular calcification, whereby calcium is taken up into the blood vessel walls.
A longitudinal study, Payne concludes, is urgently needed in order to determine if calcium and vitamin D lead to vascular calcification and brain lesions in the long term.
She reported the study findings at a meeting of the American Society for Nutrition, part of Experimental Biology 2007 in Washington, DC.