Some of us may prefer not to sunbathe, but humans in general crave sunlight. We have known for some time that our exposure to the sun regulates various physical processes and that long term exposure to darkness can lead to depression, or SAD (Seasonal Affective Disorder). What is new, however, is the research showing the unintended consequences of the long promoted use of sunblock to prevent skin cancer. The ointments and lotions we lather on our epidermis blocks out the benefits as well, and low vitamin D levels can set us up for a host of problems, including increased cancer risk. More recently, however,  two large scale clinical studies appear to indicate that we are compromising our grey matter as well.

When people with chronically low vitamin D levels were tested against those with borderline, normal and optimal vitamin D levels, the ones with the lowest levels scored the lowest on certain cognitive function and memory tests. All I can say is: when you see the sun this winter, greet it with new appreciation!

Read more: http://www.scientificamerican.com/article.cfm?id=does-d-make-a-difference