Low blood levels of Vitamin D mean increased risk of depression for people over the age of 65. The risks are worse for women than for men, suggesting that women in fact need higher tissue levels of this vitamin than men do. People over the age of 65 also have aging skin receptors, so that it is harder for them to absorb Vitamin D from sunlight. (It is the UV-B type of sunlight that triggers our skin receptors to produce vitamin D.) Researchers from the US National Institute on Aging have been looking at the causal pathway between depression and Vitamin D deficiency. In 2008, Dutch scientists performed similar studies. They found that low levels of D and higher blood levels of the parathyroid hormone (PTH) were associated with higher rates of depression among 1,282 community residents aged between 65 and 95. We already know that Vitamin D directly affects proteins in the brain associated with memory, cognition, learning, motor control and social behavior. The US Institute study published in the Journal of Clinical Endocrinology and Metabolism now suggests that low Vitamin D levels will pose mood disorder problems for seniors, and in particular, women over the age of 65.