sweet potatoes: critical for immune system and overall health at this time of year.

They contain Vitamin D which is critical for immune system and overall health at this time of year.  Both a vitamin and a hormone, vitamin D is primarily made in our bodies as a result of getting adequate sunlight. You may have heard about seasonal affective disorder (or SAD, as it is also called), which is linked to inadequate sunlight and therefore a vitamin D deficiency. Vitamin D plays an important role in our energy levels, moods, and helps to build healthy bones, heart, nerves, skin, and teeth, and it supports the thyroid gland.

Read more: http://www.care2.com/greenliving/9-reasons-to-love-sweet-potatoes.html#ixzz2nhkGBvqC