Sunlight, Skin Cells, and Vitamin D
by Beth Biggee, MD
“When you look at the sun during your walking meditation, the mindfulness of the body helps you to see that the sun is in you; without the sun there is no life at all and suddenly you get in touch with the sun in a different way.”
Daylight savings time ended this month making the days darker and this means less Vitamin D. Vitamin D is produced from the sun in our skin cells. Literally as Thich Nhat Hahn states, the sun is in you. The lower layers of your skin take the sunlight through a photochemical reaction to make vitamin D precursors. With less sunlight this time of year, particularly at the latitude in my home city Boston, we are most vulnerable. A study in the Journal of Clinical Endocrinology Metabolism in 1988 is titled: Influence of season and latitude on the cutaneous synthesis of vitamin D 3: exposure to winter sunlight in Boston and Edmonton will not promote Vitamin D3 synthesis in human skin.
I just found out about a new App that can help you track your Vitamin D from sun exposure. Make sure if you are walking out midday in the sunshine to wear sunscreen. A medical review did not find compelling evidence that sunscreen decreases Vitamin D levels in real life situations.
A deficiency in Vitamin D is defined as 25 hydroxylase Vitamin D level less than 20ng/ml. Low vitamin D has been linked to osteoporosis, low muscle mass leading to balance problems with falls, diffuse aches and pains, autoimmune disorders, and mood disorders.
In Boston during the winter there is very little sunlight so we can obtain Vitamin D from food such as oily fish, cheese, egg yolk, beef liver, mushrooms exposed to UV light, or vitamin D fortified foods such as milk, cereal and bread. For many however, foods are not enough to get the Vitamin D level above 20ng/ml and supplements are needed.
Too much Vitamin D however can accumulate in tissues causing harmful effects, so it is best to review what supplement dose to take with your healthcare provider. The dose may change depending on your age, medical condition (as some diseases such Chron’s or Celiac can block absorption of D in the gut), diet (vegetarian or vegan), location, and time of year. It would be best to test your Vitamin D before supplementing. Then have a plan on what dose to supplement and for how long as the seasons change, and retest.