Sunlight

by Dr. Lyle Norton

"Doc, what does sunlight have to do with health?"  A lot.  You probably have heard about the SAD lights that give full spectrum light (artificial sunlight) so that the neurotransmitters that improve mood and help prevent depression are produced.  The sunlight entering the eye causes different hormones to be produced that initiate both wakefulness and antidepressant activity.  That is part of the function of sunlight.  It elevates the spirit and lightens the mood.  A sunny day just makes you feel like singing.

An obvious reason for sunlight is that it warms you.  It is pretty amazing when you think about it.  The sun is 93 million miles away.  If it were 1 million miles closer, we would burn up.  If it were 1 million miles further away, we would freeze.  The balance of heat on our planet is an amazingly precise thing. It's almost as if Someone planned it that way!

Sunlight is needed on the skin to synthesize Vitamin D from 7-hydroxycholesterol.  It is the ultraviolet light that accomplishes this conversion in the skin.  For young individuals that are fair skinned, 30 minutes a day on just the face and hands is adequate to convert the needed amount.  It is proportional to the amount of skin exposure so that if your arms and legs are also exposed the amount of time needed is lessened.  If you are dark skinned the amount of time needed is greater.  Vitamin D is needed to absorb calcium and enhances the immune system and inhibits tumors.  Elderly people produce Vitamin D at about half the rate that younger people do and since calcium isn't absorbed as well in the elderly, the need for sunlight is greater.  Depending on who you are and where you live, it may be more of a challenge for you to get enough sunlight.

"Doc, I thought sun tanning caused cancer.  Are you saying it's good for me?"  Balance is the key.  Too much sunlight can cause damage.  Too little is not good either.  If you don't get enough sunlight (Vitamin D) you are at risk for depression, osteoporosis, colorectal cancer and breast cancer.  Other cancers need more study to make a determination on how they are affected by sunlight.  Suffice it to say, you need sunlight, just not too much.  So go for a walk in the sunshine today!