Vitamin D Part III: SAD – Seasonal Affective Disorder
Competency #17 Vitamin D
Reference: American Journal of Clinical Nutrition, Vol. 69, No. 5, 842-856, May 1999
As winter approaches, we all have a little dread about how the effects of winter. SAD hits all of us who live in Wisconsin to greater or lesser degrees. Now, there are some clues as to why. From submarine studies, we know that the serum Vit D level drops from 50 milliunits/ml to 20 if you provide no supplement at all. These submariners are under the sea for 3 months at a time and get no sunlight so they make a great study population. It takes 2000 IU a day to keep their blood levels at a steady state of about 80 units, which is considered the current optimum. If you want more detail, the American Jr of Clin Nutrition has a wonderful article from 1999 that gives all that (American Journal of Clinical Nutrition, Vol. 69, No. 5, 842-856, May 1999) Submariners have also allowed us to learn that the half life of Vit D is about a month.
We have just gotten our last good dose of sunshine in Wisconsin. The sun is hereafter too low to make any significant Vit D. It takes 4 half lives to get a drug out of your system. So, Vit D will halve each month for the next: Oct, Nov, Dec, JANUARY, we all go nuts. Our Vit D is used up then too. No wonder the winter blues hit hard in Jan and Feb. And, in fact, measurements of most Americans shows blood levels below 40 by Feb.
Now, in the most reputable journal of all, the monthly AARP newsletter, recently published reports from the University of Toronto and the University of Sidney both show that you can raise your brain serotonin, the source of mood enhancement, by taking Vit D. There is lots of older literature comparing Vit D to artificial sunshine to deal with depression. Both work, but older literature looked at doses of 400U a day for fear of Vit D toxicity. The Toronto folks suggest you need 2000 IU a day. This is the highest level someone has used in a clinical trial with no side effects or toxicity.
Vit D Toxicity: Is it real? Is it actually a myth! Vieth, in the above detailed article traced down every single last case of Vit D toxicity since 1939 and found mostly cases of hyperparathyroidism that was being masked by being Vit D deficient. I found an article on one family of 11 from S. Africa that inadvertently cooked a meal with peanut oil that had 600,000 IU of Vit D per ml. Each person got 15-20 mls of peanut oil and all 11 got confused, had nausea and vomiting. And all fully recovered. Most interesting was the fact that all their blood levels of active Vit D were Normal. So we know that 12,000,000 IU of Vit D is toxic, but that you recover from it. We also know that lifeguards and farmers will get blood levels of 240 and not be toxic. So, 2000 IU a day is so far below anything toxic, its a laugher. Your kidneys set the pace.
WWW: What Will Work for Me: I find myself a little short in Jan. I am going to try it this winter. 2000 IU a day and will see if I get by a little easier. Between the submariners and our recent studies, we know 2000 IU gets your blood level to 32 nanograms. Optimum health may require a higher baseline, but for now, that appears to be sensible. I have a very bright UVB grow light in the basement. Maybe a little indoor gardening will be in the picture too.
Final Tidbits on Battling Winter Blues with Food: There is evidence that people who eat more oils and less carbs are more cheerful and have higher mood measures. Same for fish.