Vitamin D3 is a general immuno-suppressant. Macrophages, monocytes, and other effectors cells of immune system have receptors for Vit D. At a recent Allergy meeting there was a poster presentation that showed supplementing Vit D reduced acute asthma exacerabations in the active group vs. placebo. Also, people high risk for developing MS nowadays are prescribed moderately strong doses of Vit D3. (2000 U/day)
The therapeutic-toxic gap of Vit D is much wider (unlike Vit A). Therefore relatively high doses are well tolerated. There is currently a proposal before FDA to raise the daily requirement of Vit D in an adult to 1-2000 units.
More time is spent indoor over the past 50 years, resulting in less sun exposure. And inadequate intake leads to vitamin D deficiency. Increases in TH2 balance leads to more asthma and allergies. I have not checked in my asthmatic patients, but I am thinking about it.
I think that some of the other information coming out about vit D deficiency and risk factors for other medical problems is interesting as well. D deficiency may be associated with increased risk for multiple sclerosis and insulin resistance.
I remember back in med school, learning that MS risk was greater in northern/colder climates, and the going theory was that “some kind of virus” that thrived in cold climates was responsible! Lack of sunlight or D deficiency was never suspected.
Today’s average sun exposure is far less than 20 or 30 years ago. Using a sunscreen of only 15 SPF blocks 95% of our skin’s ability to make vitamin D. Today people in general have far less unprotected sun exposure – between kids staying indoors and watching TV/playing video games/computer games, and more careful use of sunscreen by both kids and adults – people are just not making vitamin D with their skin the way we used to.
People with darker skin do not make as much vitamin D with sun exposure, and there is evidence that older skin does not make vit D as well either. Obese people are also more susceptible to D deficiency.
Vitamin D is not present in very many foods – cheese does not generally contain D, and yogurt rarely has much (unless it is fortified); the D in milk is destroyed when exposed to light.
All this means that the average person today has far lower D levels than people only 20 years ago.
I wonder if D deficiency and its associated insulin resistance is one more contributing factor to the obesity crisis (along with about a zillion other causes.) I have a question for anyone out there with a lot of experience with sarcoidosis. I have read that dark skinned people in Africa have low levels of sarcoidosis, but people of African ancestry who move to more northern climates have higher levels of sarcoidosis than the average population. I also understand that sarcoid nodules can actually PRODUCE vitamin D – and that countries with the highest level of sarcoidosis are Iceland and Sweden.
I’ve only recently started testing and treating, but I did have a new patient last week who was treated by his primary care doc last year, with marked improvement in his chronic tendonitis. The patient is a 35 year dentist, with naturally dark skin, who had been suffering from elbow tendonitis for over a year, despite NSAIDs and PT. After doing some reading about vit D, he asked his doc to check it. Level came back at 6. Post treatment level was 39 (8 weeks of weekly 50,000 IU of ergocalciferol/vit D2). Patient tells me that he was surprised that his symptoms resolved completely after treatment. Single case, but interesting.
How to replace— I like 1000-2000 u otc daily or.. 50000 units ergocalciferol weekly