Vitamin D

Manchester United

Hey - Manchester United uses UV lights to increase their vitamin D levels. I don't know much about "football," but they're pretty good, right? 

(Hey Bills, check it out.)

http://www.telegraph.co.uk/sport/football/teams/manchester-united/8275326/Manchester-Uniteds-Ryan-Giggs-and-Rio-Ferdinand-buy-into-cutting-edge-methods-at-Carrington.html

Vitamin D and exercise

Dave at Crossfit Buffalo asked me to post something on vitamin D's benefits for exercise. 

Scientifically speaking, Vitamin D supplementation might increase your exercise performance. Practically speaking, it's a good bet that it will if your levels are low.

It's a textbook phenomenon that a low level of vitamin D (vitamin D deficiency) decreases muscle strength. Most research that I've seen over the past 10 years or so bears this out. I've personally seen extreme cases of it - like a patient being able to stand up from a wheelchair after vitamin D status is normalized.

Furthermore, a great many people have vitamin D deficiency. I'd estimate that around 30 to 40 percent of people in my city who are not taking supplements have it.

So if we put two and two together, you reading this are somewhat likely to have vitamin D deficiency, and vitamin D deficiency leads (at least in extreme cases) to lower muscle strength, so taking vitamin D might improve your exercise performance.

There isn't much direct evidence that I've seen in the literature that vitamin D supplementation in young, healthy athletes helps athletic performance. However, there's a chance. And vitamin D is safe up to 4000 units per day for adults.

Personally, I think this is one reason why the Buffalo Bills are always losing.

tanning beds

I'm overall skeptical of industrial tanning. Anything that damages the skin - which is what you're doing with tanning, little by little - puts you at risk for skin cancer.

However ...

Yesterday I went tanning for the first time. The store advertised their bulbs as providing vitamin D - because they included Ultraviolet B (UVB) radiation. 

Afterwards, I had a huge burst of energy. I cleaned my kitchen in 12 minutes. The only biochemical explanation I know for this is the production of vitamin D - basically, the reversal of a vitamin-deficient state. (Actually, a steroid deficiency - because vitamin D is a steroid hormone, not really a "vitamin.")

It made me think of a several-hundred year old trend in English thought - that the sun makes you "mad." Certainly I had enough energy to make me look a bit crazy. 

But then again there appear to be multiple positive effects of vitamin D on health. 

I think I'm going back. 

vitamin D and alopecia

I recently heard of a case of unexplained alopecia in a 5 year old child. The child was given vitamin D supplementation (I'm not sure if it was 1,000 or 2,000 units per day), on the assumption that like every other child in the northeast USA, the child was at risk of vitamin D deficiency. The alopecia disappeared in 3 months.

A quick review of the literature shows me no link between vitamin D deficiency per se and alopecia. However there is a syndrome of rickets with alopecia that occurs when people have a receptor mutation that makes them resistant to vitamin D. So there is some indirect evidence that low vitamin D states could cause alopecia.

colon cancer

There's more evidence of a link between vitamin D and cancer, and you can probably reduce your cancer risk over time by taking this supplement.
In  a study in the American Journal of Preventive Medicine (link below), researchers analyzed data from five studies on vitamin D and colon cancer and found that people with higher levels had a 50 percent lower risk of colon cancer over the years.
Vitamin D is made when sunlight strikes skin, but can be taken as a pill also. In low areas like Buffalo, this is just about the only option for getting vitamin D for most of the year.  1,000 to 2,000 units a day is absolutely safe, and is enough to lower your cancer risk.
Vitamin D levels may explain why many cancers are less frequent in the southeastern US, and more frequent in the Northeast.

thrombosis

Skin necrosis after warfarin administration suggests an inheritable cause of thrombosis.

recommended intake of vitamin D

A new article in the American Journal of Clical Nutrition (2006:84:18-28) reviews the evidence on how much vitamin D we need. The authors recommend that the USRDA be changed.

Taking 1,000 units a day only gets adequate vitamin D levels in something over 50 percent of the population. So probably, if you want to be safe, you need to take more. As I have indicated elsewhere, there is absolutely no evidence that 2,000 units a day will hurt you, even with the unscientific and paranoid methods used to calculate the current USRDA of 400 to 600 units.

I'm not a zealot

I am not a nutritional zealot. I'm not pushing a bunch of supplements at you from all sides. In fact, based on the current nutritional and natural foods marketplace, I'm hesitant about advocating on any nutritional topic. In the marketplace, there are too many claims of dubious value, and I don't want to be associated with them.

Even before medical school, I have always had a sense that there was something wrong with human health, in a deep way. It didn't make sense that so many people would have so many odd diseases, or malaise, or general weakness. Over time I began to see life itself not so much as an "on-off" condition, not as a binary state, but as a quantity. Some people are more full of life than other people. Some situations make people more full of life than other situations. And this "life" that people have in them, it is not imaginary. It is a real thing, though you can't touch it, or measure it. Still, you can sense its relative presence or absence.

Looking back on my education, I see now that I have been watching for something in the human body that would explain this variation in quantity of life, and the relative absence of life in some people that leads to sickness, malase, and weakness. I have considered every organ system, every physiologic process, and every mental state looking for this answer.

What I have found, and what seems to be the problem, is widespread vitamin D deficiency.

fracture risk

A trial published in the New England Journal of Medicine finds little benefit to taking calcium plus vitamin D - basically no fewer fractures in the women taking the medication. I don't find this too surprising in that the dose of vitamin D was low - 400 units a day. It has been shown that it probably takes something like 2,000 units a day just to keep your level from going down. Furthermore, unless the subjects were getting a new bottle of the vitamin D supplement once a month or so, it is likely that it was decaying through oxidation, and not much was left in the bottles after a few weeks.

There was a higher incidence of kidney stones in the treatment arm of the study, so this is something to watch.

osteoporosis

A new study by vitamin D researcher Michael Holick shows that about half of elderly women receiving prescription medications for osteoporosis don't have enough vitamin D. This is bad because inadequate vitamin D causes osteoporosis. Conversely, if you get enough, you have fewer fractures and more muscle strength.

It makes sense that if we're going to spend the energy to diagnose and treat osteoporosis, we should probably spend the effort to treat what might be causing it. It's ridiculous that we don't. It's like treating kids for lead poisoning with chelating agents without checking out the paint in the house. Or it's like treating diabetes without adjusting the diet.