Vitamin D
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A discussion about vitamin D usually begins with a big yawn. "Vitamin D? I get enough drinking milk!"
Over the years, vitamin D has been neglected and misunderstood. Vitamin D had previously been viewed as nothing more than a nutrient necessary to prevent childhood rickets. More recent experiences from a number of directions, however, suggest that vitamin D is a crucial factor in such varied phenomena as blood pressure control, bone health, inflammation, metabolic syndrome, and even coronary plaque.
Substantial data from UCLA has demonstrated that the higher your heart scan score, the more likely you are to be deficient in vitamin D. It's also well established that the closer you live to the equator (thereby receiving more sun exposure), the less likely you will suffer a heart attack. This means that people living in northern climates like Wisconsin, Michigan, Massachusetts, etc., have less sun exposure, lower vitamin D blood levels, and have greater heart disease by this route. Vitamin D deficiency is, in fact, extraordinarily common. Most recent estimates suggest that around 70% of American adults are deficient.
The preferred source for vitamin D is sun exposure. Twenty minutes of sun exposure while wearing a light summer shirt and shorts generates an amazing 10,000 units of vitamin D. Compare this to the 100 or so units you receive by drinking milk. Most of us don't get sun exposure everyday. In the upper Midwest, for instance, people obtain almost no exposure whatsoever from October to April every year. Studies have clearly shown that vitamin D deficiency develops within 4-8 weeks from the time sun exposure ceases. The consequences? Heightened inflammation, increased blood pressure, thinning bones, and perhaps greater coronary plaque growth.
One of the most potent means of reducing inflammation, as measured by C-reactive protein (CRP), is to replace vitamin D. A British study showed a 40% reduction in CRP and other inflammatory measures by replacing vitamin D in people who were deficient. Several studies have also demonstrated a substantial drop in blood pressure just by supplementing vitamin D.
The most recent experience in the Track Your Plaque program, in which we aim for blood vitamin D levels (25-OH-vitamin D3) of 50-60 ng/ml, we have been witnessing unprecedented levels of drops in heart scan scores.
How much vitamin D should you take orally? This depends on your sun exposure. If you live in Florida and live an outdoor lifestyle and get sun exposure every day, no oral replacement may be necessary, unless your blood levels suggests that you remain deficient. If you live in the northern U.S. and, like the vast majority of Americans, get occasional and sporadic sun exposure during summer months only, then year-round vitamin D supplementation may be necessary to restore blood vitamin D levels to normal. Recent data suggest that the replacement dose for vitamin D ranges from 1000-6000 units per day, much higher than the RDA of 300-600 units. We find that in women, 3000-4000 units per day ensures that the majority will enjoy full vitamin D replacement; men require 4000-6000 units per day. Discuss your use of vitamin D with your doctor, especially if you desire a blood level for diagnosis of the extent of deficiency and to determine whether your dose is sufficient. Also, please be aware that oil-filled capsules are far more effectively absorbed than tablet forms of vitamin D.
References:
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Heaney RP, Davies KM, Chen TC, Holick MF, Barger-Lux MJ.Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol. Am J Clin Nutr. 2003 Jan;77(1):204-10.
Mathieu C, Gysemans C, Giulietti A, Bouillon R. Vitamin D and diabetes. Diabetologia. 2005 Jul;48(7):1247-57. Epub 2005 Jun 22.
Watson KE, Abrolat ML, Malone LL, Hoeg JM, Doherty T, Detrano R, Demer LL. Active serum vitamin D levels are inversely correlated with coronary calcification. Circulation. 1997 Sep 16;96(6):1755-60.
Grimes DS, Hindle E, Dyer T. Sunlight, cholesterol and coronary heart disease. QJM. 1996 Aug;89(8):579-89.
Timms PM, Mannan N, Hitman GA, Noonan K, Mills PG, Syndercombe-Court D, Aganna E, Price CP, Boucher BJ. Circulating MMP9, vitamin D and variation in the TIMP-1 response with VDR genotype: mechanisms for inflammatory damage in chronic disorders? QJM. 2002 Dec;95(12):787-96.
Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety.
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