Vitamin D’s Crucial Role in Cardiovascular ProtectionSeptember 2007
By William Davis, MD
Cholesterol is Not Everything
Judging from the constant onslaught of drug company advertising, you’d think that a cure for coronary heart disease has been discovered, and that the cure is cholesterol-lowering statin drugs. Existing data show that this is clearly not the case. Risk for heart attack is certainly reduced, usually by about 25–30%, but not eliminated. Thus, statin drugs could only prevent about one in every three heart attacks.39
This is because there are many other causes for heart disease beyond LDL: low HDL, increased triglycerides, diabetes, inflammation, and hidden causes of heart disease like lipoprotein(a). But how about vitamin D? The scientific information so far is hugely promising.
“I foresee an increasing number of studies linking vitamin D deficiency to most of the diseases of modern civilization. Furthermore, I foresee a backlash by many in organized medicine who simply cannot accept the possibility that such a simple and cheap compound can have such health benefits. I foresee lawsuits against practicing physicians who don’t accept the importance of vitamin D. For example, researchers at Harvard just announced that the five year survival for patients with early stage, non-small cell carcinoma of the lung was almost three times better in those with evidence of the highest vitamin D levels compared to those with the lowest. Five-year survival for those with the highest levels approached 80%! I predict similar claims will be filed against cardiologists for letting heart disease patients die vitamin D-deficient as the evidence mounts that vitamin D prevents and treats heart disease.”
—Dr. John Cannell The Vitamin D Council www.vitamindcouncil.com
Optimizing Vitamin D Levels
Given the vast benefits of vitamin D for cardiovascular and whole-body health, ensuring optimal vitamin D status is an essential part of every wellness program. The best way to know your vitamin D status is to have your doctor measure the blood level of 25-hydroxyvitamin D (not to be confused with 1,25-dihydroxyvitamin D). The minimum level of 25-hydroxyvitamin D required for health is controversial, and can also vary by the method used for measurement. However, most authorities have argued that a rock-bottom minimum 25-hydroxyvitamin D level of 30 ng/mL, or 75 nmol/L, is the point at which phenomena associated with deficiency begin to be corrected.40 Noted vitamin D authority Dr. Reinhold Vieth of the University of Toronto has argued that a blood level of 40 ng/mL (100 nmol/L) should be achieved.7 Dr. Michael Holick of the University of Boston proposes that serum level of 25-hydroxyvitamin D is in the range of 30-50 ng/mL (75-125 nmol/L).34 Another study showed that elderly men and women were at an increased risk of bone loss when their levels of 25-hydroxyvitamin D fell below 45 ng/mL (110 nmol/L), suggesting that maintaining 25-hydroxyvitamin D above 45 ng/mL may be crucial for all aging adults.41 If vitamin D levels are low, consider supplementation to help reverse a vitamin D deficiency. Re-checking your vitamin D status after several months of supplementation is prudent to ensure that a deficiency has been averted.
New studies are showing that the dose required to achieve a healthy blood level of vitamin D is somewhere in the neighborhood of 1,000–4,000 IU per day in the absence of sun exposure.42 That’s more than five times the Institute of Medicine’s recommended adequate intake, though still less than obtained through several minutes of midday sun exposure. Vitamin D toxicity does not usually develop unless vitamin D intake exceeds 10,000 units per day or blood levels exceed 80 ng/mL (200 nmol/L).1,7 In fact, some scientists believe that the tolerable upper intake level of vitamin D intake should be revised from 2,000 IU/day to 10,000 IU/day.43
If you live in the northern US (states like Massachusetts, New York, Pennsylvania, Wisconsin, Michigan, the Dakotas, etc.), Canada, or northern Europe, there’s a high likelihood that you’re deficient. If you’re like most Americans, you get sun sporadically during summer weekends, and virtually none from September to April. Dark-skinned individuals are at even greater risk of vitamin D deficiency, since melanin pigment in skin acts as a natural sunscreen. Dark-skinned individuals require around five times longer sun exposure to obtain the same amount of vitamin D as fair-skinned persons. African-Americans, for this reason, are among the most vitamin D deficient of all.
Ten minutes of sun exposure in midday, wearing shorts and t-shirt to expose skin surface area, will provide most Caucasians plentiful vitamin D during the summer. This limited time minimizes the risk of skin cancer. (If you are especially fair-skinned, you might do fine with somewhat less.) If you are in the sun any longer than this, you should apply a sunscreen (which blocks both sunlight as well as vitamin D activation in the skin).
However, if sun exposure is sporadic, supplementation is crucial to obtain the full benefit of vitamin D’s panel of biologic effects. Vitamin D3 (cholecalciferol) is preferable to vitamin D2 (ergocalciferol), as it is absorbed 70% better than D2 and it more effectively increases blood levels.44 Many vitamin D supplements contain only 400 IU per capsule or tablet. More and more manufacturers are producing 1,000 and 5,000 IU capsules to suit the growing demand for higher dose vitamin D supplements. In northern climates or sun-deprived lifestyles, 1,000 IU per day is a reasonable starting dose. You may wish to consult your physician and check your blood level of vitamin D to determine if even higher doses of vitamin D are appropriate for you.
To obtain a dose of 1,000–2,000 IU or more per day, a specific vitamin D supplement will be required, rather than a combination supplement with calcium or other nutrients. Note the quantity of vitamin D (if any) included with your other supplements, such as calcium and multivitamins (usually 200–400 IU), and reduce the amount of specific vitamin D accordingly (to equal your total desired dose).
Supplementing with very high doses of vitamin D over an extended period of time can lead to elevated blood calcium levels, which can adversely affect nerve and muscle function, and can contribute to kidney stones.45-48 Individuals using large doses of vitamin D should be carefully monitored for signs and symptoms of vitamin D toxicity such as poor appetite, constipation, weakness, heart arrhythmias, and elevated blood levels of cholesterol, calcium, or liver enzymes.49 Individuals with hypercalcemia (high blood calcium levels) should not take vitamin D.49 If you have kidney disease or if you use digoxin or other cardiac glycoside drugs, consult a physician before using supplemental vitamin D.4
“Personally, I take 5,000 units in the late fall, winter, and early spring, and then I vary doses the rest of the time depending on sun exposure. I also have my 25-hydroxyvitamin D level checked twice a year, once in the early spring and again in the early fall. My 10-year old daughter takes 2,000 units a day in the winter months, and my three year old takes 1,000 units a day in the winter.”
—Dr. John Cannell The Vitamin D Council www.vitamindcouncil.com
The understanding of vitamin D is rapidly evolving. Compelling and substantial evidence suggests that most people—particularly those living in northern climates or with limited sun exposure—are substantially deficient. Replenishing vitamin D can help normalize blood pressure, support healthy blood sugar, improve insulin resistance, and dampen inflammation—all processes that contribute to heart disease. Growing evidence is adding support to the idea that vitamin D deficiency contributes to coronary risk, and that replacement of vitamin D can reduce risk. The vitamin D in dairy products and foods fails to provide sufficient quantities for the majority of Americans. In the absence of substantial sun exposure every day, vitamin D replacement is required in order to achieve adequate blood levels of this essential nutrient.
Dr. William Davis is an author and cardiologist practicing in Milwaukee, Wisconsin. He is author of the book, Track your Plaque:
The only heart disease prevention program that shows you how touse the new heart scans to detect, track, and control coronary plaque. He can be contacted through www.trackyourplaque.com.
If you have any questions or wish to discuss any aspect of this article, please call one of our Health Advisors at 1-800 226-2370.
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