The possibility that something as readily accessible as Vitamin D, aka "the Sunshine Vitamin," might reduce blood pressure in African Americans is big news. With over 40% of all African Americans tussling with high blood pressure, Blacks have significantly higher rates of hypertension than other US populations along with lower levels of circulating 25-hydroxyvitamin D (vitamin D3 or cholecalciferol). A possible precursor to coronary artery disease (i.e. heart disease, stroke, heart failure, and peripheral vascular disease or hardening of the arteries in the legs and feet), hypertension poses a clear public-health threat to the Black community. To date, there has been no definitive reason identified for the potentially life-threatening health disparity posed by this high level of hypertension. However, recent research presented in the American Heart Association's journal, Hypertension, suggests that Vitamin D deficiency might play a specific role in the "mechanics" of hypertension among Blacks.
Approved by the Institutional Review Board of Harvard School of Public Health and funded by various sources including NIH, researchers from seven major teaching hospitals pooled their brainpower to conduct what is believed to be the first large, controlled study on the impact of Vitamin D supplementation on blood pressure in Blacks. Two hundred eighty-three participants who self-identified as Black were randomized in the double-blind study that took place in the Northeast over 3 month periods during two winters. The study was conducted during winter months because sun exposure is a key contributor to parent Vitamin D and sun exposure declines in Northeastern winters. Ironically, pigmentation is responsible for a large part of the lower stores of Vitamin D among Blacks, since sun exposure is a key source of the Vitamin and darker pigmentation actually reduces Vitamin D production
Participants were given either a placebo or 1000, 2000, or 4000 international units of Vitamin D3- per day. Results were promising. Measured in mm Hg, systolic blood pressure (SBP), the top figure in the blood pressure reading, indicates pressure in the arteries when the heart beats. The authors reported Vitamin D supplementation significantly, yet modestly, lowered systolic blood pressure! Diastolic blood pressure, pressure in the arteries between heart beats, was unchanged by Vitamin D supplementation.
Among the 250 participants studied in the 3-month follow-up:
* SBP actually increased +1.7mm Hg on average for placebo group * 1,000 units of Vitamin D/day showed a .7 mm Hg decrease in SBP * A 3.4 mm Hg decrease in SBP was calculated among those taking 2,000 units of Vitamin D/day * The largest decline in SBP, 4 mm Hg, was among participants taking 4,000 units Vitamin D/day
Although modest in its scope and not projectable in its findings, the suggestive nature of these research outcomes shines a bright light in the dark tunnel of hypertension in Blacks. If further research confirms that Vitamin D supplementation does indeed reduce SBP in Blacks, the public health implications could be very positive. Vitamin D supplementation is readily available, relatively inexpensive, and easy to incorporate into lifestyle giving it the potential to impact large numbers of people. Although the final word is pending, with the impact of Vitamin D deficiency reaching beyond hypertension and cardiovascular disease and linking to some cancers, suboptimal bone health, and increases in inflammation, it is certainly worth asking your physician to include a Vitamin D screen in your next blood panel. They're already drawing blood, so you have nothing to lose and a quite a bit to gain!
Here are some easy-to-follow tips for making great Vitamin D-levels and healthy blood pressure a part of your life:
* Food Picks: Nutrition also plays a role in Vitamin D. Although not too many foods are naturally high in Vitamin D, the fatty fish cod liver oil, swordfish and sockeye salmon top the list of natural food-sources of Vitamin D. Dairy milk, butter, cream, and cheeses along with some orange juice, soy, almond and rice beverages and ready-to-eat cereals are all fortified with the Vitamin. Read the labels to determine the levels in each food.
* More is not necessarily better: If your labwork reports that you are Vitamin D deficient, ask your physician for guidance in selecting the right dose of supplement. An excess of Vitamin D, or Vitamin D toxicity, can create problems including weight loss and an increase in blood levels of calcium which can damage the heart, blood vessels and kidneys. Remember to ask for advice. Don't go it alone in adding Vitamin D supplements.
* Check your blood pressure readings: Make sure your legs and feet are uncrossed and your feet are flat on the floor when taking your blood pressure. Also, know your machine. Take your home machine with you to your annual check-up and check your blood pressure immediately after the health-professional takes a reading. Right down the two figures so you'll have the comparison right at your fingertips.
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