Boosting vitamin D may reduce your heart risk; research shows that the vitamin helps fight inflammation, lower blood pressure, and may also play a role in controlling cholesterol.
Research shows that this particular vitamin has substantial benefits, ranging from cancer prevention to improved heart health. A study published in the June 11 edition of Archives of Internal Medicine found a "significantly higher" prevalence of hypertension, diabetes, obesity, and high triglyceride levels in individuals with lower levels of vitamin D.
"Over the past five years, vitamin D has emerged as one of the key nutrient deficiencies contributing to the risk of many chronic diseases, including colon cancer, breast cancer, ovarian cancer, Type 2 diabetes, hypertension, and osteoporosis. Heart disease can now be added to this impressive list," says Carolyn Snyder, MPH, RD, LD, with Cleveland Clinic's Department of Nutrition Therapy.
What it is
Vitamin D is a fat-soluble vitamin with two main forms: D2 (ergocalciferol) and D3 (cholecalciferol). The latter is the naturally occurring form and the form used for low-dose supplementation, Snyder explains. Vitamin D3 is synthesized in the skin after exposure to the sun's ultraviolet (UV) rays and obtained in the diet chiefly from fish liver oils and saltwater fish. In the United States, people also get vitamin D3 from fortified milk and cereals.
According to the National Institutes of Health, your liver and kidneys convert vitamin D to form 1,25 dihydroxyvitamin D, the vitamin's physiologically active form. This active form of vitamin D functions as a hormone, sending messages to the intestines to increase the absorption of calcium and phosphorus. In fact, one of the major functions of vitamin D is to maintain normal blood levels of calcium and phosphorus.
Why you need it
Doctors have long known that deficient levels of vitamin D can lead to rickets in children--something that was much more common prior to the 1930s, at which time the government promoted fortifying food with vitamin D--and osteomalacia (softening of the bones) in adults. And now research shows that low levels of vitamin D can affect your cardiovascular system as well.
"Researchers have yet to determine the exact mechanisms connecting vitamin D with reduced risk of heart disease," Snyder explains. "But studies have already shown that vitamin D can lower inflammation by increasing levels of anti-inflammatory messengers like the cytokine named IL-10 (interleukin-10).
"Research has also shown that vitamin D can lower blood pressure, probably by inhibiting a regulatory system called the renin-angiotensin system," she adds. "An analysis of vitamin D metabolism in 2006 has further suggested that vitamin D may be directly involved in cholesterol reduction."
WHAT YOU CAN DO
* Get five to 10 minutes of sun exposure on your arms and legs, or hands, arms and face, two to three times per week without using sunblock.
* Include vitamin D-fortified foods (milk, breakfast cereals, orange juice and some breads) in your diet.
* Take multivitamins, which generally contain 400 international units of vitamin D.
HOW MUCH VITAMIN D DO YOU NEED? The Institute of Medicine (IOM) of the National academy of sciences established the following as Adequate Intakes (AI) for vitamin D in micrograms (mcg) and International Units (IUs): AGES 51-69 AGES 70+ 10 mcg * 15 mcg * or 400 IU or 600 IU * 1 mcg vitamin D = 40 International Units (IU) VITAMIN D FOOD SOURCES % OF SERVING INTERNATIONAL DAILY Food SIZE UNITS VALUE Cod liver oil 1 tablespoon 1,360 340 Salmon, cooked 1/2 ounces 360 90 Mackerel, cooked 1/2 ounces 345 90 Tuna fish, canned in oil ounces 200 50 Sardines, canned in oil 1 3/4 ounces 250 70 Milk (all varieties) 1 cup 98 25 Ready-to-eat cereals fortified 3/4 to 1 cup 40 10 with 10% of the DV for vitamin D (varies) Source: NIH's Office of Dietary Supplements
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|Date:||Oct 1, 2007|
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