(LifeWire) - In the quest for health through good nutrition, vitamin D is attracting attention. It's best known for working with calcium to strengthen bones. But increasing evidence suggests that taking vitamin D also contributes to heart health.
A 2008 study published in the journal, Circulation, reported that low levels of vitamin D doubled participants' risk for cardiac events -- such as heart attack, stroke or heart failure -- in the next five years, compared to individuals with higher levels. In addition, a body of research links inadequate vitamin D to various heart disease risk factors, including high blood pressure and diabetes.
About 80 million Americans have some form of heart disease -- and 650,000 die from it annually -- underscoring the importance of these findings. But keep in mind that scientists have not proven that low vitamin D levels cause heart disease, but simply that there's an association between the two.
Current guidelines for daily vitamin D intake are 200 international units (IU) for people age 50 or younger, 400 IU for those ages 51 to 70, and 600 IU for those 71 and over. Seniors don't synthesize vitamin D as efficiently as younger people. Recent research suggests that even higher levels might be beneficial, with some physicians pressing for 1,000 IU per day or more for the elderly.
About 20 to 30% of Americans are moderately or severely deficient in vitamin D. Deficiency is more common North of a line running roughly from northern California to Boston.
The key here is sunlight. We create much of our vitamin D supply in our skin, using the sun's ultraviolet radiation. Short, regular bursts of sunlight for 5 to 30 minutes on the exposed face, arms, legs or back can spur the synthesis of adequate amounts of vitamin D. But for much of the year, the sunlight north of the geographical line mentioned is too weak to power vitamin D production.
Another source of vitamin D is diet. Good food choices include fatty fish, such as salmon (360 IU/serving), mackerel (345 IU/serving) and tuna (200 IU/serving). Other foods are fortified with vitamin D, including milk (98 IU/cup) and fortified cereals (40 IU/cup).
If you have concerns that you're still not getting enough vitamin D, consider a supplement or multivitamin containing vitamin D.
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"Golden Opportunity to Fight Heart Disease." lownfoundation.org. Apr. 2008. Lown Cardiovascular Research Foundation. 6 Oct. 2008. <http://www.lownfoundation.org/content/view/248/78/>.
Martins, David, Myles Wolf, Deyu Pan, Ashraf Zadshir, Naureen Tareen, Ravi Thadhani, Arnold Felsenfeld, Barton Levine, Rajnish Mehrotra, and Keith Norris. "Prevalence of Cardiovascular Risk Factors and the Serum Levels of 25-Hydroxyvitamin D in the United States." Archives of Internal Medicine 167:11(2007):1159-65. 30 Sep. 2008 <http://archinte.ama-assn.org/cgi/content/short/167/11/1159>.
"National Center for Health Statistics: Heart Disease." cdc.gov. 8 Aug. 2008. Centers for Disease Control. 30 Aug. 2008 <http://www.cdc.gov/nchs/fastats/heart.htm>.
"The Nutrition Source: Vitamin D." hsph.harvard.edu. 2008. Harvard School of Public Health. 30 Sep. 2008 <http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/vitamin-d/>.
Wang, Thomas J., Michael J. Pencina, Sarah L. Booth, Paul F. Jacques, Erik Ingelsson, Katherine Lanier, Emelia J. Benjamin, Ralph B. D'Agostino, Myles Wolf, and Ramachandran S. Vasan. "Vitamin D Deficiency and Risk of Cardiovascular Disease." Circulation 117:4(2008):503-11. 30 Sep. 2008 <http://circ.ahajournals.org/cgi/content/short/CIRCULATIONAHA.107.706127v1>.