研究發現維生素K-1對心血管健康的益處

Study Finds Vitamin K-1 Cardio-Health Benefits

July 2009

Supplements of vitamin K-1 may slow hardening of the arteries in people already suffering from the condition, according to a new study.

Subjects receiving a daily vitamin K-1, plus multivitamin supplement experienced six percent less progression of coronary artery calcification (CAC), or hardening of the arteries that leads to atherosclerosis and cardiovascular disease, than people receiving only the multivitamin.

Researchers led by Sarah Booth from the USDA Human Nutrition Research Center on Aging at Tufts University wrote in the American Journal of Clinical Nutrition that such benefits were independent of changes in levels of a protein called matrix GLa protein (MGP).

MGP is a regulator of calcium formation in the circulatory system. MGP is a vitamin K-dependent protein—meaning vitamin K is required to activate this protein.

Booth and her co-workers recruited 388 healthy subjects with evidence of CAC. The subjects were randomly assigned to receive vitamin K-1, plus multivitamins or only multivitamins for three years.

Overall, no significant differences in the groups were observed. However, in people with pre-existing CAC who took at least 85% of the assigned supplements experienced a retardation of CAC progression of six percent, compared to the control group. Such decreases occurred independently of changes in serum MGP, said Booth and her co-workers.

"Vitamin K supplementation reduced the progression of existing CAC in asymptomatic older men and women when taken with recommended amounts of calcium and vitamin D. The mechanisms by which vitamin K conferred a protective role are still uncertain," wrote the researchers.

"Larger studies in other populations are needed to confirm these findings, and to assess the risks and benefits of vitamin K supplementation on clinical CVD (cardiovascular disease)," they concluded.

The study was supported financially by the U.S. Department of Agriculture, Agricultural Research Service, the National Institutes of Health and the American Heart Association. The other researchers were affiliated with Tufts University, the National Heart, Lung and Blood Institute’s Framingham Heart Study, Massachusetts General Hospital and the University of California, San Diego.

American Journal of Clinical Nutrition 89(6):1799-1807, 2009
http://www.swansonvitamins.com/health-library/articles/cardiovascular-health/study-finds-vitamin-k-1-cardio-health-benefits.html?SourceCode=INTHIR329