Can vitamin K supplements help protect against heart disease?

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Q. I have read that vitamin K supplements can help prevent heart disease. Should I take them?

A. Vitamin K — which is found in high levels in green leafy vegetables like spinach, kale, and romaine lettuce — plays a role in helping the body make blood clotting proteins. Although some observational studies have suggested a heart benefit from diets high in vitamin K, studies of supplements have not shown a protective effect.