A new study by Jane Lukacs of the University of Michigan School of Nursing suggests that the impairment of vitamin K function could compromise bone health and contribute to the development of osteoporosis. The study found that one of the early effects of declining estrogen is the impairment of vitamin K function in bone even before any bone loss that could be attributed to menopause can be measured.
"Our study suggests that the generally accepted level of vitamin K in healthy women is inadequate to maintain bone health just at the onset of menopause," Lukacs said.
Vitamin K is essential for making a bone protein called osteocalcin fully functional. This protein is part of the bone structure when it is "carboxylated" (a chemical modification of the protein that changes its shape making it easy to bind to calcium) in the presence of sufficient vitamin K. With adequate vitamin K, this protein can bind to calcium in the bone environment—sort of like glue, Lukacs said.
Vitamin K is good for the bones of guys too.
Check out what the Harvard School of Public Health says about vitamin K. The Nurse's Health Study showed a diet high in vitamin K slashes the risk of bone breaks.
Lately, researchers have demonstrated that vitamin K is also involved in building bone. Low levels of circulating vitamin K have been linked with low bone density, and supplementation with vitamin K shows improvements in biochemical measures of bone health.(31) A report from the Nurses' Health Study suggests that women who get at least 110 micrograms of vitamin K a day are 30% less likely to break a hip as women who get less than that.(32) Among the nurses, eating a serving of lettuce or other green leafy vegetable a day cut the risk of hip fracture in half when compared with eating one serving a week. Data from the Framingham Heart Study also shows an association between high vitamin K intake and reduced risk of hip fracture.(33)
Optimal Intake: The recommended daily intake for vitamin K is 80 micrograms for men and 65 for women. Because this vitamin is found in so many foods, especially green leafy vegetables and commonly used cooking oils, most adults get enough of it. According to a 1996 survey, though, a substantial number of Americans, particularly children and young adults, aren't getting the vitamin K they need.(34)
Note that the 65 mcg recommended daily intake is probably too low for post-menopausal women. So what to do about it? 3 and a half ounces of kale or swiss chard will give you over 800 mcg of vitamin K. Spinach will give you half that amount. Collard greens and turnip greens are also very high sources of vitamin K. Parsley, broccoli, and brussel sprouts are all good vitamin K sources as well.
|Share |||Randall Parker, 2006 October 01 07:28 PM Aging Diet Studies|