Study shows low vitamin K levels linked to mobility limitation, disability, in aging population
Low levels of circulating vitamin K are linked to increased risk of mobility limitation and disability in older adults, identifying a new factor to consider for maintaining mobility and independence in older age, according to a new study by researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Massachusetts. The study was published in the Journal of Gerontology: Medical Sciences.
The study examined two biomarkers, circulating levels of vitamin K, phylloquinone, and a functional measure of vitamin K, plasma ucMGP. Using participant data from the Health, Aging, and Body Composition Study (Health ABC), researchers looked at 635 men and 688 women ages 70 to 79 years old. In Health ABC, mobility was assessed every six months for six to ten years through annual clinic visits and phone interviews in the intervening time.
For the new analysis, researchers defined mobility limitation as two consecutive semi-annual reports of having any amount of difficulty either with walking a quarter of a mile or climbing 10 steps without resting, and mobility disability as two consecutive semi-annual reports of having a lot of difficulty or inability to walk or climb the same amount.
The study found that older adults with low levels of circulating vitamin K were more likely to develop mobility limitation and disability. The other biomarker, plasma ucMGP, did not show clear associations with mobility limitation and disability. Specifically, older adults with low circulating vitamin K levels were nearly 1.5 times more likely to develop mobility limitation and nearly twice as likely to develop mobility disability compared to those with sufficient levels. This was true for both men and women, according to the study abstract.
Circulating vitamin K levels reflect the amount of vitamin K in the diet. The best food sources of vitamin K include leafy greens such as spinach, kale, and broccoli, researchers said. For an average adult, one cup of raw spinach provides 145 micrograms (mcg) of vitamin K1, or 181 percent of the Daily Value; one cup of raw kale provides 113 mcg, or 141 percent; and half of a cup of chopped boiled broccoli provides 110 mcg, or 138 percent.