Washington: Scientists have found that a low level of circulating vitamin K is associated with restricted mobility and disability in older adults. According to the study, this newly identified factor can be considered to maintain mobility and independence in old people.
The study was published in the 'Journal of Gerontology: Medical Sciences'. "Because of our growing population of older people, it's important for us to understand the variety of risk factors for mobility disability," said Kyla Shea, first and corresponding author on the study.
"Low vitamin K status has been associated with the onset of chronic diseases that lead to disability, but the work to understand this connection is in its infancy. Here, we're building on previous studies that found that low levels of circulating vitamin K are associated with slower gait speed and a higher risk of osteoarthritis," she continued.
The new 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), 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.
"The connection we saw with low levels of circulating vitamin K further supports vitamin K's association with a mobility disability," said senior author Sarah Booth. "Although the two biomarkers we looked at are known to reflect vitamin K status, biomarker levels can also be affected by additional known or unknown factors. Further experiments to understand the mechanisms of biomarkers and vitamin K and their role in mobility are needed," Booth added.
The study used data from 635 men and 688 women of ages 70-79 years, who participated in Health ABC. 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.
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 and some dairy products. For an average adult, one cup of raw spinach provides 145 micrograms (mcg) of vitamin K1 or 181 per cent of the daily value; one cup of raw kale provides 113 mcg or 141 per cent, and half of a cup of chopped boiled broccoli provides 110 mcg or 138 per cent.
