Older adults with low vitamin K levels may face a higher risk of mobility disability, according to new research.

Vitamin K is found in leafy greens such as spinach and broccoli, as well as some dairy products. Previous studies linked vitamin K to long-term conditions that increase disability risk, including cardiovascular disease and osteoarthritis. However, this is the first study to examine the direct relationship between vitamin K and mobility disability in older adults.

The study, published in The Journals of Gerontology: Series A, was led by M. Kyla Shea, a vitamin K researcher at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, MA. Shea explains, “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.”

Vitamin K is a group of fat-soluble compounds. Phylloquinone, the main dietary form, is abundant in leafy greens. The researchers measured blood levels of phylloquinone and uncarboxylated matrix Gla protein (ucMGP), a protein that requires vitamin K. Levels of ucMGP rise when vitamin K is low.

The study used data from the Health ABC study, which assessed mobility every six months over 6 to 10 years. Mobility limitation was defined as experiencing any difficulty walking a quarter-mile or climbing 10 steps in two consecutive reports, while mobility disability was defined as a lot of difficulty or inability to complete the same tasks.

Results showed that participants with low phylloquinone levels were nearly 1.5 times more likely to develop mobility limitation and almost twice as likely to develop mobility disability compared with those with sufficient vitamin K. No clear relationship was found between ucMGP levels and mobility outcomes.

The researchers emphasize that further studies are needed to confirm these findings and better understand the mechanisms linking vitamin K to mobility in older adults.