Senior nutrition: Vitamin K deficiency linked to mobility limitations in older adults, research finds

13 Jun 2019 --- Low levels of circulating vitamin K in the body are linked to an increased risk of mobility limitations and disability in older adults, identifying a new factor to consider for maintaining bodily functions in older age, according to a study led by researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University.

Specifically, older adults with low circulating vitamin K levels were nearly 1.5 times more likely to develop mobility limitation and almost twice as likely to develop mobility disability compared to those with sufficient levels. This was true for both men and women.

The study, published in the Journal of Gerontology: Medical Sciences, is the first to evaluate the association between biomarkers of vitamin K levels and the onset of decreased motor functions in older adults.

“Because of our growing population of older people, it's important for us to understand the variety of risk factors for mobility disability,” says Kyla Shea, first and corresponding author and a nutrition scientist in the Vitamin K Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University.

“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 continues.

Older adults with low levels of vitamin K more likely to develop mobility limitation and disability
The new study examines two biomarkers: circulating levels of vitamin K (phylloquinone) and a functional measure of vitamin K (plasma ucMGP). Using participant data from the previous 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.

“The connection we saw with low levels of circulating vitamin K further supports vitamin K's association with mobility disability,” says senior author Sarah Booth, a vitamin K and nutrition researcher, and director of the HNRCA. “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.”

The study used data from 635 men and 688 women aged 70-79, approximately 40 percent of whom were black, who participated in Health ABC, which assessed participants' mobility every six months for six to ten years through annual clinic visits and phone interviews in the intervening time. For the present analysis, the 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.

Circulating vitamin K levels reflect the amount of vitamin K in the diet. The best food sources of vitamin K are identified by the researchers as 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 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.

Growing market for Vitamin K in senior nutrition
Backed by newly emerging scientific evidence, Vitamin K is highly regarded in senior nutrition for its efficacy in aiding cardiovascular functions. According to research endorsed by the American Heart Association (AHA) and Natto Pharma, improving Vitamin K2 status may significantly alleviate arterial stiffening and calcification. In 2017, a study of 766 “otherwise healthy” adolescents revealed that those who consumed the least vitamin K1 were at 3.3 times greater risk for an unhealthy enlargement of the major pumping chamber of their heart.

Widely known for playing an integral role in the blood clotting process, research has also suggested that vitamin K may also have a critical role in bone health. Studies suggest that this nutrient plays an integral role in increasing bone strength and reducing the risk of fracture, according to a release by the Institute for Better Bone Health.

By Benjamin Ferrer

Vitamin K, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Journal of Gerontology: Medical Sciences