Vitamin K occurs in different forms and has a variety of biological functions. A growing number of older people want to be able to manage on their own for as long as possible, which is why a team of scientists from Tufts University, USA, has taken a closer look at the risk factors that are known to impair mobility. The researchers discovered that lack of vitamin K is a serious problem. Other studies suggest that vitamin K deficiencies are quite widespread because older people tend to change their diet habits and use cholesterol-lowering medicine.
A growing number of seniors suffer from walking difficulty, osteoporosis, osteoarthritis and other mobility impairments that increase their risk of poor quality of life, falls, fractures, hospitalization and premature death. It is commonly known that low levels of vitamin K in the blood are linked to the development of chronic diseases such as atherosclerosis and osteoporosis, but the understanding of the mechanisms by which vitamin K affects our musculoskeletal function has been limited. Therefore, a team of scientists from Tuft University in the United States wanted a closer look, especially as earlier studies have shown that low blood levels of vitamin K are linked to slower walking speed in old age and an increased risk of osteoarthritis.
There are different forms of vitamin K. Their main function is to serve as co-factors in the production and activation of numerous vitamin K-dependent proteins.
Lack of vitamin K doubles the risk of mobility impairments
The Tufts University researchers gathered data from 635 men and 688 women in the age group 70-79 years. All were participants of the HEALTH ABC (Health, Aging and Body Composition) study. The scientists looked at two biological markers for vitamin K in the blood of the participants: Circulating levels of vitamin K1 (phylloquinone) and plasma levels of ucMGP.
Once every six months for a period of six to 10 years, the participants’ mobility was assessed through visits to the doctor and phone interviews. The severity of their impairment limitation was defined by looking at their ability to walk 250 meters, climb nine steps, and carry out similar basic physical activities.
The scientists could see that the participants with the lowest levels of circulating vitamin K1 (phylloquinone) were most likely to have mobility impairments and other disabilities such as osteoarthritis. No clear association was found with respect to the other biomarker, plasma ucMGP.
The seniors with low blood levels of vitamin K1 were nearly 50 percent more likely to develop mobility impairment and twice as likely to show signs of other mobility-limiting disabilities than those with adequate amounts of the vitamin in their blood. According to lead researcher Sarah Booth, the new study confirms older findings in terms of vitamin K and its importance for mobility and bone health. She suggests that the two biomarkers involved in the study may also be influenced by other known and unknown factors. The study is published in The Journals of Gerontology
Content of vitamin K1 in dietary sources according to the new study:
How much vitamin K do we need?
According to the Danish health authorities, the reference intake (RI) level for vitamin K1 is 75 micrograms per day for adults. There is no specific recommendation for vitamin K2. For prevention of osteoporosis and atherosclerosis, a daily dose of 75-90 micrograms is recommended.
If there is a suspicion of osteoporosis or atherosclerosis, it is normally advised to take a supplement with twice that amount – or around 150-180 micrograms per day.
Widespread lack of vitamin K and poor utilization
Although vitamin K deficiencies are considered to be rare, there are studies suggesting the opposite, and it is vitamin K2 in particular that directly influences our bones. Besides unhealthy eating habits and diets with few fermented products, a vitamin K deficiency may also occur after prolonged use of medical drugs such as antibiotics, antacids, acetylsalicylic acid, cholesterol-lowering statins, and anticoagulants that work as vitamin K antagonists. It is, however, important to stress that patients on blood thinners should never take supplements of vitamin K.
M Kyla Shea et al. Vitamin K Status and Mobility Limitation and Disability in Older Adults: The Health, Ageing, and Body Composition Study. The Journals of Gerontology: Series A, 2019
Tufts University, Health Sciences Campus. Low vitamin K levels linked to mobility limitation and disability in older adults. ScienceDaily. June 13, 2019
Solmaz Akbari. Vitamin K and Bone Metabolism: A Review of the Latest Evidence in Preclinical Studies. BioMed Research International 2018
Nutrition insight. Role of Vitamin K in Bone Health Underlined in New Study. Jun 2017
Henrik Hey. K2 vitamin anbefalinger og advarsler. 2016
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