Is Vitamin K the New Vitamin D?

Over the past several years, monitoring vitamin D levels for optimal health and well-being has become commonplace. Dr. Deanne Minich, an internationally recognized teacher, author, scientist, and speaker in the fields of nutrition and functional medicine, believes that the next vitamin to receive similar attention is vitamin K.

Vitamin K is best known as a factor in blood clotting, but recent research suggests that it has a number of other important functions. Vitamin K comes in two forms. Vitamin K-1 is found in leafy greens and in cashews, avocados, blueberries, blackberries, and lentils. Vitamin K-2 is found in fermented foods, cheese, chicken liver, meat, and eggs. The gut microbiome also produces a small amount of K-2.

From a recent study that looked at 2,092 men and 2,214 women over age 20, researchers concluded that a large portion of the population is not getting adequate vitamin K. According to this study, only 42% of men and 62.5% of women had an adequate vitamin K intake, with men over 51 years old reporting the lowest intake levels. In addition, vitamin K insufficiency and deficiency can result from blood thinners and other medications, such as warfarin, a medication to treat heart disease. As a result, even more people may have low levels of vitamin K.

Insufficient levels of dietary vitamin K may lead to higher risks of several chronic diseases.

A review of study data found that an increase in K-2, but not K-1, had an inverse relationship on aortic calcification and all-cause mortality, suggesting K-2 may be protective against cardiovascular disease. Another study of post-menopausal women similarly found that K-2 was associated with a lower risk of coronary calcification. Further, those with chronic kidney disease are at high risk of aortic and coronary calcification because the kidney disease may contribute to the vitamin K deficiency, which in turn increases arterial calcification.

Recent studies have found that deficiency and insufficiency of vitamin K plays a role in the development of diabetes and metabolic syndrome. In a ten-year study, researchers found that those with the highest K-2 intake levels had lower rates of metabolic syndrome. In another study, there was a reduced occurrence of type-2 diabetes in participants who consumed higher levels of K-1 from a Mediterranean diet. Individuals who increased their intake of vitamin K had a 51% reduction in the risk of developing diabetes compared to those that decreased or kept their vitamin K intakes the same.

Vitamin K also may have an impact on brain health. One study focused on vitamin K antagonists, like warfarin, showed a 15% higher risk of cognitive impairment when they were being used. Another study of 320 elderly men and women found those with higher serum levels of K-1 had better results on verbal episodic memory tests.

It is well known that vitamin K plays an important role in making bones strong, but joints also benefit from vitamin K as a result of its regulation of cartilage mineralization. In a study of knee osteoarthritis, researchers found 14.5% of participants with a vitamin K deficiency at the beginning of the study developed osteoarthritis even though they did not have the disease at the study’s onset.

Research shows that vitamin K is important to overall health, but screening for and prescribing vitamin K is not so straightforward. Unlike vitamin D, there is no simple single biomarker to measure vitamin K levels. So, it is important to consume a variety of leafy green vegetables, cheese, and fermented foods to help ensure an intake of both K-1 and K-2. Those on medications that impact vitamin K levels should discuss with their practitioner how to mitigate such effects and avoid the resulting health risks of vitamin K deficiencies.