Vitamin D tends to get all the hype about improving and protecting your bones. But there is growing evidence that the lesser-known vitamin K plays an important role in promoting bone density and reducing the risk of fractures.
Vitamin K is more often talked about in terms of blood clotting, which is necessary for wound healing and preventing blood loss. In fact, its name comes from the German clotting.
Lately it has been studied for its role in heart health and diabetes.
A study from Edith Cowan University, published in August, found that people who follow a diet rich in vitamin K have up to 34% less risk of cardiovascular disease linked to atherosclerosis (conditions affecting the heart or blood vessels).
A 2020 study suggests that vitamin K supplementation may reduce the risk of type 2 diabetes mellitus and improve insulin sensitivity.
Bone health, a more pressing issue
However, the relationship between vitamin K and bone metabolism (the cycle of growth and resorption of bone cells) is perhaps more pressing. It’s not just a matter of vitamin K improving bone health – insufficient intake actually harms your bones.
This has been known for over 20 years.
A 1999 study found that women who consumed less than 109 micrograms (mcg) of vitamin K per day were more likely to break their hips.
A 2003 study found an association between low dietary vitamin K intake and low bone density in women – and again, with an increased risk of hip fractures.
An adequate intake of vitamin K is considered to be 120 mcg for men and 90 mcg for women.
How to Get Vitamin K
Vitamin K comes in two forms: K1 and K2.
Vitamin K1 is mainly found in green, leafy and cruciferous vegetables.
Cruciferous vegetables include broccoli, cauliflower, cabbage, kale, bok choy, arugula, Brussels sprouts, collard greens, watercress, and radishes.
Half a cup of cooked kale provides 565 mcg of vitamin K1.
Half a cup of cooked spinach gives you 444 mcg.
So it is quite easy to get more than your daily needs.
But there are two issues to keep in mind:
You need to make this a daily habit because vitamin K is very soluble and is expelled from the body quite quickly.
Also, if you are taking blood thinners, a diet rich in vitamin K, with its blood-clotting function, may interfere with your medications. Please discuss this with your doctor.
Vitamin K2 is mainly produced by bacteria and is found in some dairy products, pork, poultry and fermented foods.
Vitamin K2 appears to have more bone-protective benefits than vitamin K1. But the body needs both, and a deficiency in either is detrimental.
And these benefits are likely most pronounced when vitamin K is consumed in tandem with vitamin D.
When it comes to supplements, as nutrition in a pill often goes, the jury is still out.