What it is
Vitamin K is a fat-soluble vitamin.
What it does
Vitamin K primarily functions as a coenzyme in processes related to blood clotting and bone metabolism.
The recommended intake for vitamin K is 120mcg per day for men and 90mcg per day for women.
Likelihood of tracking completeness: Very low
Vitamin K is not a nutrient that food manufacturers are required to disclose on nutrition labels. The vast majority of food and beverage manufacturers do not voluntarily list vitamin K content on nutrition labels, so most branded products in the MacroFactor database lack information on vitamin K. So, if you’d like to accurately track your vitamin K intake, you’ll need to make a point of mostly tracking “common foods,” which come from research-grade databases that have full nutrient reporting.
For more on when you can track using branded foods versus common foods when you’re trying to accurately monitor your intake of particular nutrients, you should check out this article.
Likelihood of insufficient intake
Most adults in developed countries consume adequate amounts of vitamin K.
For more on nutrients with a greater likelihood of insufficient or excessive intake, you should check out this article.
Signs of deficiency
The most acute sign of vitamin K deficiency is generally the inability to stop bleeding, due to inadequate blood clotting. Over time, vitamin K deficiencies can result in osteoporosis as well.
There are two types of vitamin K, sometimes referred to as K1 and K2, that have similar biological functions. Green leafy vegetables are by far the best source of vitamin K1. Some fermented foods, most notably natto (a Japanese fermented soybean product), are the best sources of vitamin K2.
If you’d like to learn more about micronutrients generally, there’s a five-part series on the MacroFactor website you might enjoy.