For my writings on vitamin K, start with the ultimate vitamin K2 resource:
The K2 resource has easy to read practical advice, click-to-expand technical explanations, cute infographics that explain the science in a fun way, supplement recommendations, and a searchable database of the K2 contents of foods.
The resource also has a corresponding podcast that focuses on the most recent developments in the science:
In 2007, I wrote On the Trail of the Elusive X Factor: A Sixty-Two Year Old Mystery Finally Solved (Vitamin K2 Revealed), an extensive article arguing that vitamin K2 was the “activator X” that Weston Price claimed to have discovered in 1945. Weston Price was one of the pioneers of nutritional anthropology, and many people had speculated about the identity of his “activator X” for decades. The article tells the history of that mystery and in the process extensively reviews the many roles of vitamin K and its interactions with other important nutrients like vitamins A and D.
After these, I recommend reading reading this article on how vitamin K interacts with other nutrients like vitamins A and D, zinc, magnesium, carbohydrate, fat, and metabolic factors like carbon dioxide and thyroid hormone:
Soon after the 2007 article, I published a hypothesis paper arguing that vitamin D toxicity causes soft tissue calcification by causing a relative deficiency of vitamin K:
Within a year, researchers at Tufts University investigated my hypothesis in the context of one of their mouse experiments, which confirmed a number my predictions:
Here are my blog posts on vitamin K: