Really interesting video on vitamin D3. Apparently, most of us are now deficient and we are not taking enough. Gives advice on safe higher doses.
I'd also recommend the book, "The Miraculous Effects of High Doses of Vit D3 and K2..."
By Jeff Bowles.
Also "Vitamin K2 and the Calcium Paradox - How a Little Known Vitamin Could Save your Life" , by Katie Rheame.
Also the following, which seems to indicate why it is so important to take K2 with higher doses of D3:
"Laura Jones, a global food science analyst at Mintel, says recent research has revealed Vitamin K2 has much broader health benefits than previously thought, and is increasingly being seen as a bone health ingredient.
"Vitamin K1 has a relatively short half-life and is rapidly cleared from the blood and is cleared by the liver within eight hours. In comparison vitamin K2 has a longer half-life of up to 72 hours, meaning it remains biologically active in the body for longer.
"Vitamin K2 is also absorbed better by the body, and is linked to cardiovascular health. It directs calcium to the bones, and prevents it from being deposited where it shouldn't be, for example arteries and organs, where it can cause harm," she says. "
Vitamin K2 contributes to maintenance of normal bone and Vitamin K1 contributes to normal blood coagulation.
K2 found in high amounts in fish, seafood, cod liver oil, milk and dairy, cooked veg - especially soups, legumes - especially lentils.