Q: I have heard that it is essential to take vitamins K2 and A with vitamin D. Is this true?
A: In a word, yes! The nutritional rumour mill has got the facts right on this one. Here’s why you’ll get the most out of your “sunshine vitamin” when combined with these other vital nutrients.
We’ve all heard so much about vitamin D in the last couple of years. It’s a well-established immune-supportive nutrient. It plays many critical roles in maintaining our defences against seasonal illness. There are receptors for vitamin D directly on white blood cells, and people who are vitamin D deficient get colds and flu more often. Vitamin D is also famous for being a foundational bone-building nutrient. It helps us absorb calcium and encourages the activity of bone-building cells, called osteoblasts.
Vitamin A has its own, often underappreciated role in immune health. The “A” originally came from the term “anti-infective,” as this nutrient’s discoverers immediately recognized its central role in preventing contagious illness. As for bone health, vitamin A encourages the activity of bone breakdown cells, called osteoclasts. That sounds like it would be bad for bone health, but removing old, weak, or damaged bone tissue is essential for maintaining strong bones. We need both vitamins D and A for healthy bone turnover.
Last but not least, vitamin K2 has unique actions that complement both vitamins A and D. For example, vitamin D helps us absorb calcium but has no control over where that calcium goes. K2 directs calcium toward bones and teeth while guiding it away from soft tissues like arteries, where it would be harmful. Vitamin K2 also keeps those osteoclasts in check, so they don’t break down too much bone. Vitamins D and K2 together have a synergistic effect on bone health. They have been shown to be more helpful in strengthening bone mineral density than either nutrient alone.
To learn more about this dynamic triad of fat-soluble vitamins, check out my book Vitamin K2 and the Calcium Paradox: How A Little-Known Vitamin Could Save Your Life.
Best-selling author and licensed naturopathic doctor Kate Rhéaume is a graduate and former faculty member of the Canadian College of Naturopathic Medicine. Dr. Kate lectures internationally on many topics related to health and wellness, and is a frequent guest on radio and television across North America.
 Kuang X, Liu C, Guo X, et al. The combination effect of vitamin K and vitamin D on human bone quality: A meta-analysis of randomized controlled trials. Food Funct. 2020; 11(4):3280-97.