How Vitamins A, D, E, and K Interact - Part 2: Playing Together Nicely
Posted Nov 19 2008 7:02am
In the last post, we explored the four fat-soluble vitamins - A, D, E, and K - and their effects on the body. Today, we’re going to look at a more important aspect of these vitamins: how they interact with each other. Just as with omega-3s and omega-6s, too much of one and not enough of the other can cause problems.
Can’t We All Just Get Along?
Calcification Recall that vitamin D helps the body absorb and use calcium. That’s all well and good as long as there is sufficient vitamin K to regulate the system. Without adequate vitamin K, whether due to deficient diet or drugs like blood thinners that interfere with K metabolism, vitamin D can cause soft-tissue calcification. This is particularly problematic when talking about heart valves and arteries. Vitamins A and D contribute to bone growth, while vitamin K ensures that the growth zones don’t become calcified too quickly, stunting growth.
Bone Health One thing that studies have shown is that vitamin A in excess is detrimental to bone strength. I have a feeling there’s more to the story than that though. My gut feeling is that vitamin A’s effects on bone strength are more directly related to a deficiency of vitamins D and K. Here’s my logic on that: vitamin D is necessary for absorption of calcium and building of strong bones. Along with that, vitamin K plays an important role in regulating the osteoclast/osteoblast balancing act. It inhibits the production of osteoclasts, while promoting the growth of osteoblasts, helping vitamin D perform its bone-building functions (osteoclasts break down bone, while osteoblasts build bone).
If you have excess vitamin A stimulating the production of osteoclasts, while vitamins D and K are deficient and unable to promote the production of osteoblasts, what happens? It’s a balancing act.
Anti-oxidant Effects As I mentioned previously, there is some research indicating that vitamin E’s most important role is as a signaling molecule, it’s commonly accepted function is largely as an antioxidant. It works to protect vitamin A from being changed by the intestines. Vitamin E also plays a role with vitamin C (which while not one of the fat-soluble vitamins, this fits the discussion). Namely, these two vitamins together produce marked increases in antioxidant activity than either vitamin flying solo.
Toxicity Chris Masterjohn points out that the fat-soluble vitamins protect the body from toxicity synergystically. That is, vitamin A protects against toxicity from the other vitamins, as does vitamin D and K.
Is Vitamin K The Real Key?
That’s just a skim of the surface of how these vitamins interact with each other and there’s no way I could discuss them all in this post. Nor is it possible even to find them all. Now, I want to touch on what may be the real question: is vitamin K the most important vitamin?
From reading Stephan’s articles on vitamin K and other such sources, it seems that vitamin K very well may be the most important vitamin of the group. Obviously it’s dangerous to say such a thing as an imbalance of K without adequate A and D is no better than the opposite, but K seems to play such an important role that without it, intake of the other vitamins is of much less importance.
In Chris Masterjohn’s excellent article on vitamin K 2, he discusses some of the mechanisms by which K 2 exerts its influence in improving the actions of vitamins A and D.
Osteocalcin, for example, is a protein responsible for organizing the deposition of calcium and phosphorus salts in bones and teeth. Cells only produce this protein in the presence of both vitamins A and D; it will only accumulate in the extracellular matrix and facilitate the deposition of calcium salts, however, once it has been activated by vitamin K2.
He further explains how vitamin K is necessary for dental health, growth, and protection from vitamin D toxicity. In fact, Dr. Price referred to vitamin K as “Activator X” (before it was scientifically identified) precisely because its inclusion in the diet seemed to improve the actions of other vitamins. Importantly, studies have shown that K 2 is the key form of the vitamin for humans, a point which we’ll come back to in the next post.
One More To Go
In the next post, I’m going to explore some of the best sources for these valuable fat-soluble vitamins. Stay tuned for some deliciousness.