There is an incredibly strong connection between Vitamin D and Iron, despite the fact that you’ve probably never heard about it before. Many people think of nutrients like drugs. You are given a drug, but for the drug to work, it generally does not need other drugs or use up nutrients. It’s just supposed to be a ‘magic pill’ that solves the problem, although in reality it rarely does.
Nutrients, however, are much more complex than that; nutrients often require other substances in the body in order to work properly. These substances, which are often other nutrients, are called ‘cofactors’ and they are vital to how nutrients work in the body. Without these cofactors, many times people can remain deficient in a nutrient despite eating and supplementing a particular vitamin and mineral, even at a high dose.
Vitamin D and Iron are Cofactors of Each Other
Case in point is our discussion here. Interestingly, the relationship between Vitamin D and Iron possibly runs both ways, as the research suggests that each are cofactors for each other. If you don’t have enough vitamin D, you can’t absorb iron properly; if you don’t have enough iron, you can’t have adequate vitamin D levels.
When I first discovered that iron and Vitamin D are dependent upon each other, I had to admit that I was a bit confused. It doesn’t seem as though the two nutrients have any similarities that should make them require each other, but once I began doing research on anemia and iron, I put the pieces together.
The Master Iron Regulator
Possibly one of the most interesting things about iron metabolism is that it is controlled by a master iron regulator called Hepcidin. This substance was only discovered in the 1990’s, which is probably one of the reasons that you’ve never heard about it, and it’s nuances are still being figured out by scientists. Please read more about it on our Hepcidin page since understanding it is truly vital to understanding how iron is regulated in the body.
In a nutshell, when hepcidin goes up, iron absorption goes down and vice versa. How does Vitamin D fit into this? Vitamin D is one of the few nutrients that can reduce hepcidin levels and allow more iron to be absorbed. We discuss this phenomenon more on the Why Doctors are Leaving African Americans Anemic. Vitamin D is truly an important indirect controller of iron metabolism by being able to reduce hepcidin levels fairly dramatically, up to 35% with a single dose, which allows iron to be absorbed more readily.
Vitamin D Regulates Inflammation
Another way that vitamin D indirectly regulates iron metabolism is that vitamin D reduces the inflammatory response in the body. And inflammation can dramatically reduce iron absorption. In fact, it’s such a well-known phenomenon that doctors even have classified a type of anemia called Anemia of Chronic Disease that recognizes inflammation as one of the Causes of Iron Deficiency Anemia.
So, any substance that can reduce the inflammatory response can help to improve iron absorption, and vitamin D fits this bill, making 2 ways that vitamin D helps to improve iron absorption and prevent anemia. Pretty cool huh?
How Does Iron Influence Vitamin D Levels
But what about the other way around, what about iron levels influencing Vitamin D? Does the Vitamin D and iron connection go both directions? Interestingly, I had been studying Vitamin D for years when I found out that I was seriously iron deficient and began researching anemia. In all of the years of studying Vitamin D, imagine my surprise when I came across the information that Vitamin D influences iron absorption, a fact that I’d never heard before.
Fortunately, I’d been keeping my vitamin D in the optimal ranges, so vitamin D deficiency was not a contributing factor to my own iron deficiency, however, I still found the connection fascinating and is important to pass along to others who may be both have Iron Poor Blood and have low Vitamin D levels and not understand why they are having problems bringing their levels up. Although part of this problem may be that they have not been DIAGNOSED with iron deficiency because the Definition of Anemia is not actually about being iron deficient.
I was even more shocked when I was poking around the Vitamin D Wiki site for references on the iron and vitamin D relationship when I found not only that vitamin D deficiency can lead to anemia, but that anemia can also contribute to low vitamin D levels in a feedback loop that runs both ways! I thought that the study must be mistaken, but it was clear that this study on infants who were both anemic and vitamin D deficient were given JUST iron and their vitamin d levels increased as well 1. Who knew that the Vitamin D and Iron connection went both ways?
“[M]ild iron-deficiency anemia may impair fat
absorption including vitamin D, which is fat
soluble, and hence decrease vitamin D
concentrations in the plasma.”
Effect of iron on serum Vitamin D
The researchers speculated that it may have been because iron has been shown in other studies to improve the intestinal absorption of other fat soluble vitamins, such as vitamin K and A. Unfortunately, a study on anemic adult women did not have the same results and correcting their anemia did not raise their Vitamin D Levels 2.
Perhaps the loop that has iron increase vitamin d levels only works in children, or perhaps there were some other, unknown factors at play in the first study, such as the mothers taking their children out in the sun and not reporting it, that were influential in vitamin D levels rising when iron was given. We’ll have to wait and see if future studies elucidate this mechanism further or if we discover the findings were not repeatable.
In any case, more and more, I find that so many nutrients are cofactors of each other such that if someone is deficient in one nutrient, they are almost certainly going to be deficient in many. In fact, Iron Deficiency Symptoms and Symptoms of Vitamin D deficiency are remarkably similar anyway, and this may be because anyone who is deficient in one is likely deficient in the other. This is one of the reasons that we discourage anyone from just taking ONE single supplemental nutrient, even if their doctor cannot find a deficiency of any other nutrients.
For one thing, most ‘regular’ medical testing does not directly discover nutrient deficiencies, even if doctors look for them. Secondly, like with the Vitamin D and Magnesium connection, taking high doses of one nutrient can diminish the levels of another, leading to uncomfortable side effects or new health problems. So, we recommend at least get a yearly Vitamin D Level, you can even get one done in your own home with an In Home Vitamin D Test and getting on the proper Multivitamin With Iron and a separate Vitamin D Supplement since Vitamin D and Iron are so important for iron absorption. But even just putting your existing lab work through our Blood Chemistry Analysis Program can help you to find nutrient deficiencies your doctor never knew could be discovered on the standard blood testing you probably already have.