If you spend much time on bodybuilding forums across the internet, you will inevitably run into discussions about “heme iron” and how it may help or hinder your lifting progress. You may also notice a small but vocal group of folks who insist that heme iron can have terrible consequences for your health.

Of course, your first question when encountering this type of discussion is likely, “What the heck is heme iron?”.

Let’s find out and then take a look at what it can do for, or TO, your health.

What Is Heme Iron?

Iron is vital to a healthy body because it’s the main vehicle for carrying oxygen in your blood to all parts of your body. As with most substances in your body, you need to get iron from the foods you eat.

According to the National Institutes of Health, dietary iron exists in two forms: heme and nonheme. Heme iron is found mainly in animal products and is absorbed much more readily than nonheme iron, which is found mostly in plant-based foods. The main structural difference between the two types of iron is that heme iron has been combined with  protoporphyrin IX, a potent biochemical “carrier” that helps shuttle nutrients from one place to another in the body.

So that’s the basic idea of heme iron, but what about health concerns?

To find out, there are at least a couple of  areas we need to consider, and where scientific research has been done.

Heart Disease

One of the problems with  heme iron consumption that is often cited has to with the risk of cardiovascular disease, or CVD.

There are plenty of studies that look into the association between red meat consumption and heart disease, and while you can find arguments on both sides, the results tend to depend on how and how much red meat is eaten.

Red meat is a major source of heme iron for many people, so these studies might also give us some insight into the effects of heme iron on CVD. To examine this issue, Chinese researchers conducted a literature review in 2015 and found that, among more than 250,000 total subjects and about 15,000 cases of CVD, elevated consumption of heme iron does appear to be associated with an increase in CVD risk. They found no such relationship between nonheme iron and CVD.

Cancer

The other major type of disease often associated with heavy meat consumption is cancer, and specifically colon cancer. As with heart disease, there has been some evidence uncovered over the years that eating meat may put at least some people at risk for the disease. And again, by association, some have wondered whether heme iron could be a problem.

Researchers from the Netherlands set out to examine this idea in 2013 and reviewed about five years of data for more than 4000 subjects in the Netherlands Cohort Study. What they found was that the consumption of heme iron may indeed be positively correlated with the incidence of colorectal cancer (CRC).

Is Heme Iron Bad?

All of this sounds fairly bleak, so does that mean that heme iron IS bad for you?

Well, first consider that any long-term study that uses dietary habits as one of its inputs relies on self-reported behavior by subjects. People often forget or exaggerate what they have done or not done, so it’s unlikely that researchers got  a completely accurate picture of how the subjects ate.

Consider, too, that you NEED iron to stay healthy, and that heme iron is more absorbable than nonheme iron.

Weighing all the evidence, it’s most likely that most people can handle at least moderate amounts of red meat — and heme iron — without suffering terrible health consequences. Of course, talk to your doctor to find out if you have any issues which might make heme iron especially troublesome for you, but don’t necessarily assume that it’s terrible for you based on solely on internet conversations.

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