Does Iron Fuel Clogged Arteries? Lessons from 48,000 Autopsies

One of the most fascinating projects I worked on as a young researcher asked a deceptively simple question: Does iron fuel clogged arteries?

The idea wasn’t mine originally. It came from Dr. Jerome Sullivan, a prominent pathologist who proposed an intriguing theory. He noticed that women tend to have lower rates of heart disease than men—at least until menopause. Why? He believed the answer was iron. Every month, menstruation lowers women’s iron levels, and once that monthly blood loss stops, their risk of heart disease begins to climb. Sullivan suggested that iron could directly oxidize LDL (the “bad” cholesterol), making it stickier and more likely to form artery-clogging plaque.

That idea grabbed me. So, shortly after my training at Johns Hopkins, I asked another famed pathologist, Dr. Grover Hutchins, if I could test the theory by reviewing patients who had died at Johns Hopkins and had a history of iron overload. These patients either had hemochromatosis (a genetic condition where the body stores too much iron) or had received numerous blood transfusions. If iron really fueled heart disease, these patients should have been prime examples.

To investigate, I dug into history—literally. I reviewed the original autopsy reports dating back to 1889, with the first autopsy conducted by Dr. William Welch on a patient of Sir William Osler. In those early decades, heart disease was uncommon because infectious illnesses like pneumonia usually claimed lives before heart trouble could take hold. But by the 1960s, medicine had advanced, and many autopsy cases included postmortem angiograms and cholesterol levels, giving us much richer data to study.

After analyzing 48,000 autopsies between 1889 and 1992, our findings were striking. Iron overload by itself rarely caused coronary artery disease. However, in patients who also had high cholesterol, the picture changed: iron seemed to make LDL more dangerous, more prone to spark artery-clogging plaque. In other words, iron wasn’t guilty on its own, but in the presence of too much LDL, it played an important supporting role.

So what’s the takeaway? Iron in of itself does not promote coronary artery disease but rather, the combination of high iron and high cholesterol is where the real risk lies.

The good news is that with today’s tools—diet, exercise, and effective medications—lowering cholesterol (and high iron levels) are more achievable than ever. And if you can keep LDL levels in check, even excess iron doesn’t have to spell heart trouble.

Michael MIller, MD is a preventive cardiologist and author of “Heal Your Heart: The Positive Emotions Prescription to Prevent & Reverse Heart Disease”, published by Penguin Random House.