The Link Between Excess Iron and Diabetes
Iron deficiency anemia affects more than 3 million people per year in the U.S. However, a lesser known problem is too much iron, or iron overload. Iron overload affects 200,000 people per year in the U.S. This can be much more devastating, and even deadly if it goes untreated because it “rusts” the organs. It affects men more than women because men accumulate iron over a lifetime, whereas women lose iron from menstruation. After menopause, iron overload can become a problem for women as well. Many women are anemic through their menstruating years and are told to take iron, but are rarely told to come off it after menopause which can induce iron overload. There is a line of evidence building that shows a correlation between the development of diabetes due to excess iron.
We know there is a strong association between diabetes and cardiovascular disease. Iron overload may explain the uptick in heart attack of post menopausal women. The original theory was that estrogen had a protective effect on heart disease and replacement therapy was suggested. Researchers began to question the role of excess iron in heart disease. In 2002, a study was conducted that aimed to determine if phlebotomy (bloodletting) affected risk for heart disease. Iron depletion at near-deficiency levels were associated with a reduction of risk, and improvements in lipids were observed. Blood pressure reduced, triglycerides reduced, and there was also an increase in response to glucose and insulin. These are all metabolic markers, and these were completely revered with iron repletion.
Iron can easily become oxidized, so it acts as an oxidant. That means it takes poorly reactive free radicals and converts them into highly reactive ones. As iron accumulates in the body, it affects the pancreas and interferes with insulin synthesis, the hormone that regulates blood sugar. This is a two way street meaning that insulin stimulates cellular uptake of iron creating a sort of vicious circle.
There are some other clues that iron overload affects blood sugar negatively. Excess iron also deposits into muscle and damages it, inhibiting its ability to uptake glucose. Type 3 diabetes is a newer term for dementia due to diabetes. Excessive iron has been found in patients with Alzheimer's. Gout has been linked to insulin resistance, and phlebotomy (blood donation) leads to a decrease in gout flare ups.
It’s important to note that iron is the least sensitive marker for iron, ironically. Only about 1% of the body’s iron is floating in the serum. Ferritin is the storage molecule for iron and is a much more reliable marker for iron stores. However, when the body is inflamed it will store more iron in ferritin because viruses and bacteria replicate with bacteria. It’s a protective mechanism but that can lead to a false positive if you are inflamed. So you have to look at other markers of inflammation and correlate it.
Elevated ferritin levels have been linked to insulin resistance in even seemingly healthy people. In one study, ferritin was proportional to glucose concentration, blood pressure, and HDL. In epidemiological studies, the higher the ferritin levels, the higher the incidence of type 2 diabetes.
Signs of iron overload are vague and overlap with many disease processes which makes it impossible to diagnose with symptoms alone. Fatigue, joint pain, impotence or loss of libido, skin bronzing, palpitations, depression, and abdominal pain. These are just some of the symptoms and because of its ability to damage all organs, the symptoms can vary wildly.
So how do we accumulate iron? It can come from excess consumption, either from the diet or from supplementation. Or, we absorb too much of it. This is called hemochromatosis. Hemochromatosis is a genetic defect (one of the most common) causing the body to absorb more iron that it needs. Unfortunately, it’s often misdiagnosed or completely missed altogether. The average person will wait 9 years for a correct diagnosis. So what is hemochromatosis? The mutations C282Y and H63D are the genetic snips that can cause hemochromatosis. If you’ve had a DNA test and want to find out if you are at risk for hemochromatosis, you can download our worksheet here.
Outside of hemochromatosis, there are some diet choices that may increase iron absorption. This includes food high in vitamin C, beta carotene, HCL supplements (digestive enzymes), red meat and liver, sugar, and alcohol. So these can be strategies if you are iron deficient, but should be avoided when your ferritin levels are high.
Bloodletting, or blood donation is a reliable way to reduce iron stores. It also reduces blood viscosity, which is a risk for heart attack. Anecdotally, many have reported weight loss with frequent blood donation. This may be more evidence of the correlation between iron and diabetes.
If you are worried about excess iron, let’s hop on a free functional medicine consult call:
References:
Eugene D. Weinberg. (2008) Iron Out-of-Balance: A Risk Factor for Acute and Chronic Diseases. Hemoglobin 32:1-2, pages 117-122.
Facchini FS, Saylor KL. Effect of iron depletion on cardiovascular risk factors: studies in carbohydrate-intolerant patients. Ann N Y Acad Sci. 2002 Jun;967:342-51. doi: 10.1111/j.1749-6632.2002.tb04290.x. PMID: 12079862.
José Manuel Fernández-Real, Georgina Peñarroja, Antoni Castro, Fernando García-Bragado, Ildefonso Hernández-Aguado, Wifredo Ricart; Blood Letting in High-Ferritin Type 2 Diabetes : Effects on Insulin Sensitivity and β-Cell Function. Diabetes 1 April 2002; 51 (4): 1000–1004. https://doi.org/10.2337/diabetes.51.4.1000
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