After menopause, a woman’s risk for diabetes and heart disease goes up. One likely culprit is the loss of estrogen because of menopause. But another factor also may play an important role—excess iron.
Background: After menopause, women are at higher risk for metabolic syndrome, a cluster of symptoms including abdominal obesity and high blood sugar, often due to insulin resistance. The syndrome increases the risk of developing diabetes and heart disease.
Why does the risk go up after menopause? It’s true that the loss of estrogen is known to negatively affect the lining of blood vessels in ways that increase many of these risk factors. But another line of evidence points to excess iron as an additional risk factor. Because iron in blood is no longer lost with each menstrual cycle, iron levels generally increase after menopause. Korean researchers set out to determine whether there was a statistical link between high iron levels, insulin resistance and metabolic syndrome.
Study: 2,734 postmenopausal women in a large health database all had extensive exams that included blood samples, so the researchers could sort them into four groups based on blood levels of ferritin, a protein that’s a marker for body levels of iron. They then analyzed ferritin levels against rates of insulin resistance and metabolic syndrome.
Results: After the researchers adjusted for other known factors (age, smoking, drinking and amount of exercise), it was evident that women with the highest levels of ferritin, compared to women with the lowest levels, were…
- More than twice as likely to have insulin resistance
- Almost twice as likely to have metabolic syndrome.
What’s so bad about excess iron? It promotes oxidation (think: rust), which can lead to body-wide inflammation—and that in turns increases all the above risk factors. Plus, there is evidence that too much iron may interfere with normal glucose and insulin activity in muscles. Because this is an observational study, however, it can’t determine whether high ferritin levels cause insulin resistance/metabolic syndrome—or are simply a marker for these risk factors.
Bottom line: The authors advise that getting your iron level checked—it’s part of a regular checkup anyway—could be an early tip-off to these risk factors. Then you can take lifestyle steps, including weight loss if needed, that can independently reduce your risks.
You may also want to talk with a nutritionist about your diet. After menopause, a woman’s daily iron requirement goes from 18 mg to 8 mg. However, recent research has found that some postmenopausal women may still be at risk for iron deficiency anemia—an issue best dealt with by eating more iron-rich foods.
In particular, be cautious about your vitamin/mineral supplement(s). According to the National Institutes of Health, postmenopausal women should not take a supplement that includes iron unless they have been diagnosed with iron deficiency. If you are concerned about anemia, get tested and discuss with your doctor whether supplementing with iron is appropriate for you.
You may also be interested in this Bottom Line article on the best multivitamin for people at high risk of diabetes.