Here's one reason eating a lot of red meat is a bad idea: researchers have found a strong association between heart disease and the type of iron that's found only in meat.
The iron in question is "heme iron" and a study by the Indiana University School of Public Health-Bloomington found that heme iron consumption increased the risk for coronary heart disease by 57%, while no association was found for nonheme iron, which is in plant and other non-meat sources.
The body treats the two kinds of iron differently. It can better control absorption of iron from vegetable sources, including iron supplements, but not so with iron from meat sources.
"Heme iron is absorbed at a much greater rate in comparison to nonheme iron (37% vs. 5%). Once absorbed, it may contribute as a catalyst in the oxidation of LDLs (low-density lipoproteins), causing tissue-damaging inflammation, which is a potential risk factor for CHD (coronary heart disease)," the researchers wrote.
It adds up
Iron stores in the body increase over time, they noted. The only way to reduce iron in the body is by bleeding, donating blood or menstruation. Some dietary choices, such as coffee and tea, also can inhibit iron absorption.
The study was published online ahead of print in the Journal of Nutrition. Along with first author Jacob Hunnicutt, a graduate student in the school's Department of Epidemiology and Biostatistics, the study's co-authors are Ka He and Pengcheng Xun, faculty members in the department.
Hunnicutt said the link between iron intake, body iron stores and coronary heart disease has been debated for decades by researchers, with epidemiological studies providing inconsistent findings. The new IU research, a meta-analysis, examined 21 previously published studies and data involving 292,454 participants during an average 10.2 years of follow-up