Scientists have discovered a strong association between heme iron – found in red meat, fish, poultry – and potentially deadly coronary heart disease.
The study by the Indiana University School of Public Health-Bloomington found that heme iron consumption increased the risk for coronary heart disease by 57 per cent. There was no association between nonheme iron, which is found in plant and other non-meat sources, and coronary heart disease, researchers said.
The study first author Jacob Hunnicutt, a graduate student in the school’s Department of Epidemiology and Biostatistics, 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 research, a meta-analysis, examined 21 previously published studies and data involving 292,454 participants during an average 10.2 years of follow-up. The new study is unique because it looks at the associations of total iron consumption as well as heme and nonheme iron intake in comparison to the risk of coronary heart disease.
The only positive association involved the intake of heme iron, researchers said. 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. “The observed positive association between heme iron and risk of CHD may be explained by the high bioavailability of heme iron and its role as the primary source of iron in iron-replete participants,” researchers said.
“Heme iron is absorbed at a much greater rate in comparison to nonheme iron (37 per cent vs 5 per cent).”Once absorbed, it may contribute as a catalyst in the oxidation of LDLs, causing tissue-damaging inflammation, which is a potential risk factor for CHD,” they said. The study was published in the Journal of Nutrition.