The effect of proteins from animal source foods on heme iron bioavailability in humans

•Heme iron from RBC concentrates is better absorbed than heme iron from hemoglobin.•Heme iron absorption is decreased when ingested with fish and chicken meat.•Collagen, casein and albumin did not affect the heme iron absorption.

Forty-five women (35–45 year) were randomly assigned to three iron (Fe) absorption sub-studies, which measured the effects of dietary animal proteins on the absorption of heme Fe. Study 1 was focused on heme, red blood cell concentrate (RBCC), hemoglobin (Hb), RBCC + beef meat; study 2 on heme, heme + fish, chicken, and beef; and study 3 on heme and heme + purified animal protein (casein, collagen, albumin). Study 1: the bioavailability of heme Fe from Hb was similar to heme only (∼13.0%). RBCC (25.0%) and RBCC + beef (21.3%) were found to be increased 2- and 1.6-fold, respectively, when compared with heme alone (p < 0.05). Study 2: the bioavailability from heme alone (10.3%) was reduced (p < 0.05) when it was blended with fish (7.1%) and chicken (4.9%), however it was unaffected by beef. Study 3: casein, collagen, and albumin did not affect the bioavailability of Fe. Proteins from animal source foods and their digestion products did not enhance heme Fe absorption.