Iron deficiency rescued by the "meat factor"?
By Anne Dorthe Sørensen
Iron deficiency is one of the most prevalent worldwide public health problems. In European countries, the prevalence of iron deficiency is 10 to 40 % among women of childbearing age, and 6 to 40 % among teenage girls and the prevalence is much higher in developing countries. The consequences are serious for both children and adults. In infants and children it may affect the mental development and learning abilities and may also affect behavioural and physical development. In adults it will lead to diminished work capacity, impaired concentration ability, higher susceptibility to infections and deceases including longer recovery time due to reduced capability of the immune function.
While iron supplementation is generally considered an effective curative strategy for combating iron deficiency, several adverse effects are associated with the very low iron bioavailability of these iron supplements. Specifically, the high levels of iron contained within these supplements, meant to offset their low iron bioavailability, result in relatively large amounts of unabsorbed iron present in the intestinal lumen where iron may participate in redox reactions and formation of radicals with the possibility of performing oxidative damage.
Utilisation of the unique properties of meat components to enhance nonhaem iron bioavailability, commonly designated the "meat factor", could provide an approach to decrease the amount of iron used in supplementation or increase non-haem iron bioavailability in pork-based food products that may reduce the prevalence of iron deficiency in dietary prevention strategies.
Interest in the "meat factor" is not a new issue. Research within this area has been done since 1950 and maybe even before. This demonstrates that the "meat factor" story is a complex and complicated issue that puzzles the researchers. Three major issues are often debated. The first issue is the uncertainty concerning the origin of the "meat factor", which generates a long list of unanswered questions. Is it a protein, carbohydrate or lipid? Is it one component or a combination of components that are responsible for the special effects in meats? Is it general for all types/varieties of meats? The second major issue is how to quantify and confirm the existence of "meat factor" activity. The third major issue is that the "meat factor" effect tends to disappear when using certain methods to separate meat components in the attempt to isolate fractions with "meat factor" activity.
In Q-PorkChains WP III.1.c the overall aim is to characterise the "meat factor" with focus on the three major issues raised here. In this study, it is assumed that the "meat factor" originates from protein – as the muscle protein is digested to peptides in the gastro intestinal tract it performs its action e.g. enhancing iron bioavailability. The effects of test samples on iron bioavailability are predicted by models mimicking digestion which correlates qualitatively with studies on iron absorption in humans. Finally, methods suitable to separate meat components and preserving the "meat factor" effect has been established. Now the meat factor enhanced effect remains to be confirmed in a human single meal intervention study.