GEN-IRON-FISH · Effects of consuming fish on iron bioavailability in women with the G277S transferrin gene mutation

Final Activity Report Summary - GEN-IRON-FISH (Effects of consuming fish on iron bioavailability in women with the G277S transferrin gene mutation)

Iron deficiency anaemia is usually caused by low iron absorption from the diet rather than from inadequate iron intake. Genetic variants in the iron regulatory system may affect iron absorption, and hence the likelihood of iron deficiency. Transferrin is the most important protein carrier of iron in blood plasma. The G277S transferrin mutation was shown to influence iron metabolism and could increase the risk of iron deficiency anaemia. Iron in food presents two chemical forms, namely haem and non-haem. Haem iron is absorbed efficiently showing the greatest bioavailability, whereas non-haem iron is subject to a variety of dietary influences that may enhance or inhibit its uptake. Fish does not contain high levels of iron but rather certain components that enhance non-haem iron absorption. The objective of this project was to study the effect of sous-vide processed fish on non-haem iron absorption from vegetables in a group of white pre-menopausal women with low iron stores who were predisposed to iron deficiency anaemia. The subjects were screened for single ethnic background of European ancestry, with either the G277S/G277S or the G277S/G277G genotype for the transferrin gene, and compared with a control group with similar haematological characteristics who did not carry the G277S mutation (wild type G277G/G277G). Iron absorption was measured using stable isotopes and the erythrocyte incorporation technique. 162, non-smoking, 18 to 45 year-old, non-pregnant, white, menstruating women were screened and measurements of serum ferritin and haemoglobin concentration and deoxyribonucleic acid (DNA) analysis were performed. 16 women presented genotype G277G/G277S and 146 women G277G/G277G. Although we did not find any homocygote mutant, i.e. G277S/G277S, the percentages of iron-deficient menstruating white women within each transferrin genotype that were obtained in this study, i.e. 18.8 % and 13 % for G277S/G277G and G277G/G277G respectively, were in the same range as those described by Lee et al in 2001, who worked with a much larger group of white women, with the sample equalling n=1,511. The prevalence of iron deficiency was higher in women with genotype G277S/G277G compared to G277G/G277G. However, in our study group, the presence of the G277S transferrin mutation itself was not a relevant risk factor for iron deficiency anaemia. By using DNA sequencing techniques, not only the G277S mutation but also other mutations, namely L247L and H268H, in exon 7 in the transferrin gene were obtained. The iron absorption trial took place in 10 women with genotype G277S/G277G and in 15 women with genotype G277G/G277G using stable isotope methodology. The samples were being processed by the time of the project completion. The results would be presented, regarding the effects of both the mutation and fish intake on iron absorption.

Data: CORDIS, © European Union