Iron Absorption from Iron-Biofortified Sweetpotato Is Higher Than Regular Sweetpotato in Malawian Women while Iron Absorption from Regular and Iron-Biofortified Potatoes Is High in Peruvian Women

Roelinda Jongstra,Martin N Mwangi,Gabriela Burgos,Christophe Zeder,Jan W Low,Glory Mzembe,Reyna Liria,Mary Penny,Maria I Andrade,Susan Fairweather-Tait,Thomas Zum Felde,Hugo Campos,Kamija S Phiri,Michael B Zimmermann,Rita Wegmüller

doi:10.1093/jn/nxaa267

Abstract

ABSTRACTBackgroundSweetpotato and potato are fast-maturing staple crops and widely consumed in low- and middle-income countries. Conventional breeding to biofortify these crops with iron could improve iron intakes. To our knowledge, iron absorption from sweetpotato and potato has not been assessed.ObjectiveThe aim was to assess iron absorption from regular and iron-biofortified orange-fleshed sweetpotato in Malawi and yellow-fleshed potato and iron-biofortified purple-fleshed potato in Peru.MethodsWe conducted 2 randomized, multiple-meal studies in generally healthy, iron-depleted women of reproductive age. Malawian women (n = 24) received 400 g regular or biofortified sweetpotato test meals and Peruvian women (n = 35) received 500 g regular or biofortified potato test meals. Women consumed the meals at breakfast for 2 wk and were then crossed over to the other variety. We labeled the test meals with 57Fe or 58Fe and measured cumulative erythrocyte incorporation of the labels 14 d after completion of each test-meal sequence to calculate iron absorption. Iron absorption was compared by paired-sample t tests.ResultsThe regular and biofortified orange-fleshed sweetpotato test meals contained 0.55 and 0.97 mg Fe/100 g. Geometric mean (95% CI) fractional iron absorption (FIA) was 5.82% (3.79%, 8.95%) and 6.02% (4.51%, 8.05%), respectively (P = 0.81), resulting in 1.9-fold higher total iron absorption (TIA) from biofortified sweetpotato (P < 0.001). The regular and biofortified potato test meals contained 0.33 and 0.69 mg Fe/100 g. FIA was 28.4% (23.5%, 34.2%) from the regular yellow-fleshed and 13.3% (10.6%, 16.6%) from the biofortified purple-fleshed potato meals, respectively (P < 0.001), resulting in no significant difference in TIA (P = 0.88).ConclusionsFIA from regular yellow-fleshed potato was remarkably high, at 28%. Iron absorbed from both potato test meals covered 33% of the daily absorbed iron requirement for women of reproductive age, while the biofortified orange-fleshed sweetpotato test meal covered 18% of this requirement. High polyphenol concentrations were likely the major inhibitors of iron absorption. These trials were registered at www.clinicaltrials.gov as NCT03840031 (Malawi) and NCT04216030 (Peru).

Highlights

Iron deficiency anemia (IDA) is a major cause of the global burden of disease in women [1]
In Peru, the average daily consumption (±SD) of the regular and iron-biofortified potato meals was 500 ± 1 g and 500 ± 0.5 g, respectively, resulting in a daily intrinsic iron intake of 1.63 ± 0.02 mg from the regular yellowfleshed potato meal and 3.47 ± 0.05 mg from the biofortified purple-fleshed potato meal. Both test meals contained some Phytic acid (PA) and ascorbic acid (AA) and high concentrations of PP, being 3.5-fold higher in the biofortified purple-fleshed meal compared with the regular yellow-fleshed meal (528 and 148 mg Gallic acid equivalents (GAEs), respectively)
The fractional iron absorption (FIA) of both the regular yellow-fleshed and biofortified purple-fleshed potato was above the expected 5–10% for plant-based diets in low- and middleincome countries (LMICs) [40] when consumed as a single-food test meal

Summary

Introduction

Iron deficiency anemia (IDA) is a major cause of the global burden of disease in women [1]. Results: The regular and biofortified orange-fleshed sweetpotato test meals contained 0.55 and 0.97 mg Fe/100 g. FIA was 28.4% (23.5%, 34.2%) from the regular yellow-fleshed and 13.3% (10.6%, 16.6%) from the biofortified purple-fleshed potato meals, respectively (P < 0.001), resulting in no significant difference in TIA (P = 0.88). Conclusions: FIA from regular yellow-fleshed potato was remarkably high, at 28% Iron absorbed from both potato test meals covered 33% of the daily absorbed iron requirement for women of reproductive age, while the biofortified orange-fleshed sweetpotato test meal covered 18% of this requirement. High polyphenol concentrations were likely the major inhibitors of iron absorption These trials were registered at www.clinicaltrials.gov as NCT03840031 (Malawi) and NCT04216030 (Peru).

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