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Title: Resistant starch does not affect zinc homeostasis in rural Malawian children

item MAY, THADDAEUS - Baylor College Of Medicine
item WESTCOTT, CLAIRE - University Of Colorado
item THAKWALAKWA, CHRISSIE - University Of Malawi
item ORDIZ, M ISABEL - Washington University
item MALETA, KEN - University Of Malawi
item WESTCOTT, JAMIE - University Of Colorado
item RYAN, KELSEY - Washington University
item HAMBIDGE, K MICHAEL - University Of Colorado
item MILLER, LELAND - University Of Colorado
item YOUNG, GRAEME - Flinders University
item MORTIMER, ELISSA - Flinders University
item MANARY, MARK - Children'S Nutrition Research Center (CNRC)
item KREBS, NANCY - University Of Colorado

Submitted to: Journal of Trace Elements in Medicine and Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2015
Publication Date: 4/1/2015
Citation: May, T., Westcott, C., Thakwalakwa, C., Ordiz, M.I., Maleta, K., Westcott, J., Ryan, K., Hambidge, K.M., Miller, L.V., Young, G., Mortimer, E., Manary, M.J., Krebs, N.F. 2015. Resistant starch does not affect zinc homeostasis in rural Malawian children. Journal of Trace Elements in Medicine and Biology. 30:43-48.

Interpretive Summary: Rural Malawian children consume a plant based diet and are at high risk for intestinal inflammation which can cause zinc deficiency. Resistant starch is a common food additive which in other settings reduces intestinal inflammation. Resistant starch was added to 20 children’s daily diets in rural Malawi and zinc absorption was quantified which is a complex clinical procedure. Resistant starch was shown not to improve zinc absorption.

Technical Abstract: This study tested the hypothesis that Malawian children at risk for zinc deficiency will have reduced endogenous fecal zinc (EFZ) and increased net absorbed zinc (NAZ) following the addition of high amylose maize resistant starch (RS) to their diet. This was a small controlled clinical trial to determine the effects of added dietary RS on zinc homeostasis among 17 stunted children, aged 3-5 years consuming a plant-based diet and at risk for perturbed zinc homeostasis. Dual zinc stable isotope studies were performed before and after 28 d of intervention with RS, so that each child served as their own control. The RS was incorporated into fried wheat flour dough and given under direct observation twice daily for 28 d. Changes in zinc homeostatic measures were compared using paired Student's t-tests and linear regression analysis. Children had a mean height-for-age Z-score of -3.3, and consumed animal source foods twice per month. Their habitual diet contained a phytate:zinc molar ratio of 34:1. Children avidly consumed the RS without complaints. EFZ was 0.8+/-0.4mg/d (mean±SD) both before and after the intervention. Fractional absorption of zinc was 0.38+/-0.08 and 0.35+/-0.06 before and after the RS intervention respectively. NAZ was 1.1+/-0.5 and 0.6+/-0.7 before and after the RS intervention. This reduction of NAZ corresponded with diminished dietary zinc intake on the study day following intervention with RS. Regression analysis indicated no change in zinc absorption relative to dietary intake as a result of the RS intervention. Consumption of RS did not improve zinc homeostasis in rural African children without zinc deficiency. RS was well tolerated in this setting.