Resistant starch does not affect zinc homeostasis in rural Malawian children.
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
Consumption of RS did not improve zinc homeostasis in rural African children without zinc deficiency. RS was well tolerated in this setting.
Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, United States.
Thaddaeus
T
May
Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States.
Claire
C
Westcott
Community Health Department, College of Medicine, University of Malawi, Blantyre, Malawi.
Chrissie
C
Thakwalakwa
Department of Pediatrics, Washington University in St. Louis, St. Louis, MO 63130, United States.
M Isabel
MI
Ordiz
Community Health Department, College of Medicine, University of Malawi, Blantyre, Malawi.
Ken
K
Maleta
Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States.
Jamie
J
Westcott
Department of Pediatrics, Washington University in St. Louis, St. Louis, MO 63130, United States.
Kelsey
K
Ryan
Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States.
K Michael
KM
Hambidge
Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States.
Leland V
LV
Miller
Flinders University, Australia.
Graeme
G
Young
Flinders University, Australia.
Elissa
E
Mortimer
Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, United States.|Department of Pediatrics, Washington University in St. Louis, St. Louis, MO 63130, United States.|Community Health Department, College of Medicine, University of Malawi, Blantyre, Malawi.
Mark J
MJ
Manary
Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States.
Nancy F
NF
Krebs
D002675:Child, Preschool; D005243:Feces / Q000737:chemistry; D005260:Female; D005502:Food; D006706:Homeostasis / Q000187:drug effects*; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects; D008295:Malawi; D008297:Male; D012044:Regression Analysis; D012424:Rural Population; D013213:Starch / Q000494:pharmacology*; D015032:Zinc / Q000378:metabolism*
D013213:Starch; D015032:Zinc
Endogenous zinc; Malawi; Resistant starch; Zinc; Zinc homeostasis