Supplementation of Fructooligosaccharide Mildly Improves the Iron Status of Anemic Rats Fed a Low-Iron Diet

Fan Zhang,Stephen Sum Man Chung,Ken Kin Lam Yung,Chi Kong Yeung

doi:10.4236/fns.2017.82019

Abstract

Also known as a prebiotic, fructooligosaccharide (FOS) resists digestion by gastric acid and pancreatic enzymes in vivo, but is preferentially fermented by beneficial intestinal bacteria once it reaches the colon. While some studies suggest that FOS and its fermentation products may influence the iron absorption process, the effects of prolonged FOS supplementation on iron status remain unclear. The objective of this study was therefore to determine the enhancing effects of FOS supplementation on the iron status of anemic rats. Male Sprague-Dawley rats receiving a low-iron diet (12 μg/g) for 14 days showed significantly lower hemoglobin concentration, as well as lower tissue non-heme iron levels than rats receiving a regular diet (45 μg/g), confirming iron-deficiency anemia. On the first day of the feeding trial, two groups of anemic rats (n = 6) were fed the same low-iron diet with or without FOS supplementation, while two other groups of anemic rats were switched to the regular diet with or without FOS supplementation to allow recovery. FOS was provided to the rats by dissolving in water at 5% (w/v). Anemic rats fed the low-iron diet showed a mild increase (p < 0.05) in hemoglobin level after 21 days of FOS supplementation when compared to rats without FOS. For anemic rats switched to the regular diet, hemoglobin level returned to normal after 14 days and FOS supplementation showed no additional effects. Our results suggest that FOS supplementation has a mild enhancing effect on the iron status of anemic subjects on a low-iron diet.

Highlights

Fructooligosaccharide (FOS), and several other non-digestible but soluble oligosaccharides such as lactulose and galactooligosaccharide, are known as prebiotics
While a stable isotope study by Patterson et al [10] with anemic piglets surgically fitted with cecal cannulas showed that FOS had no enhancing effect on iron absorption in the colon, Tako et al [11] observed that FOS supplementation triggered an upregulation of genes encoding iron transporters in the enterocytes from the duodenum and colon of anemic piglets
Perhaps owing to the difficulties and ethical concerns associated with studies on anemic human subjects, information about the effects of FOS on humans suffering from iron-deficiency anemia is lacking

Summary

Introduction

Fructooligosaccharide (FOS), and several other non-digestible but soluble oligosaccharides such as lactulose and galactooligosaccharide, are known as prebiotics. Prebiotics selectively stimulate the growth and activity of specific species of bacteria in the colon, usually Bifidobacteria and Lactobacilli, with benefits to health [1]. Langlands et al [2] showed that FOS supplementation of diets increased surface counts of Bifidobacteria and Lactobacilli in biopsy samples taken from the cecum, transverse and descending colon, and rectum of human subjects during colonoscopy. Prebiotics may have an enhancing effect on iron absorption and several biologically plausible mechanisms have been suggested [9]. While a stable isotope study by Patterson et al [10] with anemic piglets surgically fitted with cecal cannulas showed that FOS had no enhancing effect on iron absorption in the colon, Tako et al [11] observed that FOS supplementation triggered an upregulation of genes encoding iron transporters in the enterocytes from the duodenum and colon of anemic piglets. In another study using the porcine model, Samolińska and Grela [12] reported increases in iron, zinc and copper concentrations in blood plasma during the fattening period with FOS supplementation

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