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

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.