Inulin Modifies Gut Microbiota, Fecal Lactate Concentration and Fecal pH But Does Not Influence Iron Absorption in Women With Low Iron Status

Prebiotics are non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth or activity of species in the colon that can improve host health.

Inulin-type fructans (inulin and oligofructose) are natural food ingredients with prebiotic activity. Fermentation of inulin and oligofructose by lactic acid producing bacteria results in an increase in bacterial biomass and the production of SCFA (acetate, propionate and butyrate), lactic acid and the gases CO2 and H2. They are naturally present in significant amounts in several vegetables such as garlic, artichoke, onion, asparagus, leek and wheat (1-4%). Based on consumption data, the daily intake of inulin in Europe varies between 3.2 and 11.3g mainly from wheat (2-7.8g/d). However, this might have changed recently since inulin and oligofructose are used by the food industry either as sucrose and fat replacements or due to their health benefits for the human host.

Several human absorption studies evaluated the effect of inulin/oligofructose on mineral absorption. It was shown that calcium and magnesium absorption was positively influenced. Until now, the positive effect on iron absorption was only shown in animals. The influence on human iron absorption was investigated twice. Both studies reported no effect of inulin/oligofructose on iron absorption, but this was most likely due to poorly conceived study designs.

The aim of the present study is to demonstrate that inulin consumption over several weeks can lead to enhanced iron absorption in humans under optimized conditions.