However, no effect on calcium absorption was observed, in disagreement with previous studies, which has reported a positive effect of prebiotics on calcium absorption, report the researchers in Nutrition Research.
“Magnesium absorption was increased in 12- to 15-year-old girls by 18 per cent after 36 days of an average 7 grams per day of short chain-FOS intake,” wrote the researchers from TNO Quality of Life and Cargill Research and Development Center.
“The absence of an effect on calcium absorption in this study may be due to habitual intake that was too low,” they added.
The study was welcomed by prebiotic expert Professor Glenn Gibson from the University of Reading as well-done and needed.
Prof. Gibson, who first coined the term 'prebiotic' in 1995 with Marcel Roberfroid from the Catholic University of Louvain, told NutraIngredients.com: “Human studies that are well done are needed to show the health effects or probiotics and prebiotics. This is one such study and has used good recruiting, control and analyses to show improved magnesium absorption in adolescent girls following intake of a known prebiotic.
“It is often stated that prebiotics do not have proven health benefits, yet studies such as this show that this is clearly not the case,” added Prof Gibson.
Study details
Researchers led by TNO’s Henk Hendriks recruited 14 teenage girls aged between 12 and 14, and randomly assigned them to receive either 10 grams of short chain-FOS (Actilight, Syral) or a maltodextrin placebo for 36 days in a cross-over design trial. The prebiotics were taken daily for 8 days, followed by random and intermittent intake over the next 28 days to “mimic non-continuous intake”, said the researchers. This random intake equated to an average daily intake of seven grams per day, said the researchers.
Results showed that magnesium absorption was increased by an average of 18 per cent after 36 days following FOS consumption, with no change after the initial 8 day period. No changes following the placebo were observed.
No effects on calcium absorption were observed. Hendriks and his co-workers report that the girls in this study had a low habitual calcium intake, which may explain the discrepancy with other published data. In addition, no effects on vitamin D, parathyroid hormone, or markers of bone resorption were observed.
Responding to the lack of an effect on calcium, Prof Gibson said this was “contrary to other published data.
“It would be very interesting to ascertain the mechanisms of effect behind improved mineral bioavailability following prebiotic ingestion. This would help understand some of the contradictory data,” he said.
Growing market
Prebiotic ingredients, or those that boost the growth of beneficial probiotic bacteria in the gut, are worth about €90 million in the European marketplace but are forecast to reach €179.7 million by 2010, according to Frost & Sullivan.
The big inulin producers have been influential in building the science behind inulin and oligofructose, backing research into potential benefits for a variety of health conditions ranging from bones to colorectal cancer, from immunity to satiety and weight management.
The chicory root is the major source of prebiotic ingredients. Inulin and oligofructose are the two major ingredients sourced from the root that is mainly grown in Belgium and Northern France where the world’s ‘big three’ suppliers are based.
Beneo-Orafti, Cosucra and Sensus dominate the market and supply almost all of the world’s inulin and oligofructose.
Source: Nutrition Research Volume 29, Issue 4, Pages 229-237"Short-chain fructo-oligosaccharides improve magnesium absorption in adolescent girls with a low calcium intake" Authors: Ellen G.H.M. van den Heuvel, Theo Muijs, Fred Brouns, Henk F.J. Hendriks