New Opportunities for Prebiotic Ingredient

OraftiSynergy1, a second-generation prebiotic, is an oligofructose-enriched inulin, combining a specific ratio of chicory long-chain inulin and oligofructose, for enhanced nutritional benefits.

Inulin and oligofructose are food components, naturally present in many edible fruits and vegetables, such as onions, garlic, leeks, asparagus, wheat, bananas, artichokes and chicory. Native chicory inulin is extracted industrially from the root of the chicory plant (Cichorium intybus) and it can be partially hydrolysed to produce oligofructose. OraftiSynergy1, a second-generation prebiotic, is an oligofructose-enriched inulin, combining a specific ratio of chicory long-chain inulin and oligofructose, for enhanced nutritional benefits.

Inulin and oligofructose are classified as ‘non-digestible carbohydrates’ and are recognised as dietary fibres in most countries worldwide. They reach the colon intact, where they are completely fermented by bacteria colonising the large bowel. Through their fermentation and stimulation of bacterial growth, inulin and oligofructose improve bowel habits. In humans, their selective ability to stimulate intestinal bifidobacteria (bifidogenic & prebiotic effect) has been repeatedly demonstrated in well-controlled intervention studies, with a dosage as low as 5 g/day. However, a difference in the rate of fermentation appears between fructan components with a different chain length distribution. Oligofructose is rapidly fermented, and hence this metabolic process is thought to take place in the proximal part of the colon. Longer-chain inulin molecules, on the other hand, show a slower fermentation rate and reach more distal parts of the colon, which are primarily susceptible to colonic chronic disease. Oligofructose-enriched inulin (OraftiSynergy1) combines both short-chain oligofructose and long-chain inulin and results in a wider spread and more sustained fermentation pattern that will benefit a more extended length of the colon.

By selectively modifying the composition of the gut microflora, inulin-type fructans, especially OraftiSynergy1, can influence the risk of chronic colonic disease and have been shown to reduce inflammation in ulcerative colitis (Furrie et al. 2005), or disease activity in Crohn’s disease (Lindsay et al. 2006). Promising results have also been obtained in patients with increased colon cancer risk in a double-blind placebo-controlled trial where OraftiSynergy1, in combination with probiotics, once again proved its prebiotic effect and positively altered several risk markers for colon cancer (Rafter et al. 2007). The fermentation process of inulin-type fructans does not only benefit the gastrointestinal tract, but it creates favourable metabolic conditions that positively modulate mineral absorption (mainly calcium) and improve host health ‘beyond the gut’.

Several studies using experimental animal models have demonstrated that inulin-type fructans, especially OraftiSynergy1, have the ability to increase calcium and magnesium absorption, as well as bone mineralisation. One study compared several inulin-type fructans (oligofructose, long-chain inulin and Synergy1) and showed that although all three components increased calcium absorption, the highest benefit was observed with oligofructose-enriched inulin (OraftiSynergy1) combining both shorter and longer fructan chains (Coudray et al. 2003).

In humans, several intervention studies have confirmed the observations made in rats. In 29 adolescent girls (11-14 years) supplemented with calcium (daily intake of 1500 mg/d), Griffin et al. (2002) saw a significant effect on calcium absorption with a low dose of OraftiSynergy1 (8 g/d), but not with oligofructose given at the same dose for 3 weeks. The intake of OraftiSynergy1 resulted in 38.2% true calcium absorption compared to 32.2% in the placebo group (p=0.01). Griffin et al. (2003) extended the results of this study by recruiting an additional pool of 25 girls in a study with a protocol identical to the previous one, so that finally 54 adolescents were involved. The results confirmed the beneficial impact of OraftiSynergy1 on true fractional calcium absorption compared with the placebo (36.1% vs. 33.1%; p<0.05).

Holloway et al. (2007) supplemented 15 postmenopausal women with 6 gram of either OraftiSynergy1 or a placebo twice a day for 6 weeks, in a randomised cross-over design. A significant increase (p<0.05) for both calcium and magnesium absorption was observed following the ingestion of Synergy1 compared to the placebo. The treatment was also found to positively affect markers of bone turnover.

The most important findings come from a study demonstrating that the enhancement of calcium absorption consecutive to OraftiSynergy1 intake leads to an increased bone mineralisation. A total of 100 adolescents in early puberty (aged 9 to 13 years old) were involved in a 1-year randomised, double-blinded intervention study, performed by Abrams et al. (2005). During the whole intervention period, the subjects were supplemented with 8 g/d of OraftiSynergy1 or a placebo (maltodextrin). True calcium absorption was significantly enhanced after 8 weeks in the Synergy1 group (38.5%) compared to the placebo group (30%) and this beneficial effect was maintained during the whole year (37.7% for Synergy1 vs. 31.7% for controls) (p<0.05). At the end of the experimental period, the supplementation with Synergy1 resulted in a greater increment in whole-body bone mineral content (change: 245 g/yr vs. 210 g/yr) and whole-body bone mineral density (change: 47 mg/cm2/yr vs. 32 mg/cm2/yr) (p=0.01). The net benefit of supplementation in calcium accretion to the skeleton was an average of approximately 30 mg/d. Abrams et al. (2007a) have recently confirmed that increased calcium absorption in response to Synergy1 intake primarily originates in the colon. All together, these data highlight the potential for OraftiSynergy1 in increasing calcium absorption and bone mineralisation.

Experimental data have recently accumulated demonstrating that inulin-type fructans, and in particular oligofructose and Synergy1, are able to modulate the expression of gut hormones (and their subsequent release into the blood) that are involved in appetite regulation. Amongst these hormones, glucagon-like peptide-1 (GLP-1) and grehlin have been investigated in animal studies. It was shown that the addition of oligofructose or Synergy1 (10%) to the diet of animals significantly lowered energy (and food) intake which was accompanied by lower body fat mass development in growing rats and lower fat deposition coming from high-fat diets. These effects occurred together with an increased expression of GLP-1 in the colon and/or portal blood (Cani et al. 2004; 2005). One study has shown that the plasma levels of grehlin remained significantly lower in oligofructose and Synergy1 fed rats, compared to the control group. The production of GLP-1 might obviously constitute a link between the outcome of fermentation in the colon and the modulation of food intake (Cani et al. 2006a). The effects of inulin-type fructans on appetite and energy intake were ultimately investigated in humans, in a placebo-controlled intervention study including 10 healthy volunteers (8 gram of oligofructose twice daily).  Oligofructose intake resulted in increased satiety after breakfast and dinner (p<0.05), as well as reduced hunger and prospective food consumption at dinner (p≤0.05). This led to a lower total energy intake during the day (p=0.05) as compared to the control group (Cani et al. 2006b). Data of a 1-year intervention trial in adolescents (n=100) further showed that the administration of OraftiSynergy1 (8 g/d) resulted in a significantly lower body mass index (BMI), lower body weight and lower body fat mass (p<0.05) compared with the placebo group, thus supporting adequate weight management during early adolescence (Abrams et al. 2007b).These data highlight the importance of food ingredients that act on the gut-brain axis in modulating appetite and hence body weight.

References

Abrams SA, Griffin IJ, Hawthorne KM et al.  (2005) A combination of prebiotic short- and long-chain inulin-type fructans enhances calcium absorption and bone mineralization in young adolescents. American Journal of Clinical Nutrition 82: 471- 476.

Abrams SA, Hawthorne KM, Aliu O et al.  (2007a) An inulin-type fructan enhances calcium absorption primarily via an effect on colonic absorption in humans. Journal of Nutrition 137: 2208-2212.

Abrams SA, Griffin IJ, Hawthorne KM et al. (2007b) Effect of prebiotic supplementation and calcium intake on body mass index. The Journal of Pediatrics 151: 293-298.

Cani PD, Dewever C & Delzenne NM (2004) Inulin-type fructans modulate gastrointestinal peptides involved in appetite regulation (glucagon-like peptide-1 and ghrelin) in rats. British Journal of Nutrition 92: 521-526.

Cani PD, Neyrinck AM, Maton N et al.  (2005) Oligofructose promotes satiety in rats fed a high-fat diet: involvement of glucagon-like peptide-1. Obesity Research 13: 1000-1007.

Cani PD, Knauf C & Iglesias MA (2006a) Improvement of glucose tolerance and hepatic insulin sensitivity by oligofructose requires a functional glucagon-like peptide 1 receptor. Diabetes 55: 1484-1490.

Cani PD, Joly E, Horsmans Y et al. (2006b) Oligofructose promotes satiety in healthy human: a pilot study. European Journal of Clinical Nutrition 60: 567-572.

Coudray C, Tressol JC, Gueux E et al. (2003) Effects of inulin-type fructans of different chain length and type of branching on intestinal absorption and balance of calcium and magnesium in rats. European Journal of Nutrition 42: 91-98.

Furrie E, MacFarlane S, Kennedy A et al.  (2005) Synbiotic therapy (Bifidobacterium longum/Synergy1) initiates resolution of inflammation in patients with active ulcerative colitis: a randomised controlled pilot trial. Gut 54: 242-249.

Griffin IJ, Davila PM & Abrams SA (2002) Non-digestible oligosaccharides and calcium absorption in girls with adequate calcium intakes. British Journal of Nutrition 87 (Suppl. 2): S187-S191.

Griffin IJ, Hicks PMD, Heaney RP et al.  (2003) Enriched chicory inulin increases calcium absorption mainly in girls with lower calcium absorption. Nutrition Research 23: 901-909.

Holloway L, Moynihan S, Abrams S et al. (2007) Effects of oligofructose-enriched inulin on intestinal absorption of calcium and magnesium and bone turnover markers in postmenopausal women. British Journal of Nutrition 97(2): 365-372.

Lindsay JO, Whelan K, Stagg AJ et al. (2006) Clinical, microbiological, and immunological effects of fructo-oligosaccharide in patients with Crohn’s disease. Gut 55: 348-355.
 
Rafter J, Bennett M, Caderni G et al. (2007) Dietary synbiotics reduce cancer risk factors in polypectomized and colon cancer patients. American Journal of Clinical Nutrition 85: 488-496.