Benefits
More Bifidobacteria in the Gut at 8 g a Day
In a placebo-controlled trial in 43 healthy adults aged 45 to 65, Synergy1 at 8 g a day for 4 weeks raised fecal bifidobacteria, and counts differed from maltodextrin at 4 weeks. In 219 children aged 3 to 6, 6 g a day of an Orafti short plus long chain fructan for 24 weeks left Bifidobacterium about 20% higher than placebo. These are changes in gut bacteria, not health outcomes by themselves.
Softer Stools in Young Children
In 219 children aged 3 to 6, 6 g a day of an Orafti short plus long chain fructan for 24 weeks gave softer stools, within the normal range, from week 12 onward. In a pilot trial in 2 to 5 year olds with constipation (17 finished), 4 g a day of Orafti fructans for 6 weeks softened stools versus maltodextrin. BENEO funded both trials.
Calcium Absorption and Bone Mineral Gain in Young Adolescents
In a 1-year trial in pubertal boys and girls, 8 g a day of Synergy1 (as identified by a review) raised calcium absorption versus maltodextrin by 8.5 points at 8 weeks and 5.9 at 1 year, and whole-body bone mineral content and density rose more. A 3-week trial in 59 girls also found higher absorption, but a 3-week trial in 14 girls who already absorbed calcium well found none.
Calcium and Magnesium Absorption in Postmenopausal Women
In a 6-week crossover trial in 15 postmenopausal women with a mean age of 72, Synergy1 raised calcium and magnesium absorption versus placebo and bone turnover markers rose from baseline. Only about two-thirds of the women responded, mostly those with lower spine bone density. Changes in bone density and fractures were not measured.
Body Fat in Children Over 16 Weeks
In a single trial in 42 children aged 7 to 12 with overweight or obesity, 8 g a day of oligofructose-enriched inulin (Synergy1 in the trial registry) for 16 weeks lowered percent body fat by 2.4% versus a 0.05% rise on maltodextrin, and body weight z-score by 3.1%. In a 12-week trial in women with obesity, 16 g a day of Synergy1 did not change BMI.
Mechanism of action
Fermentation by Colon Bacteria
Inulin and oligofructose pass the small intestine undigested and are fermented by colon bacteria. In Synergy1 trials, bifidobacteria rose in adults and children; a systematic review of these trials records that fecal short-chain fatty acids rose in one trial, did not change in others and fell in another.
Mineral Uptake in the Large Intestine (Animal Work)
In rats fed Synergy1, calcium crossed the cecum more readily, cecal pH fell and calcium transport genes changed, as summarized in a review. This is animal work; in people the calcium response varied, and only about two-thirds of postmenopausal women responded.
Water and Gas in the Lower Gut
Fructans, the carbohydrate class that includes inulin and oligofructose, are among the rapidly fermentable carbohydrates (FODMAPs) that bring fermentable material and water to the end of the small intestine and the colon, which can cause distension, gas and bloating in sensitive people.
Clinical trials
Randomized, placebo-controlled parallel trial: 8 g/day of a short plus long chain inulin-type fructan product versus maltodextrin for 1 year, with calcium absorption measured by stable isotopes and bone mineral by DXA. The abstract does not name the product; a review identifies it as Synergy1, taken in calcium-fortified orange juice at breakfast. PubMed lists NIH grant support, and the authors were at the USDA/ARS Children's Nutrition Research Center. (Abrams et al. 2005, Am J Clin Nutr)
Pubertal boys and girls aged 9 to 13 (95 listed in the review's table).
Calcium absorption was higher than with placebo at 8 weeks (by 8.5 percentage points, P < 0.001) and at 1 year (by 5.9 points, P = 0.04). Over the year, whole-body bone mineral content rose 35 g more (P = 0.03) and whole-body bone mineral density 0.015 g/cm2 more (P = 0.01). Children with the ff vitamin D receptor genotype responded least. Fractures were not studied.
Randomized, double-blind crossover trial in a metabolic unit: a calcium-fortified cereal with or without 9 g/day oligofructose-enriched inulin, two 3-week periods separated by a 2-week washout, about 1,500 mg/day calcium on both diets. A review identifies the product as Synergy1. (Martin et al. 2010, J Am Coll Nutr)
14 healthy girls aged 11 to 13.
Calcium absorption (67% versus 66%) and calcium retention did not differ between diets. The authors suggest the girls' already high calcium absorption may explain the lack of response.
Double-blind, placebo-controlled crossover trial: Synergy1 (a spray-dried mix of chicory oligofructose and long-chain inulin, named in the abstract) or placebo for 6 weeks each, with dual stable isotope absorption tests and bone turnover markers. Two reviews list the dose as 10 g/day; funding is not stated in the abstract. (Holloway et al. 2007, Br J Nutr)
15 postmenopausal women, mean age 72.
Calcium and magnesium absorption rose more than with placebo (P < 0.05). A bone resorption marker rose above baseline and the bone formation marker osteocalcin rose at 6 weeks. Only about two-thirds responded; responders had lower lumbar spine bone density, and marker changes occurred only in them.
Single-center, randomized, double-blind, placebo-controlled trial of oligofructose-enriched inulin versus an isocaloric maltodextrin placebo once daily for 16 weeks; primary outcome change in percent body fat by DXA (NCT02125955, where the product is listed as Synergy 1). Europe PMC lists funding from the Canadian Institutes of Health Research, the Alberta Children's Hospital Foundation and Research Institute, and a BMO endowed research fund; the registry lists the University of Calgary as sponsor. (Nicolucci et al. 2017, Gastroenterology)
42 children aged 7 to 12 above the 85th BMI percentile but otherwise healthy (22 prebiotic, 20 placebo).
Percent body fat fell 2.4% versus a 0.05% rise on placebo, body weight z-score fell 3.1% versus a 0.5% rise, and percent trunk fat fell 3.8% versus a 0.3% fall on placebo, all significant. IL-6 fell 15% versus a 25% rise on placebo, and Bifidobacterium rose versus placebo. A companion paper found BMI z-score only trended lower in the intention-to-treat analysis (P = 0.09).
Randomized, placebo-controlled trial: Orafti Synergy1 8 g/day versus maltodextrin for 4 weeks, the first phase of an 8-week vaccination study. A later paper from the trial states that Beneo-Orafti supplied the sachets, lists Beneo-Orafti as a funder, and discloses consulting fees from Beneo-Orafti to the senior author. (Lomax et al. 2012, Br J Nutr)
43 healthy adults aged 45 to 65 (22 Synergy1, 21 placebo).
Fecal bifidobacteria rose in the Synergy1 group (P < 0.001) and differed from placebo at 4 weeks (P = 0.001). No immune measure changed, including immune cell subsets, antibodies, phagocytosis, natural killer cell activity and T cell responses. After vaccination, the later paper found a higher response to one of three vaccine strains but no other antibody differences.
Randomized, placebo-controlled trial over a winter: 6 g/day of an Orafti inulin-type fructan product with shorter and longer chains (average chain length about 7 to 8; the paper does not use the name Synergy1) versus maltodextrin, stirred into food or drink (NCT03241355, sponsored by the Beneo-Institute). Supported by BENEO GmbH; three authors are or were BENEO employees. (Lohner et al. 2018, J Nutr)
270 kindergarten children aged 3 to 6 randomized; 219 finished.
At 24 weeks, relative Bifidobacterium was 19.9% higher than placebo (P < 0.001), and stools were softer within the normal range from week 12. The registered primary outcome was the frequency of infectious episodes: episodes reported by parents and their duration did not differ, while febrile episodes needing a doctor (0.65 versus 0.9 per child, P = 0.04) and sinusitis were less frequent.