Young adolescents who respond to an inulin-type fructan substantially increase total absorbed calcium and daily calcium accretion to the skeleton.
Calcium absorption and whole-body bone mineral content are greater in young adolescents who receive 8 g/d of Synergy, a mixture of inulin-type fructans (ITF), compared with those who received a maltodextrin control. Not all adolescents responded to this intervention, however. We evaluated 32 responders and 16 nonresponders to the calcium absorptive benefits of ITF. We found no differences in usual dietary calcium intakes. Responders who increased their calcium absorption by at least 3% after 8 wk of Synergy had a greater accretion of calcium to the skeleton over a year based on whole-body dual-energy x-ray absorptiometry data. The absorptive benefit to ITF use in responders is substantial and would be comparable to increasing daily calcium intake by at least 250 mg. Increased intake of ITF may be an important aspect of a multifaceted approach to enhancing peak bone mass.
Current data with inulin-type fructans and calcium, targeting bone health in adults.
In humans, there is increasing evidence that the colon can absorb nutritionally significant amounts of calcium, and this process may be susceptible to dietary manipulation by fermentable substrates, especially inulin-type fructans. Inulin-type fructans can modulate calcium absorption because they are resistant to hydrolysis by mammalian enzymes and are fermented in the large intestine to produce short-chain fatty acids, which in turn reduce luminal pH and modify calcium speciation, and hence solubility, or exert a direct effect on the mucosal transport pathway. Quite a few intervention studies showed an improvement of calcium absorption in adolescents or young adults by inulin-type fructans. In the same way, a positive effect has been reported in older women.
Prebiotics enhance magnesium absorption and inulin-based fibers exert chronic effects on calcium utilization in a postmenopausal rodent model.
Age-related changes in calcium metabolism play a role in the development of osteoporosis. A 4-wk feeding study was conducted in 5-mo-old ovariectomized (OVX) Sprague-Dawley rats to assess the effect of various dietary fibers on mineral metabolism and bone health parameters. There were 6 treatment groups: sham-Control, OVX-Control, OVX rats receiving daily estradiol (E₂) injections, and OVX rats receiving an AIN-93M diet supplement with either an inulin-based fiber (Synergy1® or Fruitafit HD®) or a novel fiber (polydextrose) at 5% wt. of diet. Calcium and magnesium metabolic balances were performed after early (3 d) and late exposure (4 wk) to dietary treatments. Rats receiving polydextrose had significantly higher net calcium absorption efficiency and retention than all control groups and a trend (P≤ 0.10) for higher calcium absorption when compared to inulin-based fibers after early exposure but the advantage did not persist over long-term exposure. The inulin-based fibers had positive chronic effects on calcium metabolism that were related to changes in the gut, that is, production of short chain fatty acids and higher cecal wall weights. All fibers improved magnesium absorption and retention in early and late metabolic balances; effects on magnesium metabolism were more pronounced than for calcium. PRACTICAL APPLICATION: Steady growth in US middle-aged and elderly populations has led to higher incidences of several chronic diseases including osteoporosis, a bone disease that primarily affects postmenopausal women. Recent research suggests that certain dietary fibers (prebiotics) enhance mineral absorption and may impart bone health benefits. This work examines the impact of prebiotic supplementation on mineral metabolism and bone health using a postmenopausal rat model. Study findings will aid future investigations in ascertaining the factors related to potential bone health benefits of prebiotic which will aid in developing an effective prebiotics food product/supplement that will address the bone health needs of consumers.
Legette LL, Lee W, Martin BR, Story JA…
J. Food Sci. Apr 2012 PMID: 22394255
Changes in calcium status in aged rats fed Lactobacillus GG and Bifidobacterium lactis and oligofructose-enriched inulin.
In this study we hypothesized that an increase in numbers of beneficial bacteria in the large intestine can affect calcium (Ca) status in the elderly. Adult and aged rats were fed a diet with or without synbiotics for 21 days. Synbiotics increased the numbers of lactobacilli and bifidobacteria in large intestine in both adult and aged rats. The plasma Ca concentration was significantly increased while osteocalcin concentration was significantly decreased only in aged rats fed synbiotics.
Naughton V, McSorley E, Naughton PJ
Appl Physiol Nutr Metab Feb 2011 PMID: 21326391
Effect of dietary mineral level and inulin inclusion on phosphorus, calcium and nitrogen utilisation, intestinal microflora and bone development.
An experiment was conducted to investigate the interaction between dietary phosphorus (P) level (4 vs 6 g total P kg(-1)) and inulin inclusion (0 vs 20 g kg(-1)) on coefficients of total tract apparent digestibility, nitrogen (N), P and calcium (Ca) utilisation, bone mineralisation, selected gastrointestinal microflora, intestinal volatile fatty acid concentrations and digesta pH in the ileum, caecum and proximal colon. Owing to the design of the experiment, as dietary P level increased, there was also an increase in dietary Ca level in order to maintain a sustainable dietary Ca/P ratio. Entire male finisher pigs (n = 10 per treatment) with a similar initial body weight (51 kg, standard deviation 2.4 kg) were used.
Inulin inclusion lowered (P < 0.01) Enterobacteriaceae populations in the proximal colon compared with pigs offered diets without added inulin. However, intestinal bacterial populations of Lactobacillus and Bifidobacterium spp. were unaffected. Inulin inclusion had no effect on mineral digestibility or bone mineralisation. Pigs offered low P and Ca diets had lower (P < 0.01) bone mineralisation than pigs offered high P and Ca diets.
Intestinal bacterial populations of Enterobacteriaceae in the proximal colon were lowered by inulin inclusion. Inulin inclusion did not affect P, Ca or N utilisation or bone mineralisation in the finisher pig when offered either a low or a high P diet. Increasing the P and Ca content of the diet led to an increase in bone mineralisation.
Varley PF, McCarney C, Callan JJ, O’Doherty JV
J. Sci. Food Agric. Nov 2010 PMID: 20661921
Effect of inulin on growth performance, intestinal tract sizes, mineral retention and tibial bone mineralisation in broiler chickens.
1. A 5-week feeding trial with 240 one-day-old male broiler chickens was conducted to investigate the responses of performance, intestinal tract measurements, relative apparent retention of minerals (Ca, Mg, Fe, Zn and Cu), and tibial bone measurements and mineral content (ash and Ca) to dietary graded levels of inulin. Treatments consisted of a maize-soybean meal control diet without or with supplemental antibiotic (flavomycin, 40 mg/kg diet) and 4 diets containing inulin at concentrations of 5, 10, 15 and 20 g/kg. 2. Growth performance of birds and morphological measurements of intestinal tract (duodenum, jejunum, ileum and caeca) showed no response to dietary levels of inulin as compared with the control diet and the control diet with flavomycin. 3. Dietary inulin improved the relative apparent retention of Ca, Zn and Cu (up to 18.4, 35.5 and 466%, respectively), did not affect that of Mg and impaired the retention of Fe. Differences among inulin treatments and control with flavomycin were significant only for Mg content. 4. Dietary inulin increased the concentration of ash and Ca in the tibiae. This effect was not reflected in the tibial bone morphology (weight, length and width). In conclusion, the results from the current study suggest that feeding inulin to broiler chickens may have a beneficial effect on bone quality.
Dietary long-chain inulin reduces abdominal fat but has no effect on bone density in growing female rats.
New strategies to improve Ca absorption and bone health are needed to address the current state of osteoporosis prevention and management. Inulin-type fructans have shown great promise as a dietary intervention strategy, but have not yet been tested in a young female model. Our objective was to investigate the effect of long chain (LC) inulin on bone mineralization and density in growing, female rats, as well as the quality of growth. Weanling Sprague-Dawley rats were assigned to inulin or cellulose treatments for either 4 or 8 weeks. Growth was measured weekly and quality of growth assessed using fat pad weights and dual-energy X-ray absorptiometry (DXA). Whole body (WB) and selected regions were analysed for bone mineral density (BMD) and body composition by DXA. Serum markers of bone turnover were assessed by enzyme-linked immunosorbent assays. Ca and P concentrations were determined in excised femurs by inductively coupled plasma spectrometry. Feeding inulin resulted in 4 % higher femoral weight (adjusted for body weight) and 6 % less feed intake. Inulin did not affect WB or regional BMD, but was associated with a 28 % lower parametrial fat pad mass, 21 % less WB fat mass and 5 % less WB mass. In summary, LC-inulin lowered body fat mass, without consequence to bone density in growing female rats.
Jamieson JA, Ryz NR, Taylor CG, Weiler HA
Br. J. Nutr. Aug 2008 PMID: 18279560
Modulation of soy isoflavones bioavailability and subsequent effects on bone health in ovariectomized rats: the case for equol.
Soy products are of particular interest because of their potential health benefits in a range of hormonal conditions, such as osteoporosis, due to their high content in phytoestrogens. Because equol, the main metabolite from soy isoflavones, is thought to be powerful, the present study was designated to evaluate the bone-sparing effects of equol by either providing the molecule through the diet or by eliciting its endogenous production by modulating intestinal microflora by short-chain fructooligosaccharides (sc-FOS) or live microbial (Lactobacillus casei) together with daidzein, its precursor.
A comparison with daidzein and genistein was also performed. Rats (3 months old) were ovariectomised (OVX) or sham-operated (SH). Ovariectomised rats were randomly assigned to six experimental diets for 3 months: a control diet (OVX), the control diet supplemented with either genistein (G), or daidzein (D), or equol (E) at the level of 10 microg/g body weight/d. The remaining OVX rats were given daidzein at the dose of 10 mug/g body weight/d, simultaneously with short-chain FOS (Actilight, Beghin-Meiji) (D+FOS) or Lactobacillus casei (Actimel, Danone) (D+L). The SH rats were given the same control diet as OVX.
Genistein, daidzein or equol exhibited a bone sparing effect. Indeed, total femoral bone mineral density (BMD) was significantly enhanced (compared to that of OVX rats), as was the metaphyseal compartment. Bone strength was improved by E consumption, but not by genistein or daidzein given alone. As far as the FOS diet is concerned, the addition of prebiotics significantly raised efficiency of the daidzein protective effect on both femoral BMD and mechanical properties. The effects of lactobacillus were similar, except that the increase in metaphyseal-BMD was not significant.
In conclusion, long-term equol consumption, like genistein and daidzein, in the ovariectomized rat, provides bone sparing effects. Adding indigestible sugars, such as FOS or live microbial as L. casei, in the diet significantly improves daidzein protective effects on the skeleton.
Mathey J, Mardon J, Fokialakis N, Puel C…
Osteoporos Int May 2007 PMID: 17333448
Effects of oligofructose-enriched inulin on intestinal absorption of calcium and magnesium and bone turnover markers in postmenopausal women.
Deficiency of oestrogen at menopause decreases intestinal Ca absorption, contributing to a negative Ca balance and bone loss. Mg deficiency has also been associated with bone loss. The purpose of the present investigation was to test the hypothesis that treatment with a spray-dried mixture of chicory oligofructose and long-chain inulin (Synergy1; SYN1) would increase the absorption of both Ca and Mg and alter markers of bone turnover. Fifteen postmenopausal women (72.2 (SD 6.4) years) were treated with SYN1 or placebo for 6 weeks using a double-blind, placebo-controlled, cross-over design. Fractional Ca and Mg absorption were measured using dual-tracer stable isotopes before and after treatment. Bone turnover markers were measured at baseline, 3 and 6 weeks. Fractional absorption of Ca and Mg increased following SYN1 compared with placebo (P < 0.05). Bone resorption (by urinary deoxypyridinoline cross-links) was greater than baseline at 6 weeks of active treatment (P < 0.05). Bone formation (by serum osteocalcin) showed an upward trend at 3 weeks and an increase following 6 weeks of SYN1 (P < 0.05). Closer examination revealed a variation in response, with two-thirds of the subjects showing increased absorption with SYN1. Post hoc analyses demonstrated that positive responders had significantly lower lumbar spine bone mineral density than non-responders (dual X-ray absorptiometry 0.887 +/- 0.102 v. 1.104 +/- 0.121 g/cm2; P < 0.01), and changes in bone turnover markers occurred only in responders. These results suggest that 6 weeks of SYN1 can improve mineral absorption and impact markers of bone turnover in postmenopausal women. Further research is needed to determine why a greater response was found in women with lower initial spine bone mineral density.
Holloway L, Moynihan S, Abrams SA, Kent K…
Br. J. Nutr. Feb 2007 PMID: 17298707
A prebiotic substance persistently enhances intestinal calcium absorption and increases bone mineralization in young adolescents.
A number of short-term (9 days to 5 weeks) studies have reported that non-digestible. oligosaccharides enhance intestinal calcium absorption. Recent interesting data from an intervention trial in adolescents (9-13 years of age) suggest that a non-digestible oligosaccharide can persistently stimulate calcium absorption over 12 months and can also enhance bone mineralization during pubertal growth.