Prebiotics enhance magnesium absorption and inulin-based fibers exert chronic effects on calcium utilization in a postmenopausal rodent model

Evaluating the Role of Probiotics, Prebiotics, and Synbiotics Supplementation in Age-related Musculoskeletal Disorders in Older Adults: A Systematic Review

The aim of this systematic review is to evaluate musculoskeletal changes in response to prebiotics, probiotics, or synbiotics supplementation in older adults or in animal models of aging musculoskeletal disorders. A comprehensive search was conducted on electronic databases, including PubMed/Medline, Cochrane, and Web of Science until April 2024. The quality assessment of clinical trials was conducted using the Cochrane Collaboration tool and for animal studies, the SYRCLE's tool was used. Our literature search resulted in 652 studies. After removing duplicates and screening the articles based on their titles and abstracts, we assessed the full text of 112 articles, which yielded 20 clinical trials and 30 animal studies in our systematic review. Most of human and animal studies reported an improvement in physical performance, a decrease in frailty index, and a lower reduction in bone mineral density in the intervention groups. Body composition tends to increase in muscle ratio, muscle mass, and reduce in appendicular lean mass and muscle atrophy. Also, the intervention induced bone turnover and mineral absorption, significantly increasing Ca, P, and Mg absorption and short-chain fatty acid concentration. Additionally, levels of inflammatory markers such as IL1, IL6, IL17, T helper 17, and TNF-α exhibited a decreasing trend, while an increase in IL10 and IFN-γ was observed. Prebiotics, probiotics, or synbiotics supplementations could effectively improve the physical performance and muscle strength and reduce the risk of bone loss and frailty in the elderly.

Konjac Oligosaccharides Alleviated Ovariectomy-Induced Bone Loss through Gut Microbiota Modulation and Treg/Th17 Regulation

Oligosaccharides from the plant Amorphophallus konjac were potentially effective in menopausal osteoporosis due to their prebiotic attributes. The present work mainly studied the regulation of konjac oligosaccharides (KOS) on menopausal bone loss. Experiments were carried out in ovariectomized (OVX) rats, and various contents of KOS were correlated with diet. After 3 months of treatment, the degree of osteoporosis was determined by bone mineral density and femoral microarchitecture. The research data showed that the 8% dietary KOS significantly alleviated bone loss in OVX rats, as it promoted the bone trabecular number by 134.2% and enhanced the bone bending stiffness by 103.1%. From the perspective of the gut-bone axis, KOS promoted gut barrier repair and decreased pro-inflammatory cytokines. Besides, KOS promoted the growth of Bifidobacterium longum and restored Treg/Th17 balance in bone marrow. The two aspects contributed to decreased osteoclastogenic activity and thus inhibited inflammation-related bone loss. This work extended current knowledge of prebiotic inhibition on bone loss and provide an alternative strategy for osteoporosis prevention.

Beneficial effect and mechanism of natural resourced polysaccharides on regulating bone metabolism through intestinal flora: A review

Bone metabolism is an important biological process for maintaining bone health. Polysaccharides of natural origin exert beneficial effects on bone metabolism. Polysaccharide molecules often have difficulty passing through the intestinal cell membrane and are directly absorbed in the gastrointestinal tract. Therefore, polysaccharides may affect intestinal flora and play a role in disease treatment. We performed a comprehensive review of the relevant literature published from 2003 to 2023. We found that several polysaccharides from traditional Chinese medicines, including Astragalus, Achyranthes bidentata and Eucommia ulmoides, and the polysaccharides from several dietary fibers mainly composed of inulin, resistant starch, and dextran could enrich the intestinal microbiota group to regulate bone metabolism. The promotion of polysaccharide decomposition by regulating the Bacteroides phylum is particularly critical. Studies on the structure-activity relationship showed that molecular weight, glycosidic bonds, and monosaccharide composition may affect the ability of polysaccharides. The mechanism by which polysaccharides regulate intestinal flora to enhance bone metabolism may be related to the regulation of short-chain fatty acids, immunity, and hormones, involving some signaling pathways, such as TGF-β, Wnt/β-catenin, BMP/Smads, and RANKL. This paper provides a useful reference for the study of polysaccharides and suggests their potential application in the treatment of bone metabolic disorders.

The Crosstalk between Gut Microbiota and Nervous System: A Bidirectional Interaction between Microorganisms and Metabolome

Several studies have shown that the gut microbiota influences behavior and, in turn, changes in the immune system associated with symptoms of depression or anxiety disorder may be mirrored by corresponding changes in the gut microbiota. Although the composition/function of the intestinal microbiota appears to affect the central nervous system (CNS) activities through multiple mechanisms, accurate epidemiological evidence that clearly explains the connection between the CNS pathology and the intestinal dysbiosis is not yet available. The enteric nervous system (ENS) is a separate branch of the autonomic nervous system (ANS) and the largest part of the peripheral nervous system (PNS). It is composed of a vast and complex network of neurons which communicate via several neuromodulators and neurotransmitters, like those found in the CNS. Interestingly, despite its tight connections to both the PNS and ANS, the ENS is also capable of some independent activities. This concept, together with the suggested role played by intestinal microorganisms and the metabolome in the onset and progression of CNS neurological (neurodegenerative, autoimmune) and psychopathological (depression, anxiety disorders, autism) diseases, explains the large number of investigations exploring the functional role and the physiopathological implications of the gut microbiota/brain axis.

Inulin: properties and health benefits

Inulin, a soluble dietary fiber, is widely found in more than 36 000 plant species as a reserve polysaccharide. The primary sources of inulin, include Jerusalem artichoke, chicory, onion, garlic, barley, and dahlia, among which Jerusalem artichoke tubers and chicory roots are often used as raw materials for inulin production in the food industry. It is universally acknowledged that inulin as a prebiotic has an outstanding effect on the regulation of intestinal microbiota via stimulating the growth of beneficial bacteria. In addition, inulin also exhibits excellent health benefits in regulating lipid metabolism, weight loss, lowering blood sugar, inhibiting the expression of inflammatory factors, reducing the risk of colon cancer, enhancing mineral absorption, improving constipation, and relieving depression. In this review paper, we attempt to present an exhaustive overview of the function and health benefits of inulin.

Effects of inulin on calcium metabolism and bone health

Inulin, a dietary fibre found in the roots of many plants, has positive effects on health. It is particularly noteworthy due to its positive impact on calcium metabolism. Inulin has significant functions, such as improving calcium absorption through passive diffusion, bolstering calcium absorption via ion exchange and expanding the absorption surface of the colon by stimulating cell growth. In addition, inulin boosts calcium absorption by increasing calcium solubility, stimulating levels of calcium-binding protein expression and increasing useful microorganisms. It increases calbindin levels and stimulates transcellular active calcium transport. An inulin intake of least 8-10 g/day supports calcium absorption and total body bone mineral content/density in adolescents through its known mechanisms of action. It also significantly enhances calcium absorption and improves bone health in postmenopausal women and adult men. Sustained and sufficient inulin supplementation in adults has a positive effect on calcium metabolism and bone mineral density.

Prebiotics improve osteoporosis indicators in a preclinical model: systematic review with meta-analysis

CONTEXT

Studies using experimental models have demonstrated that prebiotics are involved in antiosteoporotic mechanisms.

OBJECTIVE

This study was conducted to determine the impact of supplementation with prebiotics in the basal diet of ovariectomized rats with induced osteoporosis as a preclinical model.

METHODS

A comprehensive systematic search was carried out in the electronic databases PubMed, Science Direct, Web of Science, Scielo, and Google through March 2022 for studies that investigated the impact of prebiotics on bone mineral density (BMD), bone mineral content (BMC), and bone biomechanics.

RESULTS

The search returned 844 complete articles, abstracts, or book chapters. After detailed screening, 8 studies met the inclusion criteria. Rats (n = 206), were randomly divided between control and treatment groups. Weighted mean differences (WMDs) with the 95%CIs were used to estimate the combined effect size. Compared with the control group, dietary intake of prebiotics significantly increased bone density in the BMD subgroups, with WMDs as follows: 0.03 g/cm3, 95%CI, 0.01-0.05, P < 0.00001, n = 46; and 0.00 g/cm2, 95%CI, 0.00-0.02, P < 0.00001, n = 81; total BMD: WMD, 0.01, 95%CI, 0.01-0.02, P < 0.00001, n = 127; bone content in BMC: WMD, 0.02 g, 95%CI, 0.00-0.04, P = 0.05, n = 107; and the 3-point-bend test: WMD, 15.20 N, 95%CI, 5.92-24.47, P = 0.00001, n = 120.

CONCLUSION

Prebiotics improve indicators of osteoporosis, BMD, BMC, and bone biomechanics in ovariectomized rats. More studies are needed to increase the level of evidence.

SYSTEMIC REVIEW REGISTRATION

Systematic Review Protocol for Animal Intervention Studies.

Greater Consumption of Total and Individual Lignans and Dietary Fibers Were Significantly Associated with Lowered Risk of Hip Fracture-A 1:1 Matched Case-Control Study among Chinese Elderly Men and Women

The study aims to examine the association of dietary intake of lignans with the risk of hip fractures in Chinese older adults. This was a 1:1 age- and gender- matched case−control study. Dietary survey was conducted by face-to-face interviews using a 79-item validated food frequency questionnaire. Habitual intake of total and individual lignans (matairesinol, secoisolariciresinol, pinoresinol, and lariciresinol) was estimated based on the available lignans databases. Conditional logistic regression was used to examine the relationship of dietary total and individual lignans, lignan-rich foods (vegetables, fruits, nuts, and cereals) and dietary fibers with the risk of hip fracture. A total of 1070 pairs of hip fracture incident cases and controls were recruited. Compared with the lowest quartile, the highest quartile group showed a reduced hip fracture risk by 76.3% (0.237, 95% CI: 0.103−0.544, Ptrend < 0.001) for total lignans, and 62.5% (0.375, 95% CI: 0.194−0.724, Ptrend = 0.001) for dietary fibers. Similar findings were observed for individual lignans, the estimated enterolactone level, as well as lignans from vegetables and nuts. We concluded that greater consumption of total and individual lignans, and lignan-rich foods were significantly associated with decreased risk of hip fracture.

The Impact of Diet on Bone and Fracture Risk in Diabetes

PURPOSE OF REVIEW

The purpose of this review is to summarize the recently published scientific evidence on the effects of diet on diabetes and skeletal health.

RECENT FINDINGS

The impact of diet on overall health has been a growing topic of interest among researchers. An inappropriate eating habit is a relatively modified risk factor for diabetes in adults. Parallel with the significant increase in the incidence of diabetes mellitus worldwide, many studies have shown the benefits of lifestyle modifications, including diet and exercise for people with, or at risk of developing, diabetes. In the last years, accumulating evidence suggests that diabetes is a risk factor for bone fragility. As lifestyle intervention represents an effective option for diabetes management and treatment, there is potential for an effect on bone health. Healthy lifestyle is critical to prevent bone fragility. However, more studies are needed to fully understand the impact of diet and weight loss on fracture risk in diabetics.

The microbiota-gut-bone axis and bone health

The gastrointestinal tract is colonized by trillions of microorganisms, consisting of bacteria, fungi, and viruses, known as the "second gene pool" of the human body. In recent years, the microbiota-gut-bone axis has attracted increasing attention in the field of skeletal health/disorders. The involvement of gut microbial dysbiosis in multiple bone disorders has been recognized. The gut microbiota regulates skeletal homeostasis through its effects on host metabolism, immune function, and hormonal secretion. Owing to the essential role of the gut microbiota in skeletal homeostasis, novel gut microbiota-targeting therapeutics, such as probiotics and prebiotics, have been proven effective in preventing bone loss. However, more well-controlled clinical trials are still needed to evaluate the long-term efficacy and safety of these ecologic modulators in the treatment of bone disorders.

Plant Prebiotics and Their Role in the Amelioration of Diseases

Prebiotics are either natural or synthetic non-digestible (non-)carbohydrate substances that boost the proliferation of gut microbes. Undigested fructooligosaccharides in the large intestine are utilised by the beneficial microorganisms for the synthesis of short-chain fatty acids for their own growth. Although various food products are now recognized as having prebiotic properties, several others, such as almonds, artichoke, barley, chia seeds, chicory, dandelion greens, flaxseeds, garlic, and oats, are being explored and used as functional foods. Considering the benefits of these prebiotics in mineral absorption, metabolite production, gut microbiota modulation, and in various diseases such as diabetes, allergy, metabolic disorders, and necrotising enterocolitis, increasing attention has been focused on their applications in both food and pharmaceutical industries, although some of these food products are actually used as food supplements. This review aims to highlight the potential and need of these prebiotics in the diet and also discusses data related to the distinct types, sources, modes of action, and health benefits.

Prebiotic Carbohydrates for Therapeutics

The food industry is constantly shifting focus based on prebiotics as health-promoting substrates rather than just food supplements. A prebiotic is "a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-being and health." Prebiotics exert a plethora of health-promoting effects, which has lead to the establishment of multimillion food and pharma industries. The following are the health benefits attributed to prebiotics: mineral absorption, better immune response, increased resistance to bacterial infection, improved lipid metabolism, possible protection against cancer, relief from poor digestion of lactose, and reduction in the risk of diseases such as intestinal disease, non-insulin-dependent diabetes, obesity and allergy. Numerous studies in both animals and humans have demonstrated the health benefits of prebiotics.

Phytochemicals affect T helper 17 and T regulatory cells and gut integrity: implications on the gut-bone axis

The pathology of osteoporosis is multifactorial, but a growing body of evidence supports an important role of the gut-bone axis, especially in bone loss associated with menopause, rheumatoid arthritis, and periodontal disease. Aberrant T cell responses favoring an increase in the ratio of T helper 17 cells to T regulatory cells play a critical role in the underlying etiology of this bone loss. Many of the dietary phytochemicals known to have osteoprotective activity such as flavonoids, organosulfur compounds, phenolic acids, as well as the oligosaccharides also improve gut barrier function and affect T cell differentiation and activation within gut-associated lymphoid tissues and at distal sites. Here, we examine the potential of these phytochemicals to act as prebiotics and immunomodulating agents, in part targeting the gut to mediate their effects on bone.

Changes in salivary electrolyte concentrations in mid-distance trained sled dogs during 12 weeks of incremental conditioning

Regular exercise improves the health status of dogs; however, extreme exertion in the absence of adequate fluid and electrolyte replacement may negatively impact health and performance due to dehydration and cardiovascular stress. Unlike humans and horses, dogs thermoregulate predominantly through respiration and salivation, yet there is a dearth of literature defining exercise-induced changes to canine salivary electrolytes. The study objective was to investigate the effects of exercise on salivary electrolyte concentrations, and to determine if adaptations may occur in response to incremental conditioning in client-owned Siberian Huskies. Sixteen dogs were used, with an average age of 4.8 ± 2.5 years and body weight of 24.3 ± 4.3 kg. A 12-week exercise regimen was designed to increase in distance each week, but weather played a role in setting the daily distance. Saliva samples were collected at weeks 0 (pre-run, 5.7 km), 5 (pre-run, 5.7, 39.0 km), and 11 (pre-run, 5.7, 39.0 km). Samples were analyzed for sodium, chloride, potassium, calcium, magnesium, and phosphorous using photometric and indirect ion-selective electrode analysis. When compared across weeks, sodium, chloride, potassium, and calcium concentrations did not differ at any sampling time point; however, phosphorus and magnesium concentrations increased from baseline. Data were then pooled across weeks to evaluate changes due to distance and level of conditioning. Sodium, chloride, and magnesium concentrations increased progressively with distance ran, suggesting that these electrolytes are primarily being lost as exercising dogs salivate. Repletion of these minerals may assist in preventing exercise-induced electrolyte imbalance in physically active dogs.

Plant- and Nutraceutical-based Approach for the Management of Diabetes and its Neurological Complications: A Narrative Review

Diabetes is an important metabolic disease affecting many organs and systems in the body. The nervous system is one of the body systems affected by diabetes and neuropathic complications are troublesome in diabetic patients with many consequences. As diabetes has deleterious influences almost on bodily systems, an integrative approach seems to be necessary accepting the body as a whole and integrating body systems with lifestyle and living environment. Like some traditional health systems such as Ayurveda, integrative approach includes additional modalities to overcome both diabetes and diabetic complications. In general, these modalities consist of nutraceuticals and plant products. Prebiotics and probiotics are two types of nutraceuticals having active ingredients, such as antioxidants, nutrient factors, microorganisms, etc. Many plants are indicated for the cure of diabetes. All of these may be employed in the prevention and in the non-pharmacological management of mildto- moderate diabetes. Severe diabetes should require appropriate drug selection. Being complementary, prebiotics, probiotics, plants and exercise may be additive for the drug therapy of diabetes. Similarly, there are complementary approaches to prevent and cure neurological and/or behavioral manifestations of diabetes, which may be included in therapy and prevention plans. A scheme is given for the prevention and therapy of comorbid depression, which is one of the most common behavioral complications of diabetes. Within this scheme, the main criterion for the selection of modalities is the severity of diseases, so that personalized management may be developed for diabetic patients using prebiotics and probiotics in their diets, plants and drugs avoiding possible interactions.

Intake of Polydextrose Alters Hematology and the Profile of Short Chain Fatty Acids in Partially Gastrectomized Rats

Polydextrose (PDX) ingestion may increase the intestinal absorption of iron. This study evaluated the effects of 7.5% polydextrose supplementation on markers of iron uptake, transport and storage in partially gastrectomized rats. Half of a batch of 40 male Wistar rats (250 g) underwent Billroth II partial gastrectomy with anterior truncal vagotomy (GXT), while the other half underwent sham gastrectomy (SHAM). At 7 postoperative days, the animals were subdivided into four groups (n = 10): Sham Control and GXT Control (no polydextrose); Sham PDX and GXT PDX (with 7.5% PDX). The animals were euthanized after 60 day of PDX treatment. Organ weight, cecal pH, the characterization and quantification of short-chain fatty acids (SCFA), hematological parameters, hepatic iron content and the expression of ferroportin (FPT) in the jejunum, cecum, colon and liver were evaluated. PDX caused changes in the cecum of the supplemented animals, where there was a decrease in pH, increase in cecal wall and marked production of SCFA, especially acetic and propionic acids (p < 0.05). Hepatic iron levels were lower in GXT animals. PDX increased hemoglobin (HGB) values by 29.2% and hematocrit (HCT) by 55.8% in the GXT PDX group compared to the GXT Control group. The GXT PDX group had lower hepatic FPT expression (p < 0.05). PDX led to increased SCFA concentration in the supplemented animals. Considering that SCFAs play a central role in the increasing nutrients uptake, this mechanism may be involved in altering the hematology profile observed in these animals but not enough to reverse iron deficiency anemia in post-gastrectomy rats.

Effects of probiotic supplementation on performance traits, bone mineralization, cecal microbial composition, cytokines and corticosterone in laying hens

Recent researches have showed that probiotics promote bone health in humans and rodents. The objective of this study was to determine if probiotics have the similar effects in laying hens. Ninety-six 60-week-old White Leghorn hens were assigned to four-hen cages based on their BW. The cages were randomly assigned to 1 of 4 treatments: a layer diet mixed with a commercial probiotic product (containing Enterococcus faecium, Pediococcus acidilactici, Bifidobacterium animalis and Lactobacillus reuteri) at 0, 0.5, 1.0 or 2.0 g/kg feed (Control, 0.5×, 1.0× and 2.0×) for 7 weeks. Cecal Bifidobacterium spp. counts were higher in all probiotic groups (P0.05). In addition, the plasma concentrations of cytokines (interleukin-1β, interleukin-6, interleukin-10, interferon-γ and tumor necrosis factor-α) and corticosterone as well as the levels of heterophil to lymphocyte ratio were similar between the 2.0× group and the control group (P&gt;0.05). In line with these findings, no differences of cecal tonsil mRNA expressions of interleukin-1β, interleukin-6 and lipopolysaccharide-induced tumor necrosis factor-α factor were detected between these two groups (P&gt;0.05). These results suggest that immune cytokines and corticosterone may not involve in the probiotic-induced improvement of eggshell quality and bone mineralization in laying hens. In conclusion, the dietary probiotic supplementation altered cecal microbiota composition, resulting in reduced shell-less egg production and improved bone mineralization in laying hens; and the dietary dose of the probiotic up to 2.0× did not cause negative stress reactions in laying hens.

From Osteoimmunology to Osteomicrobiology: How the Microbiota and the Immune System Regulate Bone

Osteomicrobiology refers to the role of microbiota in bone health and the mechanisms by which the microbiota regulates post-natal skeletal development, bone aging, and pathologic bone loss. Here, we review recent reports linking gut microbiota to changes in bone phenotype. A pro-inflammatory cytokine milieu drives bone resorption in conditions such as sex steroid hormone deficiency. The response of the immune system to activation by the microbiome results in increased circulating osteoclastogenic cytokines in a T cell-dependent mechanism. Additionally, gut microbiota affect bone homeostasis through nutrient absorption, mediation of the IGF-1 pathway, and short chain fatty acid and metabolic products. Manipulation of microbiota through prebiotics or probiotics reduces inflammatory cytokine production, leading to changes in bone density. One mechanism of probiotic action is through upregulating tight junction proteins, increasing the strength of the gut epithelial layer, and leading to less antigen presentation and less activation of intestinal immune cells. Thus, prebiotics or probiotics may represent a future therapeutic avenue for ameliorating the risk of postmenopausal bone loss in humans.

The role of gut microbiota in the effects of maternal obesity during pregnancy on offspring metabolism

Obesity is considered a global epidemic. Specifically, obesity during pregnancy programs an increased risk of the offspring developing metabolic disorders in addition to the adverse effects on the mother per se Large numbers of human and animal studies have demonstrated that the gut microbiota plays a pivotal role in obesity and metabolic diseases. Similarly, maternal obesity during pregnancy is associated with alterations in the composition and diversity of the intestine microbial community. Recently, the microbiota in the placenta, amniotic fluid, and meconium in healthy gestations has been investigated, and the results supported the "in utero colonization hypothesis" and challenged the traditional "sterile womb" that has been acknowledged worldwide for more than a century. Thus, the offspring microbiota, which is crucial for the immune and metabolic function and further health in the offspring, might be established prior to birth. As a detrimental intrauterine environment, maternal obesity influences the microbial colonization and increases the risk of metabolic diseases in offspring. This review discusses the role of the microbiota in the impact of maternal obesity during pregnancy on offspring metabolism and further analyzes related probiotic or prebiotic interventions to prevent and treat obesity and metabolic diseases.

Bone Remodeling and the Microbiome

Exposed surfaces of mammals are colonized with 100 trillion indigenous bacteria, fungi, and viruses, creating a diverse ecosystem known as the microbiome. The gastrointestinal tract harbors the greatest numbers of these microorganisms, which regulate human nutrition, metabolism, and immune system function. Moreover, the intestinal microbiota contains pro- and anti-inflammatory products that modulate immune responses and may play a role in maintaining gut barrier function. Therefore, the community composition of the microbiota has profound effects on the immune status of the host and impacts the development and/or progression of inflammatory diseases. Accordingly, numerous studies have shown differences in the microbiota of patients with and without a given inflammatory condition. There is now strong evidence that the gut microbiome regulates bone homeostasis in health and disease, and that prebiotic and probiotics protect against bone loss. Herein, the evidence supporting the role of the microbiota and the effects of prebiotic and probiotics will be reviewed.

Prebiotics, Bone and Mineral Metabolism

Increasing interest in functional foods has driven discovery in the area of bioactive compounds. Prebiotics are non-digestible carbohydrate compounds that, when consumed, elicit health benefits and aid in the prevention and treatment of chronic diseases. While prebiotics have been shown to improve a number of chronic, inflammatory conditions, growing evidence exists for prebiotic effects on calcium metabolism and bone health. These novel dietary fibers have been shown to increase calcium absorption in the lower intestines of both preclinical and human models. Rodent models have also been imperative for understanding prebiotic effects on bone mineral density and measures of skeletal strength. Although fewer data are available for humans, bone-related prebiotic effects exist across the lifecycle, suggesting benefits for attainment of peak bone mass during adolescence and minimized bone resorption among postmenopausal women. These effects are thought to occur through prebiotic-microbe interactions in the large intestine. Current prebiotic mechanisms for improved mineral absorption and skeletal health include alterations in gut microbiota composition, production of short-chain fatty acids, altered intestinal pH, biomarker modification, and immune system regulation. While the majority of available data support improved mineral bioavailability, emerging evidence suggests alternate microbial roles and the presence of an intricate gut-bone signaling axis. Overall, the current scientific literature supports prebiotic consumption as a cost-effective and sustainable approach for improved skeletal health and/or fracture prevention. The goal of this review is to discuss both foundational and recent research in the area of prebiotics, mineral metabolism, and bone health.

Association Between Dietary Fiber Intake and Bone Loss in the Framingham Offspring Study

Dietary fiber may increase calcium absorption, but its role in bone mineralization is unclear. Furthermore, the health effect of dietary fiber may be different between sexes. We examined the association between dietary fiber (total fiber and fiber from cereal, fruits, vegetables, nuts, and legumes) and bone loss at the femoral neck, trochanter, and lumbar spine (L2 to L4 ) in older men and women. In the Framingham Offspring Study, at baseline (1996-2001), diet was assessed using the Willett food-frequency questionnaire, and bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry. Follow-up BMD was measured in 2001-2005 and 2005-2008 among 792 men (mean age 58.1 years; BMI 28.6 kg/m2 ) and 1065 women (mean age 57.3 years; BMI 27.2 kg/m2 ). We used sex-specific generalized estimating equations in multivariable regressions to estimate the difference (β) of annualized BMD change in percent (%ΔBMD) at each skeletal site per 5 g/d increase in dietary fiber. We further estimated the adjusted mean for bone loss (annualized %ΔBMD) among participants in each higher quartile (Q2, Q3, or Q4) compared with those in the lowest quartile (Q1) of fiber intake. Higher dietary total fiber (β = 0.06, p = 0.003) and fruit fiber (β = 0.10, p = 0.008) was protective against bone loss at the femoral neck in men but not in women. When examined in quartiles, men in Q2-Q4 of total fiber had significantly less bone loss at the femoral neck versus those in Q1 (all p < 0.04). For women, we did not observe associations with hip bone loss, although fiber from vegetables appeared to be protective against spine bone loss in women but not men. There were no associations with cereal fiber or nut and legume fiber and bone loss in men or women. Our findings suggest that higher dietary fiber may modestly reduce bone loss in men at the hip. © 2017 American Society for Bone and Mineral Research.

Magnesium in Chronic Kidney Disease: Should We Care?

BACKGROUND

Magnesium (Mg) is an essential cation for multiple processes in the body. The kidney plays a major role in regulating the Mg balance. In a healthy individual, total-body Mg content is kept constant by interactions among intestine, bones and the kidneys.

SUMMARY

In case of chronic kidney disease (CKD), renal regulatory mechanisms may be insufficient to balance intestinal Mg absorption. Usually Mg remains normal; however, when glomerular filtration rate declines, changes in serum Mg are observed. Patients with end-stage renal disease on dialysis are largely dependent on the dialysate Mg concentration for maintaining serum Mg and Mg homeostasis. A low Mg is associated with several complications such as hypertension, and vascular calcification, and also associated with an increased risk for both cardiovascular disease (CVD) and non-CVD mortality. Severe hypermagnesaemia is known to cause cardiac conduction defects, neuromuscular effects and muscle weakness; a slightly elevated Mg has been suggested to be beneficial in patients with end-stage renal disease. Key Messages: The role of both low and high Mg, in general, but especially in relation to CKD and dialysis patients is discussed.

Intestinal Absorption and Factors Influencing Bioavailability of Magnesium-An Update

Background:

Information on the bioavailability of the essential mineral Mg2+ is sparse.

Objective/Method:

Evaluation of the present knowledge on factors influencing the bioavailability and intestinal absorption of Mg2+.

Results:

Mg2+ is absorbed via a paracellular passive and a transcellular active pathway that involves TRPM6/7 channel proteins. The bioavailability of Mg2+ varies within a broad range, depending on the dose, the food matrix, and enhancing and inhibiting factors. Dietary factors impairing Mg2+ up-take include high doses of other minerals, partly fermentable fibres (e.g., hemicellulose), non-fermentable fibres (e.g., cellulose, lignin), phytate and oxalate, whereas proteins, medium-chain-triglycerides, and low- or indigestible carbohydrates (e.g., resistant starch, oligosaccharides, inulin, mannitol and lactulose) enhance Mg2+ uptake. The Mg2+ dose is a major factor controlling the amount of Mg2+ absorbed. In principle, the relative Mg2+ uptake is higher when the mineral is in-gested in multiple low doses throughout the day compared to a single, large intake of Mg2+. The type of Mg2+ salt appears less relevant than is often thought. Some studies demonstrated a slightly higher bioavailability of organic Mg2+ salts compared to inorganic compounds under standardized conditions, whereas other studies did not.

Conclusion:

Due to the lack of standardized tests to assess Mg2+ status and intestinal absorption, it remains unclear which Mg2+ binding form produces the highest bioavailability. The Mg2+ intake dose combined with the endogenous Mg2+ status is more important. Because Mg2+ cannot be stored but only retained for current needs, a higher absorption is usually followed by a higher excretion of the mineral.

Polydextrose: Physiological Function, and Effects on Health

Polydextrose (PDX) is a non-digestible oligosaccharide used widely across most sectors of the food industry. It is a randomly linked glucose oligomer containing small amounts of sorbitol and citric acid. The random bonds in PDX prevent mammalian digestive enzymes from readily hydrolyzing the molecule and it has a reported energy value of 1 kcal/g. These properties have led to the acceptance in many countries that PDX provides similar physiological effects as other dietary fibers and has shown prebiotic potential. Dietary intervention with prebiotics has been shown to selectively stimulate the growth and/or activity of one or a limited number of intestinal bacteria associated with several physiological benefits on health. Therefore, the objective of this review was a survey of the literature on the effect of supplementation with PDX in health, and to list the benefits for maintaining health and/or reducing the development of diseases.

Distant Site Effects of Ingested Prebiotics

The gut microbiome is being more widely recognized for its association with positive health outcomes, including those distant to the gastrointestinal system. This has given the ability to maintain and restore microbial homeostasis a new significance. Prebiotic compounds are appealing for this purpose as they are generally food-grade substances only degraded by microbes, such as bifidobacteria and lactobacilli, from which beneficial short-chain fatty acids are produced. Saccharides such as inulin and other fructo-oligosaccharides, galactooligosaccharides, and polydextrose have been widely used to improve gastrointestinal outcomes, but they appear to also influence distant sites. This review examined the effects of prebiotics on bone strength, neural and cognitive processes, immune functioning, skin, and serum lipid profile. The mode of action is in part affected by intestinal permeability and by fermentation products reaching target cells. As the types of prebiotics available diversify, so too will our understanding of the range of microbes able to degrade them, and the extent to which body sites can be impacted by their consumption.

How to Manipulate the Microbiota: Prebiotics

During the last century, human nutrition has evolved from the definition of our nutritional needs and the identification of ways to meet them, to the identification of food components that can optimise our physiological and psychological functions. This development, which aims to ensure the welfare, health and reduced susceptibility to disease during life, gave birth to the concept of "functional foods". In this context, there is an increasing interest in the physiological effects induced by the dense and diverse microbiota which inhabits the human colon and whose development depends on the fermentation of undigested food residues. Thus, much research aims at identifying ways to guide these impacts in order to benefit the health of the host. It is in this context that the concept of "prebiotics" was developed in the 1990s. Since then, prebiotics have stimulated extensive work in order to clarify their definition, their nature and their physiological properties in accordance with the evolution of knowledge on the intestinal microbiota. However many questions remain open about their specificities, their mechanism(s) of action and therefore the relevance of their current categorisation.

Prebiotic and Probiotic Regulation of Bone Health: Role of the Intestine and its Microbiome

Recent advances in our understanding of how the intestinal microbiome contributes to health and disease have generated great interest in developing strategies for modulating the abundance of microbes and/or their activity to improve overall human health and prevent pathologies such as osteoporosis. Bone is an organ that the gut has long been known to regulate through absorption of calcium, the key bone mineral. However, it is clear that modulation of the gut and its microbiome can affect bone density and strength in a variety of animal models (zebrafish, rodents, chicken) and humans. This is demonstrated in studies ablating the microbiome through antibiotic treatment or using germ-free mouse conditions as well as in studies modulating the microbiome activity and composition through prebiotic and/or probiotic treatment. This review will discuss recent developments in this new and exciting area.

Addressing potential role of magnesium dyshomeostasis to improve treatment efficacy for epilepsy: A reexamination of the literature

Magnesium (Mg(2+) ) is an abundant mineral in the body serving many biochemical functions. Magnesium supplementation has been shown to raise seizure threshold in animal and human studies, but the etiological contribution of magnesium deficiency to the onset and maintenance of epilepsy, as well as the degree to which it impacts antiepileptic drug efficacy, remains poorly understood. This may be due, at least in part, to the inherent limitations of commonly used serum levels as a measure of functional magnesium status, as well as insufficient data regarding relative bioavailabilities of various magnesium salts and chelates for use with humans. To date, 1 randomized clinical trial has been conducted assessing Mg(2+) supplementation in epilepsy, and findings yielded promising results. Yet a notable dearth in the literature remains, and more studies are needed. To better understand the potential role of magnesium deficiency as a causal factor in epilepsy, more convenient and accurate measurement methods should to be developed and employed in randomized, controlled trials of oral magnesium supplementation in epilepsy. Findings from such studies have the potential to facilitate far-reaching clinical and economic improvements in epilepsy treatment standards.

Dietary and pharmacological compounds altering intestinal calcium absorption in humans and animals

The intestine is the only gate for the entry of Ca to the body in humans and mammals. The entrance of Ca occurs via paracellular and intracellular pathways. All steps of the latter pathway are regulated by calcitriol and by other hormones. Dietary and pharmacological compounds also modulate the intestinal Ca absorption process. Among them, dietary Ca and P are known to alter the lipid and protein composition of the brush-border and basolateral membranes and, consequently, Ca transport. Ca intakes are below the requirements recommended by health professionals in most countries, triggering important health problems. Chronic low Ca intake has been related to illness conditions such as osteoporosis, hypertension, renal lithiasis and incidences of human cancer. Carbohydrates, mainly lactose, and prebiotics have been described as positive modulators of intestinal Ca absorption. Apparently, high meat proteins increase intestinal Ca absorption while the effect of dietary lipids remains unclear. Pharmacological compounds such as menadione, dl-butionine-S,R-sulfoximine and ursodeoxycholic acid also modify intestinal Ca absorption as a consequence of altering the redox state of the epithelial cells. The paracellular pathway of intestinal Ca absorption is poorly known and is under present study in some laboratories. Another field that needs to be explored more intensively is the influence of the gene × diet interaction on intestinal Ca absorption. Health professionals should be aware of this knowledge in order to develop nutritional or medical strategies to stimulate the efficiency of intestinal Ca absorption and to prevent diseases.

The fermentation of polydextrose in the large intestine and its beneficial effects

Polydextrose is a randomly bonded glucose polymer with a highly branched and complex structure. It resists digestion in the upper gastrointestinal tract and is partially fermented in the large intestine by the colonic microbes. Due to its complex structure, a plethora of microbes is required for the catabolism of polydextrose and this process occurs slowly. This gradual fermentation of polydextrose gives rise to moderate amounts of fermentation products, such as short chain fatty acids and gas. The production of these metabolites continues in the distal part of the colon, which is usually considered to be depleted of saccharolytic fermentation substrates. The fermentation of polydextrose modifies the composition of the microbiota in the colon, and has been shown to impact appetite and satiety in humans and improve the gastrointestinal function. The purpose of this short review is to summarise the in vitro, in vivo and human studies investigating the fermentation properties of polydextrose in the large intestine.

Calcium and vitamin D intake maintained from preovariectomy independently affect calcium metabolism and bone properties in Sprague Dawley rats

The interaction of habitual Ca and vitamin D intake from preovariectomy to 4 months postovariectomy on bone and Ca metabolism was assessed. Higher Ca intake suppressed net bone turnover, and both nutrients independently benefitted trabecular structure. Habitual intake of adequate Ca and ~50 nmol/L vitamin D status is most beneficial.

INTRODUCTION

Dietary strategies to benefit bone are typically tested prior to or after menopause but not through menopause transition. We investigated the interaction of Ca and vitamin D status on Ca absorption, bone remodeling, Ca kinetics, and bone strength as rats transitioned through estrogen deficiency.

METHODS

Sprague Dawley rats were randomized at 8 weeks to 0.2 or 1.0 % Ca and 50, 100, or 1,000 IU (1.25, 2.5, or 25 μg) vitamin D/kg diet (2 × 3 factorial design) and ovariectomized at 12 weeks. Urinary (45)Ca excretion from deep-labeled bone was used to assess net bone turnover weekly. Ca kinetics was performed between 25 and 28 weeks. Rats were killed at 29 weeks. Femoral and tibiae structure (by μCT), dynamic histomorphometry, and bone Ca content were assessed.

RESULTS

Mean 25(OH)D for rats on the 50, 100, 1,000 IU vitamin D/kg diet were 32, 54, and 175 nmol/L, respectively. Higher Ca intake ameliorated net bone turnover, reduced fractional Ca absorption and bone resorption, and increased net Ca absorption. Tibial and femoral trabecular structures were enhanced independently by higher Ca and vitamin D intake. Tibial bone width and fracture resistance were enhanced by higher vitamin D intake. Dynamic histomorphometry in the tibia was not affected by either nutrient. A Ca × vitamin D interaction existed in femur length, tibial Ca content, and mass of the soft tissue/extracellular fluid compartment.

CONCLUSIONS

Adequate Ca intake and serum 25(OH)D level of 50 nmol/L provided the most benefit for bone health, mostly through independent effects of Ca and vitamin D.

Can prebiotics and probiotics improve therapeutic outcomes for undernourished individuals?

It has become clear in recent years that the human intestinal microbiota plays an important role in maintaining health and thus is an attractive target for clinical interventions. Scientists and clinicians have become increasingly interested in assessing the ability of probiotics and prebiotics to enhance the nutritional status of malnourished children, pregnant women, the elderly, and individuals with non-communicable disease-associated malnutrition. A workshop was held by the International Scientific Association for Probiotics and Prebiotics (ISAPP), drawing on the knowledge of experts from industry, medicine, and academia, with the objective to assess the status of our understanding of the link between the microbiome and under-nutrition, specifically in relation to probiotic and prebiotic treatments for under-nourished individuals. These discussions led to four recommendations:   (1) The categories of malnourished individuals need to be differentiated To improve treatment outcomes, subjects should first be categorized based on the cause of malnutrition, additional health-concerns, differences in the gut microbiota, and sociological considerations. (2) Define a baseline "healthy" gut microbiota for each category Altered nutrient requirement (for example, in pregnancy and old age) and individual variation may change what constitutes a healthy gut microbiota for the individual. (3) Perform studies using model systems to test the effectiveness of potential probiotics and prebiotics against these specific categories These should illustrate how certain microbiota profiles can be altered, as members of different categories may respond differently to the same treatment. (4) Perform robust well-designed human studies with probiotics and/or prebiotics, with appropriate, defined primary outcomes and sample size These are critical to show efficacy and understand responder and non-responder outcomes. It is hoped that these recommendations will lead to new approaches that combat malnutrition. This report is the result of discussion during an expert workshop titled "How do the microbiota and probiotics and/or prebiotics influence poor nutritional status?" held during the 10th Meeting of the International Scientific Association for Probiotics and Prebiotics (ISAPP) in Cork, Ireland from October 1-3, 2012. The complete list of workshop attendees is shown in Table 1.

Probiotic use decreases intestinal inflammation and increases bone density in healthy male but not female mice

Osteoporosis can result from intestinal inflammation, as is seen with inflammatory bowel disease. Probiotics, microorganisms that provide a health benefit to the host when ingested in adequate amounts, can have anti-inflammatory properties and are currently being examined to treat inflammatory bowel disease. Here, we examined if treating healthy male mice with Lactobacillus reuteri ATCC PTA 6475 (a candidate probiotic with anti-TNFα activity) could affect intestinal TNFα levels and enhance bone density. Adult male mice were given L. reuteri 6475 orally by gavage for 3×/week for 4 weeks. Examination of jejunal and ileal RNA profiles indicates that L. reuteri suppressed basal TNFα mRNA levels in the jejunum and ileum in male mice, but surprisingly not in female mice. Next, we examined bone responses. Micro-computed tomography demonstrated that L. reuteri 6475 treatment increased male trabecular bone parameters (mineral density, bone volume fraction, trabecular number, and trabecular thickness) in the distal femur metaphyseal region as well as in the lumbar vertebrae. Cortical bone parameters were unaffected. Dynamic and static histomorphometry and serum remodeling parameters indicate that L. reuteri ingestion increases osteoblast serum markers and dynamic measures of bone formation in male mice. In contrast to male mice, L. reuteri had no effect on bone parameters in female mice. Taken together our studies indicate that femoral and vertebral bone formation increases in response to oral probiotic use, leading to increased trabecular bone volume in male mice.