The effect of feeding different sugar-sweetened beverages to growing female Sprague-Dawley rats on bone mass and strength

Skeletal Effects of a Prolonged Oral Metformin Treatment in Adult Wistar Rats

INTRODUCTION

We previously showed that a 3-week oral metformin (MET) treatment enhances the osteogenic potential of bone marrow stromal cells (BMSCs) and improves several bone histomorphometric parameters in Wistar rats with metabolic syndrome (MetS). However, the skeletal effects of extended periods of MET need to be completely elucidated. Hence, in this study, the impact of a prolonged (3-month) MET treatment was investigated on bone architecture, histomorphometric and biomechanics variables, and osteogenic potential of BMSCs in Wistar rats with or without MetS.

MATERIALS AND METHODS

Young male Wistar rats (n=36) were randomized into four groups (n=9) that received either 20% fructose (F), MET (MET), F plus MET treatments (FMET), or drinking water alone (Veh). Rats were euthanized, blood was collected, and bones were dissected and processed for peripheral quantitative computed tomography (pQCT) analysis, static and dynamic histomorphometry, and bone biomechanics. In addition, BMSCs were isolated to determine their osteogenic potential.

RESULTS

MET affected trabecular and cortical bone, altering bone architecture and biomechanics. Furthermore, MET increased the pro-resorptive profile of BMSCs. In addition, fructose-induced MetS practically did not affect the the structural or mechanical variables of the skeleton.

CONCLUSION

A 3-month treatment with MET (with or without MetS) affects bone architecture and biomechanical variables in Wistar rats.

Nutrition and Bone Marrow Adiposity in Relation to Bone Health

Bone remodeling is energetically demanding process. Energy coming from nutrients present in the diet contributes to function of different cell type including osteoblasts, osteocytes and osteoclasts in bone marrow participating in bone homeostasis. With aging, obesity and osteoporosis the function of key building blocks, bone marrow stromal cells (BMSCs), changes towards higher accumulation of bone marrow adipose tissue (BMAT) and decreased bone mass, which is affected by diet and sex dimorphism. Men and women have unique nutritional needs based on physiological and hormonal changes across the life span. However, the exact molecular mechanisms behind these pathophysiological conditions in bone are not well-known. In this review, we focus on bone and BMAT physiology in men and women and how this approach has been taken by animal studies. Furthermore, we discuss the different diet interventions and impact on bone and BMAT in respect to sex differences. We also discuss the future perspective on precision nutrition with a consideration of sex-based differences which could bring better understanding of the diet intervention in bone health and weight management.

Chronic Fructose and Sucrose Intake and 24-Hour Urine Composition

Key Points

Higher dietary intakes of fructose and sucrose are associated with lower 24-hour urine calcium. Higher dietary intakes of fructose and sucrose are associated with other modest changes in 24-hour urine composition.

Background

Consumption of sugar, including fructose and sucrose, is associated with higher risk of kidney stones. The association is believed to be because of an acute rise in urine calcium after sugar intake. However, the association between chronic sugar intake and urine composition is not known.

Methods

We conducted a cross-sectional analysis of dietary intake from a food frequency questionnaire and 24-hour urine collections from 6457 kidney stone- and non–stone-former participants from the Nurses' Health Study I (1,297), Nurses' Health Study II (4,053), and Health Professionals Follow-up Study (1,107). We used multivariate adjusted linear regression to examine the association between long-term intake of free fructose, total fructose, and sucrose and 24-hour urine composition.

Results

Higher free and total fructose and sucrose intakes were each associated with lower 24-hour urine calcium. Comparing the highest versus lowest quintiles, mean urine calcium was 23 (31–15) mg/d lower for free fructose (P -trend <0.001), 26 (34–18) mg/d for total fructose (P -trend <0.001), and 8 (17–1) mg/d for sucrose (P -trend 0.03). Higher total fructose intake was associated with slightly higher calcium phosphate supersaturation (P -trend 0.002), and higher sucrose intake was associated with higher calcium oxalate (P -trend 0.03) and calcium phosphate (P -trend <0.001) supersaturations. Differences in 24-hour urine calcium were similar between kidney stone- and non–stone-former participants.

Conclusions

In contrast to the acute rise in urine calcium previously seen in short-term studies, higher long-term intake of free and total fructose and sucrose was associated with lower 24-hour urine calcium excretion in those with and without a history of kidney stones. Other modest differences in urine composition were noted for each sugar. Future studies should test potential mechanisms for the observed lower 24-hour urine calcium with chronic sugar intake.

The Effects of Different Dietary Patterns on Bone Health

Bone metabolism is a process in which osteoclasts continuously clear old bone and osteoblasts form osteoid and mineralization within basic multicellular units, which are in a dynamic balance. The process of bone metabolism is affected by many factors, including diet. Reasonable dietary patterns play a vital role in the prevention and treatment of bone-related diseases. In recent years, dietary patterns have changed dramatically. With the continuous improvement in the quality of life, high amounts of sugar, fat and protein have become a part of people's daily diets. However, people have gradually realized the importance of a healthy diet, intermittent fasting, calorie restriction, a vegetarian diet, and moderate exercise. Although these dietary patterns have traditionally been considered healthy, their true impact on bone health are still unclear. Studies have found that caloric restriction and a vegetarian diet can reduce bone mass, the negative impact of a high-sugar and high-fat dietary (HSFD) pattern on bone health is far greater than the positive impact of the mechanical load, and the relationship between a high-protein diet (HPD) and bone health remains controversial. Calcium, vitamin D, and dairy products play an important role in preventing bone loss. In this article, we further explore the relationship between different dietary patterns and bone health, and provide a reference for how to choose the appropriate dietary pattern in the future and for how to prevent bone loss caused by long-term poor dietary patterns in children, adolescents, and the elderly. In addition, this review provides dietary references for the clinical treatment of bone-related diseases and suggests that health policy makers should consider dietary measures to prevent and treat bone loss.

A prospective study of changes in bone health in adult cancer patients treated with pelvic radiotherapy

Background

Cancer is a major health problem in today's world. Many patients of pelvic malignancies need treatment by radiation therapy. Post-treatment morbidity due to loss of bone health is less commonly studied. Our study aims at studying the impact of pelvic radiation therapy on bone health including bone mineral density and blood parameters and time of maximum change in Indian patients after pelvic radiotherapy.

Materials and methods

Patients suffering from histologically confirmed pelvic malignancies were included. Patients having metastasis, primary bone tumor or uncontrolled co-morbid conditions were excluded. Patients were treated with concomitant chemoradiation using conventional fractionation of external beam radiotherapy followed by brachytherapy where indicated. T score and Z score of bone mineral density, serum alkaline phosphatase, vitamin D3, phosphorus and calcium were measured before radiation therapy and 6 weeks, three months, and six months after completion of radiation therapy. A p-value ≤ 0.05 was considered statistically significant.

Results

We found that there was a significant decrease in mean Z score and a significant rise of mean serum alkaline phosphatase at three months post radiation therapy. This was associated with an insignificant changes of mean T score, vitamin D3, phosphorus and calcium after radiation therapy. No pelvic insufficiency fractures were detected.

Conclusion

In Indian patients, alkaline phosphatase rises, and Z score falls significantly after radiation therapy at three months after treatment. This suggests maximum bone turnover at three months after treatment. Pharmacological intervention, when necessary, may be considered by careful monitoring of patients by this time.

High Consumption of Sugar-Sweetened Beverages Is Associated with Low Bone Mineral Density in Young People: The Brazilian Birth Cohort Consortium

Sugar-sweetened beverages (SSB) consumption may be associated with a reduction in bone mineral density (BMD). The aim of this study was to evaluate the association between the consumption of SSB and BMD among young people. We performed a cross-sectional study that evaluated 6620 young people (18-23 years of age) from three Brazilian birth cohorts (Ribeirão Preto, Pelotas, and São Luís). We analyzed the daily frequency and the amount and energy contribution of the SSB, which were obtained through a food frequency questionnaire. Total body and lumbar spine BMD (g/cm2), measured by dual-energy X-ray absorptiometry, were the outcomes. Unadjusted linear regression models, adjusted for sex, socioeconomic class, physical activity, smoking, alcohol consumption, and body mass index were used. The highest tertile of SSB consumption frequency (2.1-16.7 times/day) was associated with a lower lumbar spine BMD (β = -0.009; 95% CI: -0.017; -0.001; standardized β = -0.03). This association persisted after adjustment for confounders (β = -0.008; 95% CI: -0.016; -0.001; standardized β = -0.03). No association was observed between SSB consumption frequency and total body BMD or between the amount and energy contribution of SSB and total body or lumbar spine BMD. A high frequency of SSB consumption was associated with a low lumbar spine BMD.

Bone fragility during the COVID-19 pandemic: the role of macro- and micronutrients

Bone fragility is the susceptibility to fracture due to poor bone strength. This condition is usually associated with aging, comorbidities, disability, poor quality of life, and increased mortality. International guidelines for the management of patients with bone fragility include a nutritional approach, mainly aiming at optimal protein, calcium, and vitamin D intakes. Several biomechanical features of the skeleton, such as bone mineral density (BMD), trabecular and cortical microarchitecture, seem to be positively influenced by micro- and macronutrient intake. Patients with major fragility fractures are usually poor consumers of dairy products, fruit, and vegetables as well as of nutrients modulating gut microbiota. The COVID-19 pandemic has further aggravated the health status of patients with skeletal fragility, also in terms of unhealthy dietary patterns that might adversely affect bone health. In this narrative review, we discuss the role of macro- and micronutrients in patients with bone fragility during the COVID-19 pandemic.

Obesity and Bone Health: A Complex Relationship

Recent scientific evidence has shown an increased risk of fractures in patients with obesity, especially in those with a higher visceral adipose tissue content. This contradicts the old paradigm that obese patients were more protected than those with normal weight. Specifically, in older subjects in whom there is a redistribution of fat from subcutaneous adipose tissue to visceral adipose tissue and an infiltration of other tissues such as muscle with the consequent sarcopenia, obesity can accentuate the changes characteristic of this age group that predisposes to a greater risk of falls and fractures. Other factors that determine a greater risk in older subjects with obesity are chronic proinflammatory status, altered adipokine secretion, vitamin D deficiency, insulin resistance and reduced mobility. On the other hand, diagnostic tests may be influenced by obesity and its comorbidities as well as by body composition, and risk scales may underestimate the risk of fractures in these patients. Weight loss with physical activity programs and cessation of high-fat diets may reduce the risk. Finally, more research is needed on the efficacy of anti-osteoporotic treatments in obese patients.

Effects of High-Fructose Corn Syrup on Bone Health and Gastrointestinal Microbiota in Growing Male Mice

Here, we explored the correlation between gut microbiota and bone health and the effects of high-fructose corn syrup (HFCS) on both. Sixteen 3-week-old male C57BL/6J mice were randomly divided into two groups and given purified water (control group) or 30% HFCS in water (HFCS group) for 16 weeks. The effects of HFCS were assessed via enzyme-linked immunosorbent assays, histopathological assays of colon and bone, and 16S rDNA sequence analysis of gut microbiota. The serum of HFCS group mice had lower levels of bone alkaline phosphatase (BALP), bone Gla protein (BGP), insulin-like growth factor 1 (IGF-1), and testosterone, and higher levels of type I collagen carboxyl-terminal telopeptide (ICTP) and tartrate-resistant acid phosphatase (TRAP) than that of the control group. HFCS caused trabecular bone damage by decreasing trabecular number and thickness and increasing trabecular separation. The HFCS group colons were shorter than the control group colons. The HFCS-fed mice showed mild, localized shedding of epithelial cells in the mucosal layer, focal lymphocytic infiltration of the lamina propria, mild submucosal edema, and loosely arranged connective tissue. The HFCS group displayed lower abundance and altered composition of gut microbiota. The abundance of Defluviitaleaceae UCG-011, Erysipelatoclostridium, Ruminococcaceae UCG-009, Lactobacillus, Blautia, and Parasutterella increased, positively correlating with BALP, BGP, IGF-1, and testosterone levels, and negatively correlating with ICTP and TRAP levels. Our study revealed a potential diet-gut microbiota-bone health axis.

The Role of Macronutrients, Micronutrients and Flavonoid Polyphenols in the Prevention and Treatment of Osteoporosis

Osteoporosis is considered an age-related disorder of the skeletal system, characterized primarily by decreased bone mineral density (BMD), microstructural quality and an elevated risk of fragility fractures. This silent disease is increasingly becoming a global epidemic due to an aging population and longer life expectancy. It is known that nutrition and physical activity play an important role in skeletal health, both in achieving the highest BMD and in maintaining bone health. In this review, the role of macronutrients (proteins, lipids, carbohydrates), micronutrients (minerals—calcium, phosphorus, magnesium, as well as vitamins—D, C, K) and flavonoid polyphenols (quercetin, rutin, luteolin, kaempferol, naringin) which appear to be essential for the prevention and treatment of osteoporosis, are characterized. Moreover, the importance of various naturally available nutrients, whether in the diet or in food supplements, is emphasized. In addition to pharmacotherapy, the basis of osteoporosis prevention is a healthy diet rich mainly in fruits, vegetables, seafood and fish oil supplements, specific dairy products, containing a sufficient amount of all aforementioned nutritional substances along with regular physical activity. The effect of diet alone in this context may depend on an individual’s genotype, gene-diet interactions or the composition and function of the gut microbiota.

Kefir alters craniomandibular bone development in rats fed excess dose of high fructose corn syrup

INTRODUCTION

Dietary high fructose corn syrup (HFCS) is involved in the pathogenesis of oral diseases as well as metabolic diseases. The aim of this study was to investigate the effects of HFCS-feeding on the craniomandibular bone development at an early age and also the potential of milk kefir for preventive treatment.

MATERIALS AND METHODS

In this study, Control, Kefir, HFCS, and HFCS plus Kefir groups were formed; kefir was given by gastric gavage, while HFCS (20% beverages) was given in drinking water; for 8 weeks.

RESULTS

Based on morphological evaluations, immunohistochemical, and gene expression results, it was clearly determined that excess dose of HFCS consumption decreased osteoblastic activity in craniomandibular bones while increasing osteoclastic activity. However, it has been determined that the intake of kefir with the HFCS-feeding greatly suppresses the effects of HFCS on bone tissues.

CONCLUSION

In conclusion, dietary the excess dose of HFCS at an early age has been observed to pose a risk for cranial and mandible bone development. The healing effects of kefir may be a new approach to the treatment via kefir consumption in young's.

Sugar-sweetened beverage consumption and bone health: a systematic review and meta-analysis

BACKGROUND

Current evidence demonstrate that sugar-sweetened beverages (SSBs) and bone health are related; however, there has been only a few reviews on the link between SSBs and bone health. A systematic review and meta-analysis was performed to investigate the association between SSBs consumption and bone health in chidren and adults.

METHODS

Relevant studies of SSBs and bone health published up to 15 March 2021 were searched using PubMed, the Web of Science, Cochrane Library, and a reference search. A random-effects meta-analysis was conducted to estimate the standardized mean difference (SMD). Subgroup analyses were performed to identify whether effects were modified by age, sex, measured skeletal sites, type of SSBs, and SSBs intake questionnaire.

RESULTS

Twenty-six publications including 124,691 participants were selected on the review. The results from this meta-analysis showed a significant inverse association between SSBs intake and bone mineral density (BMD) in adults (ES: -0.66, 95% CI: - 1.01, - 0.31, n = 4312). Eighteen of the 20 studies included in the qualitative-only review in children and adults supported the findings from the meta-analysis. When subgroup analysis was performed according to skeletal site, a large effect was found on whole body BMD (ES: -0.97, 95% CI: - 1.54, - 0.40). There was a moderate effect on BMD in females (ES: -0.50, 95% CI: - 0.87, - 0.13). There was a moderate or large effect on BMD in individuals aged under 50 years (under 30 years: ES: -0.57, 95% CI: - 0.97, - 0.17; 30 to 50 years: ES: -1.33, 95% CI: - 1.72, - 0.93). High consumption of carbonated beverages had a moderate effect on BMD (ES: -0.73, 95% CI: - 1.12, - 0.35).

CONCLUSION

The meta-analysis showed that SSBs consumption such as carbonated beverages were inversely related to BMD in adults. Qualitative review supported the results of meta-analysis.

TRIAL REGISTRATION

This review was registered in the PROSPERO database under identifier CRD42020164428 .

Better muscle strength with healthy eating

PURPOSE

Hand grip strength (HGS) can predict physical function in next year when it is positively associated with nutritional and health status. This study aimed to determine the relationship between the healthy eating index (HEI)-2015 and hand grip strength.

METHODS

This cross-sectional study was conducted on data from 4010 participants in the Ravansar non-communicable disease (RaNCD) cohort study. HGS was measured using a hand-held hydraulic hand grip dynamometer. HEI-2015 was calculated using data from the food frequency questionnaire.

RESULTS

The mean of total HEI-2015 score was significantly higher in participants with an optimal HGS than in participants with a weak HGS (P = 0.006). Higher adherence to healthy eating was associated with optimal muscle strength (OR 1.26; CI 95% 1.02-1.62). This association was remained after being adjusted for potential confounders (P = 0.01). Among the HEI-2015 components, we only found association between whole fruit, added sugar, and HGS (P = 0.01, 0.019).

CONCLUSIONS

Our findings indicated that adherence to HEI-2015 could promote muscle strength. Among the HEI-2015 components, higher intake of whole fruit and lower adherence to added sugar had significantly positive effects on HGS.

LEVEL OF EVIDENCE

Level V, descriptive cross-sectional study.

Soy Protein is an Efficacious Alternative to Whey Protein in Sorghum–Soy Fortified Blended Foods in Rats

Background

Previously we found that extruded corn–soy blend (CSB) and sorghum–soy blend (SSB) fortified blended foods (FBFs) containing whey protein concentrate (WPC) were equally nutritious food aid products. WPC provides high-quality protein; however, it is the most expensive ingredient in these FBFs.

Objectives

The primary objective of this study was to determine if soy protein can serve as an alternative to WPC and the secondary objective was to evaluate different sucrose amounts in the FBFs.

Methods

Nine extruded FBFs were formulated: 1 CSB and 1 SSB, both containing 9.5% WPC and 15% sucrose, served as comparison FBFs. Three additional CSB and 4 SSB FBFs were formulated containing no WPC, but with increased soy flour to meet protein requirements and varying sucrose concentrations. The sucrose content ranged from 0% to 10% for the CSBs and 0% to 15% for the SSBs. Male weanling Sprague Dawley rats were individually housed and divided into 10 diet groups (n = 9–10) which consumed either AIN-93G or a dry FBF for 28 d. At study conclusion, blood, livers, and body composition data were collected. Results were analyzed using 1-factor ANOVA with Tukey's test.

Results

Outcomes were not significantly different between the SSB groups, with the exception of significantly higher protein efficiency for the WPC-containing group. Among the CSB groups, caloric and protein efficiencies were significantly higher for the WPC-containing CSB group. There were no significant differences in hemoglobin or hepatic iron concentrations between FBF groups, but hepatic iron concentrations were significantly higher in all FBF groups than in the AIN-93G group. Groups consuming diets with ≤10% sucrose had significantly higher bone mineral density than groups consuming diets with 15% sucrose.

Conclusions

These results suggest that extruded SSB, but not necessarily CSB, FBFs with soy protein and 5%–10% added sucrose are efficacious and cost-effective alternatives to WPC-containing FBFs.

Bone Growth is Influenced by Fructose in Adolescent Male Mice Lacking Ketohexokinase (KHK)

Fructose is metabolized in the cytoplasm by the enzyme ketohexokinase (KHK), and excessive consumption may affect bone health. Previous work in calcium-restricted, growing mice demonstrated that fructose disrupted intestinal calcium transport. Thus, we hypothesized that the observed effects on bone were dependent on fructose metabolism and took advantage of a KHK knockout (KO) model to assess direct effects of high plasma fructose on the long bones of growing mice. Four groups (n = 12) of 4-week-old, male, C57Bl/6 background, congenic mice with intact KHK (wild-type, WT) or global knockout of both isoforms of KHK-A/C (KHK-KO), were fed 20% glucose (control diet) or fructose for 8 weeks. Dietary fructose increased by 40-fold plasma fructose in KHK-KO compared to the other three groups (p < 0.05). Obesity (no differences in epididymal fat or body weight) or altered insulin was not observed in either genotype. The femurs of KHK-KO mice with the highest levels of plasma fructose were shorter (2%). Surprisingly, despite the long-term blockade of KHK, fructose feeding resulted in greater bone mineral density, percent volume, and number of trabeculae as measured by µCT in the distal femur of KHK-KO. Moreover, higher plasma fructose concentrations correlated with greater trabecular bone volume, greater work-to-fracture in three-point bending of the femur mid-shaft, and greater plasma sclerostin. Since the metabolism of fructose is severely inhibited in the KHK-KO condition, our data suggest mechanism(s) that alter bone growth may be related to the plasma concentration of fructose.

Dietary sugar intake does not pose any risk of bone loss and non-traumatic fracture and is associated with a decrease in all-cause mortality among Chinese elderly: Finding from an 11-year longitudinal study of Mr. and Ms. OS Hong Kong

BACKGROUND

The association of dietary sugar intake and skeletal health remains uncertain in the elderly. We aimed to investigate the association of sugar intake with the bone health and mortality of Chinese elderly.

METHODS

An analysis was conducted through an 11-year longitudinal study (Mr. and Ms. OS Hong Kong). Four thousand Chinese elderly aged 65 and older were recruited from the local community between 2001 and 2003. Sugar intake was assessed at baseline by a validated 329-item Food Frequency Questionnaire and a local sugar database. The bone mineral density (BMD) was examined at baseline and the fourth year follow-up by a dual-energy X-ray absorptiometry. Data on the incidence of non-traumatic fractures (total, hip and osteoporotic sites) and all-cause mortality were collected. The multivariable logistic and Cox regression models were used to test the associations of sugar intake with bone health and all-cause mortality.

RESULTS

No significant association was observed between sugar intakes and BMD changes in the fourth year's follow-up. During a total 34,483 person years' follow-up, we documented 433 non-traumatic fractures and 769 deaths. Although lack of significant association with the incidence of non-traumatic fractures, high added sugar intakes were significantly associated with a low risk of all-cause mortality among the elderly with a hazard ratio of 0.750 (95% CI: 0.590-0.954, P for trend = 0.007) in the highest quintile compared with that in the lowest quintile.

CONCLUSION

The amount of sugar consumed by the Chinese elderly did not pose any risk of bone loss and fracture. Moreover, high sugar intake of the elderly was associated with a low rate of all-cause mortality.

High Fructose and High Fat Exert Different Effects on Changes in Trabecular Bone Micro-structure

OBJECTIVES

To compare the effects of high-fat diet (HFD) and high-fructose diet (HFrD) on bone metabolism at different time points, dynamically observe the bone histology and femur trabecular micro-architecture, and analyze the underlying mechanisms.

METHODS

Sixty -Five male 6- to 7-week-old C57BL/6J mice were given HFD, HFrD, or standard diets (SD) for 8, 16, and 24 weeks. Micro-computed tomography (μCT) and bone histology were used to measure bone mass and trabecular micro-structure. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression of genes related to bone and lipid metabolisms.

RESULTS

Compared to SD mice, femoral trabecular bone mass was significantly increased in both HFrD mice and HFD mice at 8 weeks, it continued to be higher in HFrD mice at 16 and 24 weeks with the highest level at 16 weeks, but it was significantly decreased in HFD mice at 16 and 24 weeks. HFD mice showed more epididymal fat accumulation than HFrD mice. mRNA expression of Runx2 was up-regulated at 8 and 16 weeks, but down-regulated at 24 weeks similarly in both HFrD mice and HFD mice. mRNA expression of MMP9 and CTSK was up-regulated at 8 and 16 weeks in HFD mice, but down-regulated at 24 weeks in both HFrD mice and HFD mice.

CONCLUSIONS

Our data indicated that the HFrD and HFD had different modulating effects on bone mass. After short-term feeding, both HFrD and HFD showed positive effects on bone mass; however, after long-term feeding, bone mass was decreased in HFD mice. In contrast, the bone mass was first increased and then decreased in the HFrD mice. On the basis of these findings, we speculated that chronic consumption of fat and fructose would exert detrimental effects on bone mass which might a combination action of body mass, fat mass, and bone formation/bone resorption along with proinflammatory factor and bone marrow environment.

Obesity and type 2 diabetes, not a diet high in fat, sucrose, and cholesterol, negatively impacts bone outcomes in the hyperphagic Otsuka Long Evans Tokushima Fatty rat

BACKGROUND

Obesity and type 2 diabetes (T2D) increase fracture risk; however, the association between obesity/T2D may be confounded by consumption of a diet high in fat, sucrose, and cholesterol (HFSC).

OBJECTIVE

The study objective was to determine the main and interactive effects of obesity/T2D and a HFSC diet on bone outcomes using hyperphagic Otuska Long Evans Tokushima Fatty (OLETF) rats and normophagic Long Evans Tokushima Otsuka (LETO) controls.

METHODS

At 8weeks of age, male OLETF and LETO rats were randomized to either a control (CON, 10 en% from fat as soybean oil) or HFSC (45 en% from fat as soybean oil/lard, 17 en% sucrose, and 1wt%) diet, resulting in four treatment groups. At 32weeks, total body bone mineral content (BMC) and density (BMD) and body composition were measured by dual-energy X-ray absorptiometry, followed by euthanasia and collection of blood and tibiae. Bone turnover markers and sclerostin were measured using ELISA. Trabecular microarchitecture of the proximal tibia and geometry of the tibia mid-diaphysis were measured using microcomputed tomography; whole-bone and tissue-level biomechanical properties were evaluated using torsional loading of the tibia. Two-factor ANOVA was used to determine main and interactive effects of diet (CON vs. HFSC) and obesity/T2D (OLETF vs. LETO) on bone outcomes.

RESULTS

Hyperphagic OLEFT rats had greater final body mass, body fat, and fasting glucose than normophagic LETO, with no effect of diet. Total body BMC and serum markers of bone formation were decreased, and bone resorption and sclerostin were increased in obese/T2D OLETF rats. Trabecular bone volume and microarchitecture were adversely affected by obesity/T2D, but not diet. Whole-bone and tissue-level biomechanical properties of the tibia were not affected by obesity/T2D; the HFSC diet improved biomechanical properties only in LETO rats.

CONCLUSIONS

Obesity/T2D, regardless of diet, negatively impacted the balance between bone formation and resorption and trabecular bone volume and microarchitecture in OLETF rats.

Fat, Sugar, and Bone Health: A Complex Relationship

With people aging, osteoporosis is expected to increase notably. Nutritional status is a relatively easily-modified risk factor, associated with many chronic diseases, and is involved in obesity, diabetes, and coronary heart disease (CHD), along with osteoporosis. Nutrients, such as fats, sugars, and proteins, play a primary function in bone metabolism and maintaining bone health. In Western nations, diets are generally high in saturated fats, however, currently, the nutritional patterns dominating in China continue to be high in carbohydrates from starch, cereals, and sugars. Moreover, high fat or high sugar (fructose, glucose, or sucrose) impart a significant impact on bone structural integrity. Due to diet being modifiable, demonstrating the effects of nutrition on bone health can provide an approach for osteoporosis prevention. Most researchers have reported that a high-fat diet consumption is associated with bone mineral density (BMD) and, as bone strength diminishes, adverse microstructure changes occur in the cancellous bone compartment, which is involved with lipid metabolism modulation disorder and the alteration of the bone marrow environment, along with an increased inflammatory environment. Some studies, however, demonstrated that a high-fat diet contributes to achieving peak bone mass, along with microstructure, at a younger age. Contrary to these results, others have shown that a high-fructose diet consumption leads to stronger bones with a superior microarchitecture than those with the intake of a high-glucose diet and, at the same time, research indicated that a high-fat diet usually deteriorates cancellous bone parameters, and that the incorporation of fructose into a high-fat diet did not aggravate bone mass loss. High-fat/high-sucrose diets have shown both beneficial and detrimental influences on bone metabolism. Combined, these studies showed that nutrition exerts different effects on bone health. Thus, a better understanding of the regulation between dietary nutrition and bone health might provide a basis for the development of strategies to improve bone health by modifying nutritional components.

Metabolic effects of intermittent access to caloric or non-caloric sweetened solutions in mice fed a high-caloric diet

Human consumption of obesogenic diets and soft drinks, sweetened with different molecules, is increasing worldwide, and increases the risk of metabolic diseases. We hypothesized that the chronic consumption of caloric (sucrose, high-fructose corn syrup (HFCS), maltodextrin) and non-caloric (sucralose) solutions under 2-hour intermittent access, alongside the consumption of a high-fat high-sucrose diet, would result in differential obesity-associated metabolic abnormalities in mice. Male C57BL/6 mice had ad libitum access to an HFHS diet and to water (water control group). In addition, some mice had access, 2h/day, 5days/week (randomly chosen) for 12weeks, to different solutions: i) a sucrose solution (2.1kJ/ml), ii) an HFCS solution (2.1kJ/ml), iii) a maltodextrin solution (2.1kJ/ml) and a sucralose solution (60mM) (n=15/group). Despite no changes in total caloric intake, 2h-intermittent access to the sucrose, HFCS or maltodextrin solutions led to increased body weight and accumulation of lipids in the liver when compared to the group consuming water only. The HFCS and sucrose solutions induced a higher fat mass in various fat depots, glucose intolerance, increased glucose oxidation at the expense of lipid oxidation, and a lower hypothalamic expression of NPY in the fasted state. HFCS also reduced proopiomelanocortin expression in the hypothalamus. 2h-intermittent access to sucralose did not result in significant changes in body composition, but caused a stronger expression of CART in the hypothalamus. Finally, sucrose intake showed a trend to increase the expression of various receptors in the nucleus accumbens, linked to dopamine, opioid and endocannabinoid signaling. In conclusion, 2h-intermittent access to caloric solutions (especially those sweetened with sucrose and HFCS), but not sucralose, resulted in adverse metabolic consequences in high-fat high-sucrose-fed mice.

Diets High in Fat or Fructose Differentially Modulate Bone Health and Lipid Metabolism

Diets high in fat or carbohydrates can lead to obesity and diabetes, two interrelated conditions that have been associated with osteoporosis. Here, we contrasted the effects of a high fat (HF) versus fructose-enriched carbohydrate (CH) versus regular chow (SC) diet on bone morphology, fat content and metabolic balance in BALB/cByJ mice over a 15-week period. For 13 weeks, there were no differences in body mass between groups with small differences in the last 2 weeks. Even without the potentially confounding factor of altered body mass and levels of load bearing, HF consumption was detrimental to bone in the distal femur with lower trabecular bone volume fraction and thinner cortices than controls. These differences in bone were accompanied by twofold greater abdominal fat content and fourfold greater plasma leptin concentrations. High-fat feeding caused a decrease in de-novo lipid synthesis in the liver, kidney, white adipose and brown adipose tissue. In contrast to HF, the fructose diet did not significantly impact bone quantity or architecture. Fructose consumption also did not significantly alter leptin levels or de-novo lipid synthesis but reduced epididymal adipose tissue and increased brown adipose tissue. Cortical stiffness was lower in the CH than in HF mice. There were no differences in glucose or insulin levels between groups. Together, a diet high in fat had a negative influence on bone structure, adipose tissue deposition and lipid synthesis, changes that were largely avoided with a fructose-enriched diet.

BMI and BMD: The Potential Interplay between Obesity and Bone Fragility

Recent evidence demonstrating an increased fracture risk among obese individuals suggests that adipose tissue may negatively impact bone health, challenging the traditional paradigm of fat mass playing a protective role towards bone health. White adipose tissue, far from being a mere energy depot, is a dynamic tissue actively implicated in metabolic reactions, and in fact secretes several hormones called adipokines and inflammatory factors that may in turn promote bone resorption. More specifically, Visceral Adipose Tissue (VAT) may potentially prove detrimental. It is widely acknowledged that obesity is positively associated to many chronic disorders such as metabolic syndrome, dyslipidemia and type 2 diabetes, conditions that could themselves affect bone health. Although aging is largely known to decrease bone strength, little is yet known on the mechanisms via which obesity and its comorbidities may contribute to such damage. Given the exponentially growing obesity rate in recent years and the increased life expectancy of western countries it appears of utmost importance to timely focus on this topic.

Fructose consumption does not worsen bone deficits resulting from high-fat feeding in young male rats

Dietary-induced obesity (DIO) resulting from high-fat (HF) or high-sugar diets produces a host of deleterious metabolic consequences including adverse bone development. We compared the effects of feeding standard rodent chow (Control), a 30% moderately HF (starch-based/sugar-free) diet, or a combined 30%/40% HF/high-fructose (HF/F) diet for 12weeks on cancellous/cortical bone development in male Sprague-Dawley rats aged 8weeks. Both HF feeding regimens reduced the lean/fat mass ratio, elevated circulating leptin, and reduced serum total antioxidant capacity (tAOC) when compared with Controls. Distal femur cancellous bone mineral density (BMD) was 23-34% lower in both HF groups (p<0.001) and was characterized by lower cancellous bone volume (BV/TV, p<0.01), lower trabecular number (Tb.N, p<0.001), and increased trabecular separation versus Controls (p<0.001). Cancellous BMD, BV/TV, and Tb.N were negatively associated with leptin and positively associated with tAOC at the distal femur. Similar cancellous bone deficits were observed at the proximal tibia, along with increased bone marrow adipocyte density (p<0.05), which was negatively associated with BV/TV and Tb.N. HF/F animals also exhibited lower osteoblast surface and reduced circulating osteocalcin (p<0.05). Cortical thickness (p<0.01) and tissue mineral density (p<0.05) were higher in both HF-fed groups versus Controls, while whole bone biomechanical characteristics were not different among groups. These results demonstrate that "westernized" HF diets worsen cancellous, but not cortical, bone parameters in skeletally-immature male rats and that fructose incorporation into HF diets does not exacerbate bone loss. In addition, they suggest that leptin and/or oxidative stress may influence DIO-induced alterations in adolescent bone development.

Effects of a metabolic syndrome induced by a fructose-rich diet on bone metabolism in rats

OBJECTIVE

The aims of this study were: first, to evaluate the possible effects of a fructose rich diet (FRD)-induced metabolic syndrome (MS) on different aspects of long bone histomorphometry in young male rats; second, to investigate the effects of this diet on bone tissue regeneration; and third, to correlate these morphometric alterations with changes in the osteogenic/adipogenic potential and expression of specific transcription factors, of marrow stromal cells (MSC) isolated from rats with fructose-induced MS.

MATERIALS/METHODS

MS was induced in rats by treatment with a FRD for 28 days. Halfway through treatment, a parietal wound was made and bone healing was evaluated 14 days later. After treatments, histomorphometric analysis was performed in dissected femoral and parietal bones. MSC were isolated from the femora of control or fructose-treated rats and differentiated either to osteoblasts (evaluated by type 1 collagen, Alkaline phosphatase and extracellular nodule mineralization) or to adipocytes (evaluated by intracellular triglyceride accumulation). Expression of Runx2 and PPARγ was assessed by Western blot.

RESULTS

Fructose-induced MS induced deleterious effects on femoral metaphysis microarchitecture and impaired bone regeneration. Fructose treatment decreased the osteogenic potential of MSC and Runx2 expression. In addition, it increased the adipogenic commitment of MSC and PPARγ expression.

CONCLUSIONS

Fructose-induced MS is associated with deleterious effects on bone microarchitecture and with a decrease in bone repair. These alterations could be due to a deviation in the adipogenic/osteogenic commitment of MSC, probably by modulation of the Runx2/PPARγ ratio.

Bone quality and strength are greater in growing male rats fed fructose compared with glucose

Optimization of peak bone mass during adolescence is important for osteoporosis prevention. Studies in rodents and humans have demonstrated the harmful effects of sugar intake on bone health. With the high levels of sucrose in the diets of adolescents, it is necessary to understand the influence of glucose and fructose on growing bones. This study compared the effects of dietary glucose and fructose on bone formation, microarchitecture, and strength. Because of the different metabolic effects of glucose and fructose, we hypothesized that their individual effects on bone would be different. Eighteen male Sprague-Dawley rats (age, 60 days) were randomly assigned to high-fructose (n = 9; 40% fructose, 10% glucose) or high-glucose diet (n = 9; 50% glucose) for 12 weeks. Bone measurements included histology and histomorphometry of trabecular bone in the distal femur and a 3-point bending test of the whole tibia. Whole liver mass and postprandial serum glucose, insulin, and triglycerides were used to assess differences in energy metabolism between the diets. There were no differences in food intake, body weight, or visceral adiposity between groups, but fructose consumption led to heavier livers (P = .001) and elevated serum triglycerides (P = .00). The distal femurs of fructose-fed rats had greater bone volume (bone volume/total volume; P = .03), lower bone surface (bone surface/bone volume; P = .02), and thicker trabeculae (trabecular thickness; P = .01). The tibias of the fructose-fed rats also withstood a greater maximum flexure load (P = .032). These results indicate that consumption of the high-fructose diet resulted in stronger bones with enhanced microarchitecture than consumption of the high-glucose diet.

Bone health: part 1, nutrition

Nutrition, in sufficient amount and substance, is crucial for healthy growth and development of the skeleton and surrounding tissues, especially in physically active populations. Inadequate nutrition has been linked to maladies such as the female athlete triad, as well as poor training or competitive performance and increased risk of injury. Dietary choices favoring items high in quality protein of animal or plant origin, polyunsaturated fatty acids, fruits and vegetables high in potassium and fiber, and dairy products or other beverages fortified with calcium and vitamin D are essential to athletes to ensure adequate vitamin and mineral availability to the skeleton, which in turn can affect peak physical performance.

Yacon flour and Bifidobacterium longum modulate bone health in rats

Yacon flour has been considered a food with prebiotic potential because of the high levels of fructooligosaccharides, which allows for its use in formulating synbiotic foods. The purpose of this study was to evaluate the effect of yacon flour and probiotic (Bifidobacterium longum) on the modulation of variables related to bone health. Thirty-two Wistar rats were divided into 4 groups: control, yacon flour, diet+B. longum, and yacon flour+B. longum. After euthanasia, the bones were removed for analysis of biomechanical properties (thickness, length, and strength of fracture) and mineral content (Ca, Mg, and P); the cecum was removed for analysis of the microbiota and short-chain fatty acids. Tibia Ca, P, and Mg content was significantly (P<.05) higher in groups fed diet+B. longum, yacon flour+B. longum than in the control group. An increase in fracture strength was observed in the yacon flour (8.1%), diet+B. longum (8.6%), and yacon flour+B. longum (14.6%) in comparison to the control group. Total anaerobe and weight of the cecum were higher (P<.05) in rats consuming the yacon flour diet compared with the other groups. Cecal concentration of propionate was higher in all experimental groups compared with the control (P<.05). Yacon flour in combination with B. longum helped increase the concentration of minerals in bones, an important factor in the prevention of diseases such as osteoporosis.

Consumption of different sources of omega-3 polyunsaturated fatty acids by growing female rats affects long bone mass and microarchitecture

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) consumption has been reported to improve bone health. However, sources of ω-3 PUFAs differ in the type of fatty acids and structural form. The study objective was to determine the effect of various ω-3 PUFAs sources on bone during growth. Young (age 28d) female Sprague-Dawley rats were randomly assigned (n=10/group) to a high fat 12% (wt) diet consisting of either corn oil (CO) or ω-3 PUFA rich, flaxseed (FO), krill (KO), menhaden (MO), salmon (SO) or tuna (TO) for 8 weeks. Bone mass was assessed by dual-energy X-ray absorptiometry (DXA) and bone microarchitecture by micro-computed tomography (μCT). Bone turnover markers were measured by enzyme immunoassay. Lipid peroxidation was measured by calorimetric assays. Results showed that rats fed TO, rich in docosahexaenoic acid (DHA, 22:6ω-3) had higher (P<0.009) tibial bone mineral density (BMD) and bone mineral content (BMC) and lower (P=0.05) lipid peroxidation compared to the CO-fed rats. Reduced lipid peroxidation was associated with increased tibial BMD (r2=0.08, P=0.02) and BMC (r2=0.71, P=0.01). On the other hand, rats fed FO or MO, rich in alpha-linolenic acid (ALA, 18:3ω-3), improved bone microarchitecture compared to rats fed CO or SO. Serum osteocalcin was higher (P=0.03) in rats fed FO compared to rats fed SO. Serum osteocalcin was associated with improved trabecular bone microarchitecture. The animal study results suggest consuming a variety of ω-3 PUFA sources to promote bone health during the growth stage.

Fructose and metabolic diseases: new findings, new questions

There has been much concern regarding the role of dietary fructose in the development of metabolic diseases. This concern arises from the continuous increase in fructose (and total added caloric sweeteners consumption) in recent decades, and from the increased use of high-fructose corn syrup (HFCS) as a sweetener. A large body of evidence shows that a high-fructose diet leads to the development of obesity, diabetes, and dyslipidemia in rodents. In humans, fructose has long been known to increase plasma triglyceride concentrations. In addition, when ingested in large amounts as part of a hypercaloric diet, it can cause hepatic insulin resistance, increased total and visceral fat mass, and accumulation of ectopic fat in the liver and skeletal muscle. These early effects may be instrumental in causing, in the long run, the development of the metabolic syndrome. There is however only limited evidence that fructose per se, when consumed in moderate amounts, has deleterious effects. Several effects of a high-fructose diet in humans can be observed with high-fat or high-glucose diets as well, suggesting that an excess caloric intake may be the main factor involved in the development of the metabolic syndrome. The major source of fructose in our diet is with sweetened beverages (and with other products in which caloric sweeteners have been added). The progressive replacement of sucrose by HFCS is however unlikely to be directly involved in the epidemy of metabolic disease, because HFCS appears to have basically the same metabolic effects as sucrose. Consumption of sweetened beverages is however clearly associated with excess calorie intake, and an increased risk of diabetes and cardiovascular diseases through an increase in body weight. This has led to the recommendation to limit the daily intake of sugar calories.

Metabolic effects of fructose and the worldwide increase in obesity

While virtually absent in our diet a few hundred years ago, fructose has now become a major constituent of our modern diet. Our main sources of fructose are sucrose from beet or cane, high fructose corn syrup, fruits, and honey. Fructose has the same chemical formula as glucose (C(6)H(12)O(6)), but its metabolism differs markedly from that of glucose due to its almost complete hepatic extraction and rapid hepatic conversion into glucose, glycogen, lactate, and fat. Fructose was initially thought to be advisable for patients with diabetes due to its low glycemic index. However, chronically high consumption of fructose in rodents leads to hepatic and extrahepatic insulin resistance, obesity, type 2 diabetes mellitus, and high blood pressure. The evidence is less compelling in humans, but high fructose intake has indeed been shown to cause dyslipidemia and to impair hepatic insulin sensitivity. Hepatic de novo lipogenesis and lipotoxicity, oxidative stress, and hyperuricemia have all been proposed as mechanisms responsible for these adverse metabolic effects of fructose. Although there is compelling evidence that very high fructose intake can have deleterious metabolic effects in humans as in rodents, the role of fructose in the development of the current epidemic of metabolic disorders remains controversial. Epidemiological studies show growing evidence that consumption of sweetened beverages (containing either sucrose or a mixture of glucose and fructose) is associated with a high energy intake, increased body weight, and the occurrence of metabolic and cardiovascular disorders. There is, however, no unequivocal evidence that fructose intake at moderate doses is directly related with adverse metabolic effects. There has also been much concern that consumption of free fructose, as provided in high fructose corn syrup, may cause more adverse effects than consumption of fructose consumed with sucrose. There is, however, no direct evidence for more serious metabolic consequences of high fructose corn syrup versus sucrose consumption.

Dietary fructose inhibits intestinal calcium absorption and induces vitamin D insufficiency in CKD

Renal disease leads to perturbations in calcium and phosphate homeostasis and vitamin D metabolism. Dietary fructose aggravates chronic kidney disease (CKD), but whether it also worsens CKD-induced derangements in calcium and phosphate homeostasis is unknown. Here, we fed rats diets containing 60% glucose or fructose for 1 mo beginning 6 wk after 5/6 nephrectomy or sham operation. Nephrectomized rats had markedly greater kidney weight, blood urea nitrogen, and serum levels of creatinine, phosphate, and calcium-phosphate product; dietary fructose significantly exacerbated all of these outcomes. Expression and activity of intestinal phosphate transporter, which did not change after nephrectomy or dietary fructose, did not correlate with hyperphosphatemia in 5/6-nephrectomized rats. Intestinal transport of calcium, however, decreased with dietary fructose, probably because of fructose-mediated downregulation of calbindin 9k. Serum calcium levels, however, were unaffected by nephrectomy and diet. Finally, only 5/6-nephrectomized rats that received dietary fructose demonstrated marked reductions in 25-hydroxyvitamin D(3) and 1,25-dihydroxyvitamin D(3) levels, despite upregulation of 1alpha-hydroxylase. In summary, excess dietary fructose inhibits intestinal calcium absorption, induces marked vitamin D insufficiency in CKD, and exacerbates other classical symptoms of the disease. Future studies should evaluate the relevance of monitoring fructose consumption in patients with CKD.

Effect of moderate intake of sweeteners on metabolic health in the rat

The rise in prevalence of obesity, diabetes, metabolic syndrome, and fatty liver disease has been linked to increased consumption of fructose-containing foods or beverages. Our aim was to compare the effects of moderate consumption of fructose-containing and non-caloric sweetened beverages on feeding behavior, metabolic and serum lipid profiles, and hepatic histology and serum liver enzymes, in rats. Behavioral tests determined preferred (12.5-15%) concentrations of solutions of agave, fructose, high fructose corn syrup (HFCS), a combination of HFCS and Hoodia (a putative appetite suppressant), or the non-caloric sweetener Stevia (n=5/gp). HFCS intake was highest, in preference and self-administration tests. Groups (n=10/gp) were then assigned to one of the sweetened beverages or water as the sole source of liquid at night (3 nights/wk, 10wks). Although within the normal range, serum cholesterol was higher in the fructose and HFCS groups, and serum triglycerides were higher in the Agave, HFCS, and HFCS/Hoodia groups (vs. water-controls, p<0.05). Liver histology was normal in all groups with no evidence of steatosis, inflammation, or fibrosis; however serum alanine aminotransferase was higher in the fructose and HFCS groups (vs. water-controls, p<0.05). Serum inflammatory marker levels were comparable among Stevia, agave, fructose, HFCS, and water-consuming groups, however levels of IL-6 were significantly lower in association with the ingestion of Hoodia. There were no differences in terminal body weights, or glucose tolerance assessed by 120-min IVGTTs performed at the end of the 10-week regimen. We conclude that even moderate consumption of fructose-containing liquids may lead to the onset of unfavorable changes in the plasma lipid profile and one marker of liver health, independent of significant effects of sweetener consumption on body weight.