The effects of high potassium consumption on bone mineral density in a prospective cohort study of elderly postmenopausal women

Effect of salt substitution on fracture-a secondary analysis of the Salt Substitute and Stroke Study (SSaSS)

BACKGROUND

Associations of dietary sodium and potassium intake with fracture risk are inconsistent and the effects of salt substitute on fracture incidence are unknown. We assessed the effect of salt substitute compared to regular salt intake on fracture incidence using data from the Salt Substitute and Stroke Study (SSaSS).

METHODS

SSaSS was a cluster-randomized controlled trial conducted in 600 villages in northern China. Villages were randomly allocated into intervention and control groups in a 1:1 ratio. Salt substitute was provided to intervention villages and control villages continued regular salt use for 5 years. The primary outcome for this secondary analysis was the incidence of all fractures. Secondary outcomes included incidence of vertebral fracture, non-vertebral fracture, and fracture of unknown or non-specific location.

RESULTS

20,995 participants were included in this study, and 821 fractures occurred during follow-up. Intention-to-treat analyses showed no differences between the salt substitute and regular salt groups in the incidence of all fractures (rate ratio (RR) 0.96; 95% CI 0.81 to 1.14), vertebral fracture (RR 0.82; 95% CI 0.53 to 1.26), non-vertebral fracture (RR 1.05; 95% CI 0.86 to 1.29), or fracture of unknown or non-specific location (RR 0.80; 95% CI 0.54 to 1.18).

CONCLUSIONS

Use of salt substitute compared to regular salt had no detectable effect on the incidence of fracture in a population at high risk of cardiovascular disease and fracture.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02092090. Registered on March 12, 2014.

Exploring biomarkers of osteosarcopenia in older adults attending a frailty clinic

Osteosarcopenia is a new definitional approach that can increase the risk of falls and fractures in elderly compared with that of osteoporosis and sarcopenia alone. However, biomarkers for osteosarcopenia have not been well identified. Thus, we aimed to explore the biomarkers of osteosarcopenia, including bone, muscle, and geriatric markers. Outpatients attending a frailty clinic were enrolled in the study. Osteosarcopenia was defined as the coexistence of osteoporosis and sarcopenia. Osteoporosis was defined according to the criteria of the Japan Osteoporosis Society. Sarcopenia was defined according to the Asian Working Group for Sarcopenia consensus (2019). We selected 35 blood/serum pathological parameters, including bone, inflammation, nutritional, and aging markers for the study. Logistic regression analysis for osteosarcopenia was performed to explore the biomarkers of osteosarcopenia. Of the total 600 patients with a mean age of 76.6 years, 595 were enrolled in the registry during the study period. Logistic regression analysis for osteosarcopenia showed that elevated thyroid-stimulating hormone (TSH) (odds ratio [OR]:1.375; 95 % confidence interval [CI]: 1.092-1.731), bone-specific alkaline phosphatase (BAP) (OR: 1.059; 95 % CI: 1.002-1.120), and estimated glomerular filtration rate (eGFR) (OR: 1.029; 95 % CI: 1.007-1.053) increased the likelihood of osteosarcopenia. On the other hand, elevated 25-hydroxyvitamin D (25OHD) (OR: 0.905; 95 % CI: 0.841-0.974), blood urea nitrogen (BUN) (OR: 0.895; 95 % CI: 0.829-0.966) and K (OR: 0.241; 95 % CI: 0.081-0.717) decreased the likelihood of osteosarcopenia. It is worthwhile to examine these biomarkers for older adult outpatients attending a frailty clinic for screening osteosarcopenia. Further studies are needed to investigate the effects of other markers of bone metabolism.

The Relationship between Dietary Na/K Ratio and Bone Mineral Density in Korean Middle-Aged Women

BACKGROUND

Dietary Na+ or Na+/K+ ratio has been reported to be associated with bone mineral density (BMD). However, this remains unclear, and only a few studies have been reported on the Korean population. Therefore, this study aimed to determine the association between dietary Na+, K+, and Na+/K+ ratios and BMD in middle-aged Korean women.

METHODS

This study used data from the Korea National Health and Nutrition Examination Survey 2008-2011. A total of 3,690 women aged >50 years were included. Study participants were classified into quartiles (lowest quartile Q1-highest quartile Q4) according to dietary Na+, K+, and Na+/K+ ratio, and we examined the association of these parameters with BMD. Total femur and lumbar spine BMD were measured using dual-energy X-ray absorptiometry. Multiple linear regression analyses were performed using IBM SPSS ver. 19.0.

RESULTS

The mean age was 62 years, and a significant negative trend in the β-coefficient regarding dietary Na+ was only observed in the total femur BMD. However, the total femur and lumbar spine BMD decreased from Q1 to Q4 regarding the dietary Na+/K+ ratio (P-value for trend: 0.044 for total femur BMD and 0.002 for lumbar spine BMD).

CONCLUSION

A significant negative trend in the β-coefficient for both total femur and lumbar spine BMD was observed regarding the Na+/K+ ratio. Therefore, based on the results of this study, a higher dietary Na+/K+ ratio may be associated with a lower 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.

Introductory Chapter: Potassium in Human Health

Collapse

Potassium intake is associated with nutritional quality and actual diet cost: a study at formulating a low sodium high potassium (LSHP) healthy diet

Increasing potassium and reducing sodium intake have been identified as a priority intervention to reduce non-communicable diseases. A low sodium high potassium (LSHP) healthy diet can be a predictor of overall dietary quality and is associated with higher diet costs. The present study was a randomised controlled-feeding trial, formulating menus of low sodium and potassium-rich healthy diet and comparing with usual diet (a control diet based on typical Indonesian diet) to assess the association of potassium intake in the menus with other nutritional contents and diet cost. Totally seventy menus, which consisted of LSHP diets and the usual diets for a 7-d cycle, were composed from the analysis of the Indonesian food composition database. The correlation coefficient of the potassium content of all menus with nutritional quality and diet cost was analysed using the Pearson test. Multiple linear regression analysis was performed to determine the most important nutrient in determining diet cost. A comparison of nutrition quality and diet cost from the two menus was analysed using the independent t-test. LSHP diet had significantly higher carbohydrate, protein, fibre, magnesium, calcium, vitamin C, potassium density and diet cost but lower total fat, saturated fat and energy density than the usual diet (P < 0⋅05). Furthermore, there was a strong positive correlation between fibre, potassium and diet cost (coefficient correlation of >0⋅8). Potassium is a nutrient that is closely related to diet quality although the cost of the diet often may inhibit its intake. A targeted and effective strategy is required to provide affordable food for achieving a sustainable nutrient-rich diet.

The influence of vegetarian and vegan diets on the state of bone mineral density in humans

There are so many literatures about vegetarians being less prone to chronic, noninfectious diseases, which are, however, the main cause of the decline in quality of life and mortality in developed countries.However, according to various scientific sources, vegetarian and especially vegan diets often contain less saturated fats, protein, calcium, vitamins D and B12, or long-chain ω-3 PUFAs. One of the most common pathology associated with a predominantly plant diet is osteopenia and osteoporosis. An analysis of 13 studies has shown that vegetarians and vegans are at a higher risk of reducing of bone mineral density, thereby increasing the incidence of fractures.At the same time, plant-based diets are usually richer in many other micronutrients important for bone health: vitamins C and K, carotenoids, potassium, magnesium, manganese, copper, or silicon. Moreover, with the deepening of our knowledge about the role of nutrients in the body and the features of the nutritional status of the population, the quality of vegetarian and vegan diets also increases. They are less and less prone to micronutrient deficiencies. Recent studies show that BMD, as well as the risk of osteoporotic fractures, at least in vegetarians, equaled these indicators in omnivores.

Sintering of Potassium Doped Hydroxy-Fluorapatite Bioceramics

The present study describes the influence of potassium and hydroxyl substitutions on the structural, thermal and mechanical properties of fluorapatite bioceramics. A set of non-stoichiometric ion-substituted compounds, with a chemical formula of Ca10−xKx(PO4)6F(2−2x)(OH)x with 0 ≤ x ≤ 1 synthesized by the wet precipitation method, were found to be single-phase apatites crystallizing in the hexagonal P63/m space group. The structural parameters, as well as the crystallite sizes, increased accordingly to the amount of added dopant-ions. The thermal behavior of these compounds, studied within the temperature range 500–1200 °C, indicated a partial decomposition of the apatitic phase and its transformation to tricalcium phosphate β-Ca3(PO4)2 at temperatures exceeding 750 °C. A relative density of the sintered samples achieved the highest value with x = 0.25 and reached about 95% after sintering at 1050 °C for 1 h. The microstructures of the sintered samples were of a trans-granular aspect and experienced an increase in the radius of their pores as x increased. The prepared bioceramic materials were mechanically characterized by means of Young’s modulus, flexural strength and fracture toughness measurements. The overall trend of these parameters evolved comparably to the relative density, and the maximum values obtained for x = 0.25 were measured to be 96 MPa, 47 MPa and 1.14 MPa·m1/2, respectively.

Diet Modulates the Effects of Genetic Variants on the Vitamin D Metabolic Pathway and Bone Mineral Density in Mexican Postmenopausal Women

BACKGROUND

Macro- and micronutrients, such as proteins, vitamin D, and calcium (Ca), are important dietary factors that can modify bone mineral density (BMD). Genetic factors can interact with diet, affecting an individual's predisposition to osteoporosis.

OBJECTIVES

This study aimed to evaluate the associations between macro- and micronutrient intakes and BMD in Mexican postmenopausal women, and their interactions with genetic polymorphisms involved in the vitamin D metabolic pathway.

METHODS

We analyzed data from 317 postmenopausal women from the Health Workers Cohort Study, a longitudinal cohort studied in Cuernavaca, Mexico. Postmenopausal women participated in 2 data collection waves (2004-2006 and 2010-2011), with a mean time of 6.4 years. Dietary intake was assessed with a semi-quantitative FFQ. BMD (femoral neck, hip, and lumbar spine) was measured by DXA. Hybrid mixed-effects regression models were used to assess the associations of dietary macro- and micronutrients on BMD, after adjusting for confounding factors and for diet and single nucleotide polymorphism interactions.

RESULTS

At baseline, the median age was 57 years (IQR, 50-64). Mean femoral neck, hip, and lumbar spine BMDs decreased over time. We observed statistically significant longitudinal associations for diet (Ca, vitamin D, magnesium, phosphorus, and protein intake) and BMD. Increases of vitamin D, Ca, and protein intakes by 1 SD were associated with mean increases in the femoral neck BMD (0.083 SD, 0.064 SD, and 0.130 SD, respectively). Multiple significant interactions were identified between several loci (CYP2R1, CYP24A1, CYP27B1, VDR, and DHCR7/NADSYN1) and diet for BMDs (femoral neck, hip, and lumbar spine), mainly for protein intake.

CONCLUSIONS

Our data support associations of vitamin D, Ca, protein, phosphorous, and magnesium consumption with BMD in Mexican postmenopausal women and suggest possible gene-diet interactions. These results could facilitate future personalized nutrition recommendations to help prevent low BMD.

Optimizing Diet to Slow CKD Progression

Due to the unique role of the kidney in the metabolism of nutrients, patients with chronic kidney disease (CKD) lose the ability to excrete solutes and maintain homeostasis. Nutrient intake modifications and monitoring of nutritional status in this population becomes critical, since it can affect important health outcomes, including progression to kidney failure, quality of life, morbidity, and mortality. Although there are multiple hemodynamic and metabolic factors involved in the progression and prognosis of CKD, nutritional interventions are a central component of the care of patients with non-dialysis CKD (ND-CKD) and of the prevention of overweight and possible protein energy-wasting. Here, we review the reno-protective effects of diet in adults with ND-CKD stages 3-5, including transplant patients.

DASH Dietary Pattern: A Treatment for Non-communicable Diseases

Non-communicable diseases are the major inducer of mortality and morbidity in the Western world. In terms of nutrition, a diet high in fat (particularly saturated fat), salt and sugars have shown to be associated with innumerable incidence of diet- associated health diseases. Dietary modification is a central part of any treatment strategy. The Dietary Approach to Stop Hypertension (DASH) diet is one among such healthy dietary patterns, which emphasizes on the consumption of fruits, vegetables and low-fat dairy foods, including whole grains, poultry, fish, and small quantities of red meat, sweets and drinks containing sugar. This study provides certain practical evidence that prolonged adoption of DASH diet which can be a useful treatment for numerous non-communicable diseases with a sustained effect on the health that involves both accessibility and proximity to healthy eating choices. Long-term studies are required to assess whether these effects are maintained over time.

Relationship between heavy metal accumulation and histological alterations in voles from alpine and forest habitats of the West Carpathians

The interaction between toxic heavy metals and bio-elements in internal organs and femoral bones and their potential impacts on bone structural properties and renal histopathological changes in bank voles and snow voles were investigated. Our results reveal that heavy metals Hg and Pb accumulate more in femoral bones of alpine habitats than forests. In snow voles, the parameters of the primary osteons' vascular canals (length, average perimeter and area) simultaneously decreased with an increase of Pb and Sr. Wider primary osteons' vascular canals of snow voles contained decreased levels of K, but increased Ba. In bank voles, the number of primary osteons increased in alpine habitats along with K, Hg, and Pb accumulation. In the kidneys of bank voles, rising levels of Rb, Hg, and Zn were detected in alpine habitats. Hg increases the most in kidney tissue from alpine habitats in both vole species, and Hg levels (mean value 0.25 μg/g, max. value 0.55 μg/g) in the renal tissues of bank voles from alpine localities are similar to Hg levels from Hg-polluted industrial areas in other studies. This reflects that alpine areas of the Tatra Mountains are highly contaminated with Hg. The intensity of renal hemosiderosis relates significantly to Zn, Fe, and Cu levels in snow voles, with Fe and Zn levels in bank voles from forest habitats, and with Rb in bank voles from alpine habitats. The intensity of tubule necrosis in renal tissues of bank voles from alpine habitats was negatively related to Se content. In bank voles from forest habitats, significant positive correlations were found between the intensity of glomerular hyperplasia and amounts of Zn. The interactions of the detected element's association with bone tissue and internal organs are discussed.

A Review of Nutritional Requirements of Adults Aged ≥65 Years in the UK

Appropriate dietary choices in later life may reduce the risk of chronic diseases and rate of functional decline, however, there is little well-evidenced age-specific nutritional guidance in the UK for older adults, making it challenging to provide nutritional advice. Therefore, the aim of this critical review was to propose evidence-based nutritional recommendations for older adults (aged ≥65 y). Nutrients with important physiological functions in older adults were selected for inclusion in the recommendations. For these nutrients: 1) recommendations from the UK Scientific Advisory Committee for Nutrition (SACN) reports were reviewed and guidance retained if recent and age-specific, and 2) a literature search conducted where SACN guidance was not sufficient to set or confirm recommendations for older adults, searching Web of Science up to March 2020. Data extracted from a total of 190 selected publications provided evidence to support age-specific UK recommendations for protein (1.2 g·kg-1·d-1), calcium (1000 mg·d-1), folate (400 μg·d-1), vitamin B-12 (2.4 μg·d-1), and fluid (1.6 L·d-1 women, 2.0 L·d-1 men) for those ≥65 y. UK recommendations for carbohydrates, free sugars, dietary fiber, dietary fat and fatty acids, sodium, and alcohol for the general population are likely appropriate for older adults. Insufficient evidence was identified to confirm or change recommendations for all other selected nutrients. In general, significant gaps in current nutritional research among older adults existed, which should be addressed to support delivery of tailored nutritional guidance to this age group to promote healthy aging.

The association of potassium intake with bone mineral density and the prevalence of osteoporosis among older Korean adults

BACKGROUND/OBJECTIVES

Osteoporosis is characterized by low bone mass and results in vulnerability to fracture. Calcium and vitamin D are known to play an important role in bone health. Recently, potassium has been identified as another important factor in skeletal health. We examined the link between potassium intake and bone health among the Korean older adult population.

SUBJECTS/METHODS

This retrospective, cross-sectional study included 8,732 men and postmenopausal women over 50 years old who completed the Korean National Health and Nutrition Survey (KNHANES) between 2008 and 2011. Potassium consumption was evaluated using a 24-hour recall method. Bone mineral density (BMD) was measured at three sites (total hip, femur neck, and lumbar spine) by dual-energy X-ray absorptiometry (DEXA). Multinomial logistic regression was used to examine the link between potassium intake and prevalence of osteoporosis and osteopenia, after controlling for potential confounding variables.

RESULTS

The BMD of the total femur and Ward's triangle were significantly different according to the potassium intake among men (P = 0.031 and P = 0.010, respectively). Women in the top tertile for potassium intake showed higher BMD than those in the bottom tertile at all measurement sites (all P < 0.05). Daily potassium intake was significantly related to a decreased risk of osteoporosis at the lumbar spine in postmenopausal women (odds ratios: 0.68, 95% confidence interval: 0.48-0.96, P trend = 0.031). However, the dietary potassium level was not related to the risk of osteoporosis in men.

CONCLUSION

Current findings indicate that higher dietary potassium levels have a favorable effect on bone health and preventing osteoporosis in older Korean women.

PDO Rotonda’s Red Eggplant Extract: In vitro Determination of Biological Properties and Minerals Bioaccessibility

Background:

The Rotonda’s Red Eggplant belongs to the family of Solanum aethiopicum and it is cultivated in a specific area of Potenza (Basilicata, South of Italy) including villages of Rotonda, Viggianello, Castelluccio Superiore and Castelluccio Inferiore. The Red Eggplant cultivated in this area has gained the PDO, “Protected Designation of Origin”.

Objective:

The aim of this research was to evaluate the use of PDO Rotonda’s Red Eggplant extract as a possible nutraceutical supplement. The antioxidant, antihypertensive, hypoglycemic, and hypolipidemic properties were in vitro evaluated.

Methods:

The antioxidant activity was investigated by evaluating the scavenging properties against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals and by performing the Ammonium Molybdate and Folin-Ciocalteu assay. The hypoglycemic and antihypertensive activity was studied by evaluating the α-Amylase, α-Glucosidase and Angiotensin Converting Enzyme, respectively, inhibiting activity. In order to evaluate the hypolipidemic activity, the pancreatic lipase inhibiting property was determined and Oil Red O staining assay was performed. Finally, to evaluate the possible use of this extract as a minerals supplement, Selenium, Potassium and Chrome bioaccessibility was studied.

Results:

The obtained results underline the good antioxidant, hypoglycemic, antihypertensive and hypolipidemic in vitro properties of the PDO Rotonda’s Red Eggplant extract. Moreover, the obtained data show a higher minerals bioaccessibility and this higher value could be ascribable to the natural phytocomplex of PDO Rotonda’s Red Eggplant, which increases the minerals bioaccessibility if compare it with a control sample.

Conclusion:

The obtained results show that PDO Rotonda’s Red Eggplant extract, might be used as a possible nutraceutical supplement, along with traditional therapies, both for its biological properties and for its minerals bioaccessibility value.

Effect of Dietary Sodium and Potassium Intake on the Mobilization of Bone Lead among Middle-Aged and Older Men: The Veterans Affairs Normative Aging Study

Bone is a major storage site as well as an endogenous source of lead in the human body. Dietary sodium and potassium intake may play a role in the mobilization of lead from bone to the circulation. We examined whether association between bone lead and urinary lead, a marker of mobilized lead in plasma, was modified by dietary intake of sodium and potassium among 318 men, aged 48–93 years, in the Veterans Affairs (VA) Normative Aging Study. Dietary sodium and potassium were assessed by flame photometry using 24-h urine samples, and a sodium-to-potassium ratio was calculated from the resulting measures. Patella and tibia bone lead concentrations were measured by K-shell-x-ray fluorescence. Urinary lead was measured by inductively coupled plasma mass spectroscopy in 24-h urine samples. Linear regression models were used to regress creatinine clearance-corrected urinary lead on bone lead, testing multiplicative interactions with tertiles of sodium, potassium, and sodium-to-potassium ratio, separately. After adjustment for age, body mass index, smoking, vitamin C intake, calcium, and total energy intake, participants in the highest tertile of sodium-to-potassium ratio showed 28.1% (95% CI: 12.5%, 45.9%) greater urinary lead per doubling increase in patella lead, whereas those in the second and lowest tertiles had 13.8% (95% CI: −1.7%, 31.7%) and 5.5% (95% CI: −8.0%, 21.0%) greater urinary lead, respectively (p-for-interaction = 0.04). No statistically significant effect modification by either sodium or potassium intake alone was observed. These findings suggest that relatively high intake of sodium relative to potassium may play an important role in the mobilization of lead from bone into the circulation.

Dietary potassium intake is beneficial to bone health in a low calcium intake population: the Korean National Health and Nutrition Examination Survey (KNHANES) (2008-2011)

Dietary potassium may neutralize acid load and reduce calcium loss from the bone, leading to beneficial effect on bone mineral density. In this nationwide Korean population study, dietary potassium intake was associated with improved bone mineral density in older men and postmenopausal women.

INTRODUCTION

Nutrition is a major modifiable factor that affects bone health. The accompanying anion in dietary potassium may act as an alkaline source by neutralizing the acid load and reducing calcium loss from the bone. We aimed to evaluate the association between dietary potassium intake and bone mineral density (BMD) in the Korean population.

METHODS

We analyzed a total of 3135 men aged >50 years and 4052 postmenopausal women from the Korean National Health and Nutrition Examination Survey (KNHANES). Lumbar spine, total hip, and femur neck BMD were measured using dual energy X-ray absorptiometry. The daily food intake was assessed using a food frequency questionnaire.

RESULTS

When we divided the participants into tertiles based on the intake of potassium intake, the highest potassium intake tertile group showed a significantly higher total hip and femur neck BMD as compared to lower tertile groups (0.914 ± 0.004, 0.928 ± 0.003, 0.925 ± 0.004 mg/day across the tertiles, P = .014 for total hip; 0.736 ± 0.003, 0.748 ± 0.003, 0.750 ± 0.004 mg/day, P = .012 for femur neck). Postmenopausal women in the highest potassium intake tertile group showed significantly higher lumbar, total hip, and femur neck BMD as compared to those in lower potassium intake tertile groups (0.793 ± 0.004, 0.793 ± 0.003, 0.805 ± 0.004 mg/day across the tertiles, P = .029 for lumbar spine; 0.766 ± 0.003, 0.770 ± 0.002, 0.780 ± 0.003 mg/day, P = .002 for total hip; 0.615 ± 0.003, 0.619 ± 0.002, 0.628 ± 0.003 mg/day, P = .002 for femur neck).

CONCLUSIONS

Dietary potassium intake was positively associated with BMD in men aged >50 years and postmenopausal women, indicating the beneficial effects of dietary potassium intake on bone health.

The association between urinary sodium to potassium ratio and bone density in middle-aged Chinese adults

The joint effect of sodium and potassium on bone health remains uncertain. We examined the associations between urinary excretion of sodium, potassium, and their ratio and bone mineral density (BMD), and reported an inverse association between urinary sodium-to-potassium ratio and BMD in women, but not in men.

INTRODUCTION

Several studies have suggested that a higher sodium or lower potassium intake is associated with poor bone health. However, few studies have examined their joint effects. We examined the associations of urinary excretion of sodium, potassium, and the sodium-to-potassium ratio with BMD in Chinese adults.

METHODS

This community-based, cross-sectional study included 2202 women and 1063 men (40-75 years) in Guangzhou, China. The BMD of the whole body, lumbar spine, and hip sites were measured by dual-energy x-ray absorptiometry. The concentrations of sodium, potassium, and creatinine of the fasting morning first-void urine sample were measured, and creatinine-adjusted values were then used for further analyses. General information was collected via face-to-face interviews.

RESULTS

For women, after multivariable adjustment, the urinary sodium-to-potassium ratio was inversely associated with BMD at the whole body, total hip, trochanter, and intertrochanter (all p trend <0.05). The mean BMD differences between extreme quartiles ranged from 1.50 to 2.98 % at these sites (all p < 0.05). Similar, but less significant, associations were observed for urinary sodium/creatinine, for which the only significant difference was found at the trochanter (2.00 %, p = 0.016). We did not find any significant associations of BMD with urinary potassium in women and with urinary sodium/creatinine, potassium/creatinine, or their ratio in men.

CONCLUSION

Our findings suggest that the urinary sodium-to-potassium ratio, but not individual creatinine-adjusted values of sodium or potassium, is a good predictor of BMD in women, but not in men.

Bone Mineral Density, Mechanical, Microstructural Properties and Mineral Content of the Femur in Growing Rats Fed with Cactus Opuntia ficus indica (L.) Mill. (Cactaceae) Cladodes as Calcium Source in Diet

Mechanical, microstructural properties, mineral content and bone mineral density (BMD) of the femur were evaluated in growing rats fed with Opuntia ficus indica (L.) Mill. (Cactaceae) cladodes at different maturity stages as calcium source. Male weanling rats were fed with cladodes at early maturity stage (25 and 60 days of age, belonging to groups N-60 and N-200, respectively) and cladodes at late maturity stage (100 and 135 days of age, belonging to groups N-400 and N-600, respectively) for 6 weeks. Additionally, a control group fed with calcium carbonate as calcium source was included for comparative purposes. All diets were fitted to the same calcium content (5 g/kg diet). The failure load of femurs was significantly lower (p ≤ 0.05) in groups N-60 and N-200 in comparison to N-400, N-600 and control groups. The cortical width (Ct.Wi) and trabecular thickness (Tb.Th) of the femurs in control and N-600 groups were significantly higher (p ≤ 0.05) than Ct.Wi and Tb.Th of femurs in groups N-60 and N-200. Trabecular separation of the femurs in N-60 and N-200 groups showed the highest values compared with all experimental groups. The highest calcium content in the femurs were observed in control, N-600 and N-400 groups; whereas the lowest phosphorus content in the bones were detected in N-200, N-600 and N-400 groups. Finally, the BMD in all experimental groups increased with age; nevertheless, the highest values were observed in N-600 and control groups during pubertal and adolescence stages. The results derived from this research demonstrate, for the first time, that the calcium found in Opuntia ficus indica cladodes is actually bioavailable and capable of improving mineral density and mechanical and microstructural properties of the bones. These findings suggest that the consumption of cladodes at late maturity stage within the diet might have a beneficial impact on bone health.

Are Dietary Supplements and Nutraceuticals Effective for Musculoskeletal Health and Cognitive Function? A Scoping Review

OBJECTIVE

The aim of our scoping review was to summarize the state of the art regarding micronutrients in order to identify which of them might effectively improve health status in the areas typically impaired in older people: bone, skeletal muscle, and cognitive function.

DESIGN

Scoping review.

METHODS

The Italian Study Group on Healthy Aging by Nutraceuticals and Dietary Supplements (HANDS) performed this scoping review, based on the following steps: doing a list of micronutrients related with musculoskeletal or cognitive functions, included in dietary supplements and nutraceuticals commercialized in Italy; planning a research on PubMed, according to an evidence-based approach, in order to the most relevant positive study for each micronutrient into each of the three areas involved (bone, skeletal muscle and cognitive function); identifying the micronutrients effective in maintaining or achieving an adequate health status in older people, specifying the effective and safe daily doses, according to the selected studies.

RESULTS

In literature we found 12 relevant positive studies (1 international society guidelines/recommendations, 1 systematic review, 7 randomized controlled trials, and 3 prospective cohort studies). We showed that only 16 micronutrients resulted to have appropriate scientific evidences in terms of improving musculoskeletal health and/or cognitive function in older people: beta-alanine, calcium, creatine, fluorides, leucine, magnesium, omega-3 fatty acids, potassium, vitamin B6, vitamin B9, vitamin B12, vitamin C, vitamin D, vitamin E, vitamin K2, and zinc.

CONCLUSION

This scoping review showed that selected micronutrients in adequate doses might have an ancillary role in musculoskeletal health and cognitive functions in older people.

Adherence to the Mediterranean diet is associated with a higher BMD in middle-aged and elderly Chinese

Previous studies showed that better adherence to the Mediterranean diet (MD) is associated with lower risk of chronic diseases, but limited data are available on bone health. We investigated the association of the MD with bone mineral density (BMD) in Chinese adults. We included 2371 participants aged 40–75 years in this community-based cross-sectional study. Dietary information was assessed at baseline and a 3-year follow-up. Alternate Mediterranean diet (aMed) scores were calculated. BMD was determined at the second survey. After adjusting for potential covariates, higher aMed scores were positively and dose-dependently associated with BMD (all P-trends < 0.05). The BMD values were 1.94% (whole body), 3.01% (lumbar spine), 2.80% (total hip), 2.81% (femur neck), 2.62% (trochanter), and 2.85% (intertrochanter) higher in the quintile 5 (highest, vs. quintile 1) aMed scores for all of the subjects (all P-values < 0.05). Similar associations were found after stratifying by gender (P-interaction = 0.338–0.968). After excluding the five non-significant components of vegetables, legumes, fish, monounsaturated to saturated fat ratio, and alcohol intake from the aMed scores, the percentage mean differences were substantially increased by 69.1–150% between the extreme quintiles. In conclusion, increased adherence to the MD shows protective associations with BMD in Chinese adults.

Achieving the Benefits of a High-Potassium, Paleolithic Diet, Without the Toxicity

The average US dietary intake of K(+) is well below the current recommended nutritional requirements. This deficiency is even more striking when comparing our current intake with that of our ancestors, who consumed large amounts of dietary K(+). K(+) deficiency has been implicated in many diseases including cardiovascular disease, kidney stones, and osteoporosis. Importantly, dietary supplementation of K(+) has favorable effects on reducing blood pressure, decreasing the risk of stroke, improving bone health, and reducing the risk of nephrolithiasis. For this comprehensive review, we scanned the literature using PubMed and MEDLINE using the following search terms: potassium intake, renal potassium excretion, and prevention of hyperkalemia. Articles were selected for inclusion if they represented primary data or review articles published between 1980 and 2015 in high-impact journals. The normal kidney has the capacity to tightly regulate K(+) homoeostasis. We discuss new findings with respect to sensing mechanisms by which the kidney maintains K(+) homeostasis in the gastrointestinal tract and distal tubule. There are widely prescribed hypertensive medications that cause hyperkalemia and thus require dietary K(+) restriction. We conclude by discussing newly approved drugs capable of binding K(+) in the gastrointestinal tract and speculate that this new pharmacology might allow diet liberalization in patients at risk for hyperkalemia, affording them the numerous benefits of a K(+)-rich diet.

Identification of a dietary pattern prospectively associated with bone mass in Australian young adults

BACKGROUND

Relatively little is known about the relations between dietary patterns and bone health in adolescence, which is a period of substantial bone mass accrual.

OBJECTIVES

We derived dietary patterns that were hypothesized to be related to bone health on the basis of their protein, calcium, and potassium contents and investigated their prospective associations with bone mineral density (BMD), bone area, and bone mineral content (BMC) in a cohort of young adults.

DESIGN

The study included 1024 young adults born to mothers who were participating in the Western Australian Pregnancy Cohort (Raine) Study. Dietary information was obtained from food-frequency questionnaires at 14 and 17 y of age. Dietary patterns were characterized according to protein, calcium, and potassium intakes with the use of reduced-rank regression. BMD, bone area, and BMC were estimated with the use of a total body dual-energy X-ray absorptiometry scan at 20 y of age.

RESULTS

We identified 2 major dietary patterns. The first pattern was positively correlated with intakes of protein, calcium, and potassium and had high factor loadings for low-fat dairy products, whole grains, and vegetables. The second pattern was positively correlated with protein intake but negatively correlated with intakes of calcium and potassium and had high factor loadings for meat, poultry, fish, and eggs. After adjustment for anthropometric, sociodemographic, and lifestyle factors, a higher z score for the first pattern at 14 y of age was positively associated with BMD and BMC at 20 y of age [differences: 8.6 mg/cm(2) (95% CI: 3.0, 14.1 mg/cm(2)) and 21.9 g (95% CI: 6.5, 37.3 g), respectively, per SD increase in z score]. The z score for this same pattern at 17 y of age was not associated with bone outcomes at 20 y of age. The second pattern at 14 or 17 y of age was not associated with BMD, BMC, or bone area.

CONCLUSIONS

A dietary pattern characterized by high intakes of protein, calcium, and potassium in midadolescence was associated with higher BMD and BMC at 20 y of age. Our results indicate that high consumption of low-fat dairy products, whole grains, and vegetables in adolescence are associated with beneficial effects on bone development.

The Effect of Risk Factors on the Levels of Chemical Elements in the Tibial Plateau of Patients with Osteoarthritis following Knee Surgery

The aim of this study was to evaluate the aforementioned chemical elements in tibial plateau samples obtained during knee arthroplasty. The gender-specific analysis of chemical element levels in the bone samples revealed that there were statistically significant differences in the concentration of Pb and Se/Pb ratio. The contents of elements in the tibial plateau in the patients with osteoarthritis (OA) can be arranged in the following descending order: F(-) > K > Zn > Fe > Sr > Pb > Mn > Se > Cd > THg. We observed statistical significant effects of environmental factors including smoking, seafood diet, and geographical distribution on the levels of the elements in tibial bone. Significant positive correlation coefficients were found for the relationships K-Cd, Zn-Sr, Zn-F(-), THg-Pb, Pb-Cd, Se-Se/Pb, Se-Se/Cd, Se/Pb-Se/Cd, Pb-Cd/Ca, Cd-Cd/Ca, and F(-)-F(-)/Ca·1000. Significant negative correlations were found for the relationships THg-Se/Pb, Pb-Se/Pb, Cd-Se/Pb, K-Se/Cd, Pb-Se/Cd, Cd-Se/Cd, THg-Se/THg, Pb-Se/THg, Se-Pb/Cd, Zn-Cd/Ca, and Se/Cd-Cd/Ca. The results reported here may provide a basis for establishing reference values for the tibial plateau in patients with OA who had undergone knee replacement surgery. The concentrations of elements in the bone with OA were determined by age, presence of implants, smoking, fish and seafood diet, and sport activity.

Increased intake of selected vegetables, herbs and fruit may reduce bone turnover in post-menopausal women

Increased consumption of vegetables/herbs/fruit may reduce bone turnover and urinary calcium loss in post-menopausal women because of increased intake of polyphenols and potassium, but comparative human studies are lacking. The main aim was to compare bone turnover markers and urinary calcium excretion in two randomised groups (n = 50) of healthy post-menopausal women consuming ≥9 servings of different vegetables/herbs/fruit combinations (three months). Group A emphasised a generic range of vegetables/herbs/fruit, whereas Group B emphasised specific vegetables/herbs/fruit with bone resorption-inhibiting properties (Scarborough Fair Diet), with both diets controlled for potential renal acid load (PRAL). Group C consumed their usual diet. Plasma bone markers, urinary electrolytes (24 h) and estimated dietary PRAL were assessed at baseline and 12 weeks. Procollagen type I N propeptide (PINP) decreased (−3.2 μg/L, p < 0.01) in the B group only, as did C-terminal telopeptide of type I collagen (CTX) (−0.065 μg/L, p < 0.01) in women with osteopenia compared to those with normal bone mineral density (BMD) within this group. Intervention Groups A and B had decreased PRAL, increased urine pH and significantly decreased urinary calcium loss. Urinary potassium increased in all groups, reflecting a dietary change. In conclusion, Group B demonstrated positive changes in both turnover markers and calcium conservation.

Lifestyle and osteoporosis

Osteoporosis is associated with a number of lifestyle factors, including nutritional factors such as intake of calcium, protein, dairy food, fruits and vegetables and vitamin D status, and behavioural factors such as physical activity, smoking and alcohol consumption. Ensuring adequate calcium intake and vitamin D status and having regular weight-bearing physical activity throughout life are important for bone health and the prevention of osteoporosis and related fractures. Studies have shown that smoking and excessive alcohol intake have adverse effects on bone health and increase the risk of fracture. There is evidence suggesting that adequate protein intake and higher intake of fruits and vegetables are beneficial to bone health.

A grape-enriched diet increases bone calcium retention and cortical bone properties in ovariectomized rats

BACKGROUND

Grapes and their associated phytochemicals have been investigated for beneficial effects on cardiovascular health, cancer prevention, and other chronic diseases, but the effect of grape consumption on bone health has not been fully determined. We previously found short-term benefits of grape products on reducing bone turnover in ovariectomized rats.

OBJECTIVE

The objective of this study was to determine the long-term benefits of a grape-enriched diet on bone in ovariectomized rats.

METHODS

Rats were ovariectomized at 3 mo of age and were administered a single dose of (45)Ca to prelabel bones at 4 mo of age. After a 1-mo equilibration period, baseline urinary (45)Ca excretion was determined. Rats (n = 22/group) were then randomly assigned to a modified AIN93M diet containing 25% freeze-dried grape powder or to a control diet for 8 wk. Urinary (45)Ca excretion was monitored throughout the study to determine changes in bone (45)Ca retention. Calcium balance was assessed after 1 and 8 wk of consuming the experimental diets, and a calcium kinetic study was performed at 8 wk. After 8 wk, femurs were collected for micro-computed tomographic imaging, 3-point bending, and reference point indentation.

RESULTS

Rats fed the grape-enriched diet had 44% greater net bone calcium retention than did rats fed the control diet. There were no differences in calcium balance due to diet at either week 1 or week 8, but there was a significant increase in net calcium absorption (10.6%) and retention (5.7%) from week 1 to week 8 in the grape-enriched diet group only. Grape-enriched diet-fed rats had 3% greater cortical thickness and 11% greater breaking strength. There were no differences in femur bone mineral density, trabecular microarchitecture, or reference point indentation variables due to diet.

CONCLUSION

This study of ovariectomized rats indicates that the consumption of grape products may improve calcium utilization and suppress bone turnover, resulting in improvements in bone quality.

Building healthy bones throughout life: an evidence-informed strategy to prevent osteoporosis in Australia

Osteoporosis imposes a tremendous burden on Australia: 1.2 million Australians have osteoporosis and 6.3 million have osteopenia. In the 2007–08 financial year, 82 000 Australians suffered fragility fractures, of which > 17 000 were hip fractures. In the 2000–01 financial year, direct costs were estimated at $1.9 billion per year and an additional $5.6 billion on indirect costs. Osteoporosis was designated a National Health Priority Area in 2002; however, implementation of national plans has not yet matched the rhetoric in terms of urgency. Building healthy bones throughout life, the Osteoporosis Australia strategy to prevent osteoporosis throughout the life cycle, presents an evidence-informed set of recommendations for consumers, health care professionals and policymakers. The strategy was adopted by consensus at the Osteoporosis Australia Summit in Sydney, 20 October 2011. Primary objectives throughout the life cycle are: to maximise peak bone mass during childhood and adolescence to prevent premature bone loss and improve or maintain muscle mass, strength and functional capacity in healthy adults to prevent and treat osteoporosis in order to minimise the risk of suffering fragility fractures, and reduce falls risk, in older people. The recommendations focus on three affordable and important interventions — to ensure people have adequate calcium intake, vitamin D levels and appropriate physical activity throughout their lives. Recommendations relevant to all stages of life include: daily dietary calcium intakes should be consistent with Australian and New Zealand guidelines serum levels of vitamin D in the general population should be above 50nmol/L in winter or early spring for optimal bone health regular weight-bearing physical activity, muscle strengthening exercises and challenging balance/mobility activities should be conducted in a safe environment.

Association between dietary intake and seasonal variations in postmenopausal women

Background

Evidence supports that increasing number of postmenopausal women are suffering from one or more chronic diseases. Dietary patterns have a pivotal role in maintaining human health. The aim of this study was to characterize the nutrients and energy intake in postmenopausal women, with the special focus on seasonal variation effect in their food intake.

Methods

The study population consisted of 30 postmenopausal women referred to Dr. Shariati Hospital, Tehran (Iran). Socio-demographic characteristics and BMI were registered. Dietary assessment was performed by a 3 day food records in each season through one year, allowing the estimation of energy, protein, carbohydrate, total fat, monounsaturated fatty acid (MUFA), polyunsaturated fatty acids (PUFA) and saturated fatty acids (SFA) intake. The mean of nutrient intake in each season was adjusted for energy intake. The effect of season on energy and nutrients intake was assessed based on the General linear model (GLM).

Results

The mean of daily intake of vitamin C, B, B2, B12, iron, zinc, phosphorus and chromium was significantly higher than Recommended Dietary Allowance (RDAs ) (p < 0.05). The mean of vitamin D, E, B6, B5, folate, calcium, magnesium, potassium and selenium consumption was significantly less than RDAs (p < 0.05). All the participants meet the goal for vitamins A, K and B3 from food. The mean of energy intake was not different between seasons. However, the mean intake of fat, vitamin C, vitamin K and folate was significantly different between seasons.

Conclusion

These findings highlight some nutrients deficiency in postmenopausal women and therefore suggest nutritional education with emphasis on seasonal variation effect.

A dairy and fruit dietary pattern is associated with a reduced likelihood of osteoporosis in Korean postmenopausal women

The aim of the present study was to identify the association of dietary patterns with osteoporosis in Korean postmenopausal women from the Korean Health and Nutrition Examination Survey 2008–10. The present cross-sectional analysis included 3735 postmenopausal women who completed a health interview, nutrition survey and a health examination including bone mineral density (BMD) measurements. The general characteristics and dietary intakes of the participants were obtained using a standardised questionnaire and a 24 h recall method, respectively. The BMD of the femoral neck and lumbar spine was measured using dual-energy X-ray absorptiometry; osteoporosis was defined based on the WHO T-score criteria. Overall, we identified four dietary patterns using factor analysis as follows: 'meat, alcohol and sugar', 'vegetables and soya sauce', 'white rice, kimchi and seaweed' and 'dairy and fruit', which accounted for 30·9% of the total variance in food intake (11·3, 7·7, 6·0 and 5·9%, respectively). The subjects in the highest quintile of the 'dairy and fruit' pattern showed a decreased risk of osteoporosis of the lumbar spine (53 %) compared with those in the lowest quintile, after adjusting for covariates (OR 0·47, 95% CI 0·35, 0·65, P for trend<0·0001). In contrast, the 'white rice, kimchi and seaweed' dietary pattern was negatively associated with bone health (OR 1·40, 95% CI 1·03, 1·90, P for trend=0·0479). The present results suggest that an increased intake of dairy foods and fruits in the traditional Korean diet, based on white rice and vegetables, may decrease the risk of osteoporosis in Korean postmenopausal women.

Heart failure as a risk factor for osteoporosis and fractures

Although heart failure (HF) and osteoporosis are common diseases, particularly in elderly populations, patients with HF have an increased risk for osteoporosis. The relationship of HF with osteoporosis is modified by gender and the severity of HF. In addition, shared risk factors, medication use, and common pathogenic mechanisms affect both HF and osteoporosis. Shared risk factors for these 2 conditions include advanced age, hypovitaminosis D, renal disease, and diabetes mellitus. Medications used to treat HF, including spironolactone, thiazide diuretics, nitric oxide donors, and aspirin, may protect against osteoporosis. In contrast, loop diuretics may make osteoporosis worse. HF and osteoporosis appear to share common pathogenic mechanisms, including activation of the renin-angiotensin-aldosterone system, increased parathyroid hormone levels, and/or oxidative/nitrosative stress. HF is a major risk factor for mortality following fractures. Thus, in HF patients, it is important to carefully assess osteoporosis and take measures to reduce the risk of osteoporotic fractures.

Alcohol consumption and bone mineral density in elderly women

OBJECTIVE

Findings regarding alcohol consumption and bone mineral density (BMD) in elderly women have been inconsistent. The objective of the present study was to explore the association of alcohol intake with BMD in elderly women.

DESIGN

This cohort study included women from the population-based Kuopio Osteoporosis Risk Factor and Prevention - Fracture Prevention Study (OSTPRE-FPS). Alcohol intake and potential confounders were assessed at baseline and after 3 years of follow-up using a lifestyle questionnaire. In addition, an FFQ was distributed in the third year to measure dietary intake, including alcohol. Women underwent BMD measurements at the femoral neck and lumbar spine at baseline and after 3 years of follow-up.

SETTING

Kuopio Province, Finland.

SUBJECTS

Three hundred elderly women (mean age 67·8 years) who provided both BMD measurements and FFQ data.

RESULTS

Alcohol consumption estimated from the FFQ and lifestyle questionnaire was significantly associated with BMD at both measurement sites after adjustment for potential confounders, including lifestyle and dietary factors (P < 0·05). Using the FFQ, women drinking >3 alcoholic drinks/week had significantly higher BMD than abstainers, 12·0 % at the femoral neck and 9·2 % at the lumbar spine. Results based on the lifestyle questionnaire showed higher BMD values for all alcohol-consuming women at the femoral neck and for women drinking 1-3 alcoholic beverages/week at the lumbar spine, compared with non-users.

CONCLUSIONS

The results from OSTPRE-FPS suggest that low to moderate alcohol intake may exert protective effects on bone health in elderly women.

Dietary silicon interacts with oestrogen to influence bone health: evidence from the Aberdeen Prospective Osteoporosis Screening Study

BACKGROUND

Silicon (Si), as Si(OH)(4), is derived mainly from plant-based foods. Dietary Si is associated with bone mineral density (BMD) in premenopausal but not postmenopausal women.

OBJECTIVE

To examine the association between Si intake and markers of bone health in middle-aged women and to test for interaction with oestrogen status.

METHODS

Femoral neck (FN) and lumbar spine (LS) BMD, urinary markers of bone resorption (free pyridinoline and deoxypyridinoline cross-links relative to creatinine, fPYD/Cr and fDPD/Cr) and serum markers of bone formation (N-terminal propeptide of type 1 collagen, P1NP) were measured in a cohort of 3198 women aged 50-62 years (n=1170 current HRT users, n=1018 never used HRT). Dietary Si, bioavailable Si and dietary confounders were estimated by food frequency questionnaire.

RESULTS

Mean FN BMD was 2% lower (p<0.005) in the lowest quartile (Q1) compared to the top quartile of energy-adjusted Si intake (Q4) (mean (SD) Q1, 16 (4.0) mg/d; Q4, 31.5 (7.3) mg/d). Energy-adjusted Si intake was associated with FN BMD for oestrogen-replete women only (late premenopausal women (r=+0.21, p=0.03); women on HRT [r=+0.09, p<0.001]). There was an interaction between oestrogen status and quartile of energy-adjusted Si intake on FN BMD, which was significant after adjustment for confounders (F=3.3, p=0.020), and stronger for bioavailable Si (F=5.0. p=0.002). Quartile of energy-adjusted dietary Si intake was negatively associated with fDPD/Cr and fPYD/Cr (p<0.001) and positively with P1NP (p<0.05).

CONCLUSIONS

This study suggests that oestrogen status is important for Si metabolism in bone health. Further work is required to elucidate the mechanism.

An in vivo comparison of hip structure analysis (HSA) with measurements obtained by QCT

SUMMARY

In a population of elderly women, bone cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), section modulus (Z), femoral neck axis length (FNAL), and width measured with hip structure analysis (HSA) on dual-energy x-ray absorptiometry (DXA) images in the femoral neck and trochanteric regions are highly correlated to quantitative computed tomography (QCT) measurements.

INTRODUCTION

HSA is a method of obtaining measurements of proximal femur structure using 2D DXA technology. This study was designed to examine the correlations between HSA measurements and 3D QCT.

METHODS

Forty-one women (mean age, 82.8 ± 2.5 years) were measured using DXA and a 64-slice CT scanner (1 mm slice thickness, 0.29 mm in plane resolution). HSA parameters were calculated at the narrow neck (NN) and trochanteric (IT) regions on the DXA image. These regions were then translated to anatomically equivalent regions on the QCT dataset by co-registering the DXA image and QCT dataset using four DXA images acquired at different angles.

RESULTS

At the NN and IT regions, high linear correlations were measured between HSA and QCT for CSA r = 0.95 and 0.93, CSMI r = 0.94 and 0.93, and Z r = 0.93 and 0.89, respectively. All correlations were highly significant (p < 0.001), but there were differences in slope and offset between the two techniques, at least in part due to differences in calibration between the two techniques. FNAL and width of the bone at the NN and IT regions, physical measurements independent of the calibration, were highly correlated (r = 0.90-0.95, p < 0.001) and had slopes close to 1.0 (range, 0.978 to 1.003).

CONCLUSION

CSA, CSMI, Z, FNAL, and width measured by HSA correlate highly to high-resolution QCT.

Nutrition, bone, and aging: an integrative physiology approach

Osteoporosis, a condition associated with significant morbidity and mortality, is prevalent in the growing elderly population. Aging is associated with characteristic changes in the complex pathways of bone remodeling and in patterns of food intake. Whereas the traditional focus of nutritional supplementation for protection of bone health has centered around calcium and vitamin D, a multitude of nutrients have been identified with effects on bone, both individually and in combination. An integrative physiology approach can assist in formulating a deeper understanding of the complex interactions of nutrition and aging with bone, with the goal of identifying modifiable risk factors for the prevention of bone loss.

Bone physiology and therapeutics in chronic critical illness

Modern medical practices allow patients to survive acute insults and be sustained by machinery and medicines for extended periods of time. We define chronic critical illness as a later stage of prolonged critical illness that requires tracheotomy. These patients have persistent elevations of inflammatory cytokines, diminished hypothalamic-pituitary function, hypercatabolism, immobilization, and malnutrition. The measurement of bone turnover markers reveals markedly enhanced osteoclastic bone resorption that is uncoupled from osteoblastic bone formation. We review the mechanisms by which these factors contribute to the metabolic bone disease of chronic critical illness and suggest potential therapeutics.

Volumetric DXA (VXA): A new method to extract 3D information from multiple in vivo DXA images

Three-dimensional geometric and structural measurements of the proximal femur are of considerable interest in understanding the strength of the femur and its susceptibility to fracture. Quantitative computed tomography (QCT) with a small voxel size (≤1 mm per side) is the current "gold standard" to examine the macrostructure of the femur, but it has a high effective radiation dose (approximately 2 to 5 mSv) and cost. Volumetric dual-energy X-ray absorptiometry (VXA) uses a commercially available DXA system (Hologic Discovery A) to reconstruct the proximal femur from four DXA scans delivering an effective radiation dose of 0.04 mSv. VXA was compared with QCT (voxel size of 0.29 × 0.29 × 1 mm) in 41 elderly women (age 82 ± 2.4 years) at slices located at the femoral neck and trochanteric regions of interest. For parameters of shape, the femoral neck axis length (FNAL) and the cross-sectional slice area (SA), accuracy and strong linear correlations (r = 0.84 to 0.98) were demonstrated. Similar correlations (r = 0.81 to 0.97) were observed for the density parameters, the cross-sectional bone area (CSA) and volumetric bone mineral density (vBMD). VXA also demonstrated strong correlations (r = 0.76 to 0.99) for the engineering parameters of the minimum, maximum, and polar cross-sectional moments of inertia (CSMIs) and the section modulus (Z). We conclude that VXA is capable of generating a variety of 3D geometric and structural measurements that are highly correlated with QCT in elderly subjects in vivo. Moreover, the VXA measurements can be made with a commercially available DXA device at a very low radiation dose.

Osteoporosis prevention and nutrition

Although calcium and vitamin D have been the primary focus of nutritional prevention of osteoporosis, recent research has clarified the importance of several additional nutrients and food constituents. Further, results of calcium and vitamin D supplementation trials have been inconsistent, suggesting that reliance on this intervention may be inadequate. In addition to dairy, fruit and vegetable intake has emerged as an important modifiable protective factor for bone health. Several nutrients, including magnesium, potassium, vitamin C, vitamin K, several B vitamins, and carotenoids, have been shown to be more important than previously realized. Rather than having a negative effect on bone, protein intake appears to benefit bone status, particularly in older adults. Regular intake of cola beverages shows negative effects and moderate alcohol intake shows positive effects on bone, particularly in older women. Current research on diet and bone status supports encouragement of balanced diets with plenty of fruit and vegetables, adequate dairy and other protein foods, and limitation of foods with low nutrient density.