The effects of a low-sodium base-producing diet including red meat compared with a high-carbohydrate, low-fat diet on bone turnover markers in women aged 45–75 years

Bone Turnover Markers: Basic Biology to Clinical Applications

Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and interpretation of these markers, which include commonly used bone formation markers bone alkaline phosphatase, osteocalcin, and procollagen I N-propeptide; and commonly used resorption markers serum C-telopeptides of type I collagen, urinary N-telopeptides of type I collagen and tartrate resistant acid phosphatase type 5b. BTMs are usually measured by enzyme-linked immunosorbent assay or automated immunoassay. Sources contributing to BTM variability include uncontrollable components (e.g., age, gender, ethnicity) and controllable components, particularly relating to collection conditions (e.g., fasting/feeding state, and timing relative to circadian rhythms, menstrual cycling, and exercise). Pregnancy, season, drugs, and recent fracture(s) can also affect BTMs. BTMs correlate with other methods of assessing bone turnover, such as bone biopsies and radiotracer kinetics; and can usefully contribute to diagnosis and management of several diseases such as osteoporosis, osteomalacia, Paget's disease, fibrous dysplasia, hypophosphatasia, primary hyperparathyroidism, and chronic kidney disease-mineral bone disorder.

Dietary interventions for better management of osteoporosis: An overview

Osteoporosis is a public health concern and a cause of bone loss, increased risk of skeletal fracture, and a heavy economic burden. It is common in postmenopausal women and the elderly and is impacted by dietary factors, lifestyle and some secondary factors. Although many drugs are available for the treatment of osteoporosis, these therapies are accompanied by subsequent side effects. Hence, dietary interventions are highly important to prevent osteoporosis. This review was aimed to provide a comprehensive understanding of the roles of dietary nutrients derived from natural foods and of common dietary patterns in the regulation of osteoporosis. Nutrients from daily diets, such as unsaturated fatty acids, proteins, minerals, peptides, phytoestrogens, and prebiotics, can regulate bone metabolism and reverse bone loss. Meanwhile, these nutrients generally existed in food groups and certain dietary patterns also play critical roles in skeletal health. Appropriate dietary interventions (nutrients and dietary patterns) could be primary and effective strategies to prevent and treat osteoporosis across the lifespan for the consumers and food enterprises.

The link between plant-based diet indices with biochemical markers of bone turn over, inflammation, and insulin in Iranian older adults

BACKGROUND

The association of plant-based diets and biomarkers of bone, insulin, and inflammation is still unclear.

OBJECTIVES

We investigated the associations between biomarkers of bone, insulin, and inflammation and three plant-based diet indices: an overall plant-based diet index (PDI); a healthy plant-based diet index (hPDI); and an unhealthy plant-based diet index (uPDI).

METHODS

We included 178 elderly subjects who referred to health centers in Tehran. Blood and urine samples were collected to measure osteocalcin. The Human C-telopeptide of type Ⅰ collagen (u-CTX-I), highly sensitive C-reactive protein (hs-CRP), parathyroid hormone (PTH), 25(OH) D, and insulin resistance and sensitivity. We created an overall PDI, hPDI, and uPDI from semi-quantitative food frequency questionnaire (FFQ) data.

RESULTS

Dietary groups of Vegetables (r = .15, p = .03), nuts (r = .16, p = .03), dairy (r = .25, p = .001), eggs (r = .27, p < .001), red meat, and animal products (r = .25, p = .001) were directly correlated with osteocalcin. Refined grains were also had a positive association with serum insulin concentration (r = .14, p = .04). PTH levels are inversely associated with PDI score (β = -0.18, p = .01). Also, serum insulin concentration was negatively associated with PDI score (β = -0.10, p = .04). Urine CTX-1 levels were significantly associated with hPDI score (β = -0.06, p = .04). u-CTX-1 levels are inversely associated with uPDI score. This significance did not change with the adjustment of the confounders (β = -0.28, p < .001).

CONCLUSIONS

More adherence to PDI and hPDI and less in uPDI may have a beneficial effect on biomarkers of bone, inflammation, and insulin thus preserving chronic diseases.

Adherence to the dietary approaches to stop hypertension (DASH) dietary pattern and osteoporosis risk in postmenopausal Iranian women

This is the first study to examine the association of adherence to the dietary approaches to stop hypertension (DASH) dietary pattern and osteoporosis risk in postmenopausal Iranian women. Findings suggest the inverse association of adherence to the DASH dietary pattern and osteoporosis risk in postmenopausal Iranian women.

INTRODUCTION

This study was aimed to examine the association of adherence to the dietary approaches to stop hypertension (DASH) dietary pattern and osteoporosis risk in postmenopausal Iranian women, hypothesizing that higher adherence to this pattern is associated with lower risk of postmenopausal osteoporosis.

METHODS

One hundred fifty-one postmenopausal Iranian women aged 50-85 years participated in this cross-sectional study. Lumbar spine and femoral neck bone mineral densities (BMDs) were measured via dual-energy X-ray absorptiometry. Postmenopausal osteoporosis was then defined using the WHO criteria as a BMD T-score of ≤ - 2.5 standard deviations. The usual past-year dietary intakes were assessed by a valid and reliable 168-item food frequency questionnaire. The DASH score was then calculated based on energy-adjusted intakes of eight major dietary components usually emphasized (i.e., fruits, vegetables, nuts and legumes, low-fat dairy products, and whole grains) or minimized (i.e., sodium, sweets, and red or processed meats) in the DASH diet. The higher the DASH score of a participant, the higher the adherence to the DASH dietary pattern.

RESULTS

After adjusting for several potential covariates in the multivariable-adjusted binary logistic regression analysis, participants in the highest tertile of DASH score had lower risk of osteoporosis at lumbar spine than those in the lowest tertile (odds ratio = 0.28; 95% confidence interval, 0.09-0.88; p = 0.029). However, no significant association was observed between adherence to the DASH dietary pattern and risk of osteoporosis at femoral neck.

CONCLUSION

Findings suggest the inverse association of adherence to the DASH dietary pattern and osteoporosis risk in postmenopausal Iranian women.

The effect of meals on bone turnover - a systematic review with focus on diabetic bone disease

INTRODUCTION

Type 2 diabetes is associated with an increased risk of bone fractures. Bone mineral density (BMD) is increased and bone turnover is low in type 2 diabetes and the increased BMD does not explain the increased fracture risk. However, the low bone turnover may lead to insufficient bone renewal with unrepaired micro-cracks and thus increase fracture risk. Ingestion of food acutely decreases bone resorption markers and the macronutrient composition of meals and meal frequency may influence bone metabolism adversely in subjects with unhealthy eating patterns, e.g., patients with type 2 diabetes.

AREAS COVERED

The treatment strategy of bone disease in type 2 diabetics is covered in this review. The current management of diabetic bone disease consists of anti-osteoporotic treatment. However, anti-resorptives may further reduce an already low bone turnover with uncertain effects. Furthermore, the acute and long-term effects of meal ingestion, weight loss alone and in combination with exercise as well as the possible underlying mechanisms are covered in this systematic review.

EXPERT COMMENTARY

Current management of diabetic bone disease is based on principles of anti-osteoporotic treatment in non-diabetic subjects. However, studies are urged to investigate whether anti-resorptives are equally beneficial in type 2 diabetes as in non-diabetic individuals.

Depletion and repletion of fruit and vegetable intake alters serum bone turnover markers: a 28-week single-arm experimental feeding intervention

This study was designed to evaluate the effects of elevated fruit and vegetable intake on bone turnover markers. In all, twenty-nine subjects (nine male and twenty female, with a mean age of 32·1 (sem 2·5) years) participated in a 28-week single-arm experimental feeding intervention trial and consumed a prescribed low-fruit and vegetable diet for 6 weeks (depletion-1), a provided high-fruit and vegetable diet for 8 weeks (fruit: 360-560 g; vegetables: 450-705 g), another prescribed low-fruit and vegetable diet for 6 weeks (depletion-2) and then their usual diets for 8 weeks (repletion). Serum bone-related biomarkers were analysed with commercial ELISA kits. Plasma carotenoid levels decreased as a result of the depletion phase and increased with the high-fruit and vegetable diet. Compared with the baseline, depletion-1 resulted in higher serum bone resorption marker C-terminal telopeptide of type 1 collagen (CTX) and lower bone formation marker alkaline phosphatase (BAP) (CTX, 0·68 (sem 0·05) v. 0·97 (sem 0·08) ng/ml and BAP, 10·7 (sem 0·7) v. 9·5 (sem 0·8) µg/l for the baseline and the depletion-1, respectively, P<0·05). High intake of fruit and vegetables decreased serum CTX (P<0·05) to 0·60 (sem 0·04) ng/ml and increased serum BAP to 11·3 (sem 0·7) µg/l (P<0·05), compared with the depletion-1 phase. Serum concentrations of CTX were inversely correlated and those of BAP were positively correlated with blood lycopene. These data show that increased fruit and vegetable consumption at or above federal dietary guidance may be beneficial to bone health.

The use of a pedometer with or without a supervised exercise program for control of pre- to mild hypertension

Purpose

Exercise training has been shown to be an effective and integral component of non-pharmacological intervention for the control of blood pressure. The purpose of this paper is to compare the effectiveness of a supervised modified exercise program of moderate-intensity exercise for one hour per week including the use of a pedometer, and with the use of a pedometer alone without additional exercise in reducing blood pressure.

Design/methodology/approach

The study was a randomized control trial, with an experimental group of 30 people and a control group of 26 people. Participants were males and females aged 30-65 years with pre- to mild hypertension, and who were not receiving any drugs for the treatment of hypertension. Participants of the experimental group were assigned to a fitness program with supervised exercise once a week at the Golden Jubilee Medical Fitness Center, given access to a pedometer, and provided with health education. Participants in the control group were assigned to use a pedometer only. All experimental and control group members participated in the study for three months, as well as a follow-up at the third and sixth month.

Findings

Comparison of the experimental and control groups at the first, third, and sixth month, using repeated measures analysis found that interaction effect groups and times were significantly different for mean systolic blood pressure (SBP), body mass index (BMI), hip circumference (HC), and high-density lipoprotein (HDL) (p<0.05). Mean SBP, diastolic blood pressure (DBP), BMI, waist circumference (WC), HC, and low-density lipoprotein (LDL) within groups were significantly different (p<0.05). Mean WC, cholesterol, LDL, and triglyceride between groups were significantly different (p<0.05). Both groups had SBP improved at the third and sixth month when compared with baseline data. Mean HDL increased in the experimental group and decreased in the control group. Multiple regression analysis showed that both groups were not statistically different after intervention, SBP was reduced in the experimental group when compared to the control group. However, at six months, members in the experimental group reported spending less time sitting or reclining on a typical day than members of the control group.

Originality/value

A supervised one-time per week fitness program combined with pedometer and pedometer alone were not different in reducing blood pressure, as both groups showed decreases in blood pressure. However, the group with the supervised exercise program tended to change sedentary behaviors in the longer term compared to those who used the pedometer alone.

The effect of dietary approaches to stop hypertension (DASH) diet on weight and body composition in adults: a systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND

Dietary approaches to stop hypertension (DASH) diet is rich in foods that are proposed to be inversely associated with obesity. Therefore, DASH might better affect body weight; however, published data are conflicting.

OBJECTIVE

To assess the effect of DASH on body weight and composition in adults.

METHODS

PubMed, EMBASE, Scopus and Google scholar were searched up to December 2015, for relevant randomized controlled clinical trials. Mean changes in body weight, body mass index (BMI) and waist circumference (WC) were extracted.

RESULTS

Thirteen articles (ten for body weight, six for BMI and two for WC) were eligible. Meta-analysis revealed that adults on DASH diet lose more weight (weighted mean difference [WMD] = -1.42 kg, 95% confidence interval [95%CI]: -2.03, -0.82) in 8-24 weeks, BMI (WMD = -0.42 kg m(-2) , 95%CI: -0.64, -0.20) in 8-52 weeks and WC (WMD = -1.05 cm, 95%CI: -1.61, -0.49) in 24 weeks compared with controls. Low caloric DASH led to even more weight reduction when compared with other low-energy diets. In addition, the effect was greater in overweight/obese participants and when compared with typical (Western or population's usual) diets.

CONCLUSION

DASH diet is a good choice for weight management particularly for weight reduction in overweight and obese participants.

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.

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.

Diet, weight, cytokines and bone health in postmenopausal women

OBJECTIVES

To investigate diet and nutrition-related factors associated with bone loss in a group of postmenopausal (PM) women. Nutritional intake, inflammatory markers and body composition (weight, body mass index, fat/lean mass) were analysed for associations with bone mineral density (BMD).

DESIGN

A cross sectional study examining correlations between BMD (Duel-energy X ray absorptiometry; (DXA) and dietary intake (3-day diaries), body composition and plasma bone and inflammatory markers: C-terminal telopeptide of type I collagen (CTX) and procollagen type I N propeptide (P1NP), C- reactive protein (CRP), interleukin 6 and 10 (IL-6, IL-10), tumour necrosis factor (TNF) and osteoprotegerin (OPG).

SETTING

Community dwelling women from the Auckland, Hawke's Bay and Manawatu regions in New Zealand.

PARTICIPANTS

142 healthy, PM women aged 50-70 years.

RESULTS

OPG (per kilogram fat mass) was increased in women with osteoporosis (p<0.001) compared to groups classified with normal BMD and osteopenia. Protein, vitamin B12, zinc, potassium and dairy intake were all positively correlated with higher BMD while dairy and potassium intakes also inversely correlated with CTX. Body composition (weight, BMI and fat/lean mass) had strong positive associations with BMD. Multiple regression analysis showed body weight, potassium and dairy intake were predictors of increased BMD in PM women and explained 39% (r2=0.39, p< 0.003) of variance.

CONCLUSION

BMD was negatively correlated with OPG and positively with weight, dairy and potassium intake. This study highlights the importance of maintaining adequate body weight and emphasising dairy and potassium predominantly sourced from fruit/vegetables to reduce bone loss at midlife.

Effect of increased fruit and vegetable consumption on bone turnover in older adults: a randomised controlled trial

Evidence suggests that increased fruit and vegetable (FV) intake may be associated with improved bone health, but there is limited evidence from intervention trials to support this. This 16-week study showed that increased FV consumption (five or more portions per day) does not have any effect on the markers of bone health in older adults.

INTRODUCTION

Observational evidence suggests that increased FV consumption may be associated with improved bone health. However, there is lack of evidence from intervention trials to support this. This study examined the effect of increased FV consumption on bone markers among healthy, free-living older adults.

METHODS

A randomised controlled trial was undertaken. Eighty-three participants aged 65-85 years, habitually consuming less than or equal to two portions of FV per day, were randomised to continue their normal diet or to consume five or more portions of FV per day for 16 weeks. FV were delivered to all participants each week, free of charge. Compliance was assessed at baseline and at 6, 12 and 16 weeks by diet histories and biomarkers of micronutrient status. Fasting serum bone markers (osteocalcin (OC) and C-terminal telopeptide of type 1 collagen (CTX)) were measured using enzyme-linked immunosorbent assay.

RESULTS

Eighty-two participants completed the intervention. The five portions per day group showed a significantly greater change in daily FV consumption compared to the two portions per day group (p < 0.001), and this was reflected in significant increases in micronutrient status. No significant differences were evident in change in bone markers between the two portions per day group and the five portions per day group over the 16 weeks (geometric mean of week 16 to baseline ratio (95% confidence interval): OC-0.95 (0.89-1.02) and 1.04 (0.91-1.18), respectively, p = 0.25; CTX-1.06 (0.95-1.19) and 0.98 (0.90-1.06) respectively, p = 0.20).

CONCLUSIONS

Increased FV consumption had no effect on bone markers in older adults. Larger intervention studies of longer duration are warranted to establish whether long-term FV consumption can benefit bone health.

Compliance with the Dietary Approaches to Stop Hypertension (DASH) diet: a systematic review

BACKGROUND

The Dietary Approaches to Stop Hypertension (DASH) diet has been recognized as effective to lower blood pressure in feeding trials, but compliance with the diet must be persistent to maximize health benefits in clinical practice. This paper reports a systematic review of the latest evidence on the method to assess DASH compliance and the corresponding patients' compliance in interventional settings.

METHODS

The databases including MEDLINE, EBM Reviews, EMBASE, and CINAHL Plus were searched for original research studies published in the period of January 1992-December 2012 that evaluated compliance with DASH diet. Studies written in English language, with DASH intervention, with complete documentation of the degree of DASH compliance and the assessment method used were included in this review. The search terms included: dietary approaches to stop hypertension, DASH, compliance, adherence, consistency, and concordance.

RESULTS

Nine studies were included. Different types of interventions were identified, ranging from feeding trial to dietary counseling. These studies differed in the assessment methods used to evaluate DASH compliance, which included objective approaches like measurement of urinary excretion, and subjective approaches like dietary intake assessment for DASH target comparison and construction of DASH scoring systems. Compliance levels were lower in educational interventions than that of the original DASH feeding trial.

CONCLUSIONS

To conclude, although no consensus existed regarding the best approach to assess DASH compliance, its suboptimal compliance warrants attention. This study implied a need to investigate effective approaches to sustain the DASH dietary pattern beyond counselling alone.

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.

Midlife women, bone health, vegetables, herbs and fruit study. The Scarborough Fair study protocol

Background

Bone loss is accelerated in middle aged women but increased fruit/vegetable intake positively affects bone health by provision of micronutrients essential for bone formation, buffer precursors which reduce acid load and phytochemicals affecting inflammation and oxidative stress. Animal studies demonstrated bone resorption inhibiting properties of specific vegetables, fruit and herbs a decade ago.

Objective: To increase fruit/vegetable intake in post menopausal women to 9 servings/day using a food specific approach to significantly reduce dietary acid load and include specific vegetables, fruit and herbs with bone resorbing inhibiting properties to assess effect on bone turnover, metabolic and inflammatory markers.

Methods/Design

The Scarborough Fair Study is a randomised active comparator controlled multi centre trial. It aimed to increase fruit and vegetable intake in 100 post menopausal women from ≤ 5 servings/day to ≥ 9 servings/day for 3 months. The women in the dietary intervention were randomly assigned to one of the two arms of the study. Both groups consumed ≥ 9 servings/day of fruit/vegetables and selected herbs but the diet of each group emphasised different fruit/vegetables/herbs with one group (B) selecting from a range of vegetables, fruit and culinary herbs with bone resorbing inhibiting properties. 50 women formed a negative control group (Group C usual diet).

Primary outcome variables were plasma bone markers assessed at baseline, 6 weeks and 12 weeks. Secondary outcome variables were plasma inflammation and metabolic markers and urinary electrolytes (calcium, magnesium, potassium and sodium) assessed at baseline and 12 weeks. Dietary intake and urine pH change also were outcome variables. The dietary change was calculated with 3 day diet diaries and a 24 hour recall. Intervention participants kept a twice weekly record of fruit, vegetable and herb intake and urine pH.

Discussion

This study will provide information on midlife women’s bone health and how a dietary intervention increasing fruit and vegetable/herb intake affects bone, inflammatory and metabolic markers and urinary electrolyte excretion. It assesses changes in nutrient intake, estimated dietary acid load and sodium: potassium ratios. The study also explores whether specific fruit/vegetables and herbs with bone resorbing properties has an effect on bone markers.

Trial registration

ACTRN 12611000763943

Association between the Healthy Eating Index and bone turnover markers in US postmenopausal women aged ≥45 y

BACKGROUND

Some studies have reported that overall diet quality affects bone status in postmenopausal women; however, the findings are inconsistent.

OBJECTIVES

Our primary objective was to examine the association between overall diet quality and bone turnover markers (BTMs) in postmenopausal women aged ≥45 y by using the Healthy Eating Index 2005 (HEI-2005)-a diet quality-assessment tool-developed by the US Department of Agriculture. Our secondary objective was to explore the associations between the components of the HEI-2005 and the MyPyramid food groups and BTMs.

DESIGN

We used cross-sectional data from NHANES 1999-2002. Multiple regression models with adjustments for relevant confounders were used to examine the relation between the total HEI-2005 score and its components and food groups and serum bone-specific alkaline phosphatase (BAP), a biomarker of bone formation, and urinary N-telopeptides/creatinine (uNTx/Cr), a biomarker of bone resorption.

RESULTS

No association was found between the total HEI-2005 score and BTMs. The milk group component of HEI-2005 had a significant negative linear relation with uNTx/Cr. Women in the lowest tertile of the MyPyramid milk group had the highest uNTx/Cr. Those in the highest tertile of energy-adjusted added sugar intake had the highest BAP.

CONCLUSIONS

Our results support the ability of a healthy diet with adequate dairy intake to promote bone health in aging women. However, we found that the HEI-2005 is not a good measure of healthy eating for optimal bone health. Further research is needed to develop an overall dietary assessment tool in relation to bone health for postmenopausal women.

Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill's epidemiologic criteria for causality

Background

Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria.

Methods

Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined.

Results

Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological pH. Finally, randomized studies did not provide evidence for an adverse role of phosphate, milk, and grain foods in osteoporosis.

Conclusions

A causal association between dietary acid load and osteoporotic bone disease is not supported by evidence and there is no evidence that an alkaline diet is protective of bone health.