Bio-Electrical Impedance Analysis: A Valid Assessment Tool for Diagnosis of Low Appendicular Lean Mass in Older Adults?

Background: The diagnosis of sarcopenia is essential for early treatment of sarcopenia in older adults, for which assessment of appendicular lean mass (ALM) is needed. Multi-frequency bio-electrical impedance analysis (MF-BIA) may be a valid assessment tool to assess ALM in older adults, but the evidences are limited. Therefore, we validated the BIA to diagnose low ALM in older adults. Methods: ALM was assessed by a standing-posture 8 electrode MF-BIA (Tanita MC-780) in 202 community-dwelling older adults (age ≥ 55 years), and compared with dual-energy X-ray absorptiometry (DXA) (Hologic Inc., Marlborough, MA, United States; DXA). The validity for assessing the absolute values of ALM was evaluated by: (1) bias (mean difference), (2) percentage of accurate predictions (within 5% of DXA values), (3) the mean absolute error (MAE), and (4) limits of agreement (Bland-Altman analysis). The lowest quintile of ALM by DXA was used as proxy for low ALM (< 22.8 kg for men, < 16.1 kg for women). Sensitivity and specificity of diagnosing low ALM by BIA were assessed. Results: The mean age of the subjects was 72.1 ± 6.4 years, with a BMI of 25.4 ± 3.6 kg/m2, and 71% were women. BIA slightly underestimated ALM compared to DXA with a mean bias of -0.6 ± 1.2 kg. The percentage of accurate predictions was 54% with a MAE of 1.1 kg, and limits of agreement were -3.0 to + 1.8 kg. The sensitivity for ALM was 80%, indicating that 80% of subjects who were diagnosed as low ALM according to DXA were also diagnosed low ALM by BIA. The specificity was 90%, indicating that 90% of subjects who were diagnosed as normal ALM by DXA were also diagnosed as normal ALM by the BIA. Conclusion: This comparison showed a poor validity of MF-BIA to assess the absolute values of ALM, but a reasonable sensitivity and specificity to recognize the community-dwelling older adults with the lowest muscle mass.

Beyond maternal education: Socio-economic inequalities in children's diet in the ABCD cohort.

OBJECTIVE: We examined whether the role of maternal education in children's unhealthy snacking diet is moderated by other socio-economic indicators. METHODS: Participants were selected from the Amsterdam Born Children and their Development cohort, a large ongoing community-based birth cohort. Validated Food Frequency Questionnaires (FFQ) (n = 2782) were filled in by mothers of children aged 5.7±0.5yrs. Based on these FFQs, a snacking dietary pattern was derived using Principal Component Analysis. Socio-economic indicators were: maternal and paternal education (low, middle, high; based on the highest education completed) household finance (low, high; based on ability to save money) and neighbourhood SES (composite score including educational level, household income and employment status of residents per postal code). Cross-sectional multivariable linear regression analysis was used to assess the association and possible moderation of maternal education and other socio-economic indicators on the snacking pattern score. Analyses were adjusted for children's age, sex and ethnicity. RESULTS: Low maternal education (B 0.95, 95% CI 0.83;1.06), low paternal education (B 0.36, 95% CI 0.20;0.52), lower household finance (B 0.18, 95% CI 0.11;0.26) and neighbourhood SES (B -0.09, 95% CI -0.11;-0.06) were independently associated with higher snacking pattern scores (p<0.001). The association between maternal education and the snacking pattern score was somewhat moderated by household finance (p = 0.089) but remained strong. Children from middle-high educated mothers (B 0.44, 95% CI 0.35;0.52) had higher snacking pattern scores when household finance was low (B 0.49, 95% CI 0.33;0.65). CONCLUSIONS: All socio-economic indicators were associated with increased risk of unhealthy dietary patterns in young children, with low maternal education conferring the highest risk. Yet, within the group of middle-high educated mothers, lower household finance was an extra risk factor for unhealthy dietary patterns. Intervention strategies should therefore focus on lower educated mothers and middle-high educated mothers with insufficient levels of household finance.

Weight development between age 5 and 10 years and its associations with dietary patterns at age 5 in the ABCD cohort.

BACKGROUND: Social inequalities in bodyweight start early in life and track into adulthood. Dietary patterns are an important determinant of weight development in children, towards both overweight and underweight. Therefore, we aimed to examine weight development between age 5 and 10 years by ethnicity, SES and thereafter by BMI category at age 5, to explore its association with dietary patterns at age 5. METHODS: Participants were 1765 children from the Amsterdam Born Children and their Development (ABCD) cohort that had valid data on BMI at age 5 and 10 and diet at age 5. Linear mixed model analysis was used to examine weight development between age 5 and 10 years and to assess if four previously identified dietary patterns at age 5 (snacking, full-fat, meat and healthy) were associated with weight development. Analyses were adjusted for relevant confounders, stratified by ethnicity and SES and thereafter stratified per BMI category at age 5. RESULTS: Overall, weight decreased in Dutch and high SES children and increased in non-Dutch and low/middle SES children. Across the range of bodyweight categories at age 5, we observed a conversion to normal weight, which was stronger in Dutch and high SES children but less pronounced in non-Dutch and low/middle SES children. Overall, the observed associations between weight development and dietary patterns were mixed with some unexpected findings: a healthy dietary pattern was positively associated with weight development in most groups, regardless of ethnicity and SES (e.g. Dutch B 0.084, 95% CI 0.038;0.130 and high SES B 0.096, 95% CI 0.047;0.143) whereas the full-fat pattern was negatively associated with weight development (e.g. Dutch B -0.069, 95% CI -0.114;-0.024 and high SES B -0.072, 95% CI -0.119;-0.026). CONCLUSIONS: We observed differential weight development per ethnic and SES group. Our results indicate that each ethnic and SES group follows its own path of weight development. Associations between dietary patterns and weight development showed some unexpected findings; follow-up research is needed to understand the association between dietary patterns and weight development.

Dietary protein intake is not associated with 5-y change in mid-thigh muscle cross-sectional area by computed tomography in older adults: the Health, Aging, and Body Composition (Health ABC) Study.

BACKGROUND: A higher protein intake is suggested to preserve muscle mass during aging and may therefore reduce the risk of sarcopenia. OBJECTIVES: We explored whether the amount and type (animal or vegetable) of protein intake were associated with 5-y change in mid-thigh muscle cross-sectional area (CSA) in older adults (n = 1561). METHODS: Protein intake was assessed at year 2 by a Block food-frequency questionnaire in participants (aged 70-79 y) of the Health, Aging, and Body Composition (Health ABC) Study, a prospective cohort study. At year 1 and year 6 mid-thigh muscle CSA in square centimeters was measured by computed tomography. Multiple linear regression analysis was used to examine the association between energy-adjusted protein residuals in grams per day (total, animal, and vegetable protein) and muscle CSA at year 6, adjusted for muscle CSA at year 1 and potential confounders including prevalent health conditions, physical activity, and 5-y change in fat mass. RESULTS: Mean (95% CI) protein intake was 0.90 (0.88, 0.92) g · kg-1 · d-1 and mean (95% CI) 5-y change in muscle CSA was -9.8 (-10.6, -8.9) cm2. No association was observed between energy-adjusted total (ß = -0.00; 95% CI: -0.06, 0.06 cm2; P = 0.982), animal (ß = -0.00; 95% CI: -0.06, 0.05 cm2; P = 0.923), or plant (ß = +0.07; 95% CI: -0.06, 0.21 cm2; P = 0.276) protein intake and muscle CSA at year 6, adjusted for baseline mid-thigh muscle CSA and potential confounders. CONCLUSIONS: This study suggests that a higher total, animal, or vegetable protein intake is not associated with 5-y change in mid-thigh muscle CSA in older adults. This conclusion contradicts some, but not all, previous research. This trial was registered at www.trialregister.nl as NTR6930.

Ethnicity and socioeconomic status are related to dietary patterns at age 5 in the Amsterdam born children and their development (ABCD) cohort.

BACKGROUND: Health inequalities are already present at young age and tend to vary with ethnicity and socioeconomic status (SES). Diet is a major determinant of overweight, and studying dietary patterns as a whole in relation to overweight rather than single nutrients or foods has been suggested. We derived dietary patterns at age 5 and determined whether ethnicity and SES were both related to these dietary patterns. METHODS: We analysed 2769 validated Food Frequency Questionnaires filled in by mothers of children (5.7 ± 0.5y) in the Amsterdam Born Children and their Development (ABCD) cohort. Food items were reduced to 41 food groups. Energy adjusted intake per food group (g/d) was used to derive dietary patterns using Principal Component Analysis and children were given a pattern score for each dietary pattern. We defined 5 ethnic groups (Dutch, Surinamese, Turkish, Moroccan, other ethnicities) and 3 SES groups (low, middle, high, based on maternal education). Multivariate ANOVA, with adjustment for age, gender and maternal age, was used to test potential associations between ethnicity or SES and dietary pattern scores. Post-hoc analyses with Bonferroni adjustment were used to examine differences between groups. RESULTS: Principal Component Analysis identified 4 dietary patterns: a snacking, full-fat, meat and healthy dietary pattern, explaining 21% of the variation in dietary intake. Ethnicity was related to the dietary pattern scores (p < 0.01): non-Dutch children scored high on snacking and healthy pattern, whereas Turkish children scored high on full-fat and Surinamese children on the meat pattern. SES was related to the snacking, full-fat and meat patterns (p < 0.01): low SES children scored high on the snacking and meat pattern and low on the full-fat pattern. CONCLUSIONS: This study indicates that both ethnicity and SES are relevant for dietary patterns at age 5 and may enable more specific nutrition education to specific ethnic and low socioeconomic status target groups.

Effect of a high protein diet and/or resistance exercise on the preservation of fat free mass during weight loss in overweight and obese older adults: a randomized controlled trial.

BACKGROUND: Intentional weight loss in obese older adults is a risk factor for accelerated muscle mass loss. We investigated whether a high protein diet and/or resistance exercise preserves fat free mass (FFM) during weight loss in overweight and obese older adults. METHODS: We included 100 overweight and obese adults (55-80 year) in a randomized controlled trial (RCT) with a 2 × 2 factorial design and intention-to-treat analysis. During a 10-week weight loss program all subjects followed a hypocaloric diet. Subjects were randomly allocated to either a high protein (1.3 g/kg body weight) or normal protein diet (0.8 g/kg), with or without a resistance exercise program 3 times/week. FFM was assessed by air displacement plethysmography. RESULTS: At baseline, mean (±SD) BMI was 32 ± 4 kg/m2. During intervention, protein intake was 1.13 ± 0.35 g/kg in the high protein groups vs. 0.98 ± 0.29 in the normal protein groups, which reflects a 16.3 ± 5.2 g/d higher protein intake in the high protein groups. Both high protein diet and exercise did not significantly affect change in body weight, FFM and fat mass (FM). No significant protein*exercise interaction effect was observed for FFM. However, within-group analysis showed that high protein in combination with exercise significantly increased FFM (+0.6 ± 1.3 kg, p = 0.011). CONCLUSION: A high protein diet, though lower than targeted, did not significantly affect changes in FFM during modest weight loss in older overweight and obese adults. There was no significant interaction between the high protein diet and resistance exercise for change in FFM. However, only the group with the combined intervention of high protein diet and resistance exercise significantly increased in FFM. TRIAL REGISTRATION: Dutch Trial Register, number NTR4556, date 05-01-2014.

A high whey protein-, leucine-, and vitamin D-enriched supplement preserves muscle mass during intentional weight loss in obese older adults: a double-blind randomized controlled trial.

BACKGROUND: Intentional weight loss in obese older adults is a risk factor for muscle loss and sarcopenia. OBJECTIVE: The objective was to examine the effect of a high whey protein-, leucine-, and vitamin D-enriched supplement on muscle mass preservation during intentional weight loss in obese older adults. DESIGN: We included 80 obese older adults in a double-blind randomized controlled trial. During a 13-wk weight loss program, all subjects followed a hypocaloric diet (-600 kcal/d) and performed resistance training 3×/wk. Subjects were randomly allocated to a high whey protein-, leucine-, and vitamin D-enriched supplement including a mix of other macro- and micronutrients (150 kcal, 21 g protein; 10×/wk, intervention group) or an isocaloric control. The primary outcome was change in appendicular muscle mass. The secondary outcomes were body composition, handgrip strength, and physical performance. Data were analyzed by using ANCOVA and mixed linear models with sex and baseline value as covariates. RESULTS: At baseline, mean ± SD age was 63 ± 5.6 y, and body mass index (in kg/m(2)) was 33 ± 4.4. During the trial, protein intake was 1.11 ± 0.28 g · kg body weight(-1) · d(-1) in the intervention group compared with 0.85 ± 0.24 g · kg body weight(-1) · d(-1) in the control group (P < 0.001). Both intervention and control groups decreased in body weight (-3.4 ± 3.6 kg and -2.8 ± 2.8 kg; both P < 0.001) and fat mass (-3.2 ± 3.1 kg and -2.5 ± 2.4 kg; both P < 0.001), with no differences between groups. The 13-wk change in appendicular muscle mass, however, was different in the intervention and control groups [+0.4 ± 1.2 kg and -0.5 ± 2.1 kg, respectively; ß = 0.95 kg (95% CI: 0.09, 1.81); P = 0.03]. Muscle strength and function improved over time without significant differences between groups. CONCLUSION: A high whey protein-, leucine-, and vitamin D-enriched supplement compared with isocaloric control preserves appendicular muscle mass in obese older adults during a hypocaloric diet and resistance exercise program and might therefore reduce the risk of sarcopenia. This trial was registered at the Dutch Trial Register (http://www.trialregister.nl) as NTR2751.

Dairy products and the risk of stroke and coronary heart disease: the Rotterdam Study.

PURPOSE: We examined whether consumption of total dairy and dairy subgroups was related to incident stroke and coronary heart disease (CHD) in a general older Dutch population. METHODS: The study involved 4,235 participants of the Rotterdam Study aged 55 and over who were free of cardiovascular disease (CVD) and diabetes at baseline (1990-1993). Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) for the intake of total dairy and dairy subgroups in relation to incident CVD events. RESULTS: Median intake of total dairy was 397 g/day, which mainly comprised low-fat dairy products (median intake of 247 g/day). During a median follow-up time of 17.3 years, 564 strokes (182 fatal) and 567 CHD events (350 fatal) occurred. Total dairy, milk, low-fat dairy, and fermented dairy were not significantly related to incident stroke or fatal stroke (p > 0.2 for upper vs. lower intake categories). High-fat dairy was significantly inversely related to fatal stroke (HR of 0.88 per 100 g/day; 95% CI 0.79, 0.99), but not to incident stroke (HR of 0.96 per 100 g/day; 95% CI 0.90, 1.02). Total dairy or dairy subgroups were not significantly related to incident CHD or fatal CHD (HRs between 0.98 and 1.05 per 100 g/day, all p > 0.35). CONCLUSIONS: In this long-term follow-up study of older Dutch subjects, total dairy consumption or the intake of specific dairy products was not related to the occurrence of CVD events. The observed inverse association between high-fat dairy and fatal stroke warrants confirmation in other studies.

Twenty-four hour urinary urea excretion and 9-year risk of hypertension: the PREVEND study.

OBJECTIVES: It is not yet clear whether dietary protein could help maintaining a healthy blood pressure (BP). We investigated the association between total protein intake, estimated from 24-h urinary urea excretion, and incident hypertension in Dutch men and women. METHODS: We analyzed data of 3997 men and women (aged 28-75 years) who participated in the Prevention of Renal and Vascular Endstage Disease (PREVEND) study, a prospective cohort study. Urea excretion was assessed in two consecutive 24-h urine collections at baseline and approximately 4 years later, from which total protein intake was estimated using the Maroni method. Participants were followed for 9 years for hypertension incidence, defined as BP at least 140/90 mmHg or initiation of antihypertensive medication. Hazard ratios (HR) were obtained in sex-specific quintiles of protein intake using time-dependent Cox regression, adjusted for age, sex, BMI, smoking, alcohol use, and 24-h urinary excretions of sodium and potassium. RESULTS: Baseline BP was on average 119/70 mmHg and 976 participants developed hypertension during follow-up. Mean protein intake (in g/kg ideal body weight) was 1.18 ±â€Š0.26 for men and 1.12 ±â€Š0.25 for women. Estimated protein intake was nonlinearly inversely associated with incident hypertension in the fully adjusted model, with nonsignificant HR of 0.77, 0.75, 0.82, and 0.83 in consecutive quintiles compared with the lowest quintile (P-trend: 0.52). CONCLUSION: Protein intake, as assessed by urinary urea excretion, was not significantly associated with 9-year hypertension incidence in Dutch men and women.

Identification of biomarkers for intake of protein from meat, dairy products and grains: a controlled dietary intervention study.

In the present controlled, randomised, multiple cross-over dietary intervention study, we aimed to identify potential biomarkers for dietary protein from dairy products, meat and grain, which could be useful to estimate intake of these protein types in epidemiological studies. After 9 d run-in, thirty men and seventeen women (22 (SD 4) years) received three high-protein diets (aimed at approximately 18% of energy (en%)) in random order for 1 week each, with approximately 14 en% originating from either meat, dairy products or grain. We used a two-step approach to identify biomarkers in urine and plasma. With principal component discriminant analysis, we identified amino acids (AA) from the plasma or urinary AA profile that were distinctive between diets. Subsequently, after pooling total study data, we applied mixed models to estimate the predictive value of those AA for intake of protein types. A very good prediction could be made for the intake of meat protein by a regression model that included urinary carnosine, 1-methylhistidine and 3-methylhistidine (98% of variation in intake explained). Furthermore, for dietary grain protein, a model that included seven AA (plasma lysine, valine, threonine, α-aminobutyric acid, proline, ornithine and arginine) made a good prediction (75% of variation explained). We could not identify biomarkers for dairy protein intake. In conclusion, specific combinations of urinary and plasma AA may be potentially useful biomarkers for meat and grain protein intake, respectively. These findings need to be cross-validated in other dietary intervention studies.

Protein intake in relation to risk of hypertension and microalbuminuria in patients with type 1 diabetes: the EURODIAB Prospective Complications Study.

BACKGROUND: A beneficial association between dietary protein intake (especially from plant sources) with incident hypertension, being strongly correlated to microalbuminuria, has been suggested in healthy populations. Evidence from diabetic populations, in which the prevalence of these diseases is high, is lacking. We examined the associations of total, animal and plant protein intake with incident hypertension (n = 1319) and microalbuminuria (n = 1045) in patients from 16 European countries with type 1 diabetes from the clinic-based EURODIAB Prospective Complications study. METHODS: Odds ratios (OR) with 95% confidence intervals (CI) for incident hypertension after 7 years of follow-up were calculated in tertiles of protein intake (energy%) with adjustments for age, sex, diabetes duration, HbA1c, BMI, physical activity, smoking, alcohol, total energy, total fat and carbohydrate intake. RESULTS: After adjustment for potential confounders, total, animal and plant protein intakes were not related to incident hypertension (298 cases). OR's (95% CI) across increasing tertiles of total protein were 1.00 (ref), 0.86 (0.60-1.25) and 0.91 (0.59-1.43). Furthermore, no relation was observed with incident microalbuminuria (135 cases), with ORs (95% CI) across increasing tertiles of total protein being 1.00 (ref), 0.88 (0.53-1.48) and 1.08 (0.57-2.04). CONCLUSION: Results from our study did not provide evidence that a protein intake commonly consumed by European patients with type 1 diabetes is associated with incident hypertension or microalbuminuria. Prospective studies with more detailed information on dietary intake (including mineral intake) are needed to confirm these findings, and to investigate the impact on vascular and renal complications of a long-term very high protein intake in patients with type 1 diabetes.

Dietary amino acids and the risk of hypertension in a Dutch older population: the Rotterdam Study.

BACKGROUND: Inverse associations between dietary protein and hypertension have been reported, which may be attributed to specific amino acids. OBJECTIVE: We examined whether the intake of glutamic acid, arginine, cysteine, lysine, or tyrosine was associated with blood pressure (BP) levels (n = 3086) and incident hypertension (n = 1810) in the Rotterdam Study. DESIGN: We calculated BP levels in quartiles of amino acid intake as a percentage of total protein intake (% of protein) with adjustment for age, sex, BMI, smoking, alcohol intake, education, and dietary factors. Subsequently, we used Cox proportional models that included the same confounders to evaluate the associations between specific amino acid intake and hypertension incidence. RESULTS: Glutamic acid contributed most to protein intake (21% of protein), whereas lysine provided 7%, arginine 5%, tyrosine 4%, and cysteine 1.5%. A higher intake of tyrosine (∼0.3% of protein) was significantly related to a 2.4-mm Hg lower systolic BP (P-trend = 0.05) but not to diastolic BP (P = 0.35). The other amino acids were not significantly associated with BP levels in a cross-sectional analysis. During 6 y of follow-up (7292 person-years), 873 cases of hypertension developed. None of the amino acids were significantly associated with incident hypertension (HR: 0.81-1.18; P-trend > 0.2). CONCLUSION: Our data do not suggest a major role for glutamic acid, arginine, lysine, tyrosine, or cysteine intake (as % of protein intake) in determining population BP or risk of hypertension.

Dietary protein, blood pressure and renal function in renal transplant recipients.

Hypertension is highly prevalent among renal transplant recipients (RTR) and a risk factor for graft failure and cardiovascular events. Protein intake has been claimed to affect blood pressure (BP) in the general population and may affect renal function. We examined the association of dietary protein with BP and renal function in RTR. We included 625 RTR (age 53 (SD 13) years; 57% male). Protein intake was assessed with a FFQ, differentiating between animal and plant protein. BP was measured according to a strict protocol. Creatinine clearance and albuminuria were measured as renal parameters. Protein intake was 83 (SD 12) g/d, of which 63% derived from animal sources. BP was 136 (SD 17) mmHg systolic (SBP) and 83 (SD 11) mmHg diastolic (DBP). Creatinine clearance was 66 (SD 26) ml/min; albuminuria 41 (10-178) mg/24 h. An inverse, though statistically insignificant, association was found between the total protein intake and both SBP (ß = - 2·22 mmHg per SD, P= 0·07) and DBP (ß = - 0·48 mmHg per SD, P= 0·5). Protein intake was not associated with creatinine clearance. Although albuminuria was slightly higher in the highest tertile of animal protein intake compared with the lowest tertile (66 v. 33 mg/d, respectively, P= 0·03), linear regression analyses did not reveal significant associations between dietary protein and albuminuria. Protein intake exceeded the current recommendations. Nevertheless, within the range of protein intake in our RTR population, we found no evidence for an association of dietary protein with BP and renal function. Intervention studies focusing on different protein types are warranted to clarify their effect on BP and renal function in RTR.

Dietary acid load and metabolic acidosis in renal transplant recipients.

BACKGROUND AND OBJECTIVES: Acidosis is prevalent among renal transplant recipients (RTRs) and adversely affects cardiometabolic processes. Factors contributing to acidosis are graft dysfunction and immunosuppressive drugs. Little is known about the potential influence of diet on acidosis in RTRs. This study examined the association of metabolic acid load with acidosis and with cardiovascular risk factors in RTRs and aimed to identify dietary factors associated with acidosis. DESIGN, PARTICIPANTS, SETTING, & MEASUREMENTS: 707 RTRs were included. Metabolic acid load was assessed by measuring 24-hour urinary net acid excretion (NAE; i.e., titratable acid + ammonium - bicarbonate). Acidosis was defined as serum [HCO(3)(-)] < 24 mmol/L. BP and insulin resistance, reflected by hemoglobin A1c, were among cardiovascular risk factors. Diet was assessed with food-frequency questionnaires. Linear regression analysis was applied to investigate association between NAE and acidosis and between dietary factors and acidosis. RESULTS: Mean age ± SD was 53 ± 13 years; 57% of patients were male. Acidosis was present in 31% of RTRs. NAE was associated with acidosis (serum HCO(3)(-): ß=-0.61; serum pH: ß=-0.010; both P<0.001). Patients with high intake of animal protein (i.e., from meat, cheese, and fish) and low intake of fruits and vegetables had significantly lower serum HCO(3)(-) and serum pH. No associations were observed between NAE and cardiovascular risk factors, such as hypertension and insulin resistance. CONCLUSIONS: In addition to conventional factors contributing to acidosis, diet might influence acid-base homeostasis in RTRs. Higher intake of fruits and vegetables and lower animal protein intake is associated with less acidosis in RTRs.

Dairy consumption and incidence of hypertension: a dose-response meta-analysis of prospective cohort studies.

Observational and clinical studies suggest that dairy intake, particularly low-fat dairy, could have a beneficial effect on blood pressure. We performed a dose-response meta-analysis of prospective cohort studies on dairy intake and risk of hypertension in the general population. A systematic literature search for eligible studies was conducted until July 2011, using literature databases and hand search. Study-specific dose-response associations were computed according to the generalized least squares for trend estimation method, and linear and piecewise regression models were created. Random-effects models were performed with summarized dose-response data. We included 9 studies with a sample size of 57 256, a total of 15 367 incident hypertension cases, and a follow-up time between 2 and 15 years. Total dairy (9 studies; range of intake, ≈100-700 g/d), low-fat dairy (6 studies; ≈100-500 g/d), and milk (7 studies; ≈100-500 g/d) were inversely and linearly associated with a lower risk of hypertension. The pooled relative risks per 200 g/d were 0.97 (95% CI, 0.95-0.99) for total dairy, 0.96 (95% CI, 0.93-0.99) for low-fat dairy, and 0.96 (95% CI, 0.94-0.98) for milk. High-fat dairy (6 studies), total fermented dairy (4 studies), yogurt (5 studies), and cheese (8 studies) were not significantly associated with hypertension incidence (pooled relative risks of ≈1). This meta-analysis of prospective cohort studies suggests that low-fat dairy and milk could contribute to the prevention of hypertension, which needs confirmation in randomized controlled trials.

Dietary acid load and risk of hypertension: the Rotterdam Study.

BACKGROUND: Mild metabolic acidosis, which can be caused by diet, may result in elevated blood pressure (BP). DESIGN: The analyses included 2241 participants aged ≥55 y who were free of hypertension at baseline (1990-1993) and who had complete dietary and BP data. Dietary data were obtained from a 170-item food-frequency questionnaire. We used 2 measures to characterize dietary acid load: (1) potential renal acid load (PRAL) by using an algorithm including protein, phosphorus, potassium, calcium, and magnesium, and (2) estimated net endogenous acid production (NEAP) based on protein and potassium. HRs for 6-y incidence of hypertension were obtained in tertiles of PRAL and NEAP with adjustment for age, sex, BMI, smoking, education, and intakes of alcohol, fiber, and total energy. RESULTS: We identified 1113 incident cases of hypertension during 8707 person-years of follow-up. The median dietary acid load ranged from -14.6 to 19.9 mEq/d across categories of PRAL. Hypertension risk was not significantly associated with dietary acid load. The multivariate HRs (95% CIs) in consecutive tertiles of PRAL were 1.00 (reference), 1.01 (0.87, 1.17), and 1.02 (0.88, 1.18) (P trend = 0.83). The median dietary acid loads were 30.4, 36.7, and 43.7 mEq/d, respectively, in consecutive tertiles of NEAP. Corresponding HRs for NEAP were 1.00 (reference), 0.92 (0.80, 1.07), and 0.94 (0.81, 1.10) (P-trend = 0.46). CONCLUSION: The findings from this prospective cohort study provided no evidence of an association between dietary acid load and risk of hypertension in older adults.

Sources of dietary protein in relation to blood pressure in a general Dutch population.

BACKGROUND: Little is known about the relation of different dietary protein types with blood pressure (BP). We examined whether intake of total, plant, animal, dairy, meat, and grain protein was related to BP in a cross sectional cohort of 20,820 Dutch adults, aged 20-65 y and not using antihypertensive medication. DESIGN: Mean BP levels were calculated in quintiles of energy-adjusted protein with adjustment for age, sex, BMI, education, smoking, and intake of energy, alcohol, and other nutrients including protein from other sources. In addition, mean BP difference after substitution of 3 en% carbohydrates or MUFA with protein was calculated. RESULTS: Total protein and animal protein were not associated with BP (p(trend) = 0.62 and 0.71 respectively), both at the expense of carbohydrates and MUFA. Systolic BP was 1.8 mmHg lower (p(trend)<0.01) in the highest (>36 g/d) than in the lowest (<27 g/d) quintile of plant protein. This inverse association was present both at the expense of carbohydrates and MUFA and more pronounced in individuals with untreated hypertension (-3.6 mmHg) than in those with normal (+0.1 mmHg) or prehypertensive BP (-0.3 mmHg; p(interaction)<0.01). Meat and grain protein were not related to BP. Dairy protein was directly associated with systolic BP (+1.6 mmHg, p(trend)<0.01), but not with diastolic BP (p(trend) = 0.24). CONCLUSIONS: Total protein and animal protein were not associated with BP in this general untreated Dutch population. Plant protein may be beneficial to BP, especially in people with elevated BP. However, because high intake of plant protein may be a marker of a healthy diet and lifestyle in general, confirmation from randomized controlled trials is warranted.

Sources of dietary protein and risk of hypertension in a general Dutch population.

Evidence suggests a small beneficial effect of dietary protein on blood pressure (BP), especially for plant protein. We examined the relationship between several types of dietary protein (total, plant, animal, dairy, meat and grain) and the risk of hypertension in a general population of 3588 Dutch adults, aged 26-65 years, who were free of hypertension at baseline. Measurements were done at baseline and after 5 and 10 years of follow-up. Hazard ratios (HR), with 95 % CI, for incident hypertension were obtained in tertiles of energy-adjusted protein, using time-dependent Cox regression models. Models were adjusted for age, sex, BMI, education, smoking, baseline systolic BP, dietary confounders and protein from other sources (if applicable). Mean BP was 118/76 mmHg at baseline. Protein intake was 85 (sd 22) g/d (approximately 15 % of energy) with 62 % originating from animal sources. The main sources of protein were dairy products (28 %), meat (24 %) and grain (19 %). During the follow-up, 1568 new cases of hypertension were identified (44 % of the participants). Energy-adjusted intake of total protein, plant protein and animal protein was not significantly associated with hypertension risk (all HR approximately 1·00, P>0·60). Protein from grain showed a significant inverse association with incident hypertension, with a HR of 0·85 (95 % CI 0·73, 1·00, P trend = 0·04) for the upper tertile ( ≥ 18 g/d) v. the lower tertile ( < 14 g/d), whereas dairy protein and meat protein were not associated with incident hypertension. In conclusion, higher intake of grain protein may contribute to the prevention of hypertension, which warrants confirmation in other population-based studies and randomised controlled trials.

Dietary acid load and rapid progression to end-stage renal disease of diabetic nephropathy in Westernized South Asian people.

Diabetic nephropathy is now the most common cause of end-stage renal failure in many countries of the world. Despite increasing implementation of preventive treatment, the chance that an individual diabetic patient will reach end-stage renal failure has been increasing rather than decreasing during recent decades. Current dietary habits in The Netherlands and the rest of the Western world are slowly shifting from relatively alkalinizing (e.g., potatoes and vegetables) toward more acidifying (e.g., rice and meat). Moreover, immigrants who consumed traditional diets in their homelands, usually adapt to Western dietary habits. This phenomenon of diet acculturation could, for instance, be involved in the up to 40 times higher chance of development of end-stage renal failure in association with diabetes in South-Asian immigrants compared with whites, in Western countries. High ingestion of nonvolatile acids with food increases susceptibility for progression to end-stage renal failure. These high dietary acid loads lead to compensatory increases in renal acid excretion and ammoniagenesis. The price paid for maintenance of acid-base homeostasis is renal tubulointerstitial injury, with subsequent decline in renal function and induction of hypertension. The tendency for metabolic acidosis that results from the changing dietary habits could be corrected by a shift toward more alkalinizing food. We hypothesize that promoting such a shift can prevent the epidemic of end-stage renal failure in diabetes.

Milk and dairy consumption and incidence of cardiovascular diseases and all-cause mortality: dose-response meta-analysis of prospective cohort studies.

BACKGROUND: The consumption of dairy products may influence the risk of cardiovascular disease (CVD) and total mortality, but conflicting findings have been reported. OBJECTIVE: The objective was to examine the associations of milk, total dairy products, and high- and low-fat dairy intakes with the risk of CVD [including coronary heart disease (CHD) and stroke] and total mortality. DESIGN: PubMed, EMBASE, and SCOPUS were searched for articles published up to February 2010. Of > 5000 titles evaluated, 17 met the inclusion criteria, all of which were original prospective cohort studies. Random-effects meta-analyses were performed with summarized dose-response data. Milk as the main dairy product was pooled in these analyses. RESULTS: In 17 prospective studies, there were 2283 CVD, 4391 CHD, 15,554 stroke, and 23,949 mortality cases. A modest inverse association was found between milk intake and risk of overall CVD [4 studies; relative risk (RR): 0.94 per 200 mL/d; 95% CI: 0.89, 0.99]. Milk intake was not associated with risk of CHD (6 studies; RR: 1.00; 95% CI: 0.96, 1.04), stroke (6 studies; RR: 0.87; 95% CI: 0.72, 1.05), or total mortality (8 studies; RR per 200 mL/d: 0.99; 95% CI: 0.95, 1.03). Limited studies of the association of total dairy products and of total high-fat and total low-fat dairy products (per 200 g/d) with CHD showed no significant associations. CONCLUSION: This dose-response meta-analysis of prospective studies indicates that milk intake is not associated with total mortality but may be inversely associated with overall CVD risk; however, these findings are based on limited numbers.