Dietary protein intake and blood pressure: a meta-analysis of randomized controlled trials

Association of Animal and Plant Proteins Intake with Hypertension in Iranian Adult Population: Isfahan Healthy Heart Program

Background:

There is evidence regarding the relationship between dietary proteins intake and blood pressure (BP), but they had inconsistent results. Therefore, this study was designed to assess the association between different kinds of protein intake (animal and plant protein) and BP.

Materials and Methods:

Data were collected from Isfahan Healthy Heart Program. We performed a cross-sectional study among 9660 randomly selected Iranian adults aged ≥19-year-old that they were selected from three large Iranian regions in 2007. A simplified validated 48-item-food frequency questionnaire was used to assess dietary intake including all kinds of protein. Systolic and diastolic BPs were measured in duplicate by trained personnel using a standard protocol. Multivariable regressions were applied to assess the relationship between protein intake and BP levels and the presence of hypertension (HTN).

Results:

More frequent consumption of animal, plant, and total protein intake were inversely associated with BP in a crude model (P < 0.001); however, after adjustment for potential confounders this relationship remained only for plant protein (P = 0.04). The risk of HTN occurrence decreased in the highest quintile of total and plant protein consumption by 19% (odds ratio [OR] = 0.81; confidence interval [CI]: [0.65–0.96]; P for trend = 0.004) and 18% (OR = 0.82; [CI: (0.67–0.94]; P for trend = 0.03), respectively.

Conclusions:

More frequent protein intake, especially plant protein consumption was inversely associated with BP and risk of HTN among Iranian adults.

Estimated Effects of Future Atmospheric CO2 Concentrations on Protein Intake and the Risk of Protein Deficiency by Country and Region

BACKGROUND

Crops grown under elevated atmospheric CO2 concentrations (eCO2) contain less protein. Crops particularly affected include rice and wheat, which are primary sources of dietary protein for many countries.

OBJECTIVES

We aimed to estimate global and country-specific risks of protein deficiency attributable to anthropogenic CO2 emissions by 2050.

METHODS

To model per capita protein intake in countries around the world under eCO2, we first established the effect size of eCO2 on the protein concentration of edible portions of crops by performing a meta-analysis of published literature. We then estimated per-country protein intake under current and anticipated future eCO2 using global food balance sheets (FBS). We modeled protein intake distributions within countries using Gini coefficients, and we estimated those at risk of deficiency from estimated average protein requirements (EAR) weighted by population age structure.

RESULTS

Under eCO2, rice, wheat, barley, and potato protein contents decreased by 7.6%, 7.8%, 14.1%, and 6.4%, respectively. Consequently, 18 countries may lose >5% of their dietary protein, including India (5.3%). By 2050, assuming today's diets and levels of income inequality, an additional 1.6% or 148.4 million of the world's population may be placed at risk of protein deficiency because of eCO2. In India, an additional 53 million people may become at risk.

CONCLUSIONS

Anthropogenic CO2 emissions threaten the adequacy of protein intake worldwide. Elevated atmospheric CO2 may widen the disparity in protein intake within countries, with plant-based diets being the most vulnerable. https://doi.org/10.1289/EHP41.

Systems biology of personalized nutrition

Personalized nutrition is fast becoming a reality due to a number of technological, scientific, and societal developments that complement and extend current public health nutrition recommendations. Personalized nutrition tailors dietary recommendations to specific biological requirements on the basis of a person's health status and goals. The biology underpinning these recommendations is complex, and thus any recommendations must account for multiple biological processes and subprocesses occurring in various tissues and must be formed with an appreciation for how these processes interact with dietary nutrients and environmental factors. Therefore, a systems biology-based approach that considers the most relevant interacting biological mechanisms is necessary to formulate the best recommendations to help people meet their wellness goals. Here, the concept of "systems flexibility" is introduced to personalized nutrition biology. Systems flexibility allows the real-time evaluation of metabolism and other processes that maintain homeostasis following an environmental challenge, thereby enabling the formulation of personalized recommendations. Examples in the area of macro- and micronutrients are reviewed. Genetic variations and performance goals are integrated into this systems approach to provide a strategy for a balanced evaluation and an introduction to personalized nutrition. Finally, modeling approaches that combine personalized diagnosis and nutritional intervention into practice are reviewed.

Glycemic index, glycemic load, and blood pressure: a systematic review and meta-analysis of randomized controlled trials

Background: High blood pressure is a strong risk factor for cardiovascular disease.Objective: The aim of this study was to determine the associations of dietary glycemic index (GI) and glycemic load (GL) with systolic blood pressure (SBP) and diastolic blood pressure (DBP) in healthy individuals.Design: A systematic review and meta-analysis of randomized controlled trials (RCTs) was carried out. Databases were searched for eligible RCTs in 2 phases. MEDLINE, Embase, CAB Abstracts, BIOSIS, ISI Web of Science, and the Cochrane Library were searched from January 1990 to December 2009. An updated search was undertaken with the use of MEDLINE and Embase from January 2010 to September 2016. Trials were included if they reported author-defined high- and low-GI or -GL diets and blood pressure, were of ≥6 wk duration, and comprised healthy participants without chronic conditions. Data were extracted and analyzed with the use of Stata statistical software. Pooled estimates and 95% CIs were calculated with the use of weighted mean differences and random-effects models.Results: Data were extracted from 14 trials comprising 1097 participants. Thirteen trials provided information on differences in GI between control and intervention arms. A median reduction in GI of 10 units reduced the overall pooled estimates for SBP and DBP by 1.1 mm Hg (95% CI: -0.3, 2.5 mm Hg; P = 0.11) and 1.3 mm Hg (95% CI: 0.2 mm Hg, 2.3; P = 0.02), respectively. Nine trials reported information on differences in GL between arms. A median reduction in GL of 28 units reduced the overall pooled estimates for SBP and DBP by 2.0 mm Hg (95% CI: 0.2, 3.8 mm Hg; P = 0.03) and 1.4 mm Hg (95% CI: 0.1, 2.6 mm Hg; P = 0.03), respectively.Conclusions: This review of healthy individuals indicated that a lower glycemic diet may lead to important reductions in blood pressure. However, many of the trials included in the analysis reported important sources of bias. This trial was registered at PROSPERO as CRD42016049026.

Maternal Macronutrient Intake and Offspring Blood Pressure 20 Years Later

BACKGROUND

Results from 2 cohort studies in Scotland established in the 1940s and 1950s (Aberdeen and Motherwell) suggested that a high protein diet during pregnancy might adversely influence offspring blood pressure at adult age. Our objective was to examine this association in the Danish Fetal Origins Cohort (DaFO88).

METHODS AND RESULTS

This was a prospective birth cohort of 965 women who gave birth in 1988-1989 in Aarhus, Denmark, and whose offspring (n=434) participated in a clinical examination ≈20 years later. Macronutrient intake was assessed in gestational week 30. Multivariable adjusted linear regression was used to examine the relation between higher maternal protein intake, at the expense of carbohydrates, and offspring blood pressure (isocaloric substitution). Main analyses were adjusted for mother's age during pregnancy, prepregnancy body mass index, parity, smoking during pregnancy, educational level, and offspring's sex. The mean total energy intake was 8.7 MJ/day (SD 2.3 MJ/day). The mean energy from carbohydrate, fat, and protein intake was 51, 31, and 16 of total energy, respectively. The results showed that after adjustment, higher maternal protein intake was associated with slightly higher offspring diastolic blood pressure (highest compared with the lowest quintile of protein intake: ∆=2.4 mm Hg; 95% CI 0.4-4.4; P=0.03 for trend). Similar differences, although not significant, were found for systolic blood pressure (∆=2.6 mm Hg; 95% CI -0.0 to 5.3; P=0.08 for trend).

CONCLUSIONS

Higher maternal dietary protein intake at the expense of carbohydrates was associated with a modest increase in offspring blood pressure in young adulthood.

Beyond the Cholesterol-Lowering Effect of Soy Protein: A Review of the Effects of Dietary Soy and Its Constituents on Risk Factors for Cardiovascular Disease

The hypocholesterolemic effect of soy is well-documented and this has led to the regulatory approval of a health claim relating soy protein to a reduced risk of cardiovascular disease (CVD). However, soybeans contain additional components, such as isoflavones, lecithins, saponins and fiber that may improve cardiovascular health through independent mechanisms. This review summarizes the evidence on the cardiovascular benefits of non-protein soy components in relation to known CVD risk factors such as hypertension, hyperglycemia, inflammation, and obesity beyond cholesterol lowering. Overall, the available evidence suggests non-protein soy constituents improve markers of cardiovascular health; however, additional carefully designed studies are required to independently elucidate these effects. Further, work is also needed to clarify the role of isoflavone-metabolizing phenotype and gut microbiota composition on biological effect.

Effects of milk proteins on blood pressure: a meta-analysis of randomized control trials

Certain foods or their components are widely used in the prevention and/or management of cardiovascular disease. Milk proteins have been suggested to have hypotensive properties. A number of clinical trials have been carried out to evaluate the effect of milk proteins from whole foods and supplements on blood pressure (BP). However, the effect of milk proteins on BP is not well understood. Therefore, we conducted a meta-analysis of randomized control trials to provide insight into and robust evidence concerning the overall impact of milk proteins on BP. The PubMed and Cochrane databases were searched for literature concerning the effects of milk proteins on BP up to May 2016. A random effects model was used to calculate the pooled estimates and 95% confidence intervals of effect sizes. The final analysis included seven randomized control trials involving 412 participants. Overall, milk protein interventions significantly lowered systolic BP by -3.33 mm Hg (95% confidence interval -5.62, -1.03) and diastolic BP by -1.08 mm Hg (95% confidence interval -3.38, -0.22). There was no statistical evidence of publication bias across the studies. In conclusion, this meta-analysis provides further evidence that milk proteins slightly but significantly lower both systolic and diastolic BP.

Association Between Protein Intake and Mortality in Hypertensive Patients Without Chronic Kidney Disease in the OLD-HTA Cohort

Protein intake may have some benefits on reducing blood pressure and cardiovascular events, but their effects are still debated. The objective of this study was to test the prognostic value of protein intake assessed by 24-hour urinary urea in a cohort of hypertensive patients with preserved renal function. A total of 1128 hypertensive patients were followed according to tertile of protein intake adjusted for ideal body weight: <0.70, 0.70 to 0.93, and >0.93 g/kg. Baseline characteristics (mean±standard deviation) were age 45.1±13.2 years, systolic/diastolic blood pressure 185±32/107±20 mm Hg, and estimated glomerular filtration rate 82±32 mL/min. After 10 years of follow-up, 289 deaths occurred, 202 of which were of cardiovascular cause. After adjustment for major cardiovascular risk factors, patients in the second and third tertiles of protein intake had a decreased risk of all-cause death (hazard ratio [95% confidence interval], 0.71 [0.56-0.91]) and cardiovascular death (0.72 [0.54-0.96]), but not of stroke death (0.72 [0.41-1.28]) in comparison to patients in the low protein intake tertile. Normal-high protein intake was associated with a better outcome in a subset of the population: younger patients, low salt intake, without aortic atherosclerosis, or previous cardiovascular events (Pinteraction<0.10 for all). Hypertensive patients having a protein intake >0.7 g/kg ideal body weight, particularly those at low risk, had lower all-cause and cardiovascular mortality rates. Physicians may encourage hyper tensive patients to have normal or high protein diet in addition to low salt consumption, moderate alcohol consumption, and regular physical activity.

Dietary Oily Fish Intake and Blood Pressure Levels: A Population-Based Study

The effect of fish consumption on blood pressure is controversial. The authors measured blood pressure and calculated oily fish servings per week in 677 community-dwellers aged 40 years and older living in rural coastal Ecuador. Using regression models with linear splines, the authors evaluated whether dietary fish intake was related to blood pressure levels, after adjusting for relevant confounders. Mean oily fish consumption was 9.1±5.6 servings per week. There was a nonlinear relationship between systolic pressure and fish servings. In the group of individuals consuming up to five servings per week, each serving significantly reduced systolic pressure by 2.3 mm Hg (P=.020). Any extra serving provided no further effects. The study shows an inverse relationship between oily fish consumption and systolic pressure. Currently recommended amounts of dietary oily fish intake per week (1-2 servings) might be insufficient to exert beneficial effects of fish in the control of blood pressure.

Nutraceuticals with a clinically detectable blood pressure-lowering effect: a review of available randomized clinical trials and their meta-analyses

AIMS

The aim of the present study was to review and comment on the available evidence on nutraceuticals with a clinically demonstrable blood pressure (BP)-lowering effect.

METHODS

We reviewed studies published in the English language from 1990 to 2015 on dietary supplements or nutraceuticals claiming to show an effect on human BP. An initial list of possibly effective agents and studies was obtained from the online reference, the Natural Medicine Comprehensive Database. Using PubMed, we searched agents identified from this list using the MeSH terms 'hypertension', 'blood pressure', 'dietary supplement' and 'nutraceuticals', alone and in combination. We then focused our attention on meta-analyses and randomized clinical trials.

RESULTS

Beyond the well-known effects on BP of the Dietary Approaches to Stop Hypertension (DASH) and the Mediterranean diet, a large number of studies have investigated the possible BP-lowering effect of different dietary supplements and nutraceuticals, most of which are antioxidant agents with a high tolerability and safety profile. In particular, a relatively large body of evidence supports the use of potassium, magnesium, L-arginine, vitamin C, cocoa flavonoids, beetroot juice, coenzyme Q10, controlled-release melatonin and aged garlic extract. The antihypertensive effect of all these nutraceuticals seems to be dose related and the overall tolerability is good.

CONCLUSION

Some nutraceuticals might have a positive impact on BP in humans. Further clinical research is needed, to identify from the available active nutraceuticals those with the best cost-effectiveness and risk-benefit ratio for widespread and long-term use in the general population with a low-added cardiovascular risk related to uncomplicated hypertension.

Effects of Different Dietary Interventions on Blood Pressure: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Previous studies have shown beneficial effects of individual dietary approaches for blood pressure (BP) control, but their relative effectiveness is not well established. We performed a systematic review of published dietary pattern interventions and estimated the aggregate BP effects through meta-analysis. PubMed, EMBASE, and Web of Science databases were searched to identify studies published between January 1, 1990 and March 1, 2015. Studies meeting specific inclusion and exclusion criteria were selected. Data were pooled using random effects meta-analysis models. Twenty-four trials with 23 858 total participants were included. The overall pooled net effect of dietary intervention on systolic BP and diastolic BP was -3.07 mm Hg (95% confidence interval, -3.85 to -2.30) and -1.81 mm Hg (95% confidence interval, -2.24 to -1.38), respectively. The Dietary Approaches to Stop Hypertension diet had the largest net effect (systolic BP, -7.62 mm Hg [95% confidence interval, -9.95 to -5.29] and diastolic BP, -4.22 mm Hg [95% confidence interval, -5.87 to -2.57]). Low-sodium; low-sodium, high-potassium; low-sodium, low-calorie; and low-calorie diets also led to significant systolic and diastolic BP reductions, whereas Mediterranean diet participants experienced a significant incremental reduction in diastolic but not systolic BP. Subgroup analysis also showed important variations in effectiveness based on duration, size, and participant demographics. In conclusion, dietary modifications are associated with clinically meaningful, though variable, reductions in BP. Some diets are more effective than others and under different circumstances, which has important implications from both clinical and public health perspectives.

An Update on Nutrients and Blood Pressure

Adverse blood pressure (BP) is a major independent risk factor for epidemic cardiovascular diseases affecting almost one-quarter of the adult population worldwide. Dietary intake is a major determinant in the development and progression of high BP. Lifestyle modifications, including recommended dietary guidelines, are advocated by the American Society of Hypertension, the International Society of Hypertension, the Japanese Society of Hypertension, and many other organisations for treating all hypertensive people, prior to initiating drug therapy and as an adjunct to medication in persons already on drug therapy. Lifestyle modification can also reduce high BP and prevent development of hypertension. This review synthesizes results from the International Study of Macro/Micronutrients and Blood Pressure (INTERMAP), a cross-sectional epidemiological study of 4,680 men and women aged 40-59 years from Japan, the People's Republic of China, the United Kingdom, and the United States, published over the past few years on cross cultural BP differences. INTERMAP has previously reported that intakes of vegetable protein, glutamic acid, total and insoluble fibre, total polyunsaturated fatty acid and linoleic acid, total n-3 fatty acid and linolenic acid, phosphorus, calcium, magnesium, and non-heme iron were inversely related to BP. Direct associations of sugars (fructose, glucose, and sucrose) and sugar-sweetened beverages (especially combined with high sodium intake), cholesterol, glycine, alanine, and oleic acid from animal sources with BP were also reported by the INTERMAP Study.

Dietary proteins improve endothelial function under fasting conditions but not in the postprandial state, with no effects on markers of low-grade inflammation

Endothelial dysfunction (ED) and low-grade inflammation (LGI) have a role in the development of CVD. The two studies reported here explored the effects of dietary proteins and carbohydrates on markers of ED and LGI in overweight/obese individuals with untreated elevated blood pressure. In the first study, fifty-two participants consumed a protein mix or maltodextrin (3×20 g/d) for 4 weeks. Fasting levels and 12 h postprandial responses of markers of ED (soluble intercellular adhesion molecule 1 (sICAM), soluble vascular cell adhesion molecule 1 (sVCAM), soluble endothelial selectin and von Willebrand factor) and markers of LGI (serum amyloid A, C-reactive protein and sICAM) were evaluated before and after intervention. Biomarkers were also combined into mean Z-scores of ED and LGI. The second study compared 4 h postprandial responses of ED and LGI markers in forty-eight participants after ingestion of 0·6 g/kg pea protein, milk protein and egg-white protein. In addition, postprandial responses after maltodextrin intake were compared with a protein mix and sucrose. The first study showed significantly lower fasting ED Z-scores and sICAM after 4 weeks on the high-protein diet (P≤0·02). The postprandial studies found no clear differences of ED and LGI between test meals. However, postprandial sVCAM decreased more after the protein mix compared with maltodextrin in both studies (P≤0·04). In conclusion, dietary protein is beneficial for fasting ED, but not for fasting LGI, after 4 weeks of supplementation. On the basis of Z-scores, postprandial ED and LGI were not differentially affected by protein sources or carbohydrates.

Protein intake in early childhood and cardiometabolic health at school age: the Generation R Study

Purpose

High protein intake in infancy has been linked to obesity. We aimed to examine the associations of protein intake in early childhood with cardiovascular and metabolic outcomes at school age.

Methods

This study was performed in 2965 children participating in a population-based prospective cohort study. Protein intake at 1 year was assessed with a food frequency questionnaire and was adjusted for energy intake. At the children’s age of 6 years, we measured their body fat percentage (BF%), blood pressure (BP), and insulin, HDL cholesterol, and triglyceride serum levels. These measures were incorporated into a cardiometabolic risk factor score, using age- and sex-specific SD scores.

Results

In covariate-adjusted models, higher protein intake was associated with a higher BF%, lower diastolic BP, and lower triglyceride levels. We observed a significant interaction of protein intake with child sex on metabolic outcomes. Stratified analyses showed that protein intake was positively associated with BF% [0.07 SD (95 % CI 0.02; 0.13) per 10 g/day] and insulin levels in girls, but not in boys. In boys, but not in girls, higher protein intake was associated with lower triglyceride levels [−0.12 SD (95 % CI −0.20; −0.04) per 10 g/day] and a lower cardiometabolic risk factor score. Protein intake was not consistently associated with systolic BP or HDL cholesterol levels.

Conclusion

Protein intake in early childhood was associated with a higher BF% and higher insulin levels at 6 years in girls and with lower triglyceride levels in boys. Further studies are needed to explore these sex differences and to investigate whether the observed changes persist into adulthood.

Electronic supplementary material

The online version of this article (doi:10.1007/s00394-015-1026-7) contains supplementary material, which is available to authorized users.

Amino Acid Intakes Are Inversely Associated with Arterial Stiffness and Central Blood Pressure in Women

BACKGROUND

Although data suggest that intakes of total protein and specific amino acids (AAs) reduce blood pressure, data on other cardiovascular disease risk factors are limited.

OBJECTIVE

We examined associations between intakes of AAs with known mechanistic links to cardiovascular health and direct measures of arterial stiffness, central blood pressure, and atherosclerosis.

METHODS

In a cross-sectional study of 1898 female twins aged 18-75 y from the TwinsUK registry, intakes of 7 cardioprotective AAs (arginine, cysteine, glutamic acid, glycine, histidine, leucine, and tyrosine) were calculated from food-frequency questionnaires. Direct measures of arterial stiffness and atherosclerosis included central systolic blood pressure (cSBP), mean arterial pressure (MAP), augmentation index (AI), pulse wave velocity (PWV), and intima-media thickness (IMT). ANCOVA was used to assess the associations between endpoints of arterial stiffness and intake (per quintile), adjusting for potential confounders.

RESULTS

In multivariable analyses, higher intakes of total protein and 7 potentially cardioprotective AAs were associated with lower cSBP, MAP, and PWV. Higher intakes of glutamic acid, leucine, and tyrosine were most strongly associated with PWV, with respective differences of -0.4 ± 0.2 m/s (P-trend = 0.02), -0.4 ± 0.2 m/s (P-trend = 0.03), and -0.4 ± 0.2 m/s (P-trend = 0.03), comparing extreme quintiles. There was a significant interaction between AA intakes and protein source, and higher intakes of AAs from vegetable sources were associated with lower central blood pressure and AI. Higher intakes of glutamic acid, leucine, and tyrosine from animal sources were associated with lower PWV.

CONCLUSIONS

These data provide evidence to suggest that intakes of several AAs are associated with cardiovascular benefits beyond blood pressure reduction in healthy women. The magnitude of the observed associations was similar to those previously reported for other lifestyle factors. Increasing intakes of these AAs could be an important and readily achievable way to reduce cardiovascular disease risk.

Dietary protein and amino acids intake and its relationship with blood pressure in adolescents: the HELENA STUDY

OBJECTIVE

To analyze the association between dietary protein and amino acids intake and systolic (SBP) and diastolic (DBP) blood pressure in European adolescents.

METHODS

Participants were from the cross-sectional study performed in Europe, Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA study; n = 1605; 12.5-17.5 years; 833 girls) selected by complex sampling. The associations between dietary protein and amino acids intake and SBP/DBP were examined by multilevel linear regression models (context variable by school); the analysis being stratified by sex. Cities, seasonality, age, socioeconomic level, parental education level, body mass index, waist circumference, Tanner stage and physical activity were used as covariates.

RESULTS

In boys, we found an inverse association between protein (animal and vegetable) intake and DBP; and a positive association between histidine and SBP. In girls, we observed a positive association among tryptophan, histidine with SBP and methionine with DBP. On the other hand, we observed an inverse association between tyrosine and both SBP and DBP levels in girls.

CONCLUSIONS

The association between amino acids and BP levels is controversial and depends on the type of amino acids, and protein intake can help control the DBP in boys.

Effective translation of current dietary guidance: understanding and communicating the concepts of minimal and optimal levels of dietary protein

Dietitians and health care providers have critical roles in the translation of the dietary guidance to practice. The protein content of diets for adults can be based on the Recommended Dietary Allowance (RDA) of 0.80 g/kg per day. Alternatively, the most recent Dietary Reference Intakes (DRIs) for macronutrients reflect expanded guidance for assessing protein needs and consider the relative relation of absolute amounts of protein, carbohydrate, and fat to total energy intake in the context of chronic disease prevention. The Acceptable Macronutrient Distribution Range (AMDR) reflects the interrelation between the macronutrients and affords dietitians and clinicians additional flexibility in diet planning. Accounting for the caloric value of RDAs for carbohydrate and fat, "flexible calories" emerge as an opportunity to create varied eating plans that provide for protein intakes in excess of the RDA but within the AMDR. Protein Summit 2.0 highlighted the growing body of scientific evidence documenting the benefits of higher protein intakes at amounts approximating twice the RDA, which include promotion of healthy body weight and preservation of lean body mass and functional ability with age. The essential amino acid (EAA) density of a food also emerged as a novel concept analogous to "nutrient density," which can enable the practitioner to calculate the caloric cost associated with a specific protein source to attain the daily requirement of EAAs to accomplish various health outcomes because these indispensable nutrients have a significant role in protein utilization and metabolic regulation. Tailoring recommendations unique to an individual's varying goals and needs remains a challenge. However, flexibility within the application of DRIs to include consideration of the AMDR provides a sound framework to guide practitioners in effective translation of current dietary guidance with a specific regard for the documented benefits of higher protein intakes.

Nutraceuticals and Blood Pressure Control: Results from Clinical Trials and Meta-Analyses

Beyond the well-known effects on blood pressure (BP) of the dietary approaches to stop hypertension (DASH) and the Mediterranean diets, a large number of studies has investigated the possible BP lowering effect of different dietary supplements and nutraceuticals, the most part of them being antioxidant agents with a high tolerability and safety profile. In particular relatively large body of evidence support the use of potassium, L-arginine, vitamin C, cocoa flavonoids, beetroot juice, coenzyme Q10, controlled-release melatonin, and aged garlic extract. However there is a need for data about the long-term safety of a large part of the above discussed products. Moreover further clinical research is advisable to identify between the available active nutraceuticals those with the best cost-effectiveness and risk-benefit ratio for a large use in general population with low-added cardiovascular risk related to uncomplicated hypertension.

Association between Macronutrients Intake, Visceral Obesity and Blood Pressure in a Sample of Obese Egyptian Women

AIM

Study the association between the total caloric intake, protein, lipid, and some classes of fatty acids of the diet, and their effects on blood pressure in a sample of Egyptian obese women with and without visceral obesity.

METHODS

Five hundred forty-nine obese women were included in the study with mean age of 38.1 ± 11.56 years and mean Body mass index [BMI] of 36.17 ± 7.23. They enrolled in a program for losing weight. Visceral fat was determined using ultrasound. Blood pressure was measured 3 times and the mean was recorded. Twenty four hours dietary recall was reported.

RESULTS

Thirty point four percentages of samples has visceral obesity ≥ 7cm; they were the older, showed higher values of BMI, visceral obesity and blood pressure. Significant difference was found between groups regarding mean value of BMI, visceral obesity, both systolic blood pressure SBP and diastolic blood pressure DBP and most of the daily macronutrients intake. In groups (2&3) positive significant correlation was recorded between (SBP) & (DBP) and total daily intake of total calories, carbohydrate, total fat, saturated fatty acids and cholesterol, and negative significant correlation with total daily intake of total protein, animal and vegetable protein, linolenic and linoleic fatty acids, while oleic fatty acid showed negative correlation with SBP&DBP in all groups.

CONCLUSION

This study emphasizes the hypothesis that the macronutrients composition of diet influences blood pressure in different ways, in obese patients with visceral obesity.

Diets higher in protein predict lower high blood pressure risk in Framingham Offspring Study adults

BACKGROUND

Short-term clinical trials suggest that dietary protein lowers blood pressure (BP); however, long-term effects of total, animal, and plant proteins are less clear. Our goal was to evaluate effects of these dietary proteins on mean systolic BP (SBP) and diastolic BP (DBP) and incident high BP (HBP) risk among middle-aged adults in the Framingham Offspring Study.

METHODS

Men and women (aged 30-54 years) without prevalent HBP, cardiovascular disease, or diabetes with 3-day dietary records from exams 3 or 5 (n = 1,361) were included and followed for a mean of 11.3 years for development of HBP. Protein intakes adjusted for body size were derived using the residual method. Analysis of covariance and Cox proportional hazard's models were used to adjust for age, sex, education, height, activity, smoking, fat calories, diet quality, and body mass index.

RESULTS

Higher protein intakes were associated with lower mean SBP and DBP. Both animal and plant proteins lowered BP and led to statistically significant reductions in HBP risk (hazard ratios of 0.68 and 0.51, respectively). Participants in the highest tertile of total protein intake had 40% less risk (95% confidence interval [CI], 0.45-0.78) of developing HBP. Beneficial effects of protein were apparent for men and women and for normal-weight and overweight individuals. Higher protein diets also characterized by higher fiber intakes led to a 59% reduction (95% CI, 0.37-0.66) in HBP risk.

CONCLUSIONS

Adults consuming more dietary protein from either plant or animal sources had lower long-term risks of HBP.

Effects of protein intake on blood pressure, insulin sensitivity and blood lipids in children: a systematic review

High protein intake in early childhood is associated with obesity, suggesting possible adverse effects on other cardiometabolic outcomes. However, studies in adults have suggested beneficial effects of protein intake on blood pressure (BP) and lipid profile. Whether dietary protein intake is associated with cardiovascular and metabolic health in children is unclear. Therefore, we aimed to systematically review the evidence on the associations of protein intake with BP, insulin sensitivity and blood lipids in children. We searched the databases Medline, Embase, Cochrane Central and PubMed for interventional and observational studies in healthy children up to the age of 18 years, in which associations of total, animal and/or vegetable protein intake with one or more of the following outcomes were reported: BP; measures of insulin sensitivity; cholesterol levels; or TAG levels. In the search, we identified 6636 abstracts, of which fifty-six studies met all selection criteria. In general, the quality of the included studies was low. Most studies were cross-sectional, and many did not control for potential confounders. No overall associations were observed between protein intake and insulin sensitivity or blood lipids. A few studies suggested an inverse association between dietary protein intake and BP, but evidence was inconclusive. Only four studies examined the effects of vegetable or animal protein intake, but with inconsistent results. In conclusion, the literature, to date provides insufficient evidence for effects of protein intake on BP, insulin sensitivity or blood lipids in children. Future studies could be improved by adequately adjusting for key confounders such as energy intake and obesity.

Molecular targets of antihypertensive peptides: understanding the mechanisms of action based on the pathophysiology of hypertension

There is growing interest in using functional foods or nutraceuticals for the prevention and treatment of hypertension or high blood pressure. Although numerous preventive and therapeutic pharmacological interventions are available on the market, unfortunately, many patients still suffer from poorly controlled hypertension. Furthermore, most pharmacological drugs, such as inhibitors of angiotensin-I converting enzyme (ACE), are often associated with significant adverse effects. Many bioactive food compounds have been characterized over the past decades that may contribute to the management of hypertension; for example, bioactive peptides derived from various food proteins with antihypertensive properties have gained a great deal of attention. Some of these peptides have exhibited potent in vivo antihypertensive activity in both animal models and human clinical trials. This review provides an overview about the complex pathophysiology of hypertension and demonstrates the potential roles of food derived bioactive peptides as viable interventions targeting specific pathways involved in this disease process. This review offers a comprehensive guide for understanding and utilizing the molecular mechanisms of antihypertensive actions of food protein derived peptides.

Differential effects of proteins and carbohydrates on postprandial blood pressure-related responses

Diet composition may affect blood pressure (BP), but the mechanisms are unclear. The aim of the present study was to compare postprandial BP-related responses to the ingestion of pea protein, milk protein and egg-white protein. In addition, postprandial BP-related responses to the ingestion of maltodextrin were compared with those to the ingestion of sucrose and a protein mix. We hypothesised that lower postprandial total peripheral resistance (TPR) and BP levels would be accompanied by higher plasma concentrations of nitric oxide, insulin, glucagon-like peptide 1 (GLP-1) and glucagon. On separate occasions, six meals were tested in a randomised order in forty-eight overweight or obese adults with untreated elevated BP. Postprandial responses of TPR, BP and plasma concentrations of insulin, glucagon, GLP-1 and nitrite, nitroso compounds (RXNO) and S-nitrosothiols (NO(x)) were measured for 4 h. No differences were observed in TPR responses. Postprandial BP levels were higher after the ingestion of the egg-white-protein meal than after that of meals containing the other two proteins (P≤ 0·01). The ingestion of the pea-protein meal induced the highest NO(x) response (P≤ 0·006). Insulin and glucagon concentrations were lowest after the ingestion of the egg-white-protein meal (P≤ 0·009). Postprandial BP levels were lower after the ingestion of the maltodextrin meal than after that of the protein mix and sucrose meals (P≤ 0·004), while postprandial insulin concentrations were higher after the ingestion of the maltodextrin meal than after that of the sucrose and protein mix meals after 1-2 h (P≤ 0·0001). Postprandial NO(x), GLP-1 and glucagon concentrations were lower after the ingestion of the maltodextrin meal than after that of the protein mix meal (P≤ 0·008). In conclusion, different protein and carbohydrate sources induce different postprandial BP-related responses, which may be important for BP management. Lower postprandial BP levels are not necessarily accompanied by higher NO(x), insulin, glucagon or GLP-1 responses.

Dietary approaches to prevent hypertension

Elevated blood pressure arises from a combination of environmental and genetic factors and the interactions of these factors. A substantial body of evidence from animal studies, epidemiologic studies, meta-analyses, and randomized controlled trials has demonstrated that certain dietary patterns and individual dietary elements play a prominent role in the development of hypertension. Changes in diet can lower blood pressure, prevent the development of hypertension, and reduce the risk of hypertension-related complications. Dietary strategies for the prevention of hypertension include reducing sodium intake, limiting alcohol consumption, increasing potassium intake, and adopting an overall dietary pattern such as the DASH (Dietary Approaches to Stop Hypertension) diet or a Mediterranean diet. In order to reduce the burden of blood pressure-related complications, efforts that focus on environmental and individual behavioral changes that encourage and promote healthier food choices are warranted.

High protein weight loss diets in obese subjects with type 2 diabetes mellitus

BACKGROUND AND AIM

Diets where carbohydrate has been partially exchanged for protein have shown beneficial changes in persons with type 2 diabetes but no studies have enrolled people with albuminuria. We aim to determine if a high protein to carbohydrate ratio (HPD) in an energy reduced diet has a beneficial effect on metabolic control and cardiovascular risk factors without negatively affecting renal function.

METHOD AND RESULTS

Adult, overweight participants with type 2 diabetes, with albuminuria (30-600 mg/24 h or an albumin-to-creatinine ratio of 3.0-60 mg/mmol), and estimated GFR of >40 ml/min/1.73 m(2) were enrolled. Participants were randomized to an HPD or an SPD. Protein:fat:carbohydrate ratio was 30:30:40% of energy for the HPD and 20:30:50% for the SPD. Main outcomes were renal function, weight loss, blood pressure, serum lipids and glycaemic control. We recruited 76 volunteers and 45 (35 men and 10 women) finished. There were no overall changes in renal function at 12 months and no significant differences in weight loss between groups (9.7 ± 2.9 kg and 6.6 ± 1.4 kg HPD and SPD group respectively; p = 0.32). Fasting blood glucose decreased significantly with no treatment effect. The decrease in HbA1c differed between treatments at 6 months (HPD -0.9 vs. SPD -0.3%; p = 0.039) but not at 12 months. HDL increased significantly with no treatment effects. There were no changes in LDL or blood pressure overall but DBP was lower in the HPD group (p = 0.024) at 12 months.

CONCLUSION

Weight loss improved overall metabolic control in this group of well controlled participants with type 2 diabetes regardless of diet composition.

The role of nutrition and nutraceutical supplements in the treatment of hypertension

Vascular biology, endothelial and vascular smooth muscle and cardiac dysfunction play a primary role in the initiation and perpetuation of hypertension, cardiovascular disease and target organ damage. Nutrient-gene interactions and epigenetics are predominant factors in promoting beneficial or detrimental effects in cardiovascular health and hypertension. Macronutrients and micronutrients can prevent, control and treat hypertension through numerous mechanisms related to vascular biology. Oxidative stress, inflammation and autoimmune dysfunction initiate and propagate hypertension and cardiovascular disease. There is a role for the selected use of single and component nutraceutical supplements, vitamins, antioxidants and minerals in the treatment of hypertension based on scientifically controlled studies which complement optimal nutrition, coupled with other lifestyle modifications.

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.

Infant macronutrient composition is associated with differences in cardiovascular structures and function in childhood

Early-life nutrition may influence cardiovascular development. Not much is known about the associations between dietary composition and cardiovascular risk factors in childhood. We examined the associations of infant macronutrient intake with cardiovascular structures and function in 2882 children participating in a prospective, population-based cohort study. Information on macronutrient intake at the age of 14 mo was obtained from food-frequency questionnaires completed by a parent. Systolic and diastolic blood pressure, carotid-femoral pulse wave velocity (PWV), fractional shortening, and left cardiac structures (left atrial diameter, aortic root diameter, and left ventricular mass) were measured at the age of 6 y. Linear regression analyses were performed by using energy-adjusted macronutrient intakes, adjusted for maternal, child, and other dietary factors. Higher total fat intake was associated with higher carotid-femoral PWV (P-trend = 0.03), whereas higher intakes of total carbohydrate and mono- and disaccharides were associated with lower carotid-femoral PWV. No consistent associations were observed for macronutrient intake with systolic blood pressure, diastolic blood pressure, fractional shortening, and aortic root diameter. Higher intakes of total, saturated, monounsaturated, and polyunsaturated fat were associated with lower left atrial diameter (all P-trend ≤ 0.01), and higher total carbohydrate and mono- and disaccharide intakes were associated with higher left atrial diameter (P-trend < 0.01 and 0.02, respectively). Furthermore, the third tertile of mono- and disaccharide intake was associated with a higher left ventricular mass (difference: 1.01 g; 95% CI: 0.18, 1.85 g; P = 0.02). Dietary macronutrient composition in infancy may lead to developmental differences in cardiovascular structures and function in childhood. Further studies are needed to investigate whether these differences have consequences for the risk of future cardiovascular disease.

Effect of soybean protein on novel cardiovascular disease risk factors: a randomized controlled trial

BACKGROUND/OBJECTIVES

Cardiovascular disease (CVD) is the leading cause of death in the United States and the world. Clinical trials have suggested that soybean protein lowers lipids and blood pressure. The effect of soybean protein on novel CVD risk factors has not been well studied. The objective of this study was to examine the effect of soybean protein on biomarkers of inflammation, endothelial dysfunction and adipocytokines.

SUBJECTS/METHODS

The effect of 8 weeks of 40 g of soybean protein supplement (89.3 mg isoflavones), 40 g of milk protein supplement and 40 g of complex carbohydrate placebo was examined in a randomized, placebo-controlled, double-blind, three-phase crossover trial among adults in New Orleans, Louisiana and Jackson, Mississippi. Plasma levels of inflammation biomarkers (C-reactive protein, interleukin-6, tumor necrosis factor-α), endothelial dysfunction biomarkers (E-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, thrombomodulin) and adipocytokines (high-molecular weight adiponectin, leptin, resistin) were measured at baseline and at the end of each intervention using immunoturbidimetric and enzyme-linked immunosorbent assay techniques.

RESULTS

Soy protein supplementation resulted in a significant mean net change (95% confidence interval) in plasma E-selectin of -3.93 ng/ml (-7.05 to -0.81 ng/ml; P=0.014) compared with milk protein, and in plasma leptin of -2089.8 pg/ml (-3689.3 to -490.3 pg/ml; P=0.011) compared with carbohydrate. There were no significant changes in any other risk factors.

CONCLUSIONS

Soy protein supplementation may reduce levels of E-selectin and leptin. Further research is warranted to investigate the mechanisms through which protein may confer protective effects on novel CVD risk factors.