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Research Nut: Pistachios

Nut intake and adiposity: meta-analysis of clinical trials.

Flores-Mateo G., D. Rojas-Rueda, J. Basora, E. Ros, J. Salas-Salvadó, 2013. Nut intake and adiposity: meta-analysis of clinical trials. Am J Clin Nutr. 97(6):1346-1355.

BACKGROUND: Epidemiologic studies have shown an inverse association between the frequency of nut consumption and body mass index (BMI) and risk of obesity. However, clinical trials that evaluated nut consumption on adiposity have been scarce and inconclusive. OBJECTIVE: We performed a systematic review and meta-analysis of published, randomized nut-feeding trials to estimate the effect of nut consumption on adiposity measures. DESIGN: MEDLINE and the Cochrane Central Register of Controlled Trials databases were searched for relevant clinical trials of nut intake that provided outcomes of body weight, BMI (in kg/m2), or waist-circumference measures and were published before December 2012. There were no language restrictions. Two investigators independently selected and reviewed eligible studies. The weighted mean difference (WMD) between nut or control diets was estimated by using a random-effects meta-analysis with 95% CIs. RESULTS: Thirty-three clinical trials met our inclusion criteria. Pooled results indicated a nonsignificant effect on body weight (WMD: -0.47 kg; 95% CI: -1.17, 0.22 kg; I2 = 7%), BMI (WMD: -0.40 kg/m(2); 95% CI: -0.97, 0.17 kg/m(2); I2 = 49%), or waist circumference (WMD: -1.25 cm; 95% CI: -2.82, 0.31 cm; I2 = 28%) of diets including nuts compared with control diets. These findings were remarkably robust in the sensitivity analysis. No publication bias was shown. CONCLUSION: Compared with control diets, diets enriched with nuts did not increase body weight, body mass index, or waist circumference in controlled clinical trials.

Should we go nuts about nuts?

Rohrmann, S., D. Faeh, 2013. Should we go nuts about nuts? BMC Medicine. 11:165.

Since the beginning of the 1990s, increasing evidence supports beneficial effects of nut consumption on health. A new analysis of the Spanish PREDIMED trial, published in BMC Medicine, has expanded our knowledge. The study showed that individuals eating nuts more than three times per week died less often from cardiovascular disease and cancer than non-consumers. The study also adds an important finding that previous epidemiological studies could not provide: a protective effect on premature mortality was only seen in the intervention group in which nut consumption increased during the 4.8 years of follow-up, not in the intervention group with additional olive oil consumption or in the control group. Nut consumption actually decreased during follow-up in the latter two groups. Questions remain to be answered on the quantity of nuts to be consumed for health benefits, on possible mechanisms of action, and on whether some types of nuts should be favored.

Frequency of nut consumption and mortality risk in the PREDIMED nutrition intervention trial.

Guasch-Ferré, M., M. Bulló, M.Á. Martínez-González, E. Ros, D. Corella, R. Estruch, M. Fitó, F. Arós, J. Wärnberg, M. Fiol, J. Lapetra, E. Vinyoles, R.M. Lamuela-Raventós, L. Serra-Majem, X. Pintó, V. Ruiz-Gutiérrez, J. Basora, J. Salas-Salvadó, on behalf of the PREDIMED study group, 2013. Frequency of nut consumption and mortality risk in the PREDIMED nutrition intervention trial. BMC Med. 11:164.

Background: Prospective studies in non-Mediterranean populations have consistently related increasing nut consumption to lower coronary heart disease mortality. A small protective effect on all-cause and cancer mortality has also been suggested. To examine the association between frequency of nut consumption and mortality in individuals at high cardiovascular risk from Spain, a Mediterranean country with a relatively high average nut intake per person. Methods: We evaluated 7,216 men and women aged 55 to 80 years randomized to 1 of 3 interventions (Mediterranean diets supplemented with nuts or olive oil and control diet) in the PREDIMED (‘PREvención con DIeta MEDiterránea’) study. Nut consumption was assessed at baseline and mortality was ascertained by medical records and linkage to the National Death Index. Multivariable-adjusted Cox regression and multivariable analyses with generalized  estimating equation models were used to assess the association between yearly repeated measurements of nut consumption and mortality. Results: During a median follow-up of 4.8 years, 323 total deaths, 81 cardiovascular deaths and 130 cancer deaths occurred. Nut consumption was associated with a significantly reduced risk of all-cause mortality (P for trend <0.05, all). Compared to non-consumers, subjects consuming nuts >3 servings/week (32% of the cohort) had a 39% lower mortality risk (hazard ratio (HR) 0.61; 95% CI 0.45 to 0.83). A similar protective effect against cardiovascular and cancer mortality was observed. Participants allocated to the Mediterranean diet with nuts group who consumed nuts >3 servings/week at baseline had the lowest total mortality risk (HR 0.37; 95% CI 0.22 to 0.66). Conclusions: Increased frequency of nut consumption was associated with a significantly reduced risk of mortality in a Mediterranean population at high cardiovascular risk.

Cross-sectional assessment of nut consumption and obesity, metabolic syndrome and other cardiometabolic risk factors: The PREDIMED study.

Ibarrola-Jurado, N, M. Bulló, M. Guasch-Ferré, E. Ros, M.A. Martínez-González, D. Corella, M. Fiol, J. Wärnberg, R. Estruch, P. Román, F. Arós, E. Vinyoles, L. Serra-Majem, X. Pintó, M.I. Covas, J. Basora, J. Salas-Salvadó, on behalf of the PREDIMED Study Investigators, 2013. Cross-sectional assessment of nut consumption and obesity, metabolic syndrome and other cardiometabolic risk factors: The PREDIMED study. PLoS ONE 8(2): e57367. doi:10.1371/journal.pone.0057367.

Introduction: Prospective studies have consistently suggested that nut consumption is inversely related to fatal and nonfatal coronary heart disease. Limited data are available on the epidemiological associations between nut intake and cardiometabolic risk factors. Objective: To evaluate associations between frequency of nut consumption and prevalence of cardiometabolic risk factors [obesity, metabolic syndrome (MetS), type-2 diabetes, hypertension, and dyslipidemia] in a Mediterranean population at high cardiovascular risk. Materials and Methods: Cross-sectional study of 7,210 men and women (mean age, 67 y) recruited into the PREDIMED study. MetS was defined by the harmonized ATPIII and IDF criteria. Diabetes and hypertension were assessed by clinical diagnosis and dyslipidemia (high triglycerides, low HDL-cholesterol, and hypercholesterolemia) by lipid analyses. Nut consumption was assessed using a validated food frequency questionnaire and categorized as <1, 1–3, and >3 servings/wk. Control of confounding was done with multivariate logistic regression. Results: Compared to participants consuming <1 serving/wk of nuts, those consuming >3 servings/wk had lower adjusted odds ratios (OR) for obesity (0.61, 95% confidence interval 0.54 to 0.68; P-trend <0.001), MetS (0.74, 0.65 to 0.85; P-trend, 0.001), and diabetes (0.87, 0.78 to 0.99; P-trend = 0.043). Higher nut consumption was also associated with lower risk of the abdominal obesity MetS criterion (OR 0.68, 0.60 to 0.79; P-trend <0.001). No significant associations were observed for the MetS components high blood pressure, dyslipidemia, or elevated fasting glucose. Conclusions: Nut consumption was inversely associated with the prevalence of general obesity, central obesity, MetS, and diabetes in subjects at high cardiovascular risk.

 

Phytosterol content and fatty acid pattern of ten different nut types.

Kornsteiner-Krenn, M., K.-H. Wagner, I. Elmadfa, 2013. Phytosterol content and fatty acid pattern of ten different nut types. International Journal for Vitamin and Nutrition Research. 83:263-270. 

Ten different nut kinds (almonds, Brazil nuts, cashews, hazelnuts, macadamias, peanuts, pecans, pine nuts, pistachios, and walnuts) were evaluated for their total oil and phytosterol content as well as their fatty acid composition. The total oil content was the predominant component; mean values oscillated between 45.2 % (cashews) and 74.7 % (macadamias). Mean total phytosterol content ranged from 71.7 mg (Brazil nuts) to 271.9 mg (pistachios) per 100 g oil. ß-sitosterol was the major sterol (mean >71.7 mg/100 g oil) followed by minor contents of campesterol, ergosterol, and stigmasterol. Almonds, cashews, hazelnuts, macadamias, and pistachios were high in monounsaturated fatty acids (MUFA; > 55 %). MUFA- and polyunsaturated fatty acid (PUFA)-rich nuts were peanuts and pecans, whereas Brazil nuts, pine nuts, and walnuts had the highest PUFA content (> 50 %); the high unsaturated/saturated fatty acid ratio ranged from 4.5 to 11.8. However, the fatty acid pattern of every nut is unique.

Bioaccessibility of pistachio polyphenols, xanthophylls, and tocopherols during simulated human digestion.

Mandalari, G., C. Bisignano, A. Filocamo, S. Chessa, M. Saró, G. Torre, R.M. Faulks, P. Dugo, 2013. Bioaccessibility of pistachio polyphenols, xanthophylls, and tocopherols during simulated human digestion. Nutrition.  29:338–344.

Objective: The bioaccessibility of bioactives from pistachios has not been previously evaluated. In the present study we quantified the release of polyphenols, xanthophylls (lutein), and tocopherols from pistachios (raw pistachios, roasted salted pistachios, and muffins made with raw pistachios) during simulated human digestion. Methods: A dynamic gastric model of digestion that provides a realistic and predictive simulation of the physical and chemical processing and accurately mimics the residence time and the luminal environment within the human stomach was used for the digestion studies. Results: More than 90% of the polyphenols were released in the gastric compartment, with virtually total release in the duodenal phase. No significant differences were observed between raw shelled and roasted salted pistachio. The presence of a food matrix (muffin) decreased the bioaccessibility of protocatechuic acid (78%) and luteolin (36%). Almost 100% bioaccessibility of lutein and tocopherols was found after duodenal digestion, with no difference among the three samples. Conclusion: The rapid release of the assayed bioactives in the stomach maximizes the potential for absorption in the duodenum and contributes to the beneficial relation between pistachio consumption and health-related outcomes.

Health benefits of nut consumption with special reference to body weight control.

Vadivel, V., C.N. Kunyanga, H.K. Biesalski, 2012. Health benefits of nut consumption with special reference to body weight control. Nutrition.  28:1089–1097.

Nuts are an integral part of the Mediterranean food patterns, and their incorporation into the regular diets of human beings is believed to provide many health benefits. The recent recognition of nuts as “heart-healthy” foods by the U.S. Food and Drug Administration has given a major boost to the positive image of nuts. Nut consumption has been associated with several health benefits, such as antioxidant, hypocholesterolemic, cardioprotective, anticancer, anti-inflammatory, and antidiabetic benefits, among other functional properties. However, although nuts possess these many health benefits, their consumption has been hampered by a lack of adequate information regarding those benefits. In addition, because nuts are energy-dense foods with high-fat content, there is a misconception among consumers that increased consumption may lead to unwanted gain in body weight with the risk of developing overweight/obesity. Nonetheless, available epidemiologic studies and short-term controlled feeding trials have supported the theory that the inclusion of nuts in the typical diet does not induce weight gain, despite an expected increase in total caloric intake. To address the misperception about nuts and body weight gain, the present review focuses mainly on the relation between nut consumption and body weight gain, in the context of the many health benefits of nuts.

Nut consumption is associated with a healthy dietary pattern in military men.

Mullie, M., P. Clarys, 2012. Nut consumption is associated with a healthy dietary pattern in military men. Food and Nutrition Sciences. 3:1048-1054.

The objective of the research was to determine the relation between nut consumption and dietary patterns described by Healthy Eating Index, Mediterranean Diet Score and principal component analysis. In a cross-sectional study, 1852 military men were contacted by mail. Using food-frequency questionnaires, nut consumption was recorded and stratified in weekly versus less than weekly. Three dietary indices were calculated and stratified in quintiles. For principal component analysis, the healthiest dietary pattern rich in fruits and vegetables was selected as Healthy Dietary Pattern. The highest quintiles of Healthy Eating Index, Mediterranean Diet Score and Healthy Dietary Pattern were systematically associated with the highest weekly consumption of nuts. The highest quintiles were also associated with the lowest intake of saturated fat, i.e. between 10 and 12 energy-percent compared with 17 to 19 energy-percent for the lowest quintiles. The mean daily nut consumption was less than 6 g a day, which is beneath the recommended quantity for cardiovascular protection. Nut consumption was associated with the healthiest dietary pattern, independently of the used method to determine the dietary pattern. Regular nut consumption seems to be a component of a cluster of several healthy behaviors.

Nuts for diabetes prevention and management.

Kamil, A., C.-Y. O. Chen, 2012. Nuts for diabetes prevention and management. Journal of Food and Drug Analysis. 20(Suppl.1): 323-327.

Type 2 diabetes mellitus is an important preventable disease and a growing public health problem. Epidemiologic and clinical studies suggest that healthy eating, physical activity, and BW control are the main driving forces to reduce diabetes risk. Owing to their low available carbohydrate content, favorable fat and protein profile as well as phytonutrient content, nut consumption has been associated with a reduced risk of development and management of diabetes. Nuts, by virtue of its cardioprotective actions, have also been shown to reduce biomarkers of risk factors for diabetic complications. Although more studies are warranted, the emerging picture is that nut consumption beneficially influences diabetes risk and management beyond blood glucose control.

Polymeric proanthocyanidins from Sicilian pistachio (Pistacia vera L.) nut extract inhibit lipopolysaccharide-induced inflammatory response in RAW 264.7 cells.

Gentile, C., M. Allegra, F. Angileri, A.M. Pintaudi, M.A. Livrea, L. Tesoriere, 2012. Polymeric proanthocyanidins from Sicilian pistachio (Pistacia vera L.) nut extract inhibit lipopolysaccharide-induced inflammatory response in RAW 264.7 cells. Eur J Nutr. 51(3):353-63.

Background: Positive effects of pistachio nut consumption on plasma inflammatory biomarkers have been described; however, little is known about molecular events associated with these effects. Purpose: We studied the anti-inflammatory activity of a hydrophilic extract from Sicilian Pistacia L. (HPE) in a macrophage model and investigated bioactive components relevant to the observed effects. Methods: HPE oligomer/polymer proanthocyanidin fractions were isolated by adsorbance chromatography, and components quantified as anthocyanidins after acidic hydrolysis. Isoflavones were measured by gradient elution HPLC analysis. RAW 264.7 murine macrophages were pre-incubated with either HPE (1- to 20-mg fresh nut equivalents) or its isolated components for 1 h, then washed before stimulating with lipopolysaccharide (LPS) for 24 h. Cell viability and parameters associated with Nuclear Factor-κB (NF-κB) activation were assayed according to established methods including ELISA, Western blot, or cytofluorimetric analysis. Results: HPE suppressed nitric oxide (NO) and tumor necrosis factor-α (TNF-α) production and inducible NO-synthase levels dose dependently, whereas inhibited prostaglandin E2 (PGE2) release and decreased cyclooxygenase-2 content, the lower the HPE amount the higher the effect. Cytotoxic effects were not observed. HPE also caused a dose-dependent decrease in intracellular reactive oxygen species and interfered with the NF-κB activation. Polymeric proanthocyanidins, but not isoflavones, at a concentration comparable with their content in HPE, inhibited NO, PGE2, and TNF-α formation, as well as activation of IκB-α. Oligomeric proanthocyanidins showed only minor effects. Conclusions: Our results provide molecular evidence of anti-inflammatory activity of pistachio nut and indicate polymeric proanthocyanidins as the bioactive components. The mechanism may involve the redox-sensitive transcription factor NF-κB. Potential effects associated with pistachio nut consumption are discussed in terms of the proanthocyanidin bioavailability.