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Research Nut: Pistachios

Intake of Nuts or Nut Products Does Not Lead to Weight Gain, Independent of Dietary Substitution Instructions: A Systematic Review and Meta-Analysis of Randomized Trials.

Guarneiri, L.L., J.A. Cooper, 2020. Intake of Nuts or Nut Products Does Not Lead to Weight Gain, Independent of Dietary Substitution Instructions: A Systematic Review and Meta-Analysis of Randomized Trials. Adv Nutr. 00:1–18.

Several clinical interventions report that consuming nuts will not cause weight gain. However, it is unclear if the type of instructions provided for how to incorporate nuts into the diet impacts weight outcomes. We performed a systematic review and meta-analysis of published nut-feeding trials with and without dietary substitution instructions to determine if there are changes in body weight (BW) or composition. PubMed and Web of Science were searched through 31 December 2019 for clinical trials involving the daily consumption of nuts or nut-based snacks/meals by adults (≥18 y) for >3 wk that reported BW, BMI, waist circumference (WC), or total body fat percentage (BF%). Each study was categorized by whether or not it contained dietary substitution instructions. Within these 2 categories, an aggregated mean effect size and 95% CI was produced using a fixed-effects model. Quality of studies was assessed through the Cochrane risk-of-bias tool. Fifty-five studies were included in the meta-analysis. In studies without dietary substitution instructions, there was no change in BW [standardized mean difference (SMD): 0.01 kg; 95% CI: −0.07, 0.08; I 2 = 0%] or BF% (SMD: −0.05%; 95% CI: −0.19, 0.09; I 2 = 0%). In studies with dietary substitution instructions, there was no change in BW (SMD: −0.01 kg; 95% CI: −0.11, 0.09; I 2 = 0%); however, there was a significant decrease in BF% (SMD: −0.32%; 95% CI: −0.61%, −0.03%; I 2 = 35.4%; P < 0.05). There was no change in BMI or WC for either category of studies. Nut-enriched diet interventions did not result in changes in BW, BMI, or WC in studies either with or without substitution instructions. Slight decreases in BF% may occur if substitution instructions are used, but more research is needed. Limitations included varying methodologies between included studies and the frequency of unreported outcome variables in excluded studies.

Changes in nut consumption influence long-term weight change in US men and women.

Liu, X., Y. Li, M. Guasch-Ferre, W.C. Willett, J.-P. Drouin-Chartier, S.N. Bhupathiraju, D.K. Tobias, 2019. Changes in nut consumption influence long-term weight change in US men and women. bmjnph 2019;0:1–10. doi:10.1136/bmjnph-2019-000034.

Background: Nut consumption has increased in the US but little evidence exists on the association between changes in nut consumption and weight change. We aimed to evaluate the association between changes in total consumption of nuts and intakes of different nuts (including peanuts) and long-term weight change, in three independent cohort studies. Methods and Findings: Data collected in three prospective, longitudinal cohorts among health professionals in the US were analysed. We included 27, 521 men (Health Professionals Follow-up Study, 1986 to 2010), 61,680 women (Nurses’ Health Study, 1986 to 2010), and 55,684 younger women (Nurses’ Health Study II, 1991 to 2011) who were free of chronic disease at baseline in the analyses. We investigated the association between changes in nut consumption over 4-year intervals and concurrent weight change over 20–24 years of follow-up using multivariate linear models with an unstructured correlation matrix to account for within-individual repeated measures. 21,322 individuals attained a body mass index classification of obesity (BMI ≥30 kg/m2) at the end of follow-up. Average weight gain across the three cohorts was 0.32 kg each year. Increases in nut consumption, per 0.5 servings/ day (14 g), was significantly associated with less weight gain per 4-year interval (p<0.01 for all): −0.19 kg (95% CI -0.21 to -0.17) for total consumption of nuts, -0.37 kg (95% CI -0.45 to -0.30) for walnuts, -0.36 kg (95% CI -0.40 to -0.31) for other tree nuts, and -0.15 kg (95% CI -0.19 to -0.11) for peanuts. Increasing intakes of nuts, walnuts, and other tree nuts by 0.5 servings/day was associated with a lower risk of obesity. The multivariable adjusted RR for total nuts, walnuts, and other tree nuts was 0.97 (95% CI 0.96 to 0.99, p=0.0036), 0.85 (95% CI 0.81 to 0.89, p=0.0002), and 0.89 (95% CI 0.87 to 0.91, p<0.0001), respectively. Increasing nut consumption was also associated with a lower risk of gaining ≥2 kg or ≥5 kg (RR 0.89–0.98, p<0.01 for all). In substitution analyses, substituting 0.5 servings/day of nuts for red meat, processed meat, French fries, desserts, or potato, chips (crisps) was associated with less weight gain (p<0.05 for all). Our cohorts were largely composed of Caucasian health professionals with relatively higher socioeconomic status; thus the results may not be generalisable to other populations. Conclusion: Increasing daily consumption of nuts is associated with less long-term weight gain and a lower risk of obesity in adults. Replacing 0.5 servings/day of less healthful foods with nuts may be a simple strategy to help prevent gradual long-term weight gain and obesity.

Daily consumption of pistachios over 12 weeks improves dietary profile without increasing body weight in healthy women: A randomized controlled intervention.

Fantino, M., B. Cé., M. Fréé, F. Bellisle, 2019. Daily consumption of pistachios over 12 weeks improves dietary profile without increasing body weight in healthy women: A randomized controlled intervention. Appetite. doi: https://doi.org/10.1016/j.appet.2019.104483.

Dietary guidelines around the world recommend the regular intake of nuts because of their nutrient contribution to the diet and reported health benefits. However, consumers are often reluctant to include nuts in their diet due to the high caloric density of nuts. In a 12-week randomized, controlled intervention, we investigated how adding a pistachio portion to the daily diet affects body weight and composition, satiety, energy and nutrient intake. Sixty healthy pre-menopausal women who did not typically consume nuts were randomly assigned to a control or an experimental groups. Experimental participants (n = 30) consumed 44 g (250 kcal) pistachios mid-morning while controls (n = 30) maintained their current eating habits for 12 weeks. Ad libitum food intake and appetite sensations following the pistachio portion were assessed in all participants before and after the intervention in four 2-consecutive-day test sessions (under laboratory and then free-living conditions). Body weight and composition (DXA) were unchanged in both groups after 12 weeks. Pre- and post-intervention tests showed that ad libitum intake adjusted to the pistachio portion, mostly via reduced intakes of carbohydrates and starch, in parallel with decreased hunger and increased satiety following the morning snack. Intakes of MUFA, PUFA, linoleic acid, thiamin, pyridoxine, copper, manganese, and zinc were significantly higher among women consuming the pistachio snack, in spite of compensatory adjustments in intake. In conclusion, daily intake of 44 g pistachios improved nutrient intake without affecting body weight or composition in healthy women. The additional calories provided by the pistachios induced satiety and sufficient adjustment of intake to prevent body weight changes.

A randomized controlled pilot study to assess effects of a daily pistachio (Pistacia Vera) afternoon snack on next-meal energy intake, satiety, and anthropometry in French women.

Carughi, A., F. Bellisle, A. Dougkas, A. Giboreau, M.J. Feeney, J. Higgs, 2019. A randomized controlled pilot study to assess effects of a daily pistachio (Pistacia Vera) afternoon snack on next-meal energy intake, satiety, and anthropometry in French women. Nutrients. Apr 2;11(4). pii: E767. doi: 10.3390/nu11040767.

Including nuts in the diet improves appetite control and does not lead to weight gain. However, for pistachios, evidence from randomized intervention studies is limited and there are no data on the effect of pistachios on satiety. The objective of this study was to assess the effect of daily consumption of pistachios as an afternoon snack on satiety, self-reported energy, self-reported nutrient intake, body weight, and body composition. This randomized controlled pilot study included two parallel groups of 30 healthy French women, in a free-living setting. For four weeks, groups were instructed to consume either 56 g (1318 kJ) of pistachios or 56 g of isoenergetic/equiprotein savory biscuits as an afternoon snack. Evening energy intake, changes in anthropometric measures, and daily intake of energy and selected nutrients were assessed. Visual analogue scales (VAS) were used to rate hunger, fullness, desire to eat, and prospective consumption. Satiety effects were not different between groups, as assessed by evening energy intake or VAS scores. Consuming pistachios or biscuits had no impact on body weight. Thiamin, vitamin B6, copper, and potassium intakes were significantly higher in the pistachio group. Consuming pistachios or biscuits as an afternoon snack resulted in similar post-snack food intake and subjective feelings of satiety. A daily pistachio snack for a month did not affect body weight or composition but it did improve micronutrient intake.

The consumption of nuts is associated with better dietary and lifestyle patterns in polish adults: Results of WOBASZ and WOBASZ II Surveys.

Witkowska, A.M., A. Wa´skiewicz, M.E. Zujko, D. Szczes´niewska, W. S´migielski, U. Stepaniak, A. Paja, W. Drygas, 2019. The consumption of nuts is associated with better dietary and lifestyle patterns in polish adults: Results of WOBASZ and WOBASZ II Surveys. Nutrients. 11, 1410; doi:10.3390/nu11061410.

In recent years, the concept of the health benefits of synergistic dietary patterns as opposed to individual foods or food constituents has been developed. The aim of this study was to determine whether nut consumption is associated with healthier nutrition and lifestyle. The research was based on complete data obtained during two Polish National Multi-Centre Health Examination Surveys—WOBASZ (2003–2005) and WOBASZ II (2013–2014). Of the 12,946 participants who completed dietary assessments, 299 subjects reported consuming any quantity of whole nuts. A control group of 1184 non-nut consumers from both surveys was randomly selected for the study, with age, gender, study (WOBASZ, WOBASZ II), educational level, and season-related interactions taken into account. In this study, nut consumption was associated with favorable food and lifestyle choices, excluding smoking. Better dietary quality consisted of having a higher Healthy Diet Indicator score, an increased intake of polyphenols and antioxidants, lower intake of red meat, but higher of poultry and fruit, more frequent consumption of antiatherogenic food products, and less frequent consumption of processed meats. There was also greater interest in special diets, such as weight-loss diet. In addition, nut eaters were more physically active in their leisure time. While limited by 24-h recall of nut intake and possible misclassification of nut/non-nut consumer status, this research supports the synergistic health-promoting attitudes of those who were classified as nut consumers.

Health benefits of pistachios consumption.

Terzo, S., S. Baldassano, G.F. Caldara, V. Ferrantelli, G. Lo Dico, F. Mulè, A. Amato, 2019. Health benefits of pistachios consumption. Nat Prod Res. 33(5):715-726.

The health benefits of nuts, mainly in relation to the improvement of dysmetabolic conditions such as obesity, type 2 diabetes mellitus and the related cardiovascular diseases, have been widely demonstrated. Compared to other nuts, pistachios have a lower fat and caloric content, and contain the highest levels of unsaturated fatty acids, potassium, γ-tocopherol, phytosterols and xanthophyll carotenoids, all substances that are well known for their antioxidant and anti-inflammatory actions. This variety of nutrients contributes to the growing body of evidence that the consumption of pistachios improves health, leading to a greater potential of healthy antioxidant and anti-inflammatory activity, glycemic control, and endothelial function. The present review examines the nutrients and phytochemicals present in pistachios as well as the potential health benefits of including pistachios in a diet.

Trends in dietary carbohydrate, protein, and fat intake and diet quality among US adults, 1999-2016.

Shan, Z., C.D. Rehm, G. Rogers, M. Ruan, D.D.Wang, F.B. Hu, D. Mozaffarian, F.F. Zhang, S.N. Bhupathiraju, 2019. Trends in dietary carbohydrate, protein, and fat intake and diet quality among US adults, 1999-2016. JAMA. 322(12):1178-1187.

IMPORTANCE: Changes in the economy, nutrition policies, and food processing methods can affect dietary macronutrient intake and diet quality. It is essential to evaluate trends in dietary intake, food sources, and diet quality to inform policy makers. OBJECTIVE: To investigate trends in dietary macronutrient intake, food sources, and diet quality among US adults. DESIGN, SETTING, AND PARTICIPANTS: Serial cross-sectional analysis of the US nationally representative 24-hour dietary recall data from 9 National Health and Nutrition Examination Survey cycles (1999-2016) among adults aged 20 years or older. EXPOSURE: Survey cycle. MAIN OUTCOMES AND MEASURES: Dietary intake of macronutrients and their subtypes, food sources, and the Healthy Eating Index 2015 (range, 0-100; higher scores indicate better diet quality; a minimal clinically important difference has not been defined). RESULTS: There were 43,996 respondents (weighted mean age, 46.9 years; 51.9% women). From 1999 to 2016, the estimated energy from total carbohydrates declined from 52.5% to 50.5% (difference, −2.02%; 95% CI, −2.41% to −1.63%), whereas that of total protein and total fat increased from 15.5%to 16.4% (difference, 0.82%; 95% CI, 0.67%-0.97%) and from 32.0%to 33.2%(difference, 1.20%; 95% CI, 0.84%-1.55%), respectively (all P < .001 for trend). Estimated energy from low-quality carbohydrates decreased by 3.25% (95% CI, 2.74%-3.75%; P < .001 for trend) from 45.1%to 41.8%. Increases were observed in estimated energy from high-quality carbohydrates (by 1.23% [95% CI, 0.84%-1.61%] from 7.42% to 8.65%), plant protein (by 0.38% [95%CI, 0.28%-0.49%] from 5.38%to 5.76%), saturated fatty acids (by 0.36% [95% CI, 0.20%-0.51%] from 11.5% to 11.9%), and polyunsaturated fatty acids (by 0.65% [95% CI, 0.56%-0.74%] from 7.58%to 8.23%) (all P < .001 for trend). The estimated overall Healthy Eating Index 2015 increased from 55.7 to 57.7 (difference, 2.01; 95% CI, 0.86-3.16; P < .001 for trend). Trends in high- and low-quality carbohydrates primarily reflected higher estimated energy from whole grains (0.65%) and reduced estimated energy from added sugars (−2.00%), respectively. Trends in plant protein were predominantly due to higher estimated intake of whole grains (0.12%) and nuts (0.09%). CONCLUSIONS AND RELEVANCE: From 1999 to 2016, US adults experienced a significant decrease in percentage of energy intake from low-quality carbohydrates and significant increases in percentage of energy intake from high-quality carbohydrates, plant protein, and polyunsaturated fat. Despite improvements in macronutrient composition and diet quality, continued high intake of low-quality carbohydrates and saturated fat remained.

Identification of plasma lipid metabolites associated with nut consumption in US men and women.

Malik, V.S., M. Guasch-Ferre, F.B. Hu, M.K. Townsend, O.A. Zeleznik, A.H. Eliassen, S.S. Tworoger, E.W. Karlson, K.H. Costenbader, A. Ascherio, K.M. Wilson, L.A. Mucci, E.L. Giovannucci, C.S. Fuchs, Y. Bao, 2019. Identification of plasma lipid metabolites associated with nut consumption in US men and women. J Nutr 149:1215–1221.

BACKGROUND: Intake of nuts has been inversely associated with risk of type 2 diabetes and cardiovascular disease, partly through inducing a healthy lipid profile. How nut intake may affect lipid metabolites remains unclear. OBJECTIVE: The aim of this study was to identify the plasma lipid metabolites associated with habitual nut consumption in US men and women. METHODS: We analyzed cross-sectional data from 1099 participants in the Nurses’ Health Study (NHS), NHS II, and Health Professionals Follow-up Study. Metabolic profiling was conducted on plasma by LC-mass spectrometry. Nut intake was estimated from food-frequency questionnaires. We included 144 known lipid metabolites that had CVs ≤25%. Multivariate linear regression was used to assess the associations of nut consumption with individual plasma lipid metabolites. RESULTS: We identified 17 lipid metabolites that were significantly associated with nut intake, based on a 1 serving (28 g)/d increment in multivariate models [false discovery rate (FDR) P value <0.05]. Among these species, 8 were positively associated with nut intake [C24:0 sphingomyelin (SM), C36:3 phosphatidylcholine (PC) plasmalogen-A, C36:2 PC plasmalogen, C24:0 ceramide, C36:1 PC plasmalogen, C22:0 SM, C34:1 PC plasmalogen, and C36:2 phosphatidylethanolamine plasmalogen], with changes in relative metabolite level (expressed in number of SDs on the log scale) ranging from 0.36 to 0.46 for 1 serving/d of nuts. The other 9 metabolites were inversely associated with nut intake with changes in relative metabolite level ranging from -0.34 to -0.44. In stratified analysis, 3 metabolites were positively associated with both peanuts and peanut butter (C24:0 SM, C24:0 ceramide, and C22:0 SM), whereas 6 metabolites were inversely associated with other nuts (FDR P value <0.05). CONCLUSIONS: A panel of lipid metabolites was associated with intake of nuts, which may provide insight into biological mechanisms underlying associations between nuts and cardiometabolic health. Metabolites that were positively associated with intake of nuts may be helpful in identifying potential biomarkers of nut intake.

Effect of pistachio on brachial artery diameter and flow-mediated dilatation: A systematic review and meta-analysis of randomized, controlled-feeding clinical studies.

Fogacci, F., A.F.G. Cicero, G. Derosa, M. Rizzo, M. Veronesi, C. Borghi, 2019. Effect of pistachio on brachial artery diameter and flow-mediated dilatation: A systematic review and meta-analysis of randomized, controlled-feeding clinical studies. Crit Rev Food Sci Nutr. 59(2):328-335.

BACKGROUND: Results of previous clinical trials evaluating the effect of pistachio supplementation on endothelial reactivity (ER) are controversial. AIMS: We aimed to assess the impact of pistachio on ER through systematic review of literature and meta-analysis of available randomized, controlled-feeding clinical studies (RCTs). METHODS: The literature search included SCOPUS, PubMed-Medline, ISI Web of Science and Google Scholar databases up to 1st August 2017 to identify RCTs investigating the impact of pistachio on ER. Two independent reviewers extracted data on study characteristics, methods and outcomes. Overall, the impact of pistachio on ER was reported in 4 trials. RESULTS: The meta-analysis did not suggest a significant change in brachial artery flow-mediated dilatation (FMD) (WMD: +0.28%; 95% CI: -0.58, 1.13; p = 0.525) while brachial artery diameter (BAD) improved (WMD: +0.04%; 95% CI: 0.03, 0.06; p<0.001) following pistachios consumption. CONCLUSION: The present meta-analysis suggests a significant effect of pistachios on ER, affecting BAD but not FMD.

Pistachio consumption modulates DNA oxidation and genes related to telomere maintenance: a crossover randomized clinical trial.

Canudas, S., P. Hernández-Alonso, S. Galié, J. Muralidharan, L. Morell-Azanza, G. Zalba, J. García-Gavilán, A. Martí, J. Salas-Salvadó, M. Bulló, 2019. Pistachio consumption modulates DNA oxidation and genes related to telomere maintenance: a crossover randomized clinical trial. Am J Clin Nutr. 0:1–8.

Background: Telomere attrition may play an important role in the pathogenesis and severity of type 2 diabetes (T2D), increasing the probability of β cell senescence and leading to reduced cell mass and decreased insulin secretion. Nutrition and lifestyle are known factors modulating the aging process and insulin resistance/secretion, determining the risk of T2D. Objectives: The aim of this study was to evaluate the effects of pistachio intake on telomere length and other cellular aging-related parameters of glucose and insulin metabolism. Methods: Forty-nine prediabetic subjects were included in a randomized crossover clinical trial. Subjects consumed a pistachio supplemented diet (PD, 50 E% [energy percentage] carbohydrates and 33 E% fat, including 57 g pistachios/d) and an isocaloric control diet (CD, 55 E% carbohydrates and 30 E% fat) for 4 mo each, separated by a 2-wk washout period. DNA oxidation was evaluated by DNA damage (via 8-hydroxydeoxyguanosine). Leucocyte telomere length and gene expression related to either oxidation, telomere maintenance or glucose, and insulin metabolism were analyzed by multiplexed quantitative reverse transcriptase-polymerase chain reaction after the dietary intervention. Results: Compared with the CD, the PD reduced oxidative damage to DNA (mean: −3.5%; 95% CI: −8.07%, 1.05%; P = 0.009). Gene expression of 2 telomere-related genes (TERT and WRAP53) was significantly upregulated (164% and 53%) after the PD compared with the CD (P = 0.043 and P = 0.001, respectively). Interestingly, changes in TERT expression were negatively correlated to changes in fasting plasma glucose concentrations and in the homeostatic model assessment of insulin resistance. Conclusions: Chronic pistachio consumption reduces oxidative damage to DNA and increases the gene expression of some telomere-associated genes. Lessening oxidative damage to DNA and telomerase expression through diet may represent an intriguing way to promote healthspan in humans, reversing certain deleterious metabolic consequences of prediabetes. This study was registered at clinicaltrials.gov as NCT01441921.