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Research Nut: Pistachios

Nut consumption for cognitive performance: A systematic review.

Theodore, L.E., N.J. Kellow, E.A. McNeil, E.O. Close, E.G. Coad, B.R. Cardoso, 2020. Nut consumption for cognitive performance: A systematic review. Adv Nutr. 00:1–16.

Diet is considered an important modifiable lifestyle factor capable of attenuating early cognitive changes in healthy older people. The inclusion of nuts in the diet has been investigated as a dietary strategy for maintenance of brain health across the lifespan. This review aimed to present up-to-date evidence regarding the association between nut intake and cognitive performance. Four databases (Ovid MEDLINE, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL) Plus, and Embase) were systematically searched from inception to April 2020. Eligible articles were interventional or observational studies in humans aged ≥18 y that measured the effects (or association) of nuts (almond, hazelnut, macadamia, pistachio, walnut, pecan, pine nut, Brazil nut, cashew, peanut) on cognitive outcomes. Out of the 2374 articles identified in the searches, 22 involving 43,793 participants met the criteria and were ultimately included in this review. Memory (immediate and delayed), attention, processing speed, executive function, and visual-spatial ability, as well as risk of mild cognitive impairment, were the outcomes investigated. Lack of consistency across the studies regarding study design, types of nut used, and cognitive outcomes measured resulted in inconsistent evidence that the regular consumption of mixed nuts has a protective effect on cognition in adults of different ages. Nonetheless, we observed that studies targeting populations with a higher risk of cognitive decline tended to find a more favorable outcome. Furthermore, homogeneous findings were observed in the studies that specifically addressed the association between walnut consumption and cognitive performance: out of the 6 studies, including 2 randomized controlled trials, only 1 did not find a positive association.

Energy extraction from nuts: walnuts, almonds, pistachios.

McArthur, B., R. Mattes, 2020. Energy extraction from nuts: walnuts, almonds, pistachios. Br J Nutr. 123(4):361-371.

The bioaccessibility of fat has implications for satiety and postprandial lipidemia. The prevailing view holds that the integrity of plant cell wall structure is the primary determinant of energy and nutrient extraction from plant cells as they pass through the gastrointestinal tract. However, comparisons across nuts (walnuts, almonds, pistachios) with varying physical properties do not support this view. In this study, masticated samples of three nuts from healthy adults were exposed to a static model of gastric digestion followed by simulated intestinal digestion. Primary outcomes were particle size and lipid release at each phase of digestion. Walnuts produced a significantly larger particle size post-mastication compared to almonds. Under gastric and intestinal conditions, the particle size was larger for walnuts compared to pistachios and almonds (P<0.05). However, the masticated and digesta particle sizes were not related to the integrity of cell walls nor lipid release. The total lipid release was comparable between nuts after the in vitro intestinal phase (P>0.05). Microstructural examination showed ruptured and fissured cell walls that would allow digestion of cellular contents and this may be governed by internal cellular properties such as oil body state. Furthermore, the cell walls of walnuts tend to rupture rather than separate and as walnut tissue passes through the gastrointestinal track, lipids tend to coalesce reducing digestion efficiency.

Association of nut intake with risk factors, cardiovascular disease, and mortality in 16 countries from 5 continents: analysis from the Prospective Urban and Rural Epidemiology (PURE) study.

de Souza, R.J., M. Dehghan, A. Mente, S.I. Bangdiwala, S.H. Ahmed, K.F. Alhabib, Y. Altuntas, A. Basiak-Rasała, G-R Dagenais, R. Diaz, L.I. Amma, R. Kelishadi, R. Khatib, S.A. Lear, P. Lopez-Jaramillo, V. Mohan, P. Poirier, S. Rangarajan, A. Rosengren, R. Ismail, S. Swaminathan, E. Wentzel-Viljoen, K. Yeates, R. Yusuf, K.K. Teo, S.S. Anand, S. Yusuf, for the PURE study investigators, 2020. Association of nut intake with risk factors, cardiovascular disease, and mortality in 16 countries from 5 continents: analysis from the Prospective Urban and Rural Epidemiology (PURE) study. The American Journal of Clinical Nutrition, nqaa108, https://doi.org/10.1093/ajcn/nqaa108

Background: The association of nuts with cardiovascular disease and deaths has been investigated mostly in Europe, the USA, and East Asia, with few data available from other regions of the world or from low- and middle-income countries. Objective: To assess the association of nuts with mortality and cardiovascular disease (CVD). Methods: The Prospective Urban Rural Epidemiology study is a large multinational prospective cohort study of adults aged 35–70 y from 16 low-, middle-, and high-income countries on 5 continents. Nut intake (tree nuts and ground nuts) was measured at the baseline visit, using country-specific validated FFQs. The primary outcome was a composite of mortality or major cardiovascular event [nonfatal myocardial infarction (MI), stroke, or heart failure]. Results: We followed 124,329 participants (age = 50.7 y, SD = 10.2; 41.5% male) for a median of 9.5 y. We recorded 10,928 composite events [deaths (n = 8,662) or major cardiovascular events (n = 5,979)]. Higher nut intake (>120 g per wk compared with <30 g per mo) was associated with a lower risk of the primary composite outcome of mortality or major cardiovascular event [multivariate HR (mvHR): 0.88; 95% CI: 0.80, 0.96; P-trend = 0.0048]. Significant reductions in total (mvHR: 0.77; 95% CI: 0.69, 0.87; P-trend <0.0001), cardiovascular (mvHR: 0.72; 95% CI: 0.56, 0.92; P-trend = 0.048), and noncardiovascular mortality (mvHR: 0.82; 95% CI: 0.70, 0.96; P-trend = 0.0046) with a trend to reduced cancer mortality (mvHR: 0.81; 95% CI: 0.65, 1.00; P-trend = 0.081) were observed. No significant associations of nuts were seen with major CVD (mvHR: 0.91; 95% CI: 0.81, 1.02; P-trend = 0.14), stroke (mvHR: 0.98; 95% CI: 0.84, 1.14; P-trend = 0.76), or MI (mvHR: 0.86; 95% CI: 0.72, 1.04; P-trend = 0.29). Conclusions: Higher nut intake was associated with lower mortality risk from both cardiovascular and noncardiovascular causes in low-, middle-, and high-income countries.

The beneficial effects of nutraceuticals and natural products on small dense LDL levels, LDL particle number and LDL particle size: a clinical review.

Talebi, S., M. Bagherniya, S.L. Atkin, G. Askari, H.M. Orafai, A. Sahebkar, 2020. The beneficial effects of nutraceuticals and natural products on small dense LDL levels, LDL particle number and LDL particle size: a clinical review. Lipids in Health and Disease. 19:66
https://doi.org/10.1186/s12944-020-01250-6.

Cardiovascular diseases (CVDs) are globally the major causes of morbidity and mortality. Evidence shows that smaller and denser low-dense lipoprotein (sdLDL) particles are independent atherogenic risk factors for CVD due to their greater susceptibility to oxidation, and permeability in the endothelium of arterial walls. sdLDL levels are an independent risk factor and of more predictive value than total LDL-C for the assessment of coronary artery disease and metabolic syndrome. Functional food ingredients have attracted significant attention for the management of dyslipidemia and subsequently increase cardio-metabolic health. However, to date there is no study that has investigated the effect of these bioactive natural compounds on sdLDL levels. Therefore, the aim of the present review is to summarize the evidence accrued on the effect of special dietary ingredients such as omega-3 polyunsaturated fatty acids, nutraceuticals and herbal medicines on the levels of sdLDL, LDL particle number, and LDL particle size. Based on the results of the existing clinical trials this review suggests that natural products such as medicinal plants, nutraceuticals and omega-3 fatty acids can be used as adjunct or complementary therapeutic agents to reduce sdLDL levels, LDL particle numbers or increase LDL particle size and subsequently may prevent and treat CVD, with the advantage that these natural agents are generally safe, accessible, and inexpensive.