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Research Nut: Brazil Nuts

Anti-atherosclerotic and cardiovascular protective benefits of Brazilian nuts.

C.K.B. Ferrari, 2020. Anti-atherosclerotic and cardiovascular protective benefits of Brazilian nuts. Front Biosci (Schol Ed). 12:38-56.

Brazil nuts are rich in magnesium, selenium, arginine and other amino acids, dietary fiber, tocopherols (vitamin E), phytosterols, linoleic acid, linolenic acid, sitosterols, monounsaturated and polyunsaturated fatty acids, polyphenols and other amino acids. Due to such a rich mixture of nutrients, Brazil nuts protect LDL from peroxidation, and improve endothelial function, blood pressure, lipid metabolism, and decrease endothelial inflammatory markers, DNA oxidation, and blood lipids (cholesterol, LDL, triglycerides). Here, we review and propose biological mechanisms by which bioactive compounds of Brazil nuts afford protections against atherosclerosis and cardiovascular diseases. Just a few nuts per day provide sufficient cardiovascular benefits, including protection against development and progression of atherosclerosis.

Brazil nut prevents oxidative DNA damage in type 2 diabetes patients.

Macan, T.P., T.A. de Amorim, A.P. Damiani, Â.C. da Luz Beretta, M.L. Magenis, T.C. Vilela, J.P. Teixeira, V.M. de Andrade, 2020. Brazil nut prevents oxidative DNA damage in type 2 diabetes patients. Drug Chem Toxicol. 1-7. doi: 10.1080/01480545.2020.1808667. 

The Brazil nut (Bertholletia excelsa, H.B.K.) originating from the Amazon region is one of the richest known sources of selenium (Se), a micronutrient that is essential and required for optimal physiological functioning. This mineral presents several health benefits, including improvement of the redox cellular status and maintenance of genomic stability. Knowing that type 2 diabetes mellitus (T2D) is strongly linked to oxidative stress and consequently DNA damage, the aim of this study was to assess the ex vivo antioxidative effects of Se through Brazil nut consumption and its potential in preventing oxidative DNA damage induced by H2O2. In order to accomplish this, the Comet assay (single-cell gel electrophoresis) was used to measure DNA damage in peripheral blood cells harvested before and after supplementation with Brazil nut. Comet assay was also applied ex vivo to measure the potential of Se to prevent oxidative damage to DNA induced by H2O2 in blood of type 2 diabetes patients collected before and after six months of supplementation with Brazil nut. We found that supplementation with Brazil nuts significantly increased serum Se levels. Furthermore, we observed a significant increase in fasting blood glucose after six months of consuming Brazil nuts; however, no significant effect was observed on the levels of glycated hemoglobin. Finally, we noticed that the cells were more resistant to H2O2-induced DNA damage after six months of supplementation with Brazil nut. Thus, consumption of Brazil nuts could decrease oxidative DNA damage in T2D patients, probably through the antioxidative effects of Se.

Comparative effects of different types of tree nut consumption on blood lipids: a network meta-analysis of clinical trials.

Liu, K., S. Hui, B. Wang, K. Kaliannan, X. Guo, L. Liang, 2020. Comparative effects of different types of tree nut consumption on blood lipids: a network meta-analysis of clinical trials. Am J Clin Nutr. 111(1):219-227.

Background: Recent evidence has confirmed that nuts are one of the best food groups at reducing LDL cholesterol and total cholesterol (TC). However, the comparative effects of different types of nuts on blood lipids are unclear. Objectives: This network meta-analysis of randomized clinical trials aimed to assess the comparative effects of walnuts, pistachios, hazelnuts, cashews, and almonds on typical lipid profiles. Methods: We conducted literature searches to identify studies comparing ≥2 of the following diets-walnut-enriched, pistachio-enriched, hazelnut-enriched, cashew-enriched, almond-enriched, and control diets-for the management of triglycerides (TGs), LDL cholesterol, TC, and HDL cholesterol. Random-effects network meta-analyses, ranking analyses based on the surface under the cumulative ranking (SUCRA) curves, and sensitivity analyses according to the potential sources of heterogeneity across the included studies were performed for each outcome. Results: Thirty-four trials enrolling 1677 participants were included in this study. The pistachio-enriched diet was ranked best for TG (SUCRA: 85%), LDL cholesterol (SUCRA: 87%), and TC (SUCRA: 96%) reductions. For TG and TC reductions, the walnut-enriched diet was ranked as the second-best diet. Regarding LDL cholesterol reduction, the almond-enriched diet was ranked second best. The pistachio-enriched and walnut-enriched diets were more effective at lowering TG, LDL cholesterol, and TC compared with the control diet. Regarding TG and TC reductions, the pistachio-enriched diet was also more effective than the hazelnut-enriched diet. For TG reduction, the walnut-enriched diet was better than the hazelnut-enriched diet. However, these findings are limited by the low quality of evidence ratings. In addition, the quality of this network meta-analysis was limited by the small number and generally poor reporting of available studies. Conclusions: The pistachio-enriched and walnut-enriched diet could be better alternatives for lowering TGs, LDL cholesterol, and TC compared with other nut-enriched diets included in this study. The findings warrant further evaluation by more high-quality studies. This network meta-analysis was registered at www.crd.york.ac.uk/PROSPERO as CRD42019131128.

Edible nuts for memory.

Arslan, J., A.-U.-H. Gilani, H. Jamshed, S.F. Khan, M.A. Kamal, 2020. Edible nuts for memory. Curr Pharm Des. 26(37):4712-4720.

Nuts hold prime significance throughout the world as they offer multiple health benefits owing to their highly nutritious profile. A number of scientific studies have demonstrated their actions against inflammation, oxidative damage, the aging process, as well as dementia or memory loss. However, only walnuts, followed by almonds, hazelnuts and pistachios, have shown promising results in empirical studies for memory improvements. So, the current review focuses on presenting hypotheses regarding anti-dementia property of nine different nuts: almond, walnut, pistachio, Brazil nut, peanut, pecans, cashew, hazelnut, and chestnut. The nutritious profile of nuts contains essential fats (mostly mono- and poly-unsaturated fatty acids), proteins (source for arginine, lysine and tryptophan), vitamins (riboflavin, folate, and various tocopherols), fibers, minerals (calcium, sodium, magnesium, phosphorus and potassium) and trace elements (copper, zinc, and selenium). Interestingly, the constituents of natural products, nuts being an excellent example, work synergistically and/or in a side-effect neutralizing manner. These latter properties can make nuts an alternate therapy for humankind to fight against memory loss.

Tree nut snack consumption is associated with better diet quality and CVD risk in the UK adult population: National Diet and Nutrition Survey (NDNS) 2008–2014.

Dikariyanto, V., S.E. Berry, G.K. Pot, L. Francis, L. Smith, W.L. Hall, 2020. Tree nut snack consumption is associated with better diet quality and CVD risk in the UK adult population: National Diet and Nutrition Survey (NDNS) 2008–2014. Public Health Nutrition. 23(17), 3160–3169.

Objectives: To examine associations of tree nut snack (TNS) consumption with diet quality and cardiovascular disease (CVD) risk in UK adults from National Diet and Nutrition Survey (NDNS) 2008–2014. Design: Cross-sectional analysis using data from 4-d food diaries, blood samples and physical measurements for CVD risk markers. To estimate diet quality, modified Mediterranean Diet Score (MDS) and modified Healthy Diet Score (HDS) were applied. Associations of TNS consumption with diet quality and markers of CVD risk were investigated using survey-adjusted multivariable linear regression adjusted for sex, age, ethnicity, socio-economic and smoking status, region of residency and total energy and alcohol intake. Setting: UK free-living population. Subjects: 4738 adults (≥19 years). Results: TNS consumers had higher modified MDS and HDS relative to non-consumers. TNS consumers also had lower BMI, WC, SBP and DBP and higher HDL compared to non-consumers, although a dose-related fully adjusted significant association between increasing nut intake (g per 4184 kJ/1000 kcal energy intake) and lower marker of CVD risk was only observed for SBP. TNS consumption was also associated with higher intake of total fat, mono-, n-3 and n-6 polyunsaturated fatty acids, fibre, vitamin A, thiamin, folate, vitamin C, vitamin E, potassium, magnesium, phosphorus, selenium and iron; and lower intake of saturated fatty acids, trans fatty acids, total carbohydrate, starch, free sugar, sodium and chloride. Conclusions: TNS consumers report better dietary quality and consumption was associated with lower CVD risk factors. Encouraging replacement of less healthy snacks with TNS should be encouraged as part of general dietary guidelines.

Nut consumption and risk of cancer: A meta-analysis of prospective studies.

Long, J., Z. Ji, P. Yuan, T. Long, K. Liu, J. Li, L. Cheng, 2020. Nut consumption and risk of cancer: A meta-analysis of prospective studies. Cancer Epidemiol Biomarkers Prev. doi: 10.1158/1055-9965.EPI-19-1167.

Background: Epidemiologic studies have investigated the association between nut intake and risk for multiple cancers. However, current findings are inconsistent and no definite conclusion has been drawn from prospective studies. We therefore conducted this meta-analysis to evaluate the relationship between nut consumption and risk of cancer. Methods: Prospective studies reporting associations between nut intake and risk for all types of cancer were identified by searching Web of Science and PubMed databases up to June 2019. Risk ratios (RR) and 95% confidence intervals (CI) were extracted and then pooled across the studies using a random-effect model. A dose–response analysis was modeled by performing restricted cubic splines when data were available. Results: Thirty-three studies that included more than 50,000 cancer cases were eligible for the analysis. When comparing the highest with the lowest category of nut intake, high consumption of nuts was significantly associated with decreased risk of overall cancer (RR= 0.90; 95% CI, 0.85–0.95). The protective effect of nut consumption was especially apparent against cancers from the digestive system (RR=0.83; 95% CI, 0.77–0.89). Among different nut classes, significant association was only obtained for intake of tree nuts. We also observed a linear dose–response relationship between nut consumption and cancer: Per 20 g/day increase in nut consumption was related to a 10% (RR=0.90; 95% CI, 0.82–0.99) decrease in cancer risk. Conclusions: Our analysis demonstrated an inverse association of dietary nut consumption with cancer risk, especially for cancers from the digestive system. Impact: This study highlights the protective effect of nuts against cancer.

Association of total nut, tree nut, peanut, and peanut butter consumption with cancer incidence and mortality: A comprehensive systematic review and dose-response meta-analysis of observational studies.

Naghshi, S., M. Sadeghian, M. Nasiri, S. Mobarak, M. Asadi, O. Sadeghi, 2020. Association of total nut, tree nut, peanut, and peanut butter consumption with cancer incidence and mortality: A comprehensive systematic review and dose-response meta-analysis of observational studies. Adv Nutr. 0:1–16.

Data on the association of nut intake with risk of cancer and its mortality are conflicting. Although previous meta-analyses summarized available findings in this regard, some limitations may distort their findings. Moreover, none of these meta-analyses examined the dose-response associations of total nut intake with the risk of specific cancers as well as associations between specific types of nuts and cancer mortality. Therefore, this study aimed to summarize available findings on the associations of total nut (tree nuts and peanuts), tree nut (walnuts, pistachios, macadamia nuts, pecans, cashews, almonds, hazelnuts, and Brazil nuts), peanut (whole peanuts without considering peanut butter), and peanut butter consumption with risk of cancer and its mortality by considering the above-mentioned points. We searched the online databases until March 2020 to identify eligible articles. In total, 43 articles on cancer risk and 9 articles on cancer mortality were included in the current systematic review and meta-analysis. The summary effect size (ES) for risk of cancer, comparing the highest with lowest intakes of total nuts, was 0.86 (95% CI: 0.81, 0.92, P < 0.001, I2 = 58.1%; P < 0.01), indicating a significant inverse association. Such a significant inverse association was also seen for tree nut intake (pooled ES: 0.87, 95% CI: 0.78–0.96, P < 0.01, I2 = 15.8%; P = 0.28). Based on the dose-response analysis, a 5-g/d increase in total nut intake was associated with 3%, 6%, and 25% lower risks of overall, pancreatic, and colon cancers, respectively. In terms of cancer mortality, we found 13%, 18%, and 8% risk reductions with higher intakes of total nuts, tree nuts, and peanuts, respectively. In addition, a 5-g/d increase in total nut intake was associated with a 4% lower risk of cancer mortality. In conclusion, our findings support the protective association between total nut and tree nut intake and the risk of cancer and its mortality.

Metabolic syndrome features and excess weight were inversely associated with nut consumption after 1-year follow-up in the PREDIMED-Plus study.

Julibert, A., M. del Mar Bibiloni, L. Gallardo-Alfaro, M. Abbate, M.Á. Martínez-González, J. Salas-Salvadó, D. Corella, M. Fitó, J.A. Martínez, Á.M. Alonso-Gómez, J. Wärnberg, J. Vioque, D. Romaguera, J. Lopez-Miranda, R. Estruch, F.J. Tinahones, J. Lapetra, L. Serra-Majem, N. Cano-Ibañez, V. Martín-Sánchez, X. Pintó, J.J. Gaforio, P. Matía-Martín, J. Vidal, C. Vázquez, L. Daimiel, E. Ros, C. Sayon-Orea, N. Becerra-Tomás, I.M. Gimenez-Alba, O. Castañer, I. Abete, L. Tojal-Sierra, J. Pérez-López, L. Notario-Barandiaran, A. Colom, A. Garcia-Rios, S. Castro-Barquero, R. Bernal, J.M. Santos-Lozano, C.I. Fernández-Lázaro, P. Hernández-Alonso, C. Saiz, M.D. Zomeño, M.A. Zulet, M.C. Belló-Mora, J. Basterra-Gortari, S. Canudas, A. Goday, J.A. Tur, PREDIMED-PLUS investigators, 2020. Metabolic syndrome features and excess weight were inversely associated with nut consumption after 1-year follow-up in the PREDIMED-Plus study. J Nutr. 00:1–10.

Background: High nut consumption has been previously associated with decreased prevalence of metabolic syndrome (MetS) regardless of race and dietary patterns. Objectives: The aim of this study was to assess whether changes in nut consumption over a 1-y follow-up are associated with changes in features of MetS in a middle-aged and older Spanish population at high cardiovascular disease risk. Methods: This prospective 1-y follow-up cohort study, conducted in the framework of the PREvención con DIeta MEDiterránea (PREDIMED)-Plus randomized trial, included 5800 men and women (55-75 y old) with overweight/obesity [BMI (in kg/m2) ≥27 and <40] and MetS. Nut consumption (almonds, pistachios, walnuts, and other nuts) was assessed using data from a validated FFQ. The primary outcome was the change from baseline to 1 y in features of MetS [waist circumference (WC), glycemia, HDL cholesterol, triglyceride (TG), and systolic and diastolic blood pressure] and excess weight (body weight and BMI) according to tertiles of change in nut consumption. Secondary outcomes included changes in dietary and lifestyle characteristics. A generalized linear model was used to compare 1-y changes in features of MetS, weight, dietary intakes, and lifestyle characteristics across tertiles of change in nut consumption. Results: As nut consumption increased, between each tertile there was a significant decrease in WC, TG, systolic blood pressure, weight, and BMI (P < 0.05), and a significant increase in HDL cholesterol (only in women, P = 0.044). The interaction effect between time and group was significant for total energy intake (P < 0.001), adherence to the Mediterranean diet (MedDiet) (P < 0.001), and nut consumption (P < 0.001). Across tertiles of increasing nut consumption there was a significant increase in extra virgin olive oil intake and adherence to the MedDiet; change in energy intake, on the other hand, was inversely related to consumption of nuts. Conclusions: Features of MetS and excess weight were inversely associated with nut consumption after a 1-y follow-up in the PREDIMED-Plus study cohort. This trial was registered at isrctn.com as ISRCTN89898870.

Defining challenge-proven coexistent nut and sesame seed allergy: A prospective multicenter European study.

Brough, H.A., J.-C. Caubet, A. Mazon, D. Haddad, M.M. Bergmann, J. Wassenberg, V. Panetta,  R. Gourgey, S. Radulovic, M. Nieto, A.F. Santos, A. Nieto, G. Lack, P.A. Eigenmann, 2020. Defining challenge-proven coexistent nut and sesame seed allergy: A prospective multicenter European study. J Allergy Clin Immunol. 145:1231-9.

Background: Peanut, tree nut, and sesame allergies are responsible for most life-threatening food-induced allergic reactions. Rates of coexistent allergy between these foods have been from mostly retrospective studies that include only a limited number of tree nuts or were not based on oral food challenges. Objective: The Pronuts study is a multicenter European study (London, Geneva, and Valencia) assessing the challenge-proven rate of coexistent peanut, tree nut, and/or sesame seed allergy. Methods: Children aged 0 to 16 years with at least 1 confirmed nut or sesame seed allergy underwent sequential diagnostic food challenges to all other nuts and sesame seed. Results: Overall, the rate of coexistent peanut, tree nut, and sesame seed allergy was 60.7% (n 5 74/122; 95% CI, 51.4% to 69.4%). Peanut allergy was more common in London, cashew and pistachio nut allergies were more common in Geneva, and walnut and pecan allergies were more common in Valencia. Strong correlations were found between cashew-pistachio, walnut-pecan, and walnut-pecan-hazelnut-macadamia clusters. Age (>36 months) and center (Valencia > Geneva > London) were associated with an increased odds of multiple nut allergies. By pursuing the diagnostic protocol to demonstrate tolerance to other nuts, participants were able to introduce a median of 9 nuts. Conclusion: We found a higher rate of coexistent nut and sesame seed allergies than previously reported. Performing sequential food challenges was labor intensive and could result in severe allergic reactions; however, it reduced dietary restrictions. Age was a significant predictor of multiple nut allergies, and thus the secondary spread of nut allergies occurred in older children.

Barriers and facilitators to nut consumption: A narrative review.

Neale, E.P., G. Tran, R.C. Brown, 2020. Barriers and facilitators to nut consumption: A narrative review. Int. J. Environ. Res. Public Health. 17, 9127; doi:10.3390/ijerph17239127

Habitual nut intake is associated with a range of health benefits; however, population consumption data suggests that most individuals do not meet current recommendations for nut intake. The literature has highlighted a range of barriers and facilitators to nut consumption, which should be considered when designing strategies to promote nut intake. Common barriers include confusion regarding the effects of nut consumption on body weight, perceptions that nuts are high in fat, or too expensive, and challenges due to dentition issues or nut allergies. Conversely, demographic characteristics such as higher education and income level, and a healthier lifestyle overall, are associated with higher nut intakes. Health professionals appear to play an important role in promoting nut intake; however, research suggests that knowledge of the benefits of nut consumption could be improved in many health professions. Future strategies to increase nut intake to meet public health recommendations must clarify misconceptions of the specific benefits of nut consumption, specifically targeting sectors of the population known to have lower nut consumption, and educate health professionals to promote nut intake. In addition, given the relatively small body of evidence exploring barriers and facilitators to nut consumption, further research exploring these factors is justified.