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Research Nut: Hazelnuts

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.

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.

Does ‘activating’ nuts affect nutrient bioavailability?

Kumari, S., A.R. Gray, K. Webster, K. Bailey, M. Reid, K.A. Han Kelvin, S.L. Tey, A. Chisholm, R.C. Brown, 2020. Does ‘activating’ nuts affect nutrient bioavailability? Food Chem. 319:126529. doi: 10.1016/j.foodchem.2020.126529. Epub 2020 Feb 29.

Claims in the lay literature suggest soaking nuts enhances mineral bioavailability. Research on legumes and grains indicate soaking reduces phytate levels, however, there is no evidence to support or refute these claims for nuts. We assessed the effects of different soaking regimes on phytate and mineral concentrations of whole and chopped almonds, hazelnuts, peanuts, and walnuts. The treatments were: 1. Raw; 2. soaked for 12 h in salt solution; 3. soaked for 4 h in salt solution; 4. soaked for 12 h in water. Phytate concentrations were analysed using high-performance liquid chromatography (HPLC) and minerals by inductively coupled plasma mass spectrometry (ICP-MS). Differences in phytate concentrations between treated and untreated nuts were small, ranging from -12% to +10%. Overall, soaking resulted in lower mineral concentrations, especially for chopped nuts, and did not improve phytate:mineral molar ratios. This research does not support claims that ‘activating’ nuts results in greater nutrient bioavailability.

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.

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.

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.