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Research Nut: Cashews

Cashew nut allergy: Clinical relevance and allergen characterisation.

Mendes, C., J. Costa, A.A. Vicente, M.B.P.P. Oliveira, I. Mafra, 2019. Cashew nut allergy: Clinical relevance and allergen characterisation. Clin Rev Allergy Immunol. 57(1):1-22.

Cashew plant (Anacardium occidentale L.) is the most relevant species of the Anacardium genus. It presents high economic value since it is widely used in human nutrition and in several industrial applications. Cashew nut is a well-appreciated food (belongs to the tree nut group), being widely consumed as snacks and in processed foods by the majority of world’s population. However, cashew nut is also classified as a potent allergenic food known to be responsible for triggering severe and systemic immune reactions (e.g. anaphylaxis) in sensitised/allergic individuals that often demand epinephrine treatment and hospitalisation. So far, three groups of allergenic proteins have been identified and characterised in cashew nut: Ana o 1 and Ana o 2 (cupin superfamily) and Ana o 3 (prolamin superfamily), which are all classified as major allergens. The prevalence of cashew nut allergy seems to be rising in industrialised countries with the increasing consumption of this nut. There is still no cure for cashew nut allergy, as well as for other food allergies; thus, the allergic patients are advised to eliminate it from their diets. Accordingly, when carefully choosing processed foods that are commercially available, the allergic consumers have to rely on proper food labelling. In this sense, the control of labelling compliance is much needed, which has prompted the development of proficient analytical methods for allergen analysis. In the recent years, significant research advances in cashew nut allergy have been accomplished, which are highlighted and discussed in this review.

Effects of daily consumption of cashews on oxidative stress and atherogenic indices in patients with type 2 diabetes: A randomized, controlled-feeding trial.

Damavandi, R.D., S.N. Mousavi, F. Shidfar, V. Mohammadi, A. Rajab, S. Hosseini, J. Heshmati, 2019. Effects of daily consumption of cashews on oxidative stress and atherogenic indices in patients with type 2 diabetes: A randomized, controlled-feeding trial. Int J Endocrinol Metab. 17(1):e70744. doi: 10.5812/ijem.70744.

Background: Cashews, as the main source of monounsaturated (MUFAs) and polyunsaturated (PUFAs) fatty acids, are associated with reduced risk of cardiovascular diseases. Despite evidence for beneficial effects of nuts on lipid profile and glycemic control, to the authors’ best knowledge, little is known about cashews. Methods: An eight-week, randomized, isocaloric, controlled-feeding study was conducted on 50 patients with type 2 diabetes mellitus (T2DM) randomly assigned to either the control or intervention group (10% of total calorie from cashews). Weight, fasting plasma glucose (FPG), serum insulin concentration and sensitivity, lipid profile ratio, high-sensitive C-reactive protein (hs-CRP), total antioxidant capacity (TAC), and paraoxonase-1 (PON-1) were measured at baseline and after eight weeks of intervention adjusted for age, gender, baseline values of FPG, insulin, HOMA-IR (homeostatic model assessment of insulin resistance), fiber, and both baseline and post-intervention vitamin C levels as covariates. Results: Weight, body mass index (BMI), and waist circumference (WC) were not significantly different in the groups after eight weeks of intervention, as well as between the two groups, compared with the baseline measures. At the end of the study, serum insulin and low-density lipoprotein-cholesterol-to-high-density lipoprotein-cholesterol (LDL-C/HDL-C) ratio significantly decreased in the cashews group compared with those of the controls (P = 0.01 and P = 0.04, respectively). Although, HOMA-IR decreased significantly in the cashews group (P = 0.03), changes were not significant compared with the baseline measures (P = 0.056). Despite more increase in PON-1 activity in the cashews group, the changes were not statistically significant. Conclusions: Daily consumption of cashews reduced serum insulin and LDL-C/HDL-C ratio in patients with T2DM. However, further studies with larger sample sizes and more duration are needed to confirm the current study results.

Nut consumption in relation to cardiovascular disease incidence and mortality among patients with diabetes mellitus.

Liu, G., M. Guasch-Ferre, Y. Hu, Y. Li, F.B. Hu, E.B. Rimm, J.E. Manson, K. Rexrode, Q. Sun, 2019. Nut consumption in relation to cardiovascular disease incidence and mortality among patients with diabetes mellitus. Circulation Research. doi.org/10.1161/CIRCRESAHA.118.314316

Rationale: The evidence regarding the potential health benefits of nut consumption among individuals with type 2 diabetes is limited. Objective: To examine intake of total and specific types of nuts, including tree nuts and peanuts, in relation to subsequent risk of cardiovascular disease (CVD), including coronary heart disease (CHD) and stroke, and all-cause and cause-specific mortality among individuals with diabetes. Methods and Results: This prospective analysis included 16,217 men and women with diabetes at baseline or diagnosed during follow-up (Nurses’ Health Study: 1980-2014, Health Professionals Follow-Up Study: 1986-2014). Nut consumption was assessed using a validated food frequency questionnaire and updated every 2-4 years. During 223,682 and 254,923 person-years of follow-up, there were 3,336 incident CVD cases and 5,682 deaths. Higher total nut consumption was associated with a lower risk of CVD incidence and mortality. The multivariate-adjusted hazard ratios (95% confidence intervals) for participants who consumed 5 or more servings of total nuts per week (1 serving=28g), compared with those who consumed less than 1 serving per month, were 0.83 (0.71-0.98; P trend=0.01) for total CVD incidence, 0.80 (0.67-0.96; P trend=0.005) for CHD incidence, 0.66 (0.52-0.84; P trend<0.001) for CVD mortality, and 0.69 (0.61-0.77; P trend<0.001) for all-cause mortality. Total nut consumption was not significantly associated with risk of stroke incidence or cancer mortality. For specific types of nuts, higher tree nut consumption was associated with lower risk of total CVD, CHD incidence, and mortality due to CVD, cancer, and all causes, while peanut consumption was associated with lower all-cause mortality only (all P trend<0.001). In addition, compared with participants who did not change the consumption of total nuts from pre- to post-diabetes diagnosis, participants who increased consumption of total nuts after diabetes diagnosis had an 11% lower risk of CVD, a 15% lower CHD risk, a 25% lower CVD mortality, and a 27% lower all-cause mortality. The associations persisted in subgroup analyses stratified by sex/cohort, body mass index at diabetes diagnosis, smoking status, diabetes duration, nut consumption before diabetes diagnosis, or diet quality. Conclusions: Higher consumption of nuts, especially tree nuts, is associated with lower CVD incidence and mortality among participants with diabetes. These data provide novel evidence that supports the recommendation of incorporating nuts into healthy dietary patterns for the prevention of CVD complications and premature deaths among individuals with diabetes.

The effect of nuts on markers of glycemic control: a systematic review and meta-analysis of randomized controlled trials.

Tindall, A.M., E.A. Johnston, P.M. Kris-Etherton, K.S. Petersen, 2019. The effect of nuts on markers of glycemic control: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr. 109:297–314.

Background: Observational evidence suggests higher nut consumption is associated with better glycemic control; however, it is unclear if this association is causal. Objectives: We aimed to conduct a systematic review and meta-analysis of randomized controlled trials to examine the effect of tree nuts and peanuts on markers of glycemic control in adults. Methods: A systematic review and meta-analysis of randomized controlled trials was conducted. A total of 1063 potentially eligible articles were screened in duplicate. From these articles, 40 were eligible for inclusion and data from these articles were extracted in duplicate. The weighted mean difference (WMD) between the nut intervention and control arms was determined for fasting glucose, fasting insulin, glycated hemoglobin (HbA1c), and homeostasis model assessment of insulin resistance (HOMA-IR) using the DerSimonian and Laird random-effects method. For outcomes where a limited number of studies were published, a qualitative synthesis was presented. Results: A total of 40 randomized controlled trials including 2832 unique participants, with a median duration of 3 mo (range: 1–12 mo), were included. Overall consumption of tree nuts or peanuts had a favorable effect on HOMA-IR (WMD: −0.23; 95% CI: −0.40, −0.06; I2=51.7%) and fasting insulin (WMD: −0.40μIU/mL;95% CI: −0.73, −0.07μ IU/mL; I2 = 49.4%). There was no significant effect of nut consumption on fasting blood glucose (WMD: −0.52 mg/dL;95% CI: −1.43,0.38mg/dL; I2 =53.4%) o rHbA1c (WMD: 0.02%; 95% CI: −0.01%, 0.04%; I2 =51.0%). Conclusions: Consumption of peanuts or tree nuts significantly decreased HOMA-IR and fasting insulin; there was no effect of nut consumption on HbA1c or fasting glucose. The results suggest that nut consumption may improve insulin sensitivity. In the future, well-designed clinical trials are required to elucidate the mechanisms that account for these observed effects.