Riley, T.M., P.M. Kris-Etherton, T.L. Hart, K.S. Petersen, 2024. Intake of pistachios as a nighttime snack has similar effects on short- and longer-term glycemic control compared with education to consume 1-2 carbohydrate exchanges in adults with prediabetes: A 12-wk randomized crossover trial. J Nutr. 154(4):1219-1231. https://doi.org/10.1016/j.tjnut.2024.01.021
Background: Nut intake is associated with better glycemic control and lower cardiovascular disease (CVD) risk. It remains unclear if nut intake timing affects glycemic control and CVD risk factors. Intake of pistachios as a nighttime snack may attenuate morning glucose production and lower fasting plasma glucose (FPG). Objectives: We assessed the effects of a nighttime (after dinner and before bedtime) pistachio snack (57g/d) on glycemic control markers, vascular health, lipids/lipoproteins, and diet quality compared with education to consume 1–2 carbohydrate (CHO) exchanges (usual care) in individuals with prediabetes. Methods: A 2-period, randomized crossover trial was conducted. Participants were provided 57g/d of dry roasted unsalted pistachios (319 kcal; fat 26g; CHO 16 g; protein 12 g; fiber 6 g) as a nighttime snack or received usual care for 12 wk. Primary (FPG) and secondary outcomes [hemoglobin A1c (HbA1c), insulin, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), lipids/lipoproteins, vascular health, and Healthy Eating Index-2015 (HEI-2015)] were measured before and after each condition. Results: A total of 66 participants (50.9 ± 11.6 y, FPG: 106.2 ± 6.4 mg/dL) were randomly assigned, and 51 participants completed the trial. No between-condition differences in FPG {0.9 mg/dL [95% confidence interval (CI): −1.2, 3.1]}, HbA1c, insulin, HOMA-IR, lipids/ lipoproteins, blood pressure, or vascular health were observed. The HEI-2015 score was higher after the pistachio condition [6.8 points (95% CI: 1.5, 12.1)] than after usual care driven by higher component scores for seafood and plant proteins [2.0 points (95% CI: 1.0, 2.9)], refined grains [2.3 points (95% CI: 1.1, 3.5)], and the fatty acid ratio [1.7 points (95% CI: 0.0, 3.5)]. Conclusions: In adults with prediabetes, consuming 57 g/d of pistachios as a nighttime snack increased diet quality but had similar effects on glycemic markers, lipids/lipoproteins, blood pressure, and vascular health compared with the usual care comparator. Pistachios may be a healthful alternative to carbohydrate-rich nighttime snacks to increase alignment with Dietary Guidelines for Americans.
Nijssen, K.M., R.P. Mensink, J. Plat, D. Ivanov, H. Preissl, P.J. Joris, 2024. Mixed nut consumption improves brain insulin sensitivity: a randomized, single-blinded, controlled, crossover trial in older adults with overweight or obesity. Am J Clin Nutr. 119(2):314-323. https://doi.org/10.1016/j.ajcnut.2023.12.010
Background: Improving brain insulin sensitivity, which can be assessed by measuring regional cerebral blood flow (CBF) responses to intranasal insulin, may prevent age-related metabolic and cognitive diseases. Objectives: This study aimed to investigate longer-term effects of mixed nuts on brain insulin sensitivity in older individuals with overweight/obesity. Methods: In a randomized, single-blinded, controlled, crossover trial, 28 healthy adults (mean ± standard deviation: 65 ± 3 years; body mass index: 27.9 ± 2.3 kg/m2) received either daily 60-g mixed nuts (15 g of walnuts, pistachio, cashew, and hazelnuts) or no nuts (control) for 16 weeks, separated by an 8-week washout period. Throughout the study, participants were instructed to adhere to the Dutch food-based dietary guidelines. During follow-up, brain insulin action was assessed by quantifying acute effects of intranasal insulin on regional CBF using arterial spin labeling magnetic resonance imaging. Furthermore, effects on peripheral insulin sensitivity (oral glucose tolerance test), intrahepatic lipids, and cardiometabolic risk markers were assessed. Results: Body weight and composition did not change. Compared with control, mixed nut consumption improved regional brain insulin action in 5 clusters located in the left (difference in CBF responses to intranasal insulin: -4.5 ± 4.7 mL/100 g/min; P < 0.001; -4.6 ± 4.8 mL/100 g/min; P < 0.001; and -4.3 ± 3.6 mL/100 g/min; P = 0.007) and right occipital lobes (-4.3 ± 5.6 mL/100 g/min; and -3.9 ± 4.9 mL/100 g/min; P = 0.028). A fifth cluster was part of the left frontal lobe (-5.0 ± 4.6 mL/100 g/min; P < 0.001). Peripheral insulin sensitivity was not affected. Intrahepatic lipid content (-0.7%-point; 95% CI: -1.3%-point to -0.1%-point; P = 0.027), serum low-density lipoprotein cholesterol concentration (-0.24 mmol/L; 95% CI: -0.44 to -0.04 mmol/L; P = 0.019), and systolic blood pressure (-5 mm Hg; 95% CI: -8 to -1 mm Hg; P = 0.006) were lower after the mixed nut intervention. Conclusions: Longer-term mixed nut consumption affected insulin action in brain regions involved in the modulation of metabolic and cognitive processes in older adults with overweight/obesity. Intrahepatic lipid content and different cardiometabolic risk markers also improved, but peripheral insulin sensitivity was not affected.
Trumbo, P.R., J. Ard, F. Bellisle, A. Drewnowski, J.A. Gilbert, R. Kleinman, A. Misra, J. Sievenpiper, M. Tahiri, K.E. Watson, J. Hill, 2024. Perspective: current scientific evidence and research strategies in the role of almonds in cardiometabolic health. Curr Dev Nutr. 9(1):104516. https://doi.org/10.1016/j.cdnut.2024.104516.
Almonds are consumed by individuals around the world. Because almonds are rich in protein, unsaturated fatty acids, and fiber, a significant amount of research has been conducted on their role in affecting various cardiometabolic endpoints (body weight, blood pressure, blood cholesterol levels, and glycemic response). The most current meta-analyses on almond consumption and various health-related endpoints suggest that almond consumption does not result in weight gain and results in small reductions in LDL cholesterol and diastolic blood pressure, as well as improved glycemic responses in certain populations (i.e. Asian Indians). A number of research gaps on almond consumption and cardiometabolic health were identified that should be addressed to further understand their role in the various cardiometabolic endpoints, including the mechanisms of action interactions with the microbiome with regular consumption and their role as part of a healthy dietary pattern for both individuals and the general population.
Gayathri, R., K. Abirami, N. Kalpana, V.S. Manasa, V. Sudha, S. Shobana, R.G. Jeevan, V. Kavitha, K. Parkavi, R.M. Anjana, R. Unnikrishnan, K. Gokulakrishnan, D.A. Beatrice, K. Krishnaswamy, R. Pradeepa, R.D. Mattes, J. Salas-Salvadó, W. Willett, V. Mohan, 2023. Effect of almond consumption on insulin sensitivity and serum lipids among Asian Indian adults with overweight and obesity- A randomized controlled trial. Front. Nutr. 9: 1055923. https://doi.org/10.3389/fnut.2022.1055923
Background: Asian Indians have an increased susceptibility to type 2 diabetes and premature coronary artery disease. Nuts, like almonds, are rich in unsaturated fat and micronutrients with known health benefits. Objectives: This study aimed to assess the efficacy of almonds for reduction of insulin resistance and improving lipid profile in overweight Asian Indian adults. Methods: This parallel-arm, randomized, controlled trial was conducted in Chennai, India on 400 participants aged 25-65 years with a body mass index ≥ 23 kg/m2. The intervention group received 43 g of almonds/day for 12 weeks, while the control group was advised to consume a customary diet but to avoid nuts. Anthropometric, clinical, and dietary data were assessed at periodic intervals. Glucose tolerance, serum insulin, glycated hemoglobin, C-peptide and lipid profile were assessed at baseline and end of the study. Insulin resistance (homeostasis assessment model-HOMA IR) and oral insulin disposition index (DIo) were calculated. Results: A total of 352 participants completed the study. Significant improvement was seen in DIo [mean (95% CI) = + 0.7 mmol/L (0.1, 1.3); p = 0.03], HOMA IR (-0.4 (-0.7, -0.04; p = 0.03) and total cholesterol (-5.4 mg/dl (-10.2, -0.6); p = 0.03) in the intervention group compared to the control group. Incremental area under the curve (IAUC) and mean amplitude of glycemic excursion (MAGE) assessed using continuous glucose monitoring systems were also significantly lower in the intervention group. Dietary 24-h recalls showed a higher significant reduction in carbohydrate and increase in mono unsaturated fatty acid (MUFA) and polyunsaturated fatty acids (PUFA) intake in the intervention group compared to the control group. Conclusion: Daily consumption of almonds increased the intake of MUFA with decrease in carbohydrate calories and decreases insulin resistance, improves insulin sensitivity and lowers serum cholesterol in Asian Indians with overweight/obesity. These effects in the long run could aid in reducing the risk of diabetes and other cardiometabolic disease.
