Effects of Pistachio Nut Supplementation on Blood Glucose in Patients with Type 2 Diabetes: A Randomized Crossover Trial

Abstract

■ AbstractBACKGROUND: Diabetes is a chronic, potentially debilitating, and often fatal disease. Dietary strategies to reduce postprandial glycemia are important in the prevention and treatment of diabetes. Nuts are rich in mono-and polyunsaturated fatty acids, which may reduce hyperglycemia and improve metabolism. OBJECTIVES: To evaluate the effectiveness of pistachio nut supplementation on glycemic and inflammatory measures in patients with type 2 diabetes. METHODS: In this double-blind, randomized, placebocontrolled, crossover trial, 48 diabetic patients were equally assigned to groups A and B. Patients in group A received a snack of 25 g pistachio nuts twice a day for 12 weeks and group B received a control meal without nuts. After 12 weeks of intervention, the patients had an 8-week washout. Then the groups were displaced, and group B received the same amount of pistachios for 12 weeks. RESULTS: With respect to the total change in variables over both phases, there was a marked decrease in HbA1c (-0.4%) and fasting blood glucose (FBG) concentrations (-16 mg/dl) in the pistachio group compared with the control group (p ≤ 0.001 for both). There was no overall significant change in BMI, blood pressure, HOMA-IR, and C-reactive protein (CRP) concentrations. Analysis of the two phases separately showed a decrease in FBG by 14 mg/dl and in HbA1c by 0.45% in the treatment group (A) after 12 weeks, while no significant differences were seen in group B (control group). In the second phase, FBG decreased from 151.36 ± 39.22 to 137.28 ± 28.65 mg/dl (-14 mg/dl) and HbA1c decreased from 7.42 ± 0.97 to 7.15 ± 0.68 mg/dl (-0.28%, p = 0.013 and p = 0.033, respectively) in the pistachio group (B). Pistachio consumption reduced systolic blood pressure (p = 0.007), BMI (p = 0.011), and CRP (p = 0.002) in patients from the treatment groups, but not insulin resistance. CONCLUSIONS: Dietary consumption of pistachio nuts as a snack has beneficial effects on glycemic control, blood pressure, obesity, and inflammation markers in diabetic patients.

Effects of pistachios on the lipid/lipoprotein profile, glycemic control, inflammation, and endothelial function in type 2 diabetes: A randomized trial

“…However, two studies that examined pistachios reported positive results. Parham et al [18] reported that 12 weeks of pistachio consumption (25g/day) significantly reduced fasting glucose by 0.89 mmol/L and HbA1c by 0.4% compared to a control group in 48 Iranian adults with type 2 diabetes. Hernandez-Alonso et al [27] reported that 4 months of 57g/d of pistachios significantly decreased fasting glucose (−0.29 mmol/l), insulin (−14.2 pmol/L), and HOMA-IR (−0.69) in 54 Spanish adults with pre-diabetes, but did not affect HbA1c.…”

“…Specific to pistachios, a study in young healthy males reported a significant reduction in interleukin-6 and no change in tumor necrosis factor-α or CRP after 4 weeks of treatment [37]. A longer study (12 weeks) in adults with type 2 diabetes reported no effect on CRP [18]. Interestingly, in a sample of adults with pre-diabetes, pistachio consumption for 4 months did not affect circulating measures of inflammation but did reduce lymphocyte gene expression of interleukin-6 [27], suggesting that pistachios may have a nominal effect on inflammation that was not detected in previous work.…”

“…A few trials reported beneficial effects on the lipid/lipoprotein profile [11–15], and a recent meta-analysis concluded that daily nut consumption reduces fasting glucose and glycated hemoglobin (HbA1c) [16]. Two studies that assessed inflammatory markers following nut interventions reported mixed results [17, 18], and one study reported a significant improvement in endothelial function following 8 weeks of walnut consumption [14]. However, most trials (regardless of the population) have studied mixed nuts or walnuts, and the health benefits of other nuts, such as pistachios, are less clear.…”

Nutritional modulation of endogenous glucagon-like peptide-1 secretion: a review

“…Jenkins and colleagues [156] also found a decrease in insulin secretion in healthy adults and in adults with hyperlipidemia following acute and prolonged almond consumption. Similarly, daily intake of 50.0 g of pistachios for 12 weeks decreased C-reactive protein blood concentrations, systolic blood pressure, and body mass index in adults with T2D [155]. In women with obesity, consumption of peanuts (42.5 g) or peanut butter (42.5 g) as part of a standard breakfast meal increased postprandial insulin blood concentrations and decreased desire to eat following a standard lunch meal [166].…”

Effect of the hydroalcoholic extract of pistachio on avoidance learning in male Wistar rats

“…The pistachio fruit or nut is the edible part of the pistachio plant and is used as flavoring in food and snacks and has been used for therapeutic purposes. Pistachios have a warm and dry nature and contain a large amount of plant protein, starch, unsaturated fats, vitamins, fiber, and minerals such as potassium and magnesium (5)(6)(7)(8). The pistachio is very nutritious and contains vitamins B1, B2, B6, E, and C, calcium, and iron and is effective in boosting physical strength and activity of brain cells (9,10).…”