Pistachios Help Prediabetics Manage Blood Glucose Levels

By Mary Jo Feeney, MS, RDN, FADA, FAND, Nutrition Consultant, American Pistachio Growers

Nutrition research continues to highlight the health-enhancing properties of pistachios including specific benefits on glucose control.

Healthy lifestyles, including diet, are associated with lower risk of chronic diseases. A large body of evidence from epidemiological studies and controlled clinical trials points to the beneficial impact of nut consumption on health outcomes and total mortality.

Such benefits often are attributed to the nutrient composition of nuts — plant protein, fatty acid profile, the presence of phytosterols, dietary fiber, vitamins, minerals, and bioactive compounds that function as antioxidants.

Relevance Of The Pistachio Research

Of particular relevance are the results of a randomized controlled clinical trial in which participants with prediabetes were able to achieve a healthier metabolic state by lowering risk factors such as fasting glucose and insulin.1 Prediabetes is the condition in which blood glucose/sugar levels are higher than normal but not high enough to be classified as Type 2 diabetes.

Without intervention, prediabetes is likely to progress into Type 2 diabetes in 10 years or less — this has far-reaching implications for morbidity and mortality especially related to cardiovascular diseases.

Diabetes places a healthcare and financial burden on Americans. More than 29 million Americans have diabetes, and another 86 million — more than one in three adults — have prediabetes. Diabetes costs the country $245 billion annually, according to the American Diabetes Association.2

Pistachio research was undertaken to examine whether a pistachio-rich diet could reduce the prediabetes stage and improve its associated metabolic risk factors. Although pistachios were studied in relation to their high polyunsaturated fatty acid profile and cardiovascular disease risk factors, this study specifically examined pistachios’ effect on glucose metabolism, insulin resistance and risk of Type 2 diabetes when regularly consumed.

About The Pistachio Clinical Trial

The study involved 54 prediabetic adults (29 males and 25 females) with fasting glucose levels between 100 and 125 mg/dL who were randomly assigned to follow either a pistachio-supplemented diet (PD) or control diet (CD) in a crossover manner. A 15-day run-in period preceded the four-month intervention and a two-week washout period separated the two crossover interventions.

The control diet (CD) and the pistachio-supplemented diets (PD) were matched for calories, protein, dietary fiber, and saturated fatty acids. In the CD, 55 percent of the calories came from carbohydrates and 30 percent from fat. In the PD, 50 percent of the consumed calories came from carbohydrates and 35 percent from fat. The PD included 2 ounces (57g) each day of pistachios, half roasted, half roasted and salted. In the CD, energy intake from other fatty foods, mostly olive oil, was adjusted to compensate for the energy from pistachios included in the PD.

Weight, waist circumference, plasma fasting glucose and serum lipid profile, dietary intake, physical activity assessment, and markers related to inflammation and satiety was conducted at different time points during the study. Fasting glucose, insulin and HOMA (homeostatic model assessment) of insulin resistance decreased significantly as a result of the PD intervention compared to the CD. Other cardiovascular risk factors (oxidized LDL, fibrinogen and platelet factor 4) also decreased significantly under the PD compared to the CD.

The authors concluded results provide evidence that regular consumption of pistachios decreases glucose and insulin levels thereby improving insulin resistance and other inflammatory and metabolic risk factors. Thus, the inclusion of pistachios in a nutritious and balanced diet continues to emerge as a practical nutritional strategy to lower the risks associated with prediabetes.

More About Pistachios

Additional research on the role of pistachios in heart health, weight management, satiety, and as a post-exercise aid can be found at AmericanPistachios.org/research-archive.

1. Hernandez-Alonso P, Salas-Salvado J, Baldrich-Mora M, Juaola-Falgarona M and Bullo M. Beneficial effect of pistachio consumption on glucose metabolism, insulin resistance, inflammation, and related metabolic risk markers: a randomized clinical trial. Diabetes Care 2014; 37:1-8.

2. National Institutes of Health, press release: “National Diabetes Education Program Releases Guiding Principles for Diabetes Care.”