New studies suggest that eating nuts could help protect against the development of type 2 diabetes in individuals who are already at high risk for the disease. Researchers reported on the potential benefits of pistachio nuts and almonds, so-called “tree nuts”.

The study conducted in 49 overweight or obese prediabetic subjects, showed that 57 g of pistachios daily for 4 months significantly reduced fasting glucose, insulin, and insulin resistance. Importantly, there was no change in body weight after eating the nuts.

The other trial reported on 137 adults at elevated risk for diabetes who were randomized to consume 43 g of almonds per day — either with meals or as a snack — or to no almonds, for 4 weeks.

Those who ate the nuts felt less hungry and fuller than those who didn’t, and they had lower postprandial blood glucose levels, without experiencing any weight gain.

The nuts have been found to be associated with a reduced risk for coronary heart disease through moderation of LDL cholesterol, triglycerides, and circulating glucose concentrations. And in studies in type 2 diabetes, they have been shown to reduce postmeal glucose and insulin levels.

They are  rich, dense food with a healthy lipid profile, and pistachios in particular are rich in antioxidant carotenoids.

In another study, 54 overweight or obese prediabetic people were randomly assigned to a control diet or a pistachios diet (57 g daily) for 4 months. They then had a 2-week washout period before crossing over to the alternative diet for another 4 months, so the individuals effectively acted as their own controls.

The diets were designed to be isocaloric and modified according to each individual’s weight: the amount of calories varied from 1900 to 2500 per day, depending on the weight of the person.

Both diets were Mediterranean in nature, and the control diet used olive oil in place of pistachios — the diets did not differ in the amount of saturated fatty acids and cholesterol content. At baseline and then monthly, anthropometric measurements were taken, blood pressure was measured, and physical activity was assessed. Blood samples were also collected at the beginning and end of each intervention period to look at hemostatic, inflammatory, oxidative, and related metabolic risk markers.

There were no statistically significant changes in body mass index (BMI) between intervention periods, but fasting glucose, insulin, and insulin-resistance markers decreased significantly after the pistachio diet compared with the control diet (P < .001).

Other metabolic risk markers such as fibrinogen, glucagonlike peptide-1 (GLP-1), oxidized LDL, and platelet factor-4 all showed a statistically significant decrease after the pistachio diet compared with control diet.

Regular consumption of pistachios could decrease insulin resistance, thus suggesting a potential protective role for pistachio consumption against development of type 2 diabetes.

Meanwhile, in the almond study, 137 adults at elevated risk of diabetes (BMI 27–35 or normal weight with a family history of diabetes) were randomized to 1 of 3 groups: 43 g per day of almonds (approximately 250 calories) with breakfast or lunch; 43 g of almonds alone as a morning or afternoon snack; or no almonds; for 4 weeks.

Those who ate the almonds felt less hungry and fuller than those who did not consume them; these effects were most noticeable when the almonds were eaten as a snack. Similarly, although almond consumption led to lower blood glucose, this reduction was significant only among those who ate the nuts as a snack.

Adding almonds to the usual diet for 4 weeks did not alter body weight or any other anthropometric measures compared with the control group.

Overall the inclusion of 43 g of almonds into a daily diet, especially as snacks, may help to moderate glycemia without promoting weight gain.

2014 European Congress on Obesity