Eating a handful of pistachios before breakfast and dinner could be a simple way to fill important nutrient gaps and help protect against diabetes, according to new research (1).

The study, in Asian Indian people with pre-diabetes, found before-meal pistachios improved measures of glycaemia (blood sugar values), including glycated haemoglobin (HbA1C) – and certain cardiometabolic risk factors.

The 12-week randomised controlled study – one of the first to investigate the effect of before-meal pistachios in Asian Indian people with pre-diabetes – involved 109 adults, aged 25-50 years.

Participants were divided into two groups – an ‘intervention’ group that ate 60g of unsalted, roasted pistachios daily (30g pre-breakfast and 30g pre-dinner), and a ‘control’ group, which ate a routine diet, without nuts.

Those in the pistachio (intervention) group had a significant decrease in HbA1C (a long-term measure of blood glucose control), serum triglycerides (a type of blood fat) and waist circumference, compared with those in the control group.

The research also found pre-meal pistachios reduced the glycaemic load of the diet.

This supports previous studies showing that when nuts are included as part of a carbohydrate-rich meal, they ‘blunt’ the glycaemic response after the meal – which helps manage blood glucose levels.

The decreases in glycaemic load in the pistachio group were at levels consistent with preventing the progression of pre-diabetes to type 2 diabetes.

The study also showed that adding 60g of pistachios to the daily diet did not adversely affect weight, and, instead, lowered waist circumference.

These finding echo earlier studies, which have consistently shown that nut consumption is not linked with weight gain, or an increased risk of overweight or obesity (2) – which are significant risk factors for type 2 diabetes.

The research also found pistachios were able to fill several nutritional gaps in the Asian Indian diet.

Specifically, those in the pistachio group had higher intakes of total energy (kilojoules), dietary fibre, protein, unsaturated fatty acids, linoleic acid, polyphenols, and the carotenoid, zeaxanthin, compared with the control group.

Did you know? An evidence review found eating a handful of nuts four times a week is linked with a 13% reduced risk of type 2 diabetes (3).

Diabetes in the Asian Indian population

India has been referred to as the ‘diabetes capital of the world’, with nearly 101 million adults with type 2 diabetes, and 136 million with pre-diabetes (4).

Asian Indians are particularly susceptible to developing type 2 diabetes at a lower BMI, due to phenotypic, or biological, factors such as an increased waist circumference, and higher insulin resistance (1).

And research also suggests this ethnic group experiences a higher ‘conversion rate’ of prediabetes to type 2 diabetes (5).

The typical Indian diet has a high glycaemic load driven by high intakes of carbohydrates and low intakes of protein, monounsaturated fatty acids, and polyphenols (1). And nut intake is critically low (6).

Did you know? The latest Dietary Guidelines for Indians, released in October 2024, recommend 35g of nuts and seeds a day for adults (for a 2,000Kcal Indian diet) – allocating a ‘portion’ of the ‘My Plate for the Day’ to nuts and seeds. 

Image: My Plate for the Day for 2,000Kcal, from the 2024 Dietary Guidelines for Indians

Source: ICMR-National Institute of Nutrition.
Available at: https://www.nin.res.in/dietaryguidelines/pdfjs/locale/DGI07052024P.pdf

The bottom line:

Asian Indian people with pre-diabetes could benefit from including pistachios in their daily diet. Eating a handful of pistachios before breakfast and dinner is a simple way to improve measures of glycaemia, as well as cardiometabolic risk factors – without adversely affecting weight.

Eating nuts, including pistachios, can also help fill important nutrient gaps in the Indian diet, including protein, dietary fibre, and unsaturated fatty acids. Increasing nut intake, which is critically low in this ethnic group, would also better align with the Dietary Guidelines for Indians.

Pre-diabetes is a condition where blood glucose levels are higher than normal, but not at high enough levels for a diagnosis of type 2 diabetes (7). People with pre-diabetes are at a high risk of developing type 2 diabetes.