Around 1.9 million Australians are living with diabetes. So, how can nuts help? We sum up the latest evidence.

In a nutshell, research suggests that nuts, within a healthy and varied diet, have a potential role in preventing type 2 diabetes, managing existing diabetes, and preventing or reducing the progression of diabetes-related complications.

What the research says

Overall, more studies are needed to better understand the impact of nuts on preventing and managing type 2 diabetes [1]. But some research findings to date suggest that higher nut consumption may:

Lower the risk of type 2 diabetes

• Evidence from a systematic literature review (SLR) and meta-analysis of five prospective cohort studies and one randomised controlled trial (RCT), showed that consuming a handful (28g) of nuts four times a week was linked with a 13% reduction in the risk of type 2 diabetes [2].

• The PREDIMED trial found consuming more than three serves of nuts per week, within a Mediterranean dietary pattern, resulted in a 22% lower prevalence of diabetes, compared with consuming less than one serve per week [3].

Improve glycaemic control

• Acute studies show reductions in postprandial glucose levels, and long-term trials have found modest positive effects on blood glucose control (that is, reductions in fasting blood glucose, and HbA1c) [1].

• For example, evidence from a SLR and meta-analysis of 12 RCTs showed that nuts significantly lowered HbA1c and fasting glucose (but not fasting insulin or HOMA-IR), compared to control diets, in people with type 2 diabetes [4].

Reduce the risk of heart disease (a diabetes-related complication)

• Evidence from a SLR and meta-analysis of RCTs showed that regular nut consumption positively impacts a range of biomarkers of CVD risk (including total cholesterol, LDL cholesterol, and triglycerides), to create an overall CVD risk reduction [5].

• An umbrella review, of more than 145 SLRs and meta-analyses, found eating a handful (~30g) of nuts a day was associated with a 21% reduced risk for CVD, and a 22% reduced risk of dying from it, compared with not eating nuts [6].

Reduce the risk of diabetes mortality

• A SLR and meta-analysis of four prospective cohort studies, involving more than 200,000 people, found a 39% reduction in the relative risk of diabetes mortality with a one (~30g) serving per day increase in nut consumption [7].

The evidence to date suggests that higher nut consumption may help in reducing the risk of developing diabetes, as well as in managing existing diabetes. However, more research is needed to better understand the impact of nuts. What is clear is that, for overall good health, we should all aim to eat a 30g handful of nuts every day!