A Review of the Effect of Walnuts (Juglans regia) Supplementation on Type 2 Diabetes Mellitus

A lot of significant studies carried out in the past demonstrated the beneficial effects of walnuts (Juglans regia) in clinical patients diagnosed with type 2 diabetes mellitus (T2DM). There are however some contradictions in the findings of the studies done. In this review, a search of some online databases (PubMed and Google scholar) was carried out to isolate some studies that examined the role of walnuts on glycaemic indices in type 2 diabetes mellitus. A randomized, cross over study recently found an increase in post-meal energy expenditure, but no difference in satiety between subjects fed walnuts versus fat-rich dairy products. This was based on reported appetite satisfaction after one meal in an outpatient setting. Other relevant studies showed that walnut extracts markedly lowered fasting blood glucose (FBS) and HBAIC and increased the insulin level in diabetic patients at the end of their study. The mechanism behind the hypoglycemic activity of walnuts could be due to increase in insulin release from remnants of β-cells in the pancreas, its antioxidant properties, the restoration of insulin sensitivity and interference with the absorption of dietary carbohydrates in the small intestine. The reported hypoglycemic effect of juglans regia may also be due to the presence of phenolic acids (gallic acid and caffeoylguinic acid) in walnuts. Various studies have shown that walnuts consumption could markedly reduce the incidence of type 2 diabetes mellitus in the population.