Abstract
In Saudi Arabia, walnuts are most edible snacks that possess different pharmacological effects. However, their effects on diabetic patients need to be examined. Thus, this study investigated the gross chemical composition, specific minerals, fatty acids and phenolic compounds of walnut seeds in addition to clarify the effect of the consumption of walnuts in different ratios (2.5, 5 and 7.5%) on streptozotocin-induced diabetes in rats. The chemical analyses revealed that the walnut seeds are rich in fat, protein and carbohydrates in addition to potassium, magnesium, calcium and phenolic compounds. Walnut seed oil had a high content of polyunsaturated fatty acids followed by monounsaturated fatty acids and saturated fatty acids thereafter. Biological results revealed that consumption of walnuts as 2.5, 5 and 7.5% of a basal diet fed to diabetic rats had a significant effect in elevating body weight gain and the feed efficiency ratio, significantly decreased the glycosylated haemoglobin (HbA1c) and glucose levels, and significantly increased circulating insulin compared to the positive controls. At the same time, consumption of 7.5% walnut seed powder in the basal diet restored the haemoglobin level and HbA1c values and also improved the antioxidant biomarker to within the values of the negative control group. Regarding the chemical constituents, walnut seeds are rich in fatty acids and phenolic compounds that give positive effects for consumption and also have ameliorative effect on streptozotocin-induced diabetes in rats.