*2.3. Nut Consumption and Biochemical and Anthropometric Parameters*

The outcome of tree nut and peanut consumption on biochemical and anthropometric parameters found in clinical trials published in the last ten years [31,41,42,54–60] are summarized in Table 3.

The trial of Li et al. [31] revealed that in Chinese T2DM patients, almond intake, compared with a control diet had a beneficial effect on glycemic control, lowering fasting insulin, fasting glucose, and Homeostatic Model Assessment—Insulin Resistance (HOMA-IR) by 4.1%, 0.8%, and 9.2%, respectively. The ingestion of a single serving (28 g) of almonds before a high-starch meal significantly reduced hemoglobin A1c (HbA1c) (*p* = 0.045) and postprandial glycemia (*p* = 0.043) in individuals with uncomplicated T2DM [54]. Another intervention study showed that almonds significantly decreased post-interventional fasting glucose by 5.9% (*p* = 0.01) and HbA1c by 3.0% (*p* = 0.04) as compared with that of control in T2DM subjects [59]. In the study of Hou et al. [60], the T2DM patients who replaced part of their starchy food with almonds or peanuts had decreased values for fasting blood glucose and 2-h postprandial blood glucose (*p* < 0.05) compared with the baseline. In addition, in the almond group a decrease in the HbA1c level from the baseline was found (*p* < 0.05) and none of the nut groups showed an increase of body mass index (BMI).

Several dietary interventions within the frame of the PREDIMED study tried to establish a relation between MDs supplemented with mixed nuts (walnuts, hazelnuts, and almonds) and biochemical or anthropometric parameters. In a clinical trial with high CV risk participants but no CVD at enrolment, data showed that MD supplemented with 30 g per day mixed nuts for 1 year significantly decreased waist circumference (Wc) compared to baseline, and also lowered LDL-C and shifted LDL size to a less atherogenic pattern [55]. Lasa et al. [56] indicated that a daily quantity of 30 g nuts (walnuts, hazelnuts, and almonds) added to MDs was associated with a significant reduction in BW (*p* = 0.021) compared with the control, with improved glucose metabolism in both the nut group and low-fat diet group. Rodríguez-Rejón et al. [58] concluded that the nut-enhanced MD lowered glycemic index and glycemic load, two indices that can be associated with T2DM and CHD.

An RCT conducted on patients with diabetes established that 75 g mixed nuts (tree nuts and peanuts) added to the diet for 3 months, besides improving the lipid profile, also significantly lowered HbA1c compared with a carbohydrate diet (*p* = 0.026) [42]. In another trial conducted on T2DM subjects, the addition of 15 mL walnut oil to the diet for three month significantly decreased HbA1c level by 7.86% (*p* = 0.005) and fasting blood glucose by 8.24% (*p* = 0.001) compared to control [61].


Nut consumption and changes in biochemical and anthropometric parameters in intervention studies.

**Table 3.**


 types fat, vegetable sources, reduced, A—almonds; BMI—body index; BW—body weight; F—women; GI—glycemic index; GL—glycemic load; GLP-1—glucagon-like peptide-1; H—hazelnuts; HbA1c—hemoglobin A1c; HOMA-IR—Homeostasis Model of Assessmentfor insulin resistance; HR—hazard ratio; M—men; MD—Mediterranean Diet; RCT—randomized controlled trial; VLDL-C—very low density lipoprotein cholesterol; W—walnuts;Wc—waistcircumference.
