Effects of Freeze-Dried Strawberry Supplementation on Metabolic Biomarkers of Atherosclerosis in Subjects with Type 2 Diabetes: A Randomized Double-Blind Controlled Trial

Abstract

Background: To our knowledge there has been no study investigating the impact of freeze-dried strawberry (FDS) supplementation on metabolic biomarkers of atherosclerosis in subjects with type 2 diabetes (T2D). Objective: This study was carried out to determine the effects of FDS supplementation on glycemic control, biomarkers of oxidative stress, inflammation and serum total antioxidant status in subjects with T2D compared to matched control subjects. Methods: Thirty-six subjects with T2D (23 females; mean body mass index 27.90 ± 3.7; mean age 51.57 ± 10 years) were randomly divided into two groups. The treatment group consumed 2 cups of FDS beverage (50 g of FDS is equivalent to 500 g of fresh strawberries) or macronutrient matched placebo powder with strawberry flavor daily for 6 weeks in a randomized double-blind controlled trial. Anthropometric measurements, dietary intakes, hemoglobin (Hb)A₁c, antioxidant status, C-reactive protein and malondialdehyde (MDA) levels were assessed at baseline and 6 weeks post-intervention. Results: FDS supplementation significantly decreased C-reactive protein levels as a biomarker of inflammation (2.5 vs. 2.04 mg/l, p < 0.05) and lipid peroxidation in the form of MDA (3.36 vs. 2.7 nmol/ml, p < 0.05) at 6 weeks compared to the baseline. Moreover, supplementation led to a decreasing trend in HbA₁c (-5.7%, p < 0.05) and significant increase in total antioxidant status in the FDS group (1.44 vs. 1.26 mmol/l, p < 0.01) compared to the placebo group. No significant changes were observed in serum glucose concentrations and anthropometric indices. Conclusions: FDS improved glycemic control and antioxidant status, and reduced lipid peroxidation and inflammatory response in patients with T2D. Supplementation with freeze-dried berry products, as natural sources of antioxidants with low glycemic index, could be considered as an adjunctive therapy in ameliorating metabolic complications of T2D.

Functional Foods for Health: The Interrelated Antioxidant and Anti-Inflammatory Role of Fruits, Vegetables, Herbs, Spices and Cocoa in Humans

“…Bilberry juice, in a parallel study on subjects with at least one risk factor for CVD was effective in modulating inflammatory markers without any impact on redox status or lipid oxidation [32]. On the contrary, in type 2 diabetic patients, freeze-dried strawberry 50g/day consumption for 6 weeks decreased CRP and MDA and increased NEAC [42]. …”

Incorporating freeze-dried strawberry powder into a high-fat meal does not alter postprandial vascular function or blood markers of cardiovascular disease risk: a randomized controlled trial

“…Longerterm strawberry supplementation has been shown to improve multiple CVD risk factors (16)(17)(18)(19)(20)(21)(22)(23)(24)(25), but less is known about the acute effects of strawberries in the context of a fat-containing meal. A modest attenuation of the 6-h postprandial triglyceride, insulin, and oxidized LDL response was found in overweight hyperlipidemic adults when 10 g freeze-dried strawberry powder was incorporated into a meal with 30 g total fat (26,27).…”

The healthy effects of strawberry bioactive compounds on molecular pathways related to chronic diseases

“…It has been shown that strawberry bioactive compounds may be stored inside the membrane, protecting lipid bilayers against oxidative damage, and may control the distribution of cholesterol through interference with TNF receptor–associated factor‐2 recruitment in lipids . Likewise, data from in vivo models have confirmed that strawberry consumption decreases the concentration of blood glucose and reduces plasma CRP, which augment the risk for developing CVDs by the increase in adiposity.…”