Raspberries Improve Postprandial Glucose and Acute and Chronic Inflammation in Adults with Type 2 Diabetes

Abstract

Background: Postprandial metabolic impairments in diabetes have been shown to play an important role in vascular complications. Dietary polyphenols and other bioactive compounds in berries have been shown to improve postprandial hyperglycemia and related metabolic impairments, but few clinical studies have been reported in diabetes. Objective: To examine the effects of daily dietary raspberries on postprandial and 4-week fasting glucose, lipids and biomarkers of inflammation in obese adults with type 2 diabetes. Design: This was a randomized crossover study with 2 different phases: a “postprandial phase” of acute raspberry supplementation (2 separate days at least 1 week apart), followed by a 1-week washout phase and then a 10-week “diet supplement phase”, with and without raspberry supplementation periods of 4 weeks each, separated by 2-week washout phase. Results: The postprandial phase revealed significantly lower levels of serum glucose at 2 and 4 h postprandial after raspberry versus control phase. In addition, among the serum biomarkers of inflammation, interleukin (IL)-6 and high-sensitivity tumor necrosis factor alpha (hsTNF-α) were also lower at 4 h postprandial following raspberry versus control meal (all p < 0.05). Finally, postprandial serum triglycerides showed a decreasing trend at 4 h in the raspberry versus control phase. Four-week daily raspberry supplementation continued to show a significant lowering effects on IL-6 and hsTNF-α versus control phase (all p < 0.05); systolic blood pressure revealed a decreasing trend after 4-week of raspberry supplementation. No effects were noted on fasting glucose and lipids, C-reactive protein and arterial elasticity. Conclusions: Thus, dietary raspberries, which are low in calories and high in polyphenols and other nutrients may lower postprandial hyperglycemia and inflammation, and in general exert selected anti-inflammatory effects in adults with diabetes. These findings deserve further investigation.

Dietary berries, insulin resistance and type 2 diabetes: an overview of human feeding trials

“…Among other commonly-consumed berries, we reported the effects of frozen raspberries in decreasing postprandial glucose and inflammatory biomarkers in T2D adults. 83 Raspberries have been previously shown to decrease postprandial insulin and glucose in adults with insulin resistance and MetS, 77 and in this work, we concluded that raspberries may have a distinct role in ameliorating postprandial dysglycemia in T2D as well.…”

Characterization of the nutrient profile of processed red raspberries for use in nutrition labeling and promoting healthy food choices

“…Processed red raspberries have been studied for their health benefits in models of age-related chronic diseases. The consumption of frozen red raspberries compared to a control lowered postprandial hyperglycemia and inflammation in adults with prediabetes or diabetes [35,36]. Red raspberry juice intake improved the lipids profile, antioxidant status and reduced the risk of developing atherosclerosis in hamsters consuming an atherogenic diet [37].…”

Effects of Acute Cocoa Supplementation on Postprandial Apolipoproteins, Lipoprotein Subclasses, and Inflammatory Biomarkers in Adults with Type 2 Diabetes after a High-Fat Meal

“…In randomized controlled clinical trials, acute interventions with dietary polyphenols have shown promise in mitigating postprandial inflammation. For example, cranberries and raspberries dampened postprandial elevations of serum IL-6 and IL-18, respectively, in adults with obesity and T2D after a HF breakfast [ 56 , 57 ]. Further, Oh et al recently showed that a spice blend supplement (6 g) taken with a HF, high-carbohydrate meal reduced IL-1β, IL-8, and tumor necrosis factor-α secretion by liposaccharide-stimulated (LPS) peripheral blood mononuclear cells of men who had overweight or obesity [ 58 ].…”