The present study investigates the effect of strawberry antioxidants in beverage form on meal-induced postprandial inflammatory and insulin responses in human subjects. Overweight adults (n 24) consumed a high-carbohydrate, moderate-fat meal (HCFM) accompanied by either a strawberry or a placebo beverage in a cross-over design. Postprandial changes in plasma anthocyanins, their metabolites, insulin, glucose and inflammatory markers were assessed for 6 h. The postprandial concentrations of pelargonidin sulfate and pelargonidin-3-O-glucoside were significantly increased when the strawberry beverage was consumed concurrently with the HCFM compared with the placebo beverage (P,0·001). The strawberry beverage significantly attenuated the postprandial inflammatory response as measured by high-sensitivity C-reactive protein and IL-6 (P,0·05) induced by the HCFM. It was also associated with a reduction in postprandial insulin response (P,0·05). Collectively, these data provide evidence for favourable effects of strawberry antioxidants on postprandial inflammation and insulin sensitivity.

The data indicate that consuming tomato products with a meal attenuates postprandial lipemia-induced oxidative stress and associated inflammatory response. The relevance of OxLDL and inflammation to vascular injury suggests a potentially important protective role of tomato in reducing cardiovascular disease risk. ClinicalTrials.gov Registration number - NCT00966550.

Insulin resistance (IR) plays a central role in the development of metabolic syndrome and is a major cardiovascular risk factor. We recently reported that consumption of a strawberry (Str) beverage compared to placebo reduced markers of oxidative stress and inflammation and reduced the insulin requirement to achieve glucose homeostasis in response to a high fat/carbohydrate meal in overweight, relatively healthy people. Therefore, we hypothesized that polyphenolic derived from Str restore impaired oxidative stress‐mediated insulin signaling through its antioxidant properties. Studies were undertaken in human skeletal muscle cells. Oxidative stress was generated using H2O2 (50, 100 μM) for different time periods (2–12hr) along with and without Str extracts (0.1–1mg/ml). Cell viability was not effected by any of the above treatments. At the end of treatments, cells were treated with insulin (100 nM) for 10 min. Activation of Insulin Receptor Substrate (IRS‐1) using different ser/tyr phosphorylation sites were studied using immunoblotting method. Str extracts reduced the oxidative stress‐induced increased levels of inhibitory phosphorylation (ser‐307), and increased levels of tyr phosphorylation on IRS‐1. These data provide mechanistic evidence by which Str polyphenols promote postprandial insulin sensitivity and suggest a role for Str intake in reducing IR and the risk for cardiometabolic disease.