Compounds found in strawberries may decrease levels of inflammatory markers and reduce the risk of a range of conditions, including metabolic syndrome, suggests a new study.
According to findings published in the British Journal of Nutrition, obese volunteers who drank a strawberry-based beverage and ate a meal with a high carbohydrate content and a moderate fat content had lower levels of inflammatory markers than volunteers who consumed a placebo beverage.
“These changes have been observed against a background of increased plasma concentration of anthocyanins derived from strawberry,” wrote researchers from the Illinois Institute of Technology and University of California-Davis.
“Overall, these findings suggest beneficial effects that accrue from consumption of fruits that have a high phenolic content,” they added.
The study was funded by the California Strawberry Commission.
Chronic inflammation is brought about by an over-expression or lack of control of the normal protective mechanisms.
In a review in Nutrition, Metabolism & Cardiovascular Diseases (2004, Vol. 14, pp. 228-232), Italian scientists noted that “obesity, insulin resistance, and diabetes are associated with a pro-inflammatory state, which in turn is associated with increased cardiovascular risk”.
Chronic inflammation has also been linked to a range of conditions linked to heart disease, osteoporosis, cognitive decline and Alzheimer's, type-2 diabetes, and arthritis.
A list of established biomarkers for inflammation exists, with commonly touted markers including C-reactive protein (CRP), interleukin-6 (IL-6), IL-10, IL-18, monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-alpha).
The new study found that consumption of the strawberry drink was associated with a 25 percent lower level of IL-6 six hours after consumption, compared with people receiving the placebo drink.
In addition, CRP levels were 13 percent lower following consumption of the strawberry beverage than following consumption of the placebo beverage.
Led by the Illinois Institute of Technology’s Britt Burton-Freeman, the researcher recruited 24 obese subjects to participate in their study.
Volunteers were fed a high-carbohydrate, moderate-fat meal, which is known to produce inflammatory and insulin responses after eating, and given either a strawberry beverage or a placebo beverage.
Results showed that blood levels of two strawberry compounds, pelargonidin sulfate and pelargonidin-3-O-glucoside, significantly increased following ingestion of the strawberry beverage at the same time as eating the test meal, compared with placebo.
Commenting on the potential mechanism, the researchers note that the effects appear to be independent of a possible antioxidant effect since antioxidant activity – like reducing levels of LDL oxidation – were observed quicker than the changes in the anti-inflammatory markers.
“These data suggest an anti-inflammatory role of strawberry with a time course of action that is delayed relative to the antioxidant effects of strawberry.
“Therefore, the antioxidant/anti-inflammatory effects of strawberry-derived compounds need to be studied further to reconcile the difference in the time course of the changes in glucose, insulin and oxidative stress/inflammatory markers observed in plasma,” they added.
Source: British Journal of Nutrition
Published online ahead of print, FirstView Article, doi: 10.1017/S0007114511001176
“Strawberry anthocyanin and its association with postprandial inflammation and insulin”
Authors: I. Edirisinghe, K. Banaszewski, J. Cappozzo, et al.