Led by Britt Burton-Freeman, PhD, an assistant research professor of biology at the National Center for Food Safety and Technology at Illinois Institute of Technology, the study examined the effect of a strawberry beverage (and a placebo) on inflammatory markers C-reactive protein, tumor necrosis factor-alpha, monocyte chemoattractant protein-1 (MCP-1) and interleukin 6 (IL-6), IL-10, and IL-18.
Twenty-four obese subjects were given high-carbohydrate meals with moderate fat levels, the type of meal that causes inflammation and insulin responses. They were then given either the strawberry beverage or a placebo. Researchers found that the subjects who drank the strawberry beverage showed a 25% reduction in IL-6 levels and a 13% lower level of C-reactive protein, compared to those who consumed the placebo. According to the researchers, the declines in inflammatory markers were accompanied by significant increases in pelargonidin sulfate and pelargonidin-3-O-glucoside, two strawberry compounds.
In an interview with Nutraceuticals World, Dr. Burton-Freeman said she and her colleagues were compelled to take a closer look at the benefits of strawberries for several reasons. For starters, they are a low calorie, nutrient dense favorite among consumers, and they are products of the California produce industry. “They are [also] rich in many non-essential nutrients (such as the anthocyanins and other polyphenols) that we were interested in understanding their bioactivity and promotion of health,” she said, adding that there are few human studies available examining intake of strawberries and their components on emerging risk factors of disease, which was another facet of attraction.
Strawberries are an important source of antioxidants and anti-inflammatory phytonutrients, including anthocyanins like cyanidins and perlargonidins; flavonols like catechins, epicatechins and quercetin; hydroxyl-benzoic acids like ellagic acid, salicylic acid; and resveratrol.
The team’s focus on chronic inflammation was borne out of “the interest in the relationship between oxidative stress and inflammation and how the diet on a meal-to-meal basis contributes to chronic inflammation and metabolic disturbances (e.g., insulin action),” Dr. Burton-Freeman said.
And although she was unable to pinpoint a possible level of market opportunity for a strawberry drink that counteracted chronic inflammation, she was excited about the market potential on the whole. “With the amount of research coming out about chronic inflammation and relationship to disease and particularly to the aging process, I can only imagine it will be big,” she said.“As people/consumers get more familiar with what inflammation is (versus how we traditionally think about inflammation), foods and products will be sought out by consumers to help manage [the condition]. Currently, most consumers don’t know what to think about ‘chronic inflammation.’”
Research into how strawberries can help combat chronic inflammation is still in the very early stages. “More research needs to be done to understand the value of the nutritional product (versus whole fruit),” commented Dr. Burton-Freeman. “Our experience has been that the whole is much better than the parts.
“Nutritional products that have scientific backing can let the science speak. One of the problems however (for all of us), is that we have no clear/well accepted clinical endpoints of chronic inflammation,” she added. “As research develops in this area, we will have more tangible endpoints for talking to consumers. We have C-Reactive Protein (CRP) now, although it still requires some development/validation. I think we will need to get the ‘X’ for inflammation and disease like we have ‘cholesterol for heart disease.’”
In the interim, Dr. Burton-Freeman said she and her colleagues are currently working on ongoing studies focused on how differing doses of strawberries and other fruits relate to bioavailability of target compounds and impact on inflammatory responses, including sources of inflammation. “We are also looking at how processing and matrix impacts anti-inflammatory properties of fruits (mainly strawberries),” she said. “We also work with grape seed extract, wild blueberries, black current, cranberry (white and red), but much of this work is not in humans yet (only grape seed extract is in humans)—we are anxious to get into humans with other fruits!”
The published study, titled “Strawberry anthocyanin and its association with postprandial inflammation and insulin,” appeared in the British Journal of Nutrition.