There is additional research which supports the efficacy of compounds in strawberries to support healthy blood lipids and carbohydrate metabolism. In an animal study, rats were for fed for four weeks strawberry pomace (the strawberry solids left after the juice is removed) either with or without the natural strawberry polyphenols. When a high fructose diet was fed, the polyphenol-rich strawberry group saw lower serum insulin, lower liver cholesterol levels, and lower serum free fatty acids. However, even the group fed the strawberry pomace with reduced polyphenols saw some improvements, leading the authors to speculate that it is more than just polyphenols which are contributing to the health benefits of strawberries.
Strawberries – An Important Source of Dietary Folate
Folate is an important B vitamin that has most recently become known for its ability to reduce the risk of neural tube birth defects that may originate during embryonic development. In a recent study, strawberries were confirmed to be a rich source of folate, with as much folate as spinach, and more than broccoli, potatoes and lentils. Cooking tended to reduce folate content in some foods. Eating fresh strawberries is a palatable way to help meet dietary recommendations for folate.
Salk Scientists Say: It’s not an Apple a day after all – it’s Strawberries!
Research has identified a number of bioactive substances in berries. One less well-known flavonoid, fisetin, is showing promise as an antioxidant and anti-inflammatory which has the potential to mitigate multiple complications of diabetes. Researchers at The Salk Institute for Biological Studies fed diabetic-like mice fisetin (in an amount equivalent to eating about 37 strawberries) and saw positive effects in kidney and brain function, and markers of inflammation . Fisetin is unique among natural substances previously tested for diabetic complications, because it impacts so many organ systems affected by the disease. The highest levels of fisetin are found naturally in strawberries. While this is emerging data in an animal model, it further
substantiates the health benefits of frequent consumption of fruit, like strawberries.
View the press release at: http://www.salk.edu/news/pressrelease_details.php?press_id=500
The full text of the article can be found at:
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0021226
Researchers Confirm Bioavailability of Antioxidants in Strawberries
The bioavailability in humans of antioxidant compounds in strawberries has been confirmed by researchers in Italy and Spain. Twelve healthy volunteers ate 500 grams (about 17 ounces) of strawberries over the course of the day, and blood samples were drawn after four, eight, 12, 16, and 30 days later. The results show that regular strawberry consumption can improve the antioxidant capacity of blood plasma and also the resistance of red blood cells to oxidative stress. Oxidative stress has been shown to be a key fact in the development of cardiovascular disease, cancer, and diabetes. Strawberries contain a large amount of phenolic compounds, such as flavonoids, which have antioxidant properties. This work confirms that those antioxidant compounds survive digestion and metabolism.
The researchers conclude that strawberries should be one of the daily portions of fruit that is an important part of healthy and balanced diet.
This work confirms studies published previously that showed the active compounds in strawberries are bioavailable.
Tulipani S et al. Strawberry consumption improves plasma antioxidant status and erythrocyte resistance to oxidative haemolysis in humans. Food Chemistry, 2011; 128 (1):180.
Ellis CL et al. Attenuation of meal-induced inflammatory and thrombotic responses in overweight men and women after 6-week daily strawberry (Fragaria) intake. A randomized placebo-controlled trial. J Atheroscler Thromb. 2011 Apr 27;18(4):318-27.
Azzini E et al. Bioavailability of strawberry antioxidants in human subjects. Br J Nutr. 2010 Oct;104(8): 1165-73.
Link to abstract – http://www.sciencedirect.com/science/article/pii/S0308814611004067
Strawberries Shown to Protect Against Diet-Induced Increases in Inflammation
High fat and carbohydrate meals, typical of the Western diet, can increase oxidative stress and inflammation in the human body, which may play a causative role in cardiovascular disease. Recently published research suggests that regular consumption of strawberries may protect against these changes. Twenty-four overweight men and women were given a test meal of bagel, cream cheese, egg, cantaloupe, and whole milk, with either a placebo beverage or a test beverage with 10 grams of freeze-dried strawberries (equivalent to about 100 grams or less than 1 cup of strawberries). The randomized, crossover study found that after 6 weeks of strawberry beverage, blood levels of the inflammatory factors PAI-1, IL-1B and IL-6 were attenuated compared to placebo. This is the first study to suggest that strawberries may provide protection from increased fibrinolytic and inflammatory factors induced by high fat and carbohydrate meals. The results are especially intriguing since the effect was shown with the equivalent of about one serving of strawberries per day.
This study was funded by The California Strawberry Commission.
Strawberries and Colon Cancer Prevention
Emerging research suggests that strawberries may prevent human esophageal cancer. Researchers from The Ohio State University are also investigating the effects of strawberries on reducing inflammation-associated colorectal cancer. Mice were given a chemical known to induce mouse colon carcinogenesis, and then fed either a standard diet or a standard diet with added freeze-dried strawberries. At the end of the 20 week study, the mice fed strawberries had significantly decreased tumor incidence. Additional research is underway to determine the effects of strawberries on colon cancer biomarkers.
These results were presented at the 2011 meeting of the American Association for Cancer Research. Both of these studies examining the beneficial impact of strawberries on cancer prevention were funded by the California Strawberry Commission. Details and video can be found at http://bit.ly/icvB2R.
New Study Finds Strawberries May Slow Precancerous Growth in Esophagus
WATSONVILLE, CA (April 6, 2011) – A new study by The Ohio State University suggests strawberries may help prevent human esophageal cancer. This news comes at a time when, according to the American Cancer Society, more than 16,000 new cases of the disease will be diagnosed in the United States this year.
According to lead researcher, Tong Chen, M.D., PhD, strawberries may help protect those at risk of esophageal cancer. This study builds on previously published research by Chen and colleagues in China, who found that freeze-dried strawberries significantly inhibited tumor development.
These results were presented at the 2011 annual meeting of the American Association for Cancer Research in Orlando, Florida. This study examining the beneficial impact of strawberries on cancer prevention was funded by the California Strawberry Commission.
Researchers from The Ohio State University are also investigating the effects of strawberries on reducing inflammation-associated colorectal cancer.
For more details regarding the study, please visit: http://bit.ly/gtXlFC
Esophageal cancer is the third most common gastrointestinal cancer and the sixth most frequent cause of cancer death in the world.
Strawberries and Cancer
Francisco Tomas-Barberan, Ph.D., of the Spanish Council for Scientific Research at the CEBAS Institute in Spain described a possible mechanism for berry benefits in cancer prevention. Ellagic acid and ellagitannins are polyphenols abundant in berries, including strawberries. While these polyphenols have high antioxidant activity in vitro, they tend to be poorly absorbed. However, gut microflora metabolize these polyphenols into urolithins, which are absorbed. Animal studies indicate that urolithins are anti- inflammatory and weakly anti-estrogenic, with implications for benefits in colon and prostate cancer. Other potential mechanisms of action for polyphenols in cancer prevention include effects on apoptosis and tumor suppressor gene expression.
