Health & Nutrition
Because of their health benefits, flavor and overall appeal, strawberries
add vibrant color to almost any kind of salad. Not only that, they can add depth and
sweetness to enhance more traditional salad dressings.
California strawberries are grown by hundreds of family farmers who are passionate about producing the sweetest and healthiest strawberries in the nation. We encourage you to learn more about where your strawberries come from!
For Health Professionals
California Strawberries: Guardians of Health
In addition to traditional nutrients such as vitamin C, folate and potassium, strawberries are also rich in phytonutrients: phenolic compounds such as flavonoids, ellagitannins and ellagic acid, which are the focus of intense study due to their antioxidant, anti-inflammatory, anticancer and antimutagenic properties. The majority of flavonoids in strawberries are anthocyanins, the compounds responsible for the blue, red and purple colors of berries, grapes and other fruits. Many compounds in strawberries besides vitamin C act as antioxidants, protecting tissues in the body against the deleterious effects of free radicals. Research shows that the antioxidants in strawberries are efficiently absorbed within one hour of being eaten.
When it comes to Cardiovascular Health, studies indicate that strawberries play a key role in helping to reduce total cholesterol, LDL oxidation, inflammatory markers, blood folate levels and contribute to a heart healthy lifestyle.
A recent study of 27 subjects found that 50g of strawberry powder per day (the equivalent of 3 cups of fresh strawberries) for eight weeks found that total cholesterol levels were reduced and other markers of atherosclerosis, such as lipid particle size and adhesion molecules were favorably impacted. In another study, 16 women with metabolic syndrome ingested 50g of strawberry powder per day for four weeks which resulted in a decrease in total and LDL cholesterol, as well as a decrease in oxidized LDL.
The specific cardio-protective nutrients in strawberries include vitamin C, folate, fiber, potassium and flavonoids such as ellagic acid, quercetin and kaempferol, all believed to have protective effects. Research indicates that consumption of strawberries not only increases blood levels of these nutrients but also lowers markers of cardiovascular disease, like homocysteine levels and blood pressure. In an analysis of data from large dietary studies in the U.S., strawberry eaters had higher intake and serum levels of folate, higher intake of fiber and vitamin C, lower homocysteine levels, and lower blood pressure than non-strawberry eaters.
The Portfolio Diet lowers cholesterol by consuming a strict regimen rich in soy and soy protein, viscous fibers found in oats and psyllium, plant sterols, and nuts. Adding two pounds of strawberries into the daily mix of Portfolio foods for one month increased the palatability of the diet while maintaining cholesterol reduction. In fact, the addition of strawberries reduced LDL oxidation better than consuming additional oat bran.
A clinical study of 20 adults demonstrated that eating a serving of strawberries daily for four weeks increased blood levels of folate.
Data from the Harvard Women’s Health Study showed that women who had higher strawberry intake were more likely to lead a heart-healthy lifestyle. On average, women in the highest strawberry intake group ate about twice as many servings of fruits and vegetables every day as did women in the lowest intake group.
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Strawberries contain folate, a B vitamin that has been associated with reduced risk of several cancers. Epidemiological studies suggest that folate is protective against cervical dysplasia, an early precancerous stage that sometimes proceeds to cervical cancer. The Nurses’ Health Study found a 31 percent reduced risk for colon cancer in women with higher dietary folate intakes.
When women in a cohort screened for breast cancer in the 1980s were followed up more than a decade later, it was found that those with the highest folate intakes had the lowest risk of cancer of the colon, rectum or both.
All of the flavonoids found in strawberries are potent antioxidants that have protective effects by scavenging oxygen free radicals. Quercetin, for example, has been found in animal studies to inhibit chemically induced cancers of the lung, tongue, colon, mammary glands and mouth. It has also been found to inhibit the growth of human prostate cancer cells and human breast cancer cells.
A serving of strawberries contains about 63 mcg of ellagic acid, an anticarcinogen that has shown promise in inhibiting cancer formation and progression in laboratory animals and cell cultures, including human cell lines. In animal studies, ellagic acid inhibited the development of chemically-induced cancers of the lung, esophagus, skin and liver. In a laboratory study using human breast cells in culture, ellagic acid inhibited carcinogenesis by 45 percent.
Various fractions of freeze-dried strawberries were tested for their ability to inhibit cell transformation in animals. Although the fraction containing ellagic acid inhibited cell transformation, so did an extract containing no ellagic acid. This confirmed that compounds in strawberries besides ellagic acid have anti-cancer properties.
Results from initial studies using freeze-dried strawberries and strawberry extracts in cell cultures and in laboratory models have been promising in preventing changes in cells that could progress toward cancer. When two varieties of freeze-dried strawberries were added to two types of human breast cancer cells and two types of human cervical cancer cells growing in culture, both strawberry varieties significantly inhibited the growth of both types of cervical cancer cells. Both also inhibited the two types of breast cancer cells, although one variety was more potent than the other.
In another study, freeze-dried strawberries when fed as five or ten percent of the diet, inhibited the development of chemically-induced esophageal cancer in a dose-dependent manner. A similar study found that freeze-dried strawberries fed after the initiation of cancer were effective in blocking the cancer’s progression.
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Age-related declines in cognitive function have been related to both oxidative stress and inflammation. The decline is manifested as alterations in both motor function and cognitive behaviors. Alterations in motor function may include decreases in balance, muscle strength and coordination, while cognitive deficits include losses in learning ability and memory. Because of their high antioxidant and anti-inflammatory activities, strawberries are being studied for their ability to slow or prevent such decline.
In a pilot study by researchers at the USDA Human Nutrition Research Center on Aging at Tufts University, long-term feeding with strawberry extract slowed age-related decline in cognitive function in laboratory models. In animal models, strawberries improved the decline in motor function that occurred with aging. The mechanism of action for this may include enhanced communication and signaling between neurons in the brain.
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The California Strawberry Commission has funded more than $2.0 million in health research since 2003. Upcoming research is designed to unlock the true power of strawberries and to provide clues about the nutrition and health benefits of strawberries. New studies are being conducted that explore the role strawberries can play in improving health.