Daily Consumption of Strawberries Shows Significant Reductions In Oxidative Stress
Strawberries are known to curb cardiovascular disease, cancer, and delay aging. A new study from Italy that supports the heart health benefits of the fruit was published in the Journal of Nutritional Biochemistry. It showed that daily consumption of strawberries may improve blood lipid levels and platelet function by a significant margin.
Strawberries are an important fruit in the Mediterranean diet because of their high content of essential nutrients and beneficial phytochemicals, which seem to exert beneficial effects in human health. In fact, studies suggest that the high antioxidant levels in strawberries can help neutralize the negative effects of free radicals in your system.
Strawberries are rich in potassium, a mineral that helps regulate the electrolytes in your body, lowering your risk of heart attack and stroke. They also contain folate, a key ingredient in the manufacture of red blood cells.
They are a rich source of vitamin C and contain more of this vitamin than citrus fruits. This is helpful in fighting off some forms of cancer and also helps with bad cholesterol. Strawberries are packed with B2, B5, B6, vitamin K, copper, and magnesium. They also contain omega fatty acids and essential fibre.
One month of eating 500 grams per day of the Alba cultivar of strawberries resulted in significant reductions in triglycerides of almost 21%.
Improvements were also recorded in antioxidant status of the 23 healthy volunteers, while levels were reduced of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker for oxidative stress, wrote the researchers.
"Through the present study we added new favorable evidence of the effects of strawberries after 30-days consumption on the overall improvement of the plasma antioxidant status, highlighting a potential beneficial role on biomarkers of antioxidant status, lipid profile and platelet function," they wrote. "Moreover, the potential effect of strawberry intake in improving the RBC antioxidant status and protection against oxidation was confirmed.
"The findings presented here are interesting, because they may partly explain the protective role of a diet rich in fruit and vegetables in preventing CVD and other chronic diseases mediated by oxidative stress."
The study adds to the potential heart health benefits of strawberries and their extracts. In 2009, researchers from Oklahoma State University reported that eight weeks of supplementation with a freeze-dried strawberry powder was associated with a reduction of LDL-cholesterol levels of 11% in obese people (Nutrition Research, Vol. 30, pp. 462-469).
A study in overweight women a year earlier reported that freeze-dried strawberry powder may reduce total and LDL cholesterol levels by 5 and 6%, respectively (Nutrition Journal, 8:43).
Led by Jose Alvarez-Suarez from Universita Politecnica delle Marche in Ancona, Italy, the researchers recruited 23 healthy volunteers with an average age of 27 to participate in their study. All participants had an initial 10 day period with no strawberries and a diet that was low in polyphenols. This was followed by 30 days of strawberry supplementation (500 grams per day) to their habitual diet, and then a further 15 days of washout where they avoided strawberries again.
Results showed that strawberry consumption produced beneficial effects on blood lipid levels, while also significantly decreasing markers of oxidative stress, including malondialdehyde (31% reduction), urinary 8-OHdG (30% reduction), and isoprostanes levels (28% reduction).
Daily strawberry consumption was also associated with significant decreases in the number of activated platelets, compared to control values.
The benefits were attributed to the high vitamin C and anthocyanin content of strawberries, along with the fiber content. Indeed, the strawberry dose was found to contribute about 0.17 g/day and 307.59 mg/day of vitamin C and anthocyanins, said the researchers. Strawberries are reported to contain 2 grams of fiber per 100 g.
"The findings supported the hypothesis that a strawberry-enriched diet may significantly improve the markers of oxidative stress, by decreasing lipid peroxidation oxidation and protecting cells against DNA," they said.
The combination of antioxidant and anti-inflammatory agents found in strawberries is well-known to fight against the onset of many different forms of cancer. Thanks to the vitamin C, folate, and the flavonoids, strawberries are a great defense against potentially cancerous cells.