Strawberry Antioxidant Properties Promote Healthy Blood

Strawberries are known to have rich antioxidant properties. Earlier work showed that strawberries can partially protect red blood cells (RBCs) from oxidation damage. This study was conducted to examine the ability of strawberries to raise the antioxidant status of blood and also to determine the capacity of strawberries to protect RBCs from oxidative damage. The authors found that 16 days of eating strawberries made blood plasma less likely to contain harmful oxidants and appeared to make RBCs more resistant to these cell damaging chemicals.

Fruits are a prime source of antioxidants and they protect the body from various chronic diseases. Strawberries are a rich source of antioxidants such as vitamin C, folic acid, flavanoids, tannin and phenolic acid. Several studies have shown that there is a significant rise in the level of antioxidant capacity of blood after the consumption of strawberries. So far, no studies have investigated the in vivo protective actions of strawberries on RBCs. Strawberries are the most commonly consumed berries, especially in northern European countries. Hence, confirming the antioxidant capacity in strawberries would promote their increased consumption.

* The study included 12 healthy, non-smoking participants (five men and seven women), aged about 34 years. Before the consumption of strawberries, the participants were asked to have a strawberry-free diet for about 10 days. Then, they were given 17.6 ounces of “Sveva” strawberries every day for 16 days.
* Blood samples were collected 10 days prior to strawberry consumption, then at the start of the experiment, and on days four, eight, 12, and 16 of the experiment. One month following completion of the experiment (the “washout period”), blood samples were again collected. Levels of antioxidant capacity, vitamin C, folic acid, flavanoid, and phenolic acid, were measured in all blood samples collected.
* Destruction of RBCs was assessed upon the addition of the oxidant toxin AAPH. Destruction of RBCs on their own without the addition of any agent was also noted.
* Levels of various nutrients in the “Sveva” strawberries were measured.

* The strawberries had high antioxidant properties, with high amounts of vitamin C and folic acid.
* The values of plasma antioxidant capacity significantly increased after four days of strawberry intake (8.5 percent increase), reaching an increase of 11.4 percent at the end of the study period. Levels of vitamin C rose significantly after consumption of strawberries, but it returned to the baseline by day 30 of follow-up.
* The destruction of RBCs was significantly reduced with the consumption of strawberries. This effect was seen in both “oxidant” and “without-oxidant” conditions.

Shortcomings/Next steps
In the present study, the participants were given strawberries in very large quantities. In reality, it is difficult for anyone to eat 17.6 oz of strawberries every day. Future studies must observe the effects of consumption of more acceptable amounts of strawberries, around 3.5 to 7 oz. Moreover, there is a need to examine the effects of consuming strawberries for a prolonged period.

Strawberries are consumed both in fresh and processed form. In many European countries strawberries form the major sources of antioxidants. Flavanoids are substances present in strawberries, which confer the antioxidant capacity. They are incorporated into the cell membranes of RBCs and prevent the oxidation of lipids. Thus, they protect the RBCs from chemical and physical  injury. The results obtained in this study suggest that regular consumption of antioxidant-rich strawberries could have beneficial effects on the antioxidant status of blood plasma and increase the capacity of RBCs to resist damage caused by oxidants.

For More Information:
Strawberry Consumption Improves Plasma Antioxidant Status and Erythrocyte Resistance to Oxidative Haemolysis in Humans
Publication Journal: Food Chemistry, 2011
By Sara Tulipani, Josè M. Alvarez-Suarez, Marche Polytechnic University, Ancona, Italy

*FYI Living Lab Reports Are Summaries of the Original Research.

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