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Citrus Fruits May Have Special Benefit For Women
A diet that includes plenty of citrus fruits, such as oranges and grapefruits, may decrease the risk of one type of stroke in women, according to a new study. Flavanones, a specific compound found in citrus fruits, may be the key.
Researchers at Norwich Medical School in the University of East Anglia in Norwich, United Kingdom used data collected over 14 years from the Nurses' Health Study. The data included reports from nearly 70,000 women who reported their food consumption, including details about their fruit and vegetable intake, every four years. The relationship between six main subclasses of flavonoids was examined to determine the risk of ischemic, hemorrhagic, and total stroke.
While no benefit was found between total flavonoid consumption and the risk of stroke, women who consumed greater amounts of flavanones, the compound found in citrus fruits, had a 19 percent lower risk of ischemic stroke than women who ate the least amounts. An ischemic stroke is caused by an obstruction in the blood flow to the brain, usually a blood clot.
Flavonoids, found in fruits, vegetables, dark chocolate, and red wine, have been studied for their health benefits, particularly on blood vessels. Flavanones are one of six subclasses of flavonoids - flavanones, anthocyanins, flavin-3-ols, flavonoid polymers, flavonols, and flavones. Flavonoids give fruits and vegetables their brilliant colors, and there are more than 5,000 of them in existence, according to some estimates. Not all flavonoids seem to have the same effect on stroke.
Dr. Aedin Cassidy, lead author of the study, said that prior research has shown that a high intake of fruits, vegetables, and specifically vitamin C is linked to a reduced risk of stroke. She explained that flavonoids are believed to provide some of that protection in a number of ways, such as acting on blood vessel function and as an anti-inflammatory agent.
In this study the flavanones came mostly from oranges, orange juice, grapefruit, and grapefruit juice. However, the researchers recommend that people increase their intake of the whole fruits rather than fruit juice which has a higher sugar and calorie content. A medium orange contains approximately 60 calories while a cup of orange juice contains twice that amount.
Adding a bit of complication to the public health message from this study is the fact that grapefruit and its juice can interact with certain medications commonly prescribed to lower the risk of heart attack and stroke, such as cholesterol-lowering statin drugs. Grapefruit juice combined with statins can increase the risk of liver problems. Grapefruit juice can also intensify the effect of some blood pressure drugs, increasing the risk for side effects.
More research is needed to confirm the association between stroke risk and flavanone consumption and to better understand why the association occurs.
The study will appear in the April issue of the American Heart Association journal, Stroke.
March 5, 2012