First it was apples, then it was dark chocolate followed by red wine, now researchers say that an orange a day will keep a stroke away.
This latest study by Aedin Cassidy and colleagues from the University of East Anglia, England, observed that intake of oranges, grapefruit and other citrus fruits was associated with moderate reduction in stroke risk in women. (1)
The researchers followed women in the study for 14 years and noticed that those who had the highest level of flavonoids in the diet were less likely to have a stroke. In particular, the stroke reduction was associated with a specific class of flavonoid, and not the total amount of flavanone.
Previous studies have reported that vitamin C, because of its potent, antioxidant activity, is also protective against stroke. However, in this study, the reduction in stroke was related to levels of flavanones and not vitamin C.
In this study, the majority of flavanones consumed by the women were obtained from eating oranges and drinking grapefruit juice. Besides citrus fruits, the other big contributor of flavonoids, was tea consumption.
The researchers indicated that perhaps eating the whole fruit is a better way to boost the level of flavanones.
Flavanones are a type of flavonoids and have been extensively investigated. Various types of health benefits have been attributed to these substances, including reduction in blood pressure and heart disease. (2) However, not all reports are consistent with the above health benefits. Furthermore, no one has ever looked into the individual flavonoids.
How flavonoids protect against stroke is not well-understood, but it is speculated that these substances may release nitric oxide in the brain and also possess anti-inflammatory effects.
Despite these positive results, there are some negatives about the study. Strokes have other risk factors like diabetes, high blood pressure, obesity and smoking. In this study, none of these parameters were assessed. Finally, the level of flavonoids in citrus fruits is variable and depends on the soil, season of growth and how it is cultivated and processed.
No one is suggesting that a diet rich in citrus fruits is harmful but its health benefits have been seriously exaggerated.
For consumers, one should not rely on a single supplement or a fruit for prevention of disease. Instead, one should lead a healthy lifestyle, eat a well-balanced diet, and exercise regularly.
Sources:
Cassidy A, et al "Dietary flavonoids and risk of stroke in women"
Abstract: http://stroke.ahajournals.org/content/early/2012/02/23/STROKEAHA.111.637835.abstract
Yamada T. Frequency of citrus fruit intake is associated with the incidence of cardiovascular disease: the Jichi Medical School cohort study.
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/21389640
Reviewed February 27, 2012
by Michele Blacksberg RN
Edited by Jessica Obert