People who start the day with a glass of orange juice have been getting some good news lately. (See our report on possible cholesterol benefits in the February 2011 Healthletter.) In the latest research exploring health benefits of OJ, French scientists report that drinking orange juice-or a control beverage containing hesperidin, a key antioxidant flavonoid specifically found in OJ-was associated with significantly lower diastolic blood pressure and improved blood-vessel function.Christine Morand, PhD, of of the Human Nutrition Unit-INRA Clermont- Ferrand, and colleagues performed a crossover study on 24 overweight but otherwise healthy men, ages 51 to 63. Daily during three successive four-week periods, the men drank 17 ounces of orange juice (which contains about 300 milligrams of hesperidin), a control drink with 300 milligrams of hesperidin capsules, and finally a control drink with placebo capsules. Each of the drinks added about 200 daily calories.At the end of both the OJ and hesperidin test periods, diastolic blood pressure was significantly lower than after the placebo testing. Diastolic blood pressure-the second number in a blood-pressure reading, after the slash-measures the pressure in your blood vessels between heartbeats, when your heart is resting. For men in their 50s or 60s with blood pressure of 150/90 mm Hg, researchers pointed out, a decrease of just three or four points in diastolic pressure could translate into a 20% reduction in the incidence of coronary artery disease.Morand and colleagues also tested a variety of measures of blood-vessel activity, including the ability of blood vessels to dilate. Both orange juice and hesperidin showed positive effects compared to placebo.Improvements in blood-vessel activity were stronger from the OJ than hesperidin alone, suggesting that other factors in juice may also have beneficial effects. Jeffrey B. Blumberg, PhD, director of Tufts HNRCA Antioxidants Research Laboratory, comments, That OJ was stronger than hesperidin alone is hardly surprising as it compares a single flavonoid against a food containing dozens of polyphenols and other phytochemicals-not to mention vitamin C, folate, calcium, potassium, etc.-and the likelihood of not only additive but synergistic mechanisms of action.Previous studies have suggested a link between the consumption of foods high in other antioxidants, such as green tea and chocolate, and improvements in blood pressure and blood-vessel function. Other studies have shown a possible association between eating citrus fruits, such as oranges, and lower risk of cardiovascular problems, but scientists have not identified a mechanism for such a benefit. (This new French study was supported by a grant from the Florida Department of Citrus, which had no role in the study design, data collection or analysis.)While research continues, its best not to count on orange juice alone to combat high blood pressure-and too much OJ will add up in liquid calories. But, combined with an overall healthy diet, exercise and watching your weight, a morning glass of juice from the sunshine tree might help keep your blood pressure in check.TO LEARN MORE: American Journal of Clinical Nutrition, January 2011; abstract at www.ajcn.org/content/93/1/73.abstract. Oranges… One of Natures Most Nutritious Foods, January 2010 Healthletter.
