What the Study FoundA group of researchers at the Mayo Clinic in the United States conducted double-blind research to study the health effects of cranberry juice. 84 study participants with known cardiovascular health risks were chosen for the study. Of these, 69 completed the four month study. 32 were given two glasses of a commercially available cranberry juice (double strength Ocean Spray) per day while the remainder were given a placebo. Using a technique called peripheral arterial tonometry (EndoPAT), the research team measured existing levels of calcium before, during and at the conclusion of the trial.
A study abstract published by the U.S. National Institutes of Health (NIH) concluded that the "decrease in the fraction of osteocalcin+ EPCs suggests a potential beneficial effect of polyphenol-rich CJ." What this means in plain English is that those study participants who drank cranberry juice showed a reduction of calcium (osteocalcin) on arterial walls and fewer carriers of calcium (EPCs or endothelial progenitor cells) in the blood stream.
Why Drink Cranberry Juice for a Healthy Heart?What is it about cranberry juice that contributes to a healthy heart? The Mayo Clinic researchers began their study from an understanding that cranberries contain extraordinarily high levels of antioxidants called polyphenols. Considered important for both bone and cardiovascular health, they wanted to explore polyphenols in greater depth. The calcium deposits found on the walls of arteries is the same calcium that is so important for healthy bones. Why does it accumulate in the arteries, where it can have such devastating effects?
The secret turned out to be in the EPCs. These are the cells that carry calcium to the blood stream, where it is deposited. While polyphenols and other antioxidants are excellent scavengers of free radicals and are beneficial for this reason alone, the polyphenols in cranberry juice also seem to decrease the levels of EPCs in the blood stream. As a result, osteocalcin is not carried into the circulatory system and deposited.
The Mayo Clinic used a popular brand of cranberry juice that contains a high sugar content. Since sugar can have negative health consequences (see our NT Pages article, Should Sugar be Regulated?), many natural health practitioners recommend using sugar-free cranberry extract in sugar-free drinks instead. The tart flavour of the cranberries can be neutralised by blending the cranberry extract with sweet fruit juices such as orange juice. Add some freshly crushed mint to the mixture and you've got a refreshing summer beverage you'll love and your body will love you for drinking. For the soft drink fizz without the soft drink sugar and additives, experiment with fruit juice, cranberry extract and carbonated water.