Cherries already have a reputation for fighting inflammation but the researchers at the US Agricultural Research Service Western Human Nutrition Research Center in Davis, California claim their test is among the first to track anti-inflammatory effects of fresh Bing cherries in a controlled experiment with healthy volunteers.
They focused their study on the anti-inflammatory impact of fresh cherries as opposed to previous studies that analysed cherry extracts. Apparently a first, the scientists tested the key inflammatory disease indicators, or markers, in blood samples from healthy volunteers who were fed precise amounts of fresh Bing cherries.
Reported in a 2003 issue of the Journal of Nutrition the California investigation paved the way for a recent followup study at the Davis centre.
They found that levels of uric acid - a compound the body uses to form painful urate crystals during a gout attack - decreased significantly in volunteers' blood (plasma) over the five hours after they ate the Bing-cherry breakfast.
The ten healthy women, aged 22 to 40, who volunteered for the first phase of this research ate a breakfast of 45 fresh, pitted Bing cherries. They were instructed not to eat strawberries or other fruits and vegetables, or to drink tea or red wine, for the two days before the cherry breakfast because these foods are high in antioxidants, thought to fight inflammation.
ARS chemists Robert A. Jacob - now retired - and Darshan S. Kelley collaborated with university scientists in the preliminary study and, recently, in a more extensive follow-up investigation.
"Our main focus in this study was gout, a very painful form of arthritis," said Kelley, reports the ARS. During gout attacks, crystals of a naturally occurring chemical, uric acid, accumulate in joints-commonly in the toes-and cause pain. Urate in blood plasma is a precursor of these uric acid crystals. So, we closely measured volunteers' levels of plasma urate, he explained.
According to the scientists, results of the study revealed that the drop in two key markers, or indicators, of inflammation - nitric oxide and C reactive protein-were not large enough to be statistically significant. "However, this downward trend agreed with that noted earlier in other scientists' test-tube studies of cherry extracts," writes the ARS.
C-reactive protein, produced by the liver, increases rapidly during inflammation, such as during a gout attack. In a healthy body, blood (serum) levels of C-reactive protein are extremely low.
According to the researchers, at the 3-hour monitoring interval, C-reactive protein and nitric oxide were somewhat lower than at the start of the study.
The follow-up study, conducted in 2003, involved more people, more cherries, and a greater array of inflammatory-response markers. Eighteen women and two men-aged 22 to 40-participated in the 64-day investigation.
Many of the new volunteers began the study with elevated C-reactive protein levels. This group ate the same daily amount of fresh Bing cherries as earlier volunteers but were asked to eat them throughout the day instead of just at breakfast for 28 consecutive days. The researchers are now analysing blood samples and full findings are expected later this year.