New research suggests that eating grapes regularly may help alleviate pain associated with symptomatic osteoarthritis of the knee. It may also improve joint flexibility and overall mobility. Researchers say these potential benefits are caused by the polyphenols found in grapes.
Millions of Americans are affected by osteoarthritis – a condition where the natural cushioning between joints wears away. According to the Arthritis Foundation, more than 27 million people have osteoarthritis and knees are an area most commonly affected. Osteoarthritis is more likely to occur in people over 45 years of age, and women are more likely to have osteoarthritis than men.
During a sixteen week clinical study, undertaken by Texas Woman’s University, researchers looked at the benefits of eating grapes on inflammation and osteoarthritis outcomes. More than 70 men and women with knee osteoarthritis were assigned to either consume grapes in the form of a whole grape freeze-dried powder, or a placebo powder.
The results, presented at the Experimental Biology conference in San Diego, California earlier this year, showed that both men and women consuming a grape-enriched diet had a significant decrease in self-reported pain related to activity and an overall decrease in total knee symptoms.
This beneficial effect was more pronounced in women. Additionally, age-related differences were observed. There was a 70 percent increase in very hard activity for those under 64 years of age consuming the grape powder, while those receiving the placebo reported a significant decrease in very hard activity.
Evidence of increased cartilage metabolism was observed in men consuming the grape-enriched diet; they had higher levels of an important cartilage growth factor (IGF-1) than those on placebo. This protective effect was not observed in the females. The researchers noted that no difference in range of motion was observed for either the grape group or the placebo group. The serum marker for inflammation (IL1-β) measured was increased in both placebo and grape groups, although much less of an increase was observed in the grape group.
“These findings provide promising data that links grape consumption to two very important outcomes for those living with knee osteoarthritis: reduced pain and improvements in joint flexibility,” said Dr. Juma in a news release from the California Grape Commission. “More research is needed to better understand the results of the serum biomarkers, as well as the age and gender differences observed.”
The research has not be published in a peer-reviewed journal.
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