Tart cherry concentrate has no significant effect on levels of serum urate (SU) or urine urate excretion in patients with gout, according to study results published in Rheumatology.1

Data from prior studies have suggested that tart cherry concentrate may be an effective adjunct to urate-lowering therapy (ULT).2 Investigators in New Zealand and Australia collected the data of 50 patients with gout for a short-term dose-ranging study of cherry concentrate. All patients had an SU >6 mg/dL at the time of enrollment. A total of 25 patients received allopurinol for SU reduction, and 25 did not receive any ULT. Patients were randomly assigned to receive 1 of 5 cherry concentrations: placebo (n=10), 7.5 mL twice daily (n=10), 15 mL twice daily (n=10), 22.5 mL twice daily (n=10), or 30 mL twice daily (n=10) in 250 mL water for 28 days. Blood samples were taken at baseline and 1, 3, and 5 hours after ingestion of the first dose. Blood and urine samples were collected on days 1, 3, 7, 14, 21, and 28. The area under the curve for SU was calculated for the 28-day study period. In addition to SU, blood samples were assessed for creatinine, hemoglobin A1c, and oxypurinol; urine samples were analyzed for urate, creatinine, and anthocyanins. Patients were monitored for adverse events throughout the study period.

Results indicated that cherry concentrate had no significant effect on SU or urine urate at any dose through the 28-day study period. Urinary anthocyanin levels fluctuated over time, although this trend was not correlated with decreases in SU area under the curve (P =.50). Allopurinol did not appear to modify the effect of cherry concentrate on SU or urine urate excretion; however, researchers indicated greater increases in urinary anthocyanins over the course of 28 days among patients in the allopurinol group compared with patients who did not receive ULT (P <.001). Cherry concentrate had no observable effect on hemoglobin A1c (P =.68), patient weight (P =.80), or frequency of gout flares (P =.76) during the study period.

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A total of 24 adverse events were observed, 18 of which occurred among patients who received cherry concentrate. Only 1 adverse event (hyperglycemia) was related to treatment. Cherry concentrate was typically well-tolerated by patients, with 38 (84.4%) indicating they would recommend it to friends or family for gout prevention, if effective.

Although the literature frequently endorses diet modification for gout control, cherry concentrate displayed no therapeutic effect on SU levels. However, as this is an unblinded study with limited cohort size, results must be extrapolated with care.

“If there is an effect of cherry concentrate on gout flares over a longer time period, it is not likely to be mediated by reduction in SU,” the investigators wrote.

References

1. Stamp LK, Chapman P, Frampton C, et al. Lack of effect of tart cherry concentrate dose on serum urate in people with gout [published online December 31, 2019]. Rheumatology (Oxford). doi:10.1093/rheumatology/kez606

2. Schlesinger N, Rabinowitz R, Schlesinger M. Pilot studies of cherry juice concentrate for gout flare prophylaxis. J Arthritis. 2012;1:101.