Lack of effect of tart cherry concentrate dose on serum urate in people with gout.

2019-12-31
Rheumatology (Oxford, England) 59(9)
- Lisa K Stamp
- Peter Chapman
- Christopher Frampton
- Stephen B Duffull
- Jill Drake
- Yuqing Zhang
- Tuhina Neogi

PubMed: 31891407
DOI: 10.1093/rheumatology/kez606

Study Design

Type: Randomized Controlled Trial (RCT)
Population: Fifty people with gout and SU > 0.36 mmol/l
Methods: Randomized to receive tart cherry juice concentrate: placebo, 7.5 ml, 15 ml, 22.5 ml or 30 ml twice daily for 28 days. Blood samples at baseline, then at 1, 3 and 5 h post cherry and on days 1, 3, 7, 14, 21 and 28.
Duration: 28 days
Funding: Unclear

Objectives

Cherry concentrate has been suggested to reduce serum urate (SU) and gout flares. The aims of this study were to determine the magnitude of the effect of tart cherry concentrate on SU in people with gout, the most effective dose of tart cherry concentrate for lowering SU, and adverse effects.

Methods

Fifty people with gout and SU > 0.36 mmol/l were recruited. Half were on allopurinol and half were on no urate-lowering therapy. Participants were randomized to receive tart cherry juice concentrate: placebo, 7.5 ml, 15 ml, 22.5 ml or 30 ml twice daily for 28 days. Blood samples were taken at baseline, then at 1, 3 and 5 h post cherry and then on days 1, 3, 7, 14, 21 and 28. The area under the curve for SU was calculated over the 28-day study period.

Results

Cherry concentrate dose had no significant effect on reduction in SU area under the curve, urine urate excretion, change in urinary anthocyanin between day 0 and day 28, or frequency of gout flares over the 28-day study period (P = 0.76). There were 24 reported adverse events, with only one (hyperglycaemia) considered possibly to be related to cherry concentrate. Allopurinol use did not modify the effect of cherry on SU or urine urate excretion.

Conclusion

Tart cherry concentrate had no effect on SU or urine urate excretion. 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.

Trial registration

Australian New Zealand Clinical Trials Registry (ANZCTR), https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=368887, ANZCTR 12615000741583).

Research Insights

tart cherry→Reduced Uric Acid Levels
no significant effect on ... frequency of gout flares over the 28-day study period (P = 0.76)
Effect
Neutral
Effect size
Small
Dose
7.5 ml, 15 ml, 22.5 ml, or 30 ml twice daily
tart cherry→Reduced Urinary Anthocyanin Level
no significant effect on ... change in urinary anthocyanin between day 0 and day 28
Effect
Neutral
Effect size
Small
Dose
7.5 ml, 15 ml, 22.5 ml, or 30 ml twice daily
tart cherry→Reduced Urine Urate Excretion
Cherry concentrate dose had no significant effect on reduction in SU area under the curve, urine urate excretion
Effect
Neutral
Effect size
Small
Dose
7.5 ml, 15 ml, 22.5 ml, or 30 ml twice daily

Adverse Events Reported

tart cherry→hyperglycemia
There were 24 reported adverse events, with only one (hyperglycaemia) considered possibly to be related to cherry concentrate.
Finding
Reported