Gout is a form of periodic inflammatory arthritis that results from the accumulation of uric acid crystals in the joints. Hyperuricaemia is associated with attacks of gout and drugs that decrease uric acid formation or increase its elimination are the main treatments offered by mainstream medicine. Gout is extremely painful and sufferers have an increased risk of cardiovascular disease. Anecdotal evidence suggests that cherries are a useful treatment for gout. Cherries are a rich source of vitamin C, and vitamin C has been shown to be effective at lowering the uric acid levels of humans (here). In addition cherries also contain anthocyanin flavonoids that are responsible for the rich red colour of the skins and flesh, as well as other polyphenolic antioxidants including catechins, flavonols, hydroxycinnamates, and chlorogenic acid. Such antioxidants may work synergistically with vitamin C and it has therefore been suggested that they may contribute to the uric acid lowering effects of cherries.
One study investigated the effects of cherries on 10 healthy women1. The subjects aged 22 to 40 years consumed 280 grams of cherries after an overnight fast in two equal servings. Blood samples were taken at baseline before consumption of the cherries and postprandially at 1.6, 3 and 5 hours. Consumption of the cherries decreased plasma urate levels for 5 hours postprandially from 214 μmol/L to 183 μmol/L. Urinary urate increased postprandially to 350 μmol/L per mmol creatinine from a baseline reading of 202 μmol/L per mmol creatinine. Plasma C-reactive protein, a measure of systemic inflammation decreased significantly postprandially. Therefore cherries are able to cause reductions in the levels of plasma uric acid, probably through increased excretion rates, and also cause a decrease in systemic inflammation, following consumption of two reasonably large intakes. It is likely that the antioxidants in the cherries were responsible for the anti-inflammatory effects seen in the subjects.
The anti-inflammatory effects of the cherries may have been caused by the presence of the anthocyanins, which have been shown to be inhibitors of the cyclooxygenase (COX) enzyme system, a system responsible for contributing to the inflammatory pathway. Interestingly, Although the vitamin C is in the oxidised dehydroascorbate form in cherries, postprandial ascorbic acid levels increase following consumption. Therefore the dehydroascorbate is reduced and contributes to the antioxidant defences of the body. Other studies have also shown the benefits of cherries in plasma urate over longer durations. For example, 10 obese subjects consumed 8 oz per day of tart cherry juice or a placebo for 4 weeks2. Consumption of the tart cherry juice lowered plasma urate levels from baseline in 70 % of the participants, compared to the placebo, despite the fact that plasma urate was not elevated initially. The tart cherry juice also lowered markers for chronic inflammation and serum triglycerides.
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