Wellington: Researchers from University of Otago have for the first time found a biological basis for the belief that eating tomatoes can cause gout to flare up in some people.

Gout is a painful and debilitating form of arthritis that affects approximately three times more men than women.

Once a person has gout - higher levels of uric acid in the blood - eating certain foods can cause their gout to flare up in a painful attack.

‘We found that the positive association between eating tomato and uric acid levels was on a par with that of consuming seafood, red meat, alcohol or sugar-sweetened drinks,’ explained PhD student Tanya Flynn and lead researchers.

Researchers noticed that a large number of gout sufferers believe tomatoes to be one of these gout trigger foods.

The researchers surveyed 2,051 New Zealanders with clinically-verified gout. Of these people 71% reported having one or more food triggers. Tomatoes were listed as a trigger in 20% of these cases.

Tomatoes were found to be the fourth most commonly mentioned trigger, after seafood, alcohol and red meat.

After determining tomatoes are a commonly cited trigger food, the authors analysed data from 12,720 male and female members of three long-running US health studies.

The results showed that tomato consumption is linked to higher levels of uric acid in the blood.

Tomatoes can alter uric acid levels to a degree comparable to other commonly accepted gout trigger foods.

Flynn emphasised that the most important thing that people with gout can do to prevent attacks is take a uric acid-lowering drug.

‘Avoiding tomatoes may be helpful for people who have experienced a gout attack after eating them, but with proper treatment this doesn't have to be a long-term avoidance,’ she noted in a paper published in the international journal BMC Musculoskeletal Disorders.