Sufferers of gout might soon be advised to add sugary drinks to the list of foods that can cause the painful and crippling affliction to flare up, according to a New Zealand study released Thursday.

Red meat, seafood and beer are already known to trigger high levels of uric acid that cause the arthritic ailment, but scientists at the universities of Otago and Auckland have also discovered a human gene variant that can "turn bad" when affected by sugary drinks.

The study showed that when the variant of the gene SLC2A9 behaved correctly, it helped transport uric acid out of the blood stream and facilitated its excretion through the kidney.

"But when people with this gene variant consume sugary drinks, it takes on Jekyll and Hyde characteristics; the apparent function of the gene variant reverses, such that we think uric acid is instead transported back into the blood stream and the risk of gout is increased," Associate Professor Tony Merriman, of Otago's Department of Biochemistry, said in a statement.

"So not only does sugar raise uric acid in the blood due to processing in the liver, but it also appears to directly interfere with excretion of uric acid from the kidney. This was a quite unpredictable interaction," he said.

"Each daily 300-milliliter serving of sugar-sweetened drink increases the chance of gout by 13 percent."

As a result of the research, he recommended that in addition to taking prescribed medicines, people with gout should avoid sugary drinks.

Gout is caused when uric acid in the blood crystallizes in the joints, causing them to become inflamed. It is the most common form of arthritis in New Zealand, particularly among men, and has strong links with other metabolic diseases such as diabetes, heart and kidney disease.

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