Soya is okay for most gout patients, study here shows

Research by Duke-NUS, NUH shows beans not linked to higher risk of disease
By Kash Cheong, The Straits Times, 7 May 2015

GOUT patients and those at risk of the disease can take soya and other beans, according to a major local study.

Researchers from Duke-NUS Graduate Medical School and the National University Hospital (NUH) found that eating such products is not associated with an increased gout risk, although many people, including some doctors, think so. Most gout patients, about 5 per cent of people over 45 here, can eat soya and other beans without fear of increased risk of attacks, they said.

Previously, many doctors and dietitians advised patients, or those at risk, to reduce their soya intake because these items contain purine. Purine-rich foods like seafood and meat are associated with higher levels of uric acid in the blood, which can lead to uric acid crystals depositing around the joints, causing aches and pains.

The belief is so prevalent that up to half of all healthcare professionals advocate it, noted Professor Koh Woon-Puay, quoting a poll by local dietitians.

But the newest study - involving 50,000 Chinese and the largest of its kind in Asia - found that those who ate the most soya products were in fact at lower risk of gout than those who ate the least.

"Soya might in fact have a protective effect but this needs to be further studied," said Dr Teng Gim Gee, a senior consultant at NUH's rheumatology division who was also involved in the study, which is part of the Singapore Chinese Health Study.

The effort began in 1993. Interviewees aged 45 to 74 were recruited and asked about their dietary habits. Researchers followed up with questions on their medical status twice in later years. Out of the 51,114 who followed through, 2,197 developed gout.

The finding confirms six other studies done in places like Japan and Taiwan, which showed that eating soya does not increase uric acid retained in the blood. Scientists have yet to confirm why this is so. But based on a Japanese study, they suspect that it may also increase uric acid excretion, thus cancelling out the effect.

In another surprising finding, the group that consumed the most poultry, such as chicken and duck, had a significantly higher risk of gout - 27 per cent higher - compared with the group that ate the most red meat, with only an 8 per cent higher risk. A possible reason is that most of the red meat consumed by those polled was pork - older Chinese seldom eat beef and lamb, unlike those in the West.

But the finding has to be further studied, said Prof Koh, who is also with the Saw Swee Hock School of Public Health.

Gout patients should substitute some high-purine seafood and meat with soya and other beans for protein, researchers urged. A serving of tofu a day is probably good, said Prof Koh.

Dr Teng said there may be exceptions. "Those who eat these products and consistently get gout pain should avoid it," she cautioned.

Although the study surveyed only Chinese subjects, there was no reason to expect different results in other racial groups, said Prof Koh.

Said gout patient Jin Pei Wen, 49: "It's a relief. At least now I can go back to drinking my favourite soya milk with peace of mind."