Soy and gout

Gout or inflammatory arthritis is affecting more than 3 million people in the United States. Gout is a disease created by a build-up of uric acid in the body fluids. The elevated level of uric acid results in the deposition of monosodium urate or uric acid crystals on the articular cartilage of joints, tendons and surrounding tissues. These crystals provoke an inflammatory reaction of these tissues. All cells contain purines, which are building blocks for RNA and DNA. During digestion the purines are converted into uric acid which is secreted by our kidneys and our gut. Defects in the functioning of the kidney that may be genetically determined are responsible for the predisposition of individuals for developing gout. Individuals with increased risk of gout should limit the intake of purine-rich food such as meat and seafood. Soy is considered as a food rich in purines and often considered less suitable for individuals with gout. But is soy really that bad for gout sufferers?

Studies about soy and gout

A Japanese study by Yamakita and co-workers of Hyogo College of Medicine concluded that tofu is a safe source of protein for gout patients due to its small and transient effect on plasma urate levels. They found that the intake of tofu by normal individuals only slightly increased the plasma level but no such significant rise was observed in gout patients (1). Another study by Hyon K and co-workers found that a moderate intake of purine rich vegetables is not associated with increased risk of gout. This was a large scale study involving more than 45.000 men over a period of 12 years. Higher intake of meat and seafood consumption showed and increased risk of gout, whereas a high intake of dairy products was linked with a decreased risk. The consumption of purine-rich vegetables or individual purine-rich vegetables was not associated with the risk of gout. Protein rich foods tend to contain higher levels of purines but the proteins seems to lower the serum uric level, especially vegetable protein (2).

(1) Yamakita J, Yamamoto T, Moriwaki Y, Takahashi S, Tsutsumi Z, Higashino K. Effect of Tofu (bean curd) ingestion and on uric acid metabolism in healthy and gouty subjects. Adv Exp Med Biol. 1998;431:839-42.
(2) Choi HK, Atkinson K, Karlson EW, Willett W, Curhan G. Purine-rich foods, dairy and protein intake, and the risk of gout in men. N Engl J Med. 2004 Mar 11;350(11):1093-103.