What Are Purines?

Purines are nucleotide bases found in any plant and animal cells. Purines include adenine, guanine, hypoxanthine, and xanthine. Purines, in combination with pyramidines, constitute the genetic codes, DNA and RNA, and energy molecules such as ATP, GTP and coenzyme A. Needless to say, purine molecules are essential constituents of life.

How Purine Rich Diet Causes Gout

In humans, purine metabolism, to be specific catabolism, in the liver produces uric acid. Breakdown of purines is among the factors that causes elevated uric acid in the blood. Therefore, with consumption of high purine foods uric acid in the body may rise above the normal level.

Even though uric acid acts as an antioxidant and has beneficial effects, such as as a free-radical scavenger, when it accumulates to a high level in the blood it may cause gout and other health problems.

Gout is a form of arthritis caused due to accumulation of uric acid crystals in joints, especially in the big toe.

In a 12-year study that followed eating habits and gout incidence in large number of men it was found that eating food rich in purine, such as meat and seafood, was associated with high risk of gout, whereas a higher level of consumption of dairy products was associated with a reduced risk. Moderate intake of purine-rich vegetables or protein was not associated with an elevated risk of gout.

According to some studies, a purine-free diet reduces blood uric acid level, on average, from 1.0 to 1.2 mg/100 ml while consumption of 4 g of ribonucleic acid (RNA), purine,  per day results in an average increase of 1.5 to 2.0 mg /100 ml.

Foods High or Low in Purines

In the following table are estimates of purine content in a variety of food items, presented in descending order. Meat and meat products appear to have high total purine content, where as cereal foods contain low purine content. Generally, there seems to exist a positive association between protein and purine content in diet.

Table 1: High or low purine food sources.