What are Purines?

Purines are nucleotide bases found in plant and animal cells. Nucleotide bases defined as purines are adenine, guanine, hypoxanthine, and xanthine. These purines in combination with pyramidine nucleotide bases make up important components of the genetic materials, DNA and RNA, and energy molecules such as ATP, GTP and coenzyme A. Therefore, purines are essential constituents of life.

Purine Rich Diet and Gout

In humans, purine metabolism, to be specific catabolism, in the liver produces uric acid. Therefore, purines are among the factors that cause elevated uric acid in the blood. With the consumption of high purine foods, serum uric acid may rise above the normal level. Even though uric acid acts as an antioxidant and has a free-radical scavenging effect, 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 by the 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) per day results in an average increase of 1.5 to 2.0 mg /100 ml.

Food High or Low in Purines

In the following table are estimates of purine content in a variety of food items. Purine rich foods are on the top of the table. 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