What foods are high in purines, is a common question from gout sufferers. If you want a simple answer, you should see my list of Purine Rich Foods.
In this part of the gout diet research guidelines, I review the main study into gout and high purine foods. As it is a big study, I have broken it down to separate parts. This article reviews the methods part of the High Purine Foods study. That link summarizes the report and introduces the study: Purine-Rich Foods, Dairy and Protein Intake, and the Risk of Gout in Men.
What Foods Are High In Purines? Study Methods
What Foods Are High In Purines? Study Population
The study involved health professionals aged from 40 to 75 in 1986. 49,932 men provided complete dietary, medical history, and medication information. 2782 (5.6 percent) were excluded as they had gout at the beginning, leaving 47,150 participants.
What Foods Are High In Purines? Assessment of Diet
Diets were assessed by reference to intakes of a preprepared list of over 130 food and drink items, updated twice during the course of the study. Full details of these food and drink lists are in separate studies.10-12
What Foods Are High In Purines? Assessment of Covariates
In order to get the best view of the affect of purines on the incidence of gout, it is usual in this type of statistical study to collect data on other factors. This is done to test if the trends shown in the results of the study are due to purines, or some other, confounding, factor. For this study, the authors also collected data on weight, regular medications, and medical conditions.
Ascertainment of New Cases of Gout
Where men reported new cases of gout, they were sent an additional questionnaire to validate their diagnosis of gout against criteria published by the American College of Rheumatology. Gout is considered confirmed if 6 or more from the 11 characteristics are positive:13
- More than one attack of acute arthritis
- Maximum inflammation developing within one day
- Gout attack in four joints or fewer (oligoarthritis)
- Redness observed over joints
- Painful or swollen first big toe joint
- Only one first big toe joint affected
- Only one foot affected
- Presence of one or more tophi (singular tophus)
- Hyperuricemia: Uric acid from blood test results higher than 7mg/dL (0.42 mg/dL)
- Asymmetric swelling within a joint
- Complete termination of an attack
The report describes various other procedures used to be as certain as possible that the reported cases were indeed gout.
What Foods Are High In Purines? Statistical Analysis
There are explanations of statistical techniques used that are beyond the scope of this summary14-16. I will confine the summary to describing the types of food included in the survey.
Food items were combined into groups to compute average daily intakes. The food groups used were:
- Total meat
- Beef, pork, or lamb; processed meat, including sausage, salami, and bologna; bacon; hot dogs; hamburgers; poultry, including chicken and turkey; chicken liver; and beef liver
- Total seafood
- Tuna; dark fish; other fish; and shrimp, lobster, or scallops
- Vegetables high in purines
- Peas, beans, lentils, spinach, mushrooms, oatmeal, and cauliflower
- Dairy products
- Low-fat dairy products, including skim or low-fat milk, sherbet, low-fat yogurt, and cottage or ricotta cheese; high-fat dairy products, including whole milk, cream, butter, sour cream, ice cream, cream cheese, and other cheeses
Each food group was categorized into quintiles – a statistical process where results are ranked in order of average daily intake, and then divided into 5 groups. Statistical adjustments were applied to take account of potentially confounding variables:
- Energy intake
- The percentages of energy derived from fat and specific types of protein
- Age (as a continuous variable)
- Alcohol use (in seven categories)
- Body-mass index (the weight in kilograms divided by the square of the height in meters, in six categories)
- The use or not of diuretics
- History of hypertension (yes or no)
- History of chronic kidney failure (yes or no)
- Fluid intake (in quintiles)
What Foods Are High In Purines? Next Steps
The methods for this gout study give a good indication of what foods are high in purines. However, the results will show that not all purines are equal. You can see the Purine Rich Foods To Avoid With Gout Results, or return to the High Purine Foods introduction.
What Foods Are High In Purines? References
- Rimm EB, Giovannucci EL, Stampfer MJ, Colditz GA, Litin LB, Willett WC. Reproducibility and validity of an expanded self-administered semiquantitative food frequency questionnaire among male health professionals. Am J Epidemiol 1992;135:1114-1126
- Willett WC, Sampson L, Stampfer MJ, et al. Reproducibility and validity of a semiquantitative food frequency questionnaire. Am J Epidemiol 1985;122:51-65
- Feskanich D, Rimm EB, Giovannucci EL, et al. Reproducibility and validity of food intake measurements from a semiquantitative food frequency questionnaire. J Am Diet Assoc 1993;93:790-796
- Wallace SL, Robinson H, Masi AT, Decker JL, McCarty DJ, Yu TF. Preliminary criteria for the classification of the acute arthritis of primary gout. Arthritis Rheum 1977;20:895-900
- Hu FB, Stampfer MJ, Manson JE, et al. Dietary fat intake and the risk of coronary heart disease in women. N Engl J Med 1997;337:1491-1499
- Hu FB, Stampfer MJ, Manson JE, et al. Dietary protein and risk of ischemic heart disease in women. Am J Clin Nutr 1999;70:221-227
- Willett W. Nutritional epidemiology. 2nd ed. New York: Oxford University Press, 1998.