Is a Purine-Restricted Diet Still Recommended for Gout?

Gout, an inflammatory arthritis triggered by crystallization of uric acid within the joints, can cause severe pain and swelling during a flare-up. It is characterized by hyperuricemia, which has long been attributed to a disorder in purine metabolism or renal excretion of uric acid and is estimated to affect more than 9 million adults in the United States.

Numerous factors have been associated with increased risk of developing gout, including age, sex, genetics, medical conditions such as diabetes and cardiovascular disease, overweight and obesity, severe illness or surgery, certain medications, as well as alcohol consumption. Although particular foods and dietary patterns have been shown to elevate serum levels of uric acid, recent research suggests genetics may play a more influential role in explaining variances in serum urate levels in comparison to diet.

A 2018 meta-analysis and systematic review, which included 13 years of research and six countries, looked for associations between various foods and beverages and risk of gout and hyperuricemia. High intakes of red meat and seafood were associated with increased risk in adults, as were alcohol consumption and high intakes of fructose and sugar-sweetened beverages.

An inverse association was found with dairy consumption and hyperuricemia, but no association was found between dairy intake and gout risk. The authors speculated that milk's lower purine content, combined with its potential to lower urate concentration, may help to explain its seemingly protective effect. However, other research has indicated that full-fat dairy products do not confer the same benefit, so only the consumption of low-fat dairy has resulted in lower serum urate levels.

Plant-based dietary patterns and those that include a higher intake of vegetables that are rich in purines have been found to have a negative association with gout risk. Despite soy having a moderate to high purine load, a limited amount of evidence has noted a lower risk of hyperuricemia and gout with a higher consumption of soy foods. Similar findings have been reported when evaluating the Dietary Approaches to Stop Hypertension eating plan, also known as the DASH diet, which has been associated with a lower risk of gout or resulted in a significant reduction in serum uric acid.

A number of studies have looked at fructose consumption, often focusing on sugar-sweetened beverages, high fructose corn syrup and fruit juice, and have found an increased risk of gout or hyperuricemia. However, consistent results have not been found when examining fresh fruit intake.

Inconsistent findings also have been noted when examining coffee consumption, which research suggests is attributed to differences in sex. Coffee intake has been associated with decreased uric acid levels in men, but some studies find these levels increased for women.

At this time, research indicates that not all purine-rich foods are created equally. Differences exist in the types of purines found in foods. Plus, other factors such as the cooking method, bioavailability and endogenous production of purines have been shown to influence serum levels.

Medication continues to be a standard treatment for gout, along with lifestyle-management strategies, which also must address other co-morbidities, such as hyperlipidemia, diabetes, hypertension and renal disease, if present. Historically, patients with gout have been encouraged to limit all foods that are high in purines; however, current guidelines from the American College of Rheumatology offer conditional recommendations for limiting purine intake for individuals diagnosed with gout due to a low certainty of evidence. Nutrition interventions also can vary depending on whether an individual is experiencing a flare-up or in remission.

The cornerstone of nutrition management for individuals with gout is a balanced eating plan that limits foods and beverages that are high in added sugars and saturated fat, as recommended in the 2020-2025 Dietary Guidelines for Americans. Eight to 16 cups of fluids are recommended daily, with an emphasis on water. A variety of fruits and vegetables are encouraged; however, vegetables that are moderate sources of purines — such as asparagus, cauliflower, mushrooms and spinach — may need to be limited to one-half cup daily during a gout flare-up. Grains, especially whole grains, are recommended, but due to the higher purine content of oats and wheat bran, limits may be established for these foods, as well. Organ meats are particularly high in purines, as are some types of seafood such as sardines, tuna and scallops, so these foods are generally limited. It is recommended that animal foods, with the exception of eggs and low-fat and nonfat dairy, be limited during an acute flare-up. Regardless of disease activity, the ACR guidelines conditionally recommend limiting alcohol intake.

For individuals with gout, the primary aim of the nutrition intervention is to reduce the uric acid concentration in the blood and help manage weight and comorbid conditions. Lifestyle changes won't cure gout, and medication is generally still needed to help manage this condition, but these dietary modifications may help decrease the frequency of gout flare-ups and damage to the bones and joints.

References:

• FitzGerald JD, Dalbeth N, Mikuls T, et al. 2020 American College of Rheumatology Guideline for the Management of Gout. Arthritis Care Res (Hoboken). 2020;72(6):744-760.
• Academy of Nutrition and Dietetics.Nutrition Care Manual. Musculoskeletal Conditions, Gout, Nutrition Intervention. Accessed August 1, 2023.
• Major TJ, Topless RK, Dalbeth N, Merriman TR. Evaluation of the diet wide contribution to serum urate levels: meta-analysis of population based cohorts. BMJ. 2018;363:k3951. Published 2018 Oct 10.
• Rongrong L, Kang Y, Chunwei L. Dietary factors and risk of gout and hyperuricemia: a meta-analysis and systematic review. Asia Pac J Clin Nutr. 2018; 27(6): 1344-1356.
• Topless RKG, Major TJ, Florez JC, et al. The comparative effect of exposure to various risk factors on the risk of hyperuricaemia: diet has a weak causal effect. Arthritis Res Ther. 2021;23(1):75. Published 2021 Mar 4.
• Jakse B, Jakse B, Pajek M, Pajek J. Uric Acid and Plant-Based Nutrition. Nutrients. 2019;11(8):1736.
• Gohari S, Ghobadi S, Jafari A, Ahangar H, Gohari S, Mahjani M. The effect of dietary approaches to stop hypertension and ketogenic diets intervention on serum uric acid concentration: a systematic review and meta-analysis of randomized controlled trials. Sci Rep. 2023;13(1):10492. Published 2023 Jun 28.