The Impact of Dietary Interventions on Hyperuricemia and Gout
Prior to these recent prospective studies, patients were advised on a relatively unpalatable low-purine, low-protein and alcohol-restricted diet. When compliant, this type of diet is expected to decrease serum uric acid by ~15% (~1-2 mg/dl or 60-120 µmol/l) at a maximum. With the strong association between gout and insulin resistance and less with the amount of total daily protein intake, however, the dietary recommendation has shifted to focus more on weight reduction, with moderate carbohydrate restriction and an increased proportion of protein and unsaturated fats. Foods that are low in purine tend to be higher in carbohydrates, which can increase further insulin resistance. Diets high in monounsaturated fats and low in carbohydrates have been shown to improve insulin sensitivity and lower postprandial glucose, plasma insulin and fasting triglycerides.
A recent small, open-labeled study was conducted to evaluate the impact of low-carbohydrate, calorie-restricted diets, generous in monounsaturated fats, tailored for insulin resistance on the level of serum uric acid and the frequency of gout attacks. Thirteen patients with gout were placed on a 1600 kcal per day diet, comprising 40% carbohydrates, 30% protein and 30% fat, for 16 weeks ( Table 1 ). Participants noted an average of 17 lb weight loss and 17% decrease in serum uric acid (1.67 mg/dl or ~100 µmol/l) without a flare of gout during the study period. Although promising, with improved lipid profile and lowered number of gout attacks, the extent of hyperuricemia achieved with this diet approximated that reached with the traditional low-purine diet. Therefore, the effectiveness of a low-carbohydrate diet still needs evaluation in a randomized, controlled trial.
A growing public interest in weight-loss programs exists. Americans spend more than $33 billion a year on weigh-loss-related products, with up to 44% of women and 29% of men being on some diet at any given time. Forms of the latest popular diet programs include high-protein/high-fat/low-carbohydrate diets, such as Atkins™, South Beach™ and Zone™. In contrast to the American Heart Association's (AHA) recommendation of a diet to be composed of 50-60% carbohydrates, less than 30% fat and 12-18% protein of total daily caloric intake, the unmodified Atkins diet is composed of 5% carbohydrates, 60% fat and 35% protein[43,44] ( Table 1 ). Several considerations regarding the potential effects of these diets on gout exist. These diets encourage patients to take in foods that are rich in purine, such as meat and seafood, which have been associated with a higher risk of gout. Moreover, these diets are high in fat and can induce ketosis and subsequent hyperuricemia, as described above. Interestingly, even the official Atkins website (www.atkins.com) cautions patients about the potential flares of gout with the diet. Unfortunately, to date, there are no controlled studies on the impact of these ketogenic diets on serum uric acid levels and frequency of gout flares. A major question is whether reduction in BMI by such diets outweighs the theoretical risk of induced ketosis in worsening hyperuricemia. In theory, weight-reduction diets that induce less ketosis would be preferred by the practitioner in gout patients, but patient preference and acceptance are critical factors in dietary weight-loss programs.
Curr Opin Rheumatol. 2006;18(2):193-198. © 2006 Lippincott Williams & Wilkins
Cite this: Recent Developments in Diet and Gout - Medscape - Mar 01, 2006.