“Enter the Zone” or Is This the Best Diet for Gout?

The Zone Diet & Gout

Dietary modifications can provide significant therapeutic benefit for people with gout, according to the findings of a recent clinical trial.

The trial, published in the  Annals of the Rheumatic Diseases, investigated the effects of specific dietary restrictions in men suffering from gout. Dietary changes included calorie restriction (to 1,600 calories per day), macronutrient modification (40% calories from carbohydrate, 30% from protein, and 30% from fat), replacement of refined carbohydrates (e.g., white flour, white rice) with complex ones (e.g., whole wheat flour, brown rice), and replacement of saturated fats (e.g., dairy fats, meat fat) with mono  and polyunsaturated ones (e.g., macadamia nuts, almonds, peanuts and peanut butter, olive oil, canola oil, and avocados).

Over a 16-week study period, the investigators observed remarkable improvements among the 13 men in the trial. These improvements included weight loss (about 17 pounds per person), a decrease in the frequency of monthly gout attacks (from 2.1 to 0.6), decreased uric acid levels in the blood (minus 17.5 %), decreased total and LDL (“bad”) cholesterol (minus 23%), decreased triglycerides (minus 59.5 %), and insignificantly increased HDL (“good”) cholesterol.

Known as the “disease of kings” because of its association with rich food and drink, gout is a form of arthritis in which uric acid crystals accumulate in a joint, commonly in the big toe, causing inflammation and severe pain. According to the U.S. Food and Drug Administration (FDA) , about 90% of people afflicted with gout are men over 40. Excessive weight gain and obesity in men between the ages of 20 and 40 may increase the risk of gout. About half of those who suffer from gout are overweight, the FDA notes.

But Was It The Zone?

The results of the trial suggest the prescribed diet could decrease the risk and severity of cardiovascular diseases as well as gout. Advocates of the “Zone” diet are likely to greet the new study with enthusiasm, because the trial’s dietary regimen had the same composition of macronutrients (i.e., protein, carbohydrate, and fat) as the popular diet promoted by Barry Sears, PhD, in his book, Enter the Zone. Such enthusiasm may be premature, however, since the improvements observed in this trial may be better explained by other aspects of the dietary regimen used in the trial.

The authors concluded from their results that weight reduction resulting from a change in the proportional intake of macronutrients (i.e., the 40/30/30 scheme) was associated with the benefits observed in the trial. However, several dietary measures used in this trial have independently produced the same therapeutic benefits without being associated with a 40/30/30 dietary regimen.

• Weight loss: Short-term calorie restriction alone, using a variety of macronutrient proportions, consistently results in weight loss.
• Uric Acid: Decreasing uric acid levels in people with gout is the primary means of alleviating attacks.⁴ However, there is no evidence that the macronutrient proportions used in this trial (40/30/30) caused the observed reduction in uric acid. The men in this trial were obese. Obese people are at increased risk of gout, and obesity contributes to elevated uric acid levels.  Weight loss alone has reduced uric acid levels in previous trials, and can at least partially explain the reductions observed here. The authors note that one patient had improved symptoms, but was unable to lose weight, suggesting that weight loss was not the only factor mediating a therapeutic response. While this may be true, it in no way proves that the factor responsible was the 40/30/30 proportions.
• Cholesterol profile: Improvements in blood cholesterol and triglyceride levels may be explained by the high amounts of nuts and fish recommended in the trial. Research consistently shows that people who frequently eat nuts have a dramatically reduced risk of heart disease,^9 10 in part because nut consumption lowers cholesterol levels.¹¹ Almonds, which were recommended in this trial, are especially effective at lowering cholesterol.^12 13 Eating fish has been reported to increase HDL cholesterol¹⁴ and is linked to a reduced risk of heart disease in most,^15 16 but not all, studies.

All Carbs Are Not Created Equal

The authors of this trial fail to convey that the type of carbohydrate eaten is probably more important than the total amount of carbohydrate eaten. Eating foods high in refined carbohydrates promotes a more rapid return of hunger and increases subsequent intake of calories compared to eating similar foods that are higher in complex carbohydrates.

Moreover, successful weight-loss programs can be based on a diet that provides a higher percentage of total calories from carbohydrate than used in this trial. For example, a recent clinical trial demonstrated significant weight loss from a diet providing 58% calories from carbohydrate, 22% calories from fat, and 20% calories from protein. Thus, the shift from refined to complex carbohydrates in the present trial, rather than the decrease in carbohydrate, may well be responsible for the weight loss and concomitant reduction in gout symptoms that were observed.

It is likely that weight loss, avoidance of alcohol, and consumption of nuts and fish accounted for much of the reduction in symptoms of gout observed in this trial. Nevertheless, it is of interest that the dietary regimen was high in protein and yet was not associated with a worsening of symptoms. Ordinarily, people with gout are advised to avoid protein-rich foods, such as mackerel, sardines, chicken, and turkey, since these foods are sources of purines— compounds known to raise uric acid levels in the body.

The fact that fish intake was associated with a reduction in symptoms in this trial, and that fish are known to positively affect many other risk factors for gout, opens the door to the possibility that fish might not be the foe of gout patients, despite their high purine content. Larger, controlled trials are needed to validate the impressive results achieved with the Zone-like diet used in this trial and to determine which elements of the diet were responsible for the therapeutic effects. Until those results are in, current dietary recommendations for gout sufferers remain valid: eat a low-purine diet, avoid alcohol, and reduce obesity by exercising regularly and eating a diet low in saturated fats.