As early as hundreds of years ago, traditional Chinese medical theory has been elaborated on the etiology of gout. Zhu Danxi, a Yuan Dynasty medical scientist, described the dialectic of gout: “The majority of the blood has been boiling since the heat, followed by cold and cold outside the fight, the hot blood gets cold, sweat and stagnation, so the pain is made, and at night the pain is even, and the line is also in the Yang”. People also recognized early that gout is related to diet, and the Ming dynasty physician Zhang Jinyue pointed out that “gout is caused by excessive fat and sweetness in the body, and dampness congests the lower jiao; the cold and dampness are combined to turn into heat and stay in the skin”. These statements about gout show that the ancient traditional medicine in China has long had a simple and profound understanding of the causes of gout. The development of modern medical research has also confirmed that the occurrence of hyperuricemia and gout is closely related to daily diet. The root cause of hyperuricemia and gout is the disorder of uric acid metabolism in the body, and the excessive accumulation of uric acid in the body and then deposited in the joints leads to gout, and the reason for the high level of uric acid in the circulation of most patients with hyperuricemia and gout is closely related to their dietary habits.
In recent years, with the development of China’s economy and the improvement of people’s living standards, the number of patients with gout and hyperuricemia is increasing, most of them are men, and there is a trend of younger age of onset. In fact, strictly speaking, high purine diet is only a trigger for gout attack, but not the root cause of gout, the essence of gout or purine metabolism disorder. Gout is a metabolic disease caused by a disorder of purine metabolism in the body, resulting in high levels of uric acid. An adult man will produce about 1000mg of uric acid in his body every day, which is absorbed by the distal tubules of the kidneys and then excreted out of the body. Gout patients end up with elevated uric acid levels due to various factors, and the distal tubules of the kidneys cannot fully absorb the uric acid produced in the body, resulting in the accumulation of uric acid in the circulation, which eventually exceeds the blood dissolution saturation and leads to the precipitation of urate crystals, forming urate crystals that flow around with the blood, thus possibly causing damage to the circulatory system. Since these uric acid crystals cannot be excreted in a timely manner, once too many urate crystals are precipitated and deposited in the tissues, especially in the joints, gout results.
An important part of the prevention and treatment of gout and hyperuricemia is to strengthen health education and dietary guidance for patients. What can and cannot be eaten? What should I pay attention to in my diet? Therefore, reasonable dietary guidance is particularly important. We introduce the following non-pharmaceutical interventions for patients with hyperuricemia and gout, such as diet and exercise.
I. Non-pharmacological interventions for hyperuricemia
Non-pharmacological interventions include lifestyle modification and medical nutrition interventions. Medical nutrition intervention refers to special interventions for patients’ diet and nutrition under clinical conditions, including individualized diet and nutrition assessment and diagnosis, formulation of corresponding nutrition intervention plans and implementation and monitoring within a certain period of time, which is an important part of metabolic disease prevention, treatment, self-management and health education. Both patients with hyperuricemia and gout need to receive individualized medical nutrition intervention, which should be based on the assessment of patients’ nutritional status and dietary structure, setting reasonable goals, and achieving good metabolic control of patients through a reasonable and scientific diet plan.
1.Lifestyle adjustment
The 2012 European Guidelines for the Prevention and Treatment of Gout and Uric Acid emphasize that lifestyle changes are the core of the treatment of HUA, including healthy diet, smoking cessation and alcohol restriction, weight control and adherence to exercise. Lifestyle changes are also beneficial to the management of concomitant diseases such as obesity, diabetes, lipid metabolism disorders and hypertension.
(1) Healthy diet. Patients with pre-existing hyperuricemia or metabolic cardiovascular risk factors and middle-aged and elderly patients should have a diet that is low in purine (Table 1). Strictly control the intake of high purine foods such as meat, seafood and animal offal, and try to focus on low purine foods. In the acute stage of gout, moderate purine foods should be restricted and the intake of high purine foods should be prohibited.
(2) Drink more water, quit smoking and limit alcohol. Drink more than 1500ml of water a day, preferably 2000ml. advocate quitting smoking, ban beer and white wine. Red wine is appropriate in moderation daily.
(3) Insist on exercise and weight control. Encourage and advocate moderate intensity exercise such as brisk walking for 30 min or more after appropriate rest after three meals. Obese or overweight patients should pay attention to weight control so that the body mass index is in the normal range (BMI<24kg/m2).
2. Active treatment of metabolic risk factors associated with elevated blood uric acid
The 2012 European guidelines for the prevention and treatment of gout and uric acid emphasize that active control of cardiovascular risk factors associated with hyperuricemia such as hyperlipidemia, hypertension, hyperglycemia, obesity and smoking should be an important part of the treatment of patients with hyperuricemia. Metformin, statin lipid-lowering drugs, fenofibrate and other glucose-lipid-lowering drugs have the effect of reducing uric acid to varying degrees at the same time, and should be used appropriately according to the patient’s condition.
3.Avoid the application of drugs that make blood uric acid rise
HUA patients should try to avoid the use of drugs that elevate blood uric acid, such as niacin, nicotine, cyclophilin, tacrolimus, pyrazinamide, thiazide diuretics, etc. For patients who need to take enteric aspirin for a long time and combined with HUA, you can use drugs to promote uric acid excretion or alkalize urine, drink more water and keep the daily urine volume above 2000ml to facilitate uric acid excretion.
Non-pharmacological treatment recommendations for gout patients
(a) The goals of non-pharmacological treatment.
1. Maintain reasonable body weight: the goal of weight control for overweight or obese patients is to lose 5%~10% of the basal body weight in 3~6 months. Ideal weight: BW (kg) = height (cm) – 105.
2. provide a nutritionally balanced diet.
3.Reducing circulating uric acid concentration to reach and maintain the ideal level.
4.Reducing the risk factors of cardiovascular diseases, including the control of blood lipids, blood sugar and blood pressure.
(II) Three major nutrients
1.Fat
Gout patients advocate low-fat and low-cholesterol diet, the energy provided by fat in the diet should not exceed 30% of the total dietary energy, and minimize the intake of saturated fatty acids and trans fatty acids. Monounsaturated fatty acids are a better source of dietary fat, and the proportion of total fat function should reach 10-20%, and patients are advised to increase the intake of n-3 fatty acids appropriately. Daily cholesterol intake in food should not exceed 300mg.
2.Carbohydrate
Carbohydrates in the diet should account for 50-60% of the total energy is preferable, and try to distribute three meals evenly every day.
3.Protein
For individuals with normal renal function, protein is recommended to account for 10-15% of total energy supply. Once patients have gouty nephropathy, those with dominant proteinuria advocate high quality low protein, and protein intake is controlled at 0.8g/kg/d.
(iii) Dietary fiber
Legumes, fiber-rich cereals, fruits and vegetables, and whole grains are good sources of dietary fiber, and improving dietary fiber intake is beneficial to health.
(iv) Low purine food
A low purine diet is advocated for gout patients. Generally, foods are divided into three categories according to the amount of purine content per unit weight of food (generally mg/100g), i.e. high, medium and low purine foods. Purine content <50mg/100g is low purine food, which is suitable for patients with hyperuricemia and gout; purine content ≥50mg/100g but <150mg/100g is defined as medium purine food, which is prohibited for patients with acute attack of gout, and can be considered for moderate consumption during remission but with attention to quantity control; purine content ≥150mg/100g is high purine food. It is prohibited for patients with hyperuricemia or gout. The purine content of three common food groups is shown in Table 1.
(V) Salt
The intake of salt (sodium chloride) should be limited to 6g per day, and the intake of salt should be strictly limited in patients with hypertension. Avoid foods with high sodium content, such as soy sauce, squash, monosodium glutamate and seasoning sauce.
(F) Smoking
Quit smoking
(vii) Alcohol
Minimal consumption of alcohol or alcoholic beverages, especially beer, is advocated. Alcohol should be strictly forbidden during the attack or progression period.
III. Exercise for HUA and gout patients
HUA patients advocate appropriate exercise, recommend moderate exercise, can be slightly rested after each meal can be moderate intensity exercise such as brisk walking 30min and above. At present, there is a lot of information to confirm that after strenuous or long time muscle activity, patients present HUA, in this case is not conducive to the improvement of the patient’s gout condition, but also may induce gouty arthritis, so HUA patients should avoid strenuous exercise and long time physical activity.
It is generally not advocated for gout patients to take part in strenuous sports or long-time physical work, such as playing ball, jumping, running, climbing, long-distance walking, traveling, etc.. These strenuous exercises can lead to increased sweating, reduced blood volume and renal blood flow, reduced excretion of uric acid and creatine, and transient hyperuricemia in gout patients. In addition, the increase of lactic acid in the body after strenuous exercise will inhibit the renal tubular excretion of uric acid, which can temporarily increase blood uric acid and aggravate gout. As for the acute phase of gouty arthritis patients need to brake, should not get out of bed activities, to avoid weight-bearing caused by arthritis aggravation.