Überschüssige Harnsäure im Körper – Ursachen und Behandlungsmöglichkeiten

Uric acid is primarily synthesized in the liver, but it is also produced in muscles, kidneys, and blood vessels. It represents the final product of purine metabolism, which is mainly derived from animal-based foods, particularly meat. Purines are components of the nitrogenous bases guanine and adenine, essential for DNA and RNA formation. Additionally, uric acid is generated endogenously as purines are released during cellular turnover. It functions as an antioxidant, and research by R. El Ridi and colleagues suggests it may play a role in preventing multiple sclerosis, supported by a meta-analysis by L. Wang and colleagues, which found lower uric acid levels in affected individuals compared to healthy controls. However, excessive uric acid can have adverse effects, necessitating maintenance within the reference range of 180–420 µmol/l (3–7 mg/dl).

Uric acid is the final product of purine metabolism and cannot be further metabolized in humans due to the absence of the uricase enzyme, which converts it into more soluble allantoin in other mammals. When its production is excessive or renal excretion is impaired, uric acid crystallizes in tissues, potentially leading to gout. However, elevated uric acid levels do not always manifest clinically. Causes of hyperuricemia include a diet rich in purines and fructose, excessive alcohol consumption, malignancies, renal dysfunction, and genetic predisposition. Research indicates that even asymptomatic hyperuricemia may increase the risk of cardiovascular diseases. In patients with cardiovascular conditions, the threshold for uric acid levels may be lower than the standard 7 mg/dl. Studies by A.G. Ioachimescu and colleagues demonstrated that each 1 mg/dl increase in uric acid levels was associated with a 39% higher mortality risk in high-risk cardiovascular patients. Given these potential hazards, healthy individuals should regularly monitor their uric acid levels, especially if they have diabetes, lipid disorders, or kidney diseases.

For patients with cardiovascular risk, as recommended by C. Borghi et al., uric acid levels should be maintained below 6 mg/dl (or below 5 mg/dl for those at very high risk). Experts have developed comprehensive guidelines in the form of a five-step ladder that outlines the stages for normalizing this parameter. The initial approach involves adopting a healthy lifestyle, including a diet that prevents excessive uric acid production. Pharmacological treatment may be considered for at-risk patients, though the decision remains with the physician. Regardless of medication, a well-balanced diet remains a safe method for regulating uric acid levels, though its effectiveness may vary across cases.

What lifestyle adjustments are necessary to prevent hyperuricemia? 1) Consistent physical activity is crucial. According to World Health Organization guidelines, adults should engage in at least 150 minutes of moderate-intensity exercise per week. 2) Excessive fructose intake should be significantly reduced. In liver cells, fructose increases phosphorus consumption for phosphorylation, leading to a decrease in intracellular phosphorus levels. This activates metabolic processes that produce uric acid, which then enters the bloodstream. Therefore, sources of simple sugars such as sweetened beverages, high-fructose corn syrup (HFCS), or sucrose should be eliminated from the diet. Regular consumption of fruit juices is also not recommended. However, consuming fruit in recommended amounts (approximately 4 servings per day) does not negatively impact uric acid levels, as confirmed by a meta-analysis by S. Ayoub-Charette and colleagues. 3) It is necessary to limit the intake of foods that elevate uric acid levels. As studies by R. Li and colleagues indicate, red meats (pork, beef, lamb, game), seafood, and alcohol should be avoided. Additionally, due to high purine content, the consumption of meat broths, sardines, herrings, cocoa products, and pickles should be restricted. Hyperuricemia is a risk factor for cardiovascular diseases, so the diet should be heart-friendly. The DASH diet is recommended, which is based on whole grains, coarse cereals, dairy products, fruits, and vegetables. This diet also includes fish, poultry, nuts, and seeds. Saturated fats should be minimized and replaced with unsaturated fatty acids. It is advised to avoid fatty meats, cheeses, offal, lard, coconut oil, and instead prefer plant-based oils such as flaxseed, rapeseed, or olive oil.

Complex carbohydrates: 6–8 servings per day, adjusted to individual needs. Opt for whole-grain products such as whole-grain bread, whole-grain pasta, oatmeal, brown rice, and buckwheat. Vegetables and fruits: 4–5 servings daily, with a 3:1 ratio favoring vegetables, totaling at least 500 g per day. Dairy products: 2–3 servings daily, preferably yogurt, milk, cottage cheese, or other cheeses (moderate fat content). Nuts, seeds, and legumes: 4–5 servings per week. Plant-based fats in raw form: daily. Lean meat and fish: 3–4 servings per week.