Uric acid is a natural waste product. It forms when the body breaks down purines, chemical compounds found in certain foods and also produced naturally by the body. The kidneys play a significant role in managing uric acid levels by filtering it from the blood. This filtering process helps maintain balance, preventing excessive buildup or deficiency.
The Body’s Uric Acid System
Uric acid begins with purines, found in various foods we consume and also synthesized internally by the body. When these purines are broken down, uric acid is produced as a byproduct. Approximately two-thirds of the body’s total uric acid is generated internally, while the remaining one-third comes from dietary sources.
Once formed, uric acid circulates in the blood. The kidneys are the primary organs responsible for maintaining healthy uric acid levels, typically excreting about 70% of the daily produced urate. Within the kidneys, uric acid undergoes filtration, reabsorption, and secretion. This process ensures that excess uric acid is removed from the bloodstream and expelled from the body through urine, helping to keep levels within a normal range.
High Uric Acid and Its Causes
Elevated levels of uric acid in the blood, known as hyperuricemia, occur when there is an imbalance between production and excretion. A healthy uric acid level is under 6.8 milligrams per deciliter (mg/dL). Hyperuricemia can arise from several factors, often in combination.
Dietary choices are a common contributor to high uric acid. Consuming foods rich in purines, such as red meat, organ meats (like liver), certain seafood (including anchovies, sardines, and shellfish), and alcohol (especially beer), can increase uric acid production. Sugary drinks and foods high in fructose can also contribute to elevated uric acid levels by increasing purine release during metabolism.
Reduced excretion by the kidneys is another significant cause, accounting for most cases of hyperuricemia. This occurs if kidneys are not filtering enough uric acid due to impaired kidney function or underlying kidney conditions. Certain medications, such as diuretics, can also hinder the kidneys’ ability to excrete uric acid.
In some instances, the body produces too much uric acid, though this is less common. This overproduction can be due to genetic factors, metabolic conditions, or rapid cell turnover, such as some cancers or their treatments.
How Uric Acid Affects Kidneys
Chronically elevated uric acid levels can harm kidney health. One consequence is kidney stone formation. Uric acid can crystallize in the kidneys, leading to painful stones. These stones can block the flow of urine and cause significant discomfort.
Sustained high uric acid levels are also associated with the development and progression of chronic kidney disease (CKD). While the exact mechanisms are complex, high uric acid can contribute to inflammation and scarring within the kidney tissue, leading to declining kidney function. Hyperuricemia is common in individuals with CKD, increasing as the disease advances.
Gouty nephropathy is a specific type of kidney damage linked to high uric acid. This involves uric acid crystal deposition directly within kidney tissue, particularly in the renal medulla. These deposits can trigger an inflammatory response, potentially leading to chronic inflammation and fibrosis in the kidneys.
Managing and Protecting Kidney Health
Managing uric acid levels is a practical step to protect kidney function. Dietary modifications are a primary approach, limiting foods high in purines such as organ meats, certain seafood, and red meat. Reducing sugary drinks and excessive alcohol can also help lower uric acid.
Staying well-hydrated is beneficial, as drinking plenty of water helps the kidneys flush out uric acid more effectively. Maintaining a healthy body weight through regular exercise can support kidney function and manage uric acid. Excess body fat can contribute to increased uric acid production and decreased excretion.
Medical consultation is advisable for individuals with persistently high uric acid or existing kidney concerns. Healthcare providers may recommend medications to lower uric acid if lifestyle changes are insufficient or if complications like gout or kidney stones are present. Regular check-ups for kidney health, including blood and urine tests, are important to monitor kidney function and address issues early.