Uric acid forms when purines break down in the body. Purines come from certain foods such as organ meats, asparagus, spinach, lentils, beer or wine as well as from the breakdown of proteins in the body. Higher than normal uric acid levels can cause gout, an inflammatory arthritis in the large joints, kidney stones Uric acid levels can vary widely from day to day.
Adult men normally have uric acid levels between 2 and 7.5 mg/dL, while adult women normally have levels between 2 and 6.5 mg/dL. Boys between the ages of 10 and 18 have levels of 3.6 to 5.5 mg/dL and girls levels fall between 3.6 and 4 mg/dL. In men older than age 40, levels range between 2 to 8.5 mg/dL and in women older than 40, between 2 and 8 mg/dL, according to RnCeus.com. Women's levels rise after menopause.
Causes of High Levels
High levels of uric acid can occur from a number of causes. Both overproduction of uric acid or decreased excretion through the kidney or stool can cause higher than normal uric acid levels. The kidneys excrete two-thirds of excess uric acid, while one-third passes through the stools, RnCeus.com states. Excess alcohol consumption, use of diuretics, diabetes, lead poisoning, kidney disease, cancer, toxemia of pregnancy or high purine intake can cause high uric acid levels. Some people have a family tendency toward high uric acid levels. Many drugs, including aspirin, caffeine, theophylline or phenothiazides can causes elevated levels.
Causes of Low Levels
Low levels of uric acid are less common than high levels and usually not serious. Diseases such as Fanconi syndrome, syndrome of inappropriate diuretic hormone secretion, also called SIADH, or liver diseases such as Wilson’s disease can cause low uric acid levels. Low purine intake can also cause low uric acid levels. Some drugs, such as allopurinol, used to treat gout, corticosteroids, estrogen, glucose and warfarin can also lower serum uric acid levels. Pregnant women may experience a temporary fall in uric acid levels by around 33 percent, but levels return to normal by the end of pregnancy.
High uric acid levels don’t always result in symptoms. If uric acid crystals accumulate in large joints, most often the big toe, they cause pain, redness and swelling called gout. Decreasing purine intake in the diet to 100 to 150 mg per day by reducing high-purine foods can reduce the risk of developing gout and kidney stones from high uric acid levels. Food that contain purine levels of more than 100 mg include all organ meats, anchovies, bacon, goose, veal, venison and fish such as haddock, codfish, mackerel and herring.