Many factors contribute to hyperuricemia, including
diet, use of
loop diuretics), and consumption of excess
 Of these, alcohol consumption is the most important.
Causes of hyperuricemia can be classified into three functional types:
 increased production of uric acid, decreased excretion of uric acid, and mixed type. Causes of increased production include high levels of
purine in the diet and increased
purine metabolism. Causes of decreased excretion include kidney disease, certain drugs, and competition for excretion between uric acid and other molecules. Mixed causes include high levels of alcohol and/or
fructose in the diet, and starvation.
Increased production of uric acid
A purine-rich diet is a common but minor cause of hyperuricemia. Diet alone generally is not sufficient to cause hyperuricemia. Purine content of foods varies (see
Gout). Foods high in the purines
hypoxanthine may be more potent in exacerbating hyperuricemia.
Hyperuricemia of this type is a common complication of
solid organ transplant.
 Apart from normal variation (with a genetic component),
tumor lysis syndrome produces extreme levels of uric acid, mainly leading to renal failure. The
Lesch-Nyhan syndrome is also associated with extremely high levels of uric acid.
Decreased excretion of uric acid
The principal drugs that contribute to hyperuricemia by decreased excretion are the primary
antiuricosurics. Other drugs and agents include
ciclosporin, 2-ethylamino-1,3,4-thiadiazole, and
SLC2A9 encodes a protein that helps to transport uric acid in the kidney. Several
single nucleotide polymorphisms of this gene are known to have a significant correlation with blood uric acid.
 Hyperuricemia cosegregating with
osteogenesis imperfecta has been shown to be associated with a mutation in
ketogenic diet impairs the ability of the kidney to excrete uric acid, due to competition for transport between uric acid and
lead is significantly correlated with both impaired kidney function and hyperuricemia (although the causal relationship among these correlations is not known). In a study of over 2500 people resident in Taiwan, a
blood lead level exceeding 7.5 microg/dL (a small elevation) had
odds ratios of 1.92 (95% CI: 1.18-3.10) for renal dysfunction and 2.72 (95% CI: 1.64-4.52) for hyperuricemia.
Causes of hyperuricemia that are of mixed type have a dual action, both increasing production and decreasing excretion of uric acid.
High intake of alcohol (
ethanol), a significant cause of hyperuricemia, has a dual action that is compounded by multiple mechanisms. Ethanol increases production of uric acid by increasing production of
lactic acid, hence
lactic acidosis. Ethanol also increases the plasma concentrations of hypoxanthine and xanthine via the acceleration of adenine nucleotide degradation, and is a possible weak inhibitor of xanthine dehydrogenase. As a byproduct of its fermentation process,
beer additionally contributes purines. Ethanol decreases excretion of uric acid by promoting
dehydration and (rarely) clinical
High dietary intake of
fructose contributes significantly to hyperuricemia.
 In a large study in the United States, consumption of four or more sugar-sweetened
soft drinks per day gave an odds ratio of 1.82 for hyperuricemia.
 Increased production of uric acid is the result of interference, by a product of fructose metabolism, in purine metabolism. This interference has a dual action, both increasing the conversion of
inosine and hence uric acid and increasing the synthesis of purine.
 Fructose also inhibits the excretion of uric acid, apparently by competing with uric acid for access to the transport protein SLC2A9.
 The effect of fructose in reducing excretion of uric acid is increased in people with a hereditary (genetic) predisposition toward hyperuricemia and/or gout.
Starvation causes the body to metabolize its own (purine-rich) tissues for energy. Thus, like a high purine diet, starvation increases the amount of purine converted to uric acid. A
very low calorie diet without
carbohydrate can induce extreme hyperuricemia; including some carbohydrate (and reducing the protein) reduces the level of hyperuricemia.
 Starvation also impairs the ability of the kidney to excrete uric acid, due to competition for transport between uric acid and ketones.