Uric acid is the end product of purine breakdown in your body. Purines are molecules found in every cell you have, and when those cells die or recycle their components, the purines get converted into uric acid. About two-thirds of the uric acid in your blood comes from this internal recycling process. The rest comes from the food and drinks you consume.
How Your Body Makes Uric Acid
Every day, billions of your cells break down and get replaced. As they do, the purines inside them are released and need to be disposed of. Your body processes these purines through a two-step chain: first, purines are converted into a substance called hypoxanthine, then into xanthine, and finally into uric acid. A single enzyme drives both of those last two steps.
The liver is the primary site where this conversion happens, with a small amount also produced in the small intestine and the lining of blood vessels. Once uric acid enters the bloodstream, your kidneys handle roughly 70% of the job of filtering it out through urine. The remaining 30% is eliminated through your gut.
Normal blood levels of uric acid fall between 3.5 and 7.2 mg/dL for men and postmenopausal women, and between 2.6 and 6.0 mg/dL for premenopausal women. But those upper limits can be misleading. Uric acid starts to crystallize in body fluids at concentrations above 6.8 mg/dL, which means levels many labs call “normal” can actually allow crystals to form in joints and tissues.
Foods That Raise Uric Acid
Purines aren’t just inside your cells. They’re also in the food you eat, and when you digest purine-rich foods, the same breakdown process adds more uric acid to your blood. The biggest contributors are organ meats like liver, kidney, and sweetbreads. Red meat (beef, lamb, pork) is a moderate source. Among seafood, anchovies, sardines, shellfish, and codfish are particularly high.
Interestingly, vegetables that contain purines, like asparagus, spinach, and green peas, don’t appear to raise uric acid levels or increase gout risk. The reason isn’t fully clear, but the purine type and the other nutrients in those vegetables seem to offset the effect.
Why Fructose Is a Surprising Source
Sugar, specifically the fructose half of table sugar and high-fructose corn syrup, triggers uric acid production through a completely different mechanism than purines do. When your liver processes fructose, it burns through its energy stores (ATP) unusually fast. Unlike glucose, which has a built-in braking system that prevents excessive processing, fructose gets phosphorylated as rapidly as possible with no feedback control.
This rapid energy drain depletes phosphate inside liver cells, which kicks off a chain reaction that converts leftover energy molecules into uric acid. The uric acid builds up inside the cells and spills into the bloodstream. This is why sugary drinks and foods high in fructose can spike uric acid levels even though they contain no purines at all.
How Alcohol Contributes
Alcohol raises uric acid through multiple routes at once. When your liver breaks down ethanol, it produces a byproduct called lactate. Lactate interferes with the kidney’s ability to excrete uric acid, so more of it stays in your blood. At the same time, some alcoholic beverages, especially beer, contain purines themselves, adding to the supply side of the equation.
Heavy or chronic drinking compounds the problem further. Alcohol-related changes in fat metabolism and the buildup of other acidic byproducts (ketoacids) also compete with uric acid for the same excretion pathways in the kidneys. The result is a double hit: your body makes more uric acid while simultaneously getting worse at removing it.
Genetics and Uric Acid Levels
Your genes play a significant role in determining your baseline uric acid level, largely by controlling how efficiently your kidneys handle it. Transporter proteins in the kidneys are responsible for filtering uric acid out of the blood and reabsorbing some of it back. Variations in the genes that code for these transporters can tip the balance toward keeping too much uric acid or, in rare cases, too little.
Large-scale genetic studies have identified several specific gene variants linked to higher uric acid and gout risk. Some variants reduce the kidney’s ability to excrete uric acid, while others increase how much gets reabsorbed back into the bloodstream. This explains why some people develop high uric acid levels despite eating a relatively healthy diet, and why gout often runs in families.
What Happens When Uric Acid Builds Up
At concentrations above 6.8 mg/dL, uric acid exceeds its solubility limit in body fluids. At that point, it can form needle-shaped crystals called monosodium urate that deposit in joints, tendons, and surrounding tissues. These crystals are what trigger the intense pain and inflammation of a gout attack. Uric acid released from dying cells also acts as a danger signal to the immune system, amplifying the inflammatory response.
Crystal deposition doesn’t happen overnight. It typically takes years of sustained elevated levels before enough crystals accumulate to cause symptoms. This is why uric acid levels can be high on a blood test long before someone ever experiences their first gout flare.