Once called “the ailment of kings” because it mainly afflicted those who could afford a rich diet, gout now affects more than 8 million non-royal Americans. To what do we owe this dubious honor? Is it because we are eating more meat than ever before?
What is gout?
Gout is a special type of arthritis in which certain joints fill up with microscopic shards of uric acid, becoming red, swollen, and exquisitely sensitive to the touch. Most people with gout have too much uric acid in their blood—higher than 6 mg/dl in women and 7 mg/dl in men (levels can reach 12 mg/dl or more in some cases). Uric acid crystals can also cause kidney stones and kidney damage. More than 20% of Americans now have abnormally high uric acid levels.
What is uric acid?
Uric acid is a breakdown product of purines—molecules that help make up some vitally important compounds present in the cells of all plants and animals, including DNA (genes), RNA (protein manufacturing) and ATP (energy). The following are the most familiar purines:
- Theobromine (cocoa beans, tea leaves, kola nuts, yerba mate)
Low-purine diets (in combination with medication) have been prescribed for gout since the middle of the 20th century. This dietary advice is based on the belief that too many purines in the diet cause high uric acid in the blood. Now, since all plants and animals are made of cells, and all cells contain purines, asking someone to eat fewer purines is a tall order. However, since most animal foods are higher in purines than most plant foods (animal foods are denser and contain more cells per unit weight), doctors advise people with gout to eat less meat. You could also lower purines in your diet by simply eating fewer whole foods of all kinds. [Actually, the best advice, if you follow this reasoning to its logical conclusion, would be to eat a 100% junk food diet of flour, sugar, candy, soda, ice cream, and fruit juice—foods that have had their cells destroyed or removed in the refining process—because these foods contain few if any purines at all—sound like a plan?] The below list is adapted from Emmerson 1996:
- All meats, including organ meats, and seafood
- Meat extracts and gravies
- Yeast and yeast extracts
- Beer, and other alcoholic beverages
- Beans, peas, lentils, oatmeal, spinach, asparagus, cauliflower, and mushrooms
- Refined cereals and cereal products, such as cornflakes, white bread, pasta, flour, and tapioca
- Milk, milk products, and eggs
- Sugar, sweets, and gelatin
- Butter, polyunsaturated margarine, and all other fats
- Fruit, nuts, and peanut butter
- Lettuce, tomatoes, and green vegetables (except spinach and asparagus)
- Vegetarian cream soups made with low-purine vegetables
- Water, fruit juice, cordials, and carbonated drinks
In actuality, scientists admit that it is impossible to know the true purine content of any food, but even if we did, purines are not the only problem.
Those kings of old must have known how to party.
It has been known for centuries that alcohol consumption can trigger gouty attacks. This connection is now well supported by scientific studies. Two 12 oz beers can raise uric acid levels in healthy men by about 10%, and drinking to intoxication doubles uric acid levels in alcoholics. Interestingly, most alcoholic drinks contain no purines, so how does alcohol raise uric acid levels?
- Alcohol cuts the kidney’s ability to rid the blood of excess purines by at least 50%.
- When the liver processes alcohol, lots of ATP (an energy molecule) is used up in the process; ATP contains purines that get broken down into uric acid.
- Beer is especially risky because it contains alcohol AND purines (derived from brewer’s yeast).
Fructose raises uric acid levels
It has been known since the late 1960s that fructose raises uric acid levels. Examples of foods which contain fructose are fresh fruit (max 10% fructose), dried fruit (max 40% fructose), table sugar (50% fructose) and corn syrup (55% fructose). Uric acid levels rise about 13% after eating meals containing fructose. People with gout have more exaggerated responses to fructose than healthy controls.
"subjects prone to developing gout in the 1700s and 1800s tended to be wealthy and sedentary, often with the ability to afford sugar, the latter of which is known to raise uric acid. Indeed, today gout is increasing in all populations, and if anything, is more common among the poor and less educated.”
Yet, as you can see in this 2007 New York Times article, fructose is not even on the list of possible dietary factors in gout, which may be why celebrated NY Times food writer Frank Bruni continues to suffer with some symptoms of gout, despite following his doctors’ advice to limit meat and alcohol and to take medication:
“I’ve noticed discernible changes in my health—or at least in the way I feel. How much of that is attributable to my reduced alcohol intake and how much to the exodus of red meat is impossible to say. I haven’t lost more than a pound or two, because carbs have rushed in where protein isn’t permitted to treat . . . the flare-ups [of gout] are subtle now that I’m medicated and reformed.”
Aye, there’s the rub! Mr. Bruni has gotten right to the meat of the problem—low-purine diets can be high in refined carbohydrates, such as sugar and flour, which raise insulin levels, and now not only do you have gout, but you have a hard time losing weight and you've further increased your risk for all kinds of other chronic diseases:
“Fructose is unique among sugars in that it rapidly causes features of metabolic syndrome both in experimental animals and humans. Fructose ingestion also leads to fatty liver and elevated triglycerides in humans and can also raise blood pressure. Intriguingly, fructose is a sugar that has the unique ability to raise serum uric acid. Serum uric acid levels rise within minutes of fructose ingestion… the increase in fructose intake closely parallels the rise in gout, obesity and metabolic syndrome that has occurred over the last two centuries. Serum uric acid levels increased from <3.5 mg/dl in the early twentieth century to over 6 mg/dl today in adult males.”
How does fructose raise uric acid levels?
“The specific reason why fructose is superior than glucose in increasing fat stores likely relates to the unique first steps in fructose metabolism. When fructose enters the hepatocyte, it is metabolized by a specific enzyme, fructokinase C. Unlike glucokinase, which has a negative feedback system to prevent excessive phosphorylation, the phosphorylation of fructose by fructokinase will proceed uninterrupted, and as a consequence intracellular phosphate depletion and ATP depletion frequently occur. The fall in intracellular phosphate results in the stimulation of AMP deaminase that helps accelerate the degradation of AMP to IMP and later to uric acid. In turn, the intracellular generation of uric acid results in oxidative stress.”
Translation: Fructose is especially good at turning into fat. The enzymes in the liver that turn fructose into fat use up lots of ATP in the process. ATP contains purines that get broken down into uric acid.
Both alcohol and fructose burn through ATP like kindling. Metabolically speaking, fructose and alcohol have a lot in common, which is why Dr. Robert Lustig mentions them both in the same breath as poisons.
But there’s more to the sugar story
Rapidly digestible carbohydrates such as sugar, flour, starch, fruit juice, and white potato are notorious for causing insulin spikes. Insulin tells the kidneys to reabsorb uric acid into the blood instead of excreting it into the urine. Why? Because insulin is, first and foremost, a growth hormone. In order to grow you need to build more cells, and to build more cells you need more purines.
Thus our dear meat-mourning Mr. Bruni is dutifully eating a low-purine, high-refined carb diet, which both lowers and raises uric acid. As comedian Steven Wright would have said, that’s like putting a humidifier and a dehumidifier in the same room and letting them fight it out.
So what is he supposed to do? What foods would he be left with if we told him he can’t eat carbs, meat, or alcohol? Fat and low-purine vegetables? Unfortunately that diet is dangerously devoid of nutrients. Which is worse for gout—meat or carbs?
My beef with the meat-purine-gout hypothesis
- We are not eating any more meat now than we did 100 years ago.
- Some cultures eating lots of meat, including 19th century Arctic peoples who lived on a diet of nearly 100% animal foods, did not develop gout. “Gout is unknown in Eskimos and Northern Indians despite their purine-rich diet.”
- Animal foods are higher in protein than plant foods. Proteins increase the elimination of purines in the urine, which can actually lower uric acid levels.
- Some plant foods are rich in purines, including legumes, spinach, asparagus, and mushrooms (dense or rapidly growing plants).
- Purines in the diet do not have much of an effect on uric acid levels, because most of the uric acid in the blood comes from inside the body, as part of everyday cell turnover: “The purine content of the diet does not usually contribute more than 1 mg/dl to the serum urate concentration.”
Studies tying animal foods to gout have been epidemiological studies which have observed that people who eat more meat tend to have higher uric acid levels and/or a higher risk of gout. These studies have not taken carbohydrate in general, nor fructose in particular, into consideration. Therefore we have no idea whether people who reported eating more meat also happened to eat more fructose, which is, in my opinion, a critical omission given that we have known since 1967 that fructose can raise uric acid levels. Furthermore there are some epidemiological studies that find no association whatsoever between meat and uric acid levels. Either way, as many of you know, epidemiological studies are not experiments and correlation does not equal causation.
What do the clinical studies show?
Unfortunately, as is the case with so many diseases, when the use of drugs to treat gout became popular in the 1950s, interest in dietary strategies fizzled. So we only have a wee handful of small, flawed studies to guide us:
There are ZERO studies that have attempted to prevent gout with diet.
I could only locate a grand total of ONE study of the oft-recommended low-purine, alcohol-free diet that is relevant to our question. In this study, 55 Brazilian adults with both high blood pressure and high uric acid levels were divided into three groups— diet alone, low-purine diet plus medication, and medication alone—for three months. Uric acid levels fell by about 2 mg/dl in all three groups by week six. However, people in this study were not gout patients, there was no control group, and the composition of the diet was not described (we are only told what was excluded from the diet), therefore we do not know if this diet contained less fructose and/or less refined carbohydrate than a standard diet. Without that information, we can’t be sure that it was the lack of purines that may have been responsible for the decrease in uric acid.
I located only ONE small pilot study exploring the role of refined carbohydrate in gout. Thirteen South African men with gout were placed on a 1600 calorie diet containing 40% unrefined carbohydrate, 30% protein, and 30% (unsaturated) fat, including four servings of fish per week. Purines were unlimited and alcohol was not restricted. Here are the results, on average, after 16 weeks:
- uric acid levels fell by 18%, from 10.3 mg/dl to 8.5 mg/dl on average; seven men had a normal uric acid level by the end of the study.
- frequency of gout attacks was reduced by 72%
- weight dropped by 17 lbs
This study is very promising, but unfortunately it is hard to know which of the interventions was responsible for the positive benefits—was it the lack of refined carbohydrate, reduction in saturated fat, or the weight loss itself? Even more confusing is that it is unclear whether these patients were eating much less meat than usual, given that they were told to avoid saturated fat. Uric acid levels fell by about 2 points, which is about the same as in the Peixoto low-purine diet study, although that group had much lower uric acid levels to begin with.
So, what should you do if you have gout?
The answer is that the research doesn’t have a clear answer for you yet. Many questions remain. We still don’t understand exactly why alcohol raises uric acid levels, why only a small percentage of people with high uric acid levels get gout, or even which carbohydrates might aggravate gout and why. For example, a brand new analysis of all available fructose studies calls into question whether fructose raises uric acid any more than any other kind of sugar.
But here’s what we do know. When we combine the available science with common sense, we can say that:
- Human beings must be well-adapted, as all animals must be, to eating purines, which are found in all whole foods.
- It is highly likely that we are poorly adapted to be able to handle much refined carbohydrate or alcohol, which have never existed in nature in significant amounts.
Dietary tips for managing gout
- Stabilize and lower your blood sugar and insulin levels by reducing carbohydrate intake, especially refined carbohydrate intake. A low glycemic index diet would be a good place to start. Depending on your chemistry, you may even need to consider a very low carbohydrate diet or ketogenic diet. Refined carbohydrate and high insulin levels have been strongly linked to metabolic syndrome and most diseases of Western civilization, and gout is probably just one more sugar-tipped arrow in the quiver of the Western diet. There is no evidence that lowering the amount of meat in your diet will protect you from these diseases, whereas there is plenty of evidence to suggest that lowering refined carbohydrate intake can. Even if it doesn't completely cure your gout, you’ll be a lot healthier for it.
- Minimize alcohol intake, especially beer.
- Consider taking a vitamin C supplement. A single randomized controlled trial found that taking 500 mg of vitamin C per day for two months reduced uric acid levels by 1.5 mg/dl.
If you focus on these goals, you may be able to have your meat and eat it too :)
Want to learn more?
For more reassuring facts about meat and health, including information about kidney disease, heart disease, and nitrites/nitrates, please see my meats page. You may be interested to read about the history of mostly-meat diets, including the diets of Arctic and African peoples. I also recently wrote a critique of the latest study trying to connect the carnitine in red meat to heart disease.
In 2015, I wrote a five-part series about fructose, how it gets processed in our bodies compared to how we process glucose, if it is more dangerous than glucose, and how some of the fructose studies use questionable methods to single out fructose as more harmful than other forms of sugar. The series begins with the biochemistry of sugar in a post entitled: "Has Fructose Been Framed". I dedicate a portion of part 3 "Why Sugar Is Bad for You: A Summary of the Research" specifically to sugar consumption and gout.
What about you? Have you tried any dietary strategies for gout that have worked?
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