This page about cooking and meat purines was last reviewed or updated on 2 May 2018
What I write here about cooking and meat purines is by no means the last word on a subject which is incompletely studied. It just attempts to demonstrate how you can reduce the purines in the meat you eat by rinsing and a summary about what is known about cooking’s effect on purines.
The recommendation to rinse is based on only one known study on the subject of meat rinsing, cooking and purines (1). There are other studies on meat cooking (no rinsing ) but they cover only a few foods, plus a few cooking methods. When you consider that a decent list of purines in foods would be a minimum of 250 foods times for example 5 cooking methods that would be 1,250 items at least.We have nothing like that and probably won’t even in 100 years because there have been only a few since 1982, which I think was the year of the first.
Raw foods purine's numbers are approximate Purines in foods' numbers are normally counted in the raw state of food, but that isn't the real number you eat if food is stored, (e.g. frozen), rinsed (washed) and cooked. So the raw foods’ numbers are not a completely accurate score for the purines you eat and drink.
On the rinsing-cuts-down-purines page, I explain that in an experiment (1) using minced (ground) beef, bacon and minced turkey, rinsing, draining and centrifuging, (spinning around a fixed axis - in this case spinning it dry) reduced purines by enough to make a likely useful difference in purine intake. Except for minced (ground) turkey.
Ground (minced) beef - chosen for this study because it is popular
And therefore in uric acid creation. Or at least these processes did in the experiment I explain. It is probably the only one so far to explain meat rinsing (for just a few types), and its effects on the purines in meat.
How long do you rinse?
You do not have to rinse for very long - two and five minutes should have useful effect; ten will probably remove more purines. You need the patience to rinse for two or five minutes and use the water needed.
It appears a good bet that rinsing and draining will lower purines in other prime beef cuts too, not only the ones tested in the study. If rinsing works for one beef cut, it should work for the other prime beef cuts.
Rinsing of high purine offal (organ meat) has not been studied. Even a 25% reduction of the purines in offal (organ meat) would not affect the widespread recommendation you avoid it if you have gout or fear you may get it.
COOKING'S AND MEAT PURINES - EFFECTS
After that short reminder about rinsing’s benefit, now to the cooking and meat purines tests in the same study. There are a few studies about cooking and purines, but not yet enough for us to be more certain about various types of cooking’s effects on different cuts of beef and poultry. Cooking has an effect, but not necessarily the one we want.
The four purine bases - adenine. guanine, hypoxanthine and xanthine - do not always behave in the same way when cooked. Hypoxanthine and adenine are the two that are thought to affect uric acid, up or down. Guanine and xanthine do not.
In a study where changes in the four purine bases in chicken were measured, adenine and guanine rose slightly after roasting but this was because the loss of the fat and moisture in tissues. Some of another- hypoxanthine - went into the cooking juices (2). In a second study, boiling and broiling (grilling from above), hypoxanthine and xanthine in beef steak and beef liver fell quite considerably. Hypoxanthine went into the cooking juices too. The juices had high levels of the uricogenic* purine hypoxanthine (3).
Similarly, in a third study purines fell when they went into water or the oil after boiling.(4) In another study of stewed chicken (6), and as in study (2) where chicken was roasted, adenine and guanine increased somewhat because of the loss of fat and moisture, and some hypoxanthine went into the hot water.
Hypoxanthine falls Researchers believe hypoxanthine is the purine, which along with adenine creates uric acid. The other two do not. So its reduction is what we want.
These studies show that hypoxanthine fell when boiled (stewed), roasted or broiled (grilled from above) Twice in chicken and once in beef steak and beef liver. But don't think this would be true for all meat. Hypoxanthine in fried bacon rose but not much (1). And the purines in the cooked beef topside in this study (7) rose, but not much, only 8.3mg/100 grams of topside.
TIP What can be said from what we know about cooking and meat purines is that it is much more important to pay attention to the purines in raw foods numbers and reduce or avoid consumption of high purine foods.
Where do the purines go during cooking ?
In the meat rinsing, it's thought they are washed away in the draining water(1). In roasting they go into the juices (2); this must be true for grilling, broiling, BBQ too; so you want to avoid the juices; and don’t put them in gravy or sauces. Meat extracts for gravies and sauces are high purine too. When boiling,(stewing) purines they went into the boiling water in studies.(4) Don’t use the resulting beef (or fish) stock as a soup base.
In the two minced (ground) beef types in the study (1), (7% and 25% fat minced beef, each for two and five minutes) the cooking methods caused a fall in purines; but the purines in fried bacon's rose but only slightly. Cooked minced (ground) turkey fell but the fall seemed too great to be true – see Turkey below.
Rinsing lowered purines more than cooking
The important idea is that the cooking reductions from sautéing, (which is cooked or browned in a pan with just a small quantity of butter, oil, or other fat), grilling and pan frying in this trial, were not nearly as large as the rinsing reductions.
RESULTS OF EXPERIMENT (1)
The beef and bacon measurements here are in milligrams (mg) per gram of protein in the meat - the best way to measure purine changes by cooking. Don’t confuse this with mg/100 grams of food, a common purines’ measurement
In the sorts of ground (minced) beef tested reductions were substantial: - 28.9% and – 31% Same for bacon rinsed 2 and 5 mins – 22% and – 25%. By comparison you can see the cooking reductions (after rinsing) were much smaller.
milligrams (mg) per gram of protein in the meat
25% fat ground (minced) beef Rinsing - 2.48 (-29.8%); Sautéing and grilling - 0.67 (-7.8%)
7% fat ground (minced) beef Rinsing - 2.47 (-31%), Sautéing and grilling - 0.38 (4.9 %).
Bacon Rinsing 2 minutes -1.34 (- 22%); Rinsing
5 minutes - 1.57 (-25.9 %)
Bacon Pan frying - 0.20 ( 2 mins) and + 0.19 (5 mins); -.3.3 %; and + 3.1%)
Numbers here are calculated using the mid point of the range of rinsing results for the reduced amounts, that is after rinsing and cooking
Turkey - mg per gram, of turkey sample.
Ground (minced) turkey had a paltry total purines rinsing reduction for both rinsing times. This could well be because turkey had more guanine than the others and guanine is the only insoluble purine base. (Guanine does not affect uric acid, but this alone does not mean turkey is low purine). But perhaps turkey did better with cooking - 0.68 mg/gram of protein (-15%); this happened only when rinsed and grilled for two minutes; not five. It seems an accidental and unreliable result.
COOKING AND BEEF PURINES - CONCLUSION
So if you count purines daily using raw foods numbers, how much should you adjust for cooking and rinsing? This is just a guess, but I’d say plus 10% if you don’t rinse, and – 10% if you do. Both percents are for a cooked portion of meat only, not the other meal items.
*Uricogenic – produces uric acid
Visit our list of purines in foods, one of the largest on the Internet
(1) Anna Ellington (Under the direction of Yen-Con Hung) Reduction of purine content in commonly consumed meat products through rinsing and cooking
(2) Abstract L.L. Young. Purine content of raw and roasted chicken broiler meat Journal of Food Science July 1982
(3) Abstract. D. Brulé, G. Sarwar, L. Savoie Effect of methods of cooking on free and total purine bases in meat and fish. Canadian Institute of Food Science and Technology Journal June 1989
(4) Abstract Colling M, Wolfram G. Effect of cooking on the purine content of foods Zeitschrift für Ernährungswissenschaft January 1988
(5) Z. Ren C. Huang H. Momma Y. Cui S. Sugiyama K. Niu R. Nagatom The consumption of fish cooked by different methods was related to the risk of hyperuricemia in Japanese adults:A three year follow up study Nutrition Metabolism and Cardiovascular Diseases September 2016
(6) L.L. Young Effect of stewing on the purine content of broiler tissues. Journal of Food Science January 1983
(7) Kiyoko Kaneko, Yasuo Aoyagi, Tomoko Fukuuchi, Katsunori Inazawa, Noriko Yamaoka Total purine and purine base content of common foodstuffs for facilitating nutritional therapy for gout and hyperuricemia Biological and Pharmaceutical Bulletin 2014