This page - lowering seafood purines – was last updated or reviewed on 30 May 2018
LOWERING FISH PURINES INFORMATION - PATCHY BUT PROMISING
This page features a couple of the main ways fish purines can be lowered – rinsing (washing), and various cooking methods. Since many fish are medium or sometimes high purine, lowering their purines before eating them is a good idea.
The first thing to know about lowering seafood purines by these methods is that, as with cooking and beef purines, we are very short of real study evidence. Most studies I could find on this subject are listed below and they are mainly about seafood products, not seafood (fish) itself. To compare against thousands of fish species, there are just a few studies on this lowering seafood purines topic.
But although patchy, what we do have is somewhat promising for the idea that fish purines can be reduced before eating. And what seems to be true is that of the tested cooking methods, boiling fish will lower purines most. However rinsing (washing) fish will lower purines more than boiling.
Is lowering seafood purines a good idea? Definitely. In a frequently quoted study (1), the researchers found an increased intake of seafood was associated with an increased risk of gout. In gout literature, it is one of the accepted facts that eating excess seafood can cause gout.
LOWERING SEAFOOD PURINES - STUDIES EXPLAINED
These fish studies are similar to the minced (ground) beef, bacon and turkey study on the rinsing cuts down purines page. Two of the fish studies about rinsing lowered purines.
Rinsing On that rinsing cuts down purines page,the study of rinsing reduced purines by more than any method of cooking - minced (ground) beef by 25% and 32%; bacon by 24%. (But not the purines in turkey). In a tilapia surimi (mince) study (3), and although this was tilapia mince (surimi) not whole fish tilapia, there was a decrease in purines content of more than 30% from rinsing, which is a good reduction. The purines vanished into the rinsing water as they did in the minced (ground) beef experiment. Tilapia is quite high in purines (126 mg/100 grams which would be higher in uric acid produced), so this was useful.
In another rinsing (washing) study of milkfish surimi (milkfish is a tasty fish found in the Indian and Pacific oceans – local names include ava, awa, bangus, bandeng), rinsing achieved a 60% reduction (4). Milkfish is also fairly high purine (139 mg or 180 mg/100 grams - both have been recorded, but lower in surimi products).
When rinsing any fish high in the purine base guanine, you probably won’t get very good results. This is because, unlike the other three - adenine , hypoxanthine and xanthine – guanine is insoluble in water and therefore won’t exit into the rinsing water. On the other hand guanine does not produce uric acid (or much) so it doesn’t really matter.
You can look up the amount of guanine in many fish here (5)
The rinsing methods used were more precise than you would use at home but you should get similar results. Rinse for 10 minutes. It’s possible soaking works too but that has not been studied..
Boiling In the tilapia surimi (mince) study quoted above the uricogenic (the purines that create uric acid) purines in the tilapia fell just over 46% during 40 minutes boiling.
In another boiling test, purines in cinnamon flounder fish (6), (a fish found in the Western Pacific and the South China Sea) fell 60%. Boiling also decreased the purines found in grass shrimps (7) - 24% after 20 minutes.
In a sardines study (8) boiling fresh sardines for 25 minutes reduced NAN (nucleic acid nitrogen, the purines precursor) by 48%.
Frying and other cooking methods We have found that boiling is the cooking method likely to lower fish purines most. That was true for minced (ground) beef too. Frying will also lower purines. A study published in 2016 (9) found that of three methods of cooking boiling did best, frying next but roasting not at all. This was not actually a cooking and eating test but the hyperuricemia measurements, after eating cooked and uncooked fish for a group of 424 Japanese adult men and women. Those who ate boiled and fried fish did not have raised uric acid.
However, those who ate raw fish (sashimi and sushi) or roasted fish did have a risk for hyperuricemia (high uric acid). Three to five times higher. Gout sufferers and diners with high uric acid who visit sashimi restaurants and sushi bars might want to consider that.
In the sardines study mentioned above frying was also next best after boiling, with a NAN reduction of 18% and 25% over 10 and 15 minutes respectively.
Finally other cooking methods - steaming, grilling,microwaving.
Grilling In a sardines study grilling them for 15 minutes increased purines by just 3%. A tiny amount. This accounted for a moisture and fat loss
With microwaving in the tilapia surimi study,(above) nearly 17% of uricogenic purines were lost during 7 minutes of this.
Gout scientific researchers consider that steaming should give a similar benefit to boiling (stewing). Just one study on this and the results were that steaming for 40 minutes reduced the uricogenic purines in tilapia surimi (mince) by nearly 25%.
CONCLUSION Despite generally good results from cooking in lowering seafood purines you should still be careful of how much seafood you eat. I have only quoted a few species and a small number of studies about lowering seafood purines, and that’s all there are.
If you want to read about lowering beef purines click here.
(1) Hyon K.Choi,M.D.,Dr.P.H.,Karen Atkinson,M.D.,M.P.H.,Elizabeth W. Karlson,M.D.,Walter Willett, M.D.,Dr.P.H., Gary Curhan,M.D., Sc.D. Purine rich foods, dairy and protein intake and the risk of gout in men New England Journal of Medicine March 11 2004
(2) Anna Ellington (Under the direction of Yen-Con Hung) Reduction of purine content in commonly consumed meat products through rinsing and cooking
(3) S.H. Lou et al Tilapia mince products changes in purine content of during processing
(4) S.H. Lou et al Changes in purine related compounds of milkfish surimi based product during processing
(5) 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
(6) S.H.Lou et al Cinnamon flounder fish
(7) S.H. Lou et al Abstract Changes in related compounds of grass shrimp under various cooking duration 1998
(8) Manar M.A. Farag Effect of different cooking methods on nucleic acid nitrogen bases content of fresh sardine fish and its nutritive value. World Journal of Dairy & Food Sciences 8(2) 2013
(9) 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