Oily fish and gout: Fish oil has many health benefits but is it bad for your gout? Here we’re going to look at what fish oil is, its health benefits, and if it increases (or decreases) your risk of recurrent gout flares.
Oily Fish and Gout
Gout is an extremely painful form of inflammatory arthritis whose root cause is heightened levels of uric acid in the bloodstream, a condition called hyperuricemia. Over time these high levels produce tiny crystals of monosodium urate which settle in joints and connective tissue causing swelling, inflammation, stiffness, and agonizing pain. A gout attack!
Uric acid is a byproduct of purine metabolism which purines exist in our body’s cells and in the cells of the food we eat. So, the more purines there are, the more uric acid is produced.
Under normal circumstances excess uric acid is continually excreted from the body via the kidneys leaving otherwise healthy levels circulating in the bloodstream.
But when the body produces too much uric acid or the kidneys fail to excrete enough uric acid then acid levels in the blood increase and will continue to increase. Then, when saturation point is reached, urate crystals precipitate out of the uric acid in the joints (and associated tissue and tendons) leading to a gout flare.
The horrible symptoms associated with a gout flare are actually caused by your immune system’s inflammatory response to the crystals. This response floods the joint with white blood cells and inflammatory mediators to help fight the crystal “invaders” and it’s this that causes the painful symptoms of a gout flare.
Once you have the gout condition you have it for life, but it can be managed if you can first reduce, then maintain, your uric acid at healthy levels, generally considered to be below 6 mg/dL (milligrams of uric acid / deciliters of blood).
And by maintaining your uric acid at healthy levels you reduce your risk of recurrent gout flares.
So the key question here is: does consuming fish oil (fish or supplements) raise your risk of recurrent gout flares?
Fish oil is derived from the flesh of oily fish — often called fatty fish — such as: herring, salmon, mackerel, tuna, sardines and anchovies.
Most of the benefits attributed to fish oil comes from its omega-3 polyunsaturated fatty acids content. It’s thought omega-3 fatty acids may help to:
- improve heart health
- reduce the risk of heart attack and stroke
- lower hypertension (high blood pressure)
- ease rheumatoid arthritis symptoms
- reduce chronic inflammation
- boost bone density
- aid eye health
But your body can’t produce its own omega-3 so it has to get it from dietary sources, mainly cold water fish and plant-based foods.
The best way to enjoy the health benefits of fish oil is by eating the fish itself although many people, for various reasons, consume it in the form of dietary supplements.
There are three main omega-3 fatty acids:
- eicosapentaenoic acid (EPA)
- docosahexaenoic acid (DHA)
- alpha-linolenic acid (ALA)
Whilst your body’s capable of converting some ALA into EPA and DLA, this happens in such very low quantities that the only really effective way of getting EPA and DHA into your system is through the food you eat, particularly cold water (oily) fish.
Oily fish like herring, salmon, tuna, and mackerel, etc., are the major sources of EPA and DHA, whilst ALA is mainly found in plant-based foods like chia seeds, flaxseeds, walnuts, soybean, green leafy vegetables, and vegetable oils.
Although oily fish are the main source of beneficial omega-3 fatty acids, they’re also rich in protein and other nutrients such as: vitamins D and B2 (riboflavin) and minerals like: iron, zinc, iodine, magnesium, calcium, phosphorus, and potassium.
So oily fish can genuinely be labeled a superfood, so much so that the American Heart Association in its latest science advisory, published in AHA Journals in 2018, recommends eating fish at least twice per week:
We conclude that 1 to 2 seafood meals per week be included to reduce the risk of congestive heart failure, coronary heart disease, ischemic stroke, and sudden cardiac death, especially when seafood replaces the intake of less healthy foods.
Similar advice is given by the World Heal Organization (WHO) and the UK’s National Health Service (NHS).
And many other health organizations around the globe also advocate the health benefits of oily fish with their high EPA and DHA content.
But is it safe to include oily fish in your gout diet?
Is Fish Oil Bad for Gout?
At least one study concluded that omega-3 polyunsaturated fatty acids found in oily fish are associated with a significant decrease in the risk of gout flares.
It found that the consumption of oily fish by gout patients lowered their risk of recurrent gout flares by as much as 33% largely due to the anti-inflammatory effects of EPA and DHA.
Unfortunately, for gout patients taking fish oil supplements the risk was not reduced, according to the authors.
So does this mean that those who don’t eat fish are left out in the cold?
Well, perhaps not…
The number of participants taking supplements in the study was very small and small data sets make it very difficult to carry out any meaningful analysis.
In addition, the report authors commented that the usual concentrations of biologically active EPA and DHA in commercially produced supplements are “far below that which is required for significant anti-inflammatory effect.”
[Note: Several studies into rheumatoid arthritis have associated fish oil supplements with beneficial anti-inflammatory effects. The difference being that higher doses were taken in these studies: the average across all studies being around 3.5 gm of total EPA and DHA per day.]
So fish oil supplements may help to reduce the risk of gout flares as long as they are of the highest quality and taken in higher doses.
But, notwithstanding the apparent link between fish consumption and a lower risk of recurrent gout flares, a key consideration — as always for gout sufferers — is purine content.
Purines in Food
Different foods contain different levels of purines so someone with gout has to be very careful with their diet.
High purine foods produce over 200 mg of uric acid per 3.5 oz (100 g) serving, whilst moderately high purine foods produce 100-200 mg of uric acid per 3.5 oz (100 g) serving.
So, generally speaking, gout patients are advised to avoid high purine foods because they increase the risk of gout flares — more purines in, more uric acid produced, higher risk of gout flares.
But moderately high purine foods may be consumed in moderation, without affecting your gout, i.e., 1 x 3.5 oz (100 g) serving per day, as long as all other meals on that day are low purine.
[Note: My guide Gout Rescue has detailed information on high, moderate, and low purine foods and ingredients, along with daily meal ideas for gout sufferers.]
Purine Content of Fish
The following fish are considered to be high in purines:
- salmon (smoked)
Whilst these are considered to have moderate amounts of purines:
- salmon (cooked)
- mackerel (smoked)
- sea bass
- sea bream
Now let’s compare these with the richest sources of omega-3 fatty acids.
Some of the highest concentrations of EPA and DHA are found in:
As you can see, most fish with high EPA and DHA are also high in purines and so would normally be avoided altogether.
However, as oily fish is the major source of highly beneficial omega-3 polyunsaturated fatty acids EPA and DHA, we may need to treat oily fish differently from other high purine foods like organ meat, game, and red meat, which have very little omega-3 compared to fish like mackerel and herring.
In other words, we have to balance the particular health benefits of fish against their purine risk for people with gout.
The most obvious way to help mitigate the purine risk is through portion control and frequency of consumption: less purines in, less uric acid produced, lower risk of gout flares.
So a 3.5 oz (100 g) serving of a high purine fish (not fried) once or twice per week should deliver the health benefits without increasing your risk of gout flares. It may even help to reduce your risk somewhat, according to the previous study.
It would be even safer to split your maximum two servings per week into one serving of a high purine fish and one serving of a moderately high purine fish, with at least three days between each.
[Note: Everyone’s metabolism is different. If this doesn’t work for you then cease and consider fish oil supplements instead.]
Purine in Fish Oil Supplements
Although purines exist in the flesh of fish they don’t in highly purified, molecularly distilled fish oil, so daily fish oil supplementation shouldn’t negatively affect your gout.
But look for pharmaceutical-grade and triple molecular distillation on the label.
The manufacturer should also supply a written guarantee of purity covering:
- product performance
- product safety
…and that the product actually contains all the ingredients and their amounts as listed on the label.
Suggested dose: 3.0 to 4.0 gm of total EPA and DHA per day, but check with your healthcare practitioner first.
[Note: Omega-3 fatty acid supplements can be safely consumed at doses of up to 5.0 mg daily, according to the European Food Safety Authority.]
Mercury in Fish
Nearly all fish and shellfish contain traces of mercury (in the form of methylmercury) that they’ve absorbed from polluted waters. The levels found in fish depend to a large extent on the size and type of fish and the amount of pollution in the water it inhabits.
Larger fish eat smaller fish and they tend to live longer so they accumulate much more mercury than smaller fish in the same aquatic habitat.
So avoid eating large fish like:
- king mackerel
Who Shouldn’t Take Fish Oil?
If you’re taking any blood-thinning medication (e.g. Warfarin), are pregnant, breastfeeding, or have a fish or shellfish allergy, you need to talk to your healthcare practitioner before taking fish oil supplements.
Health organizations, including the WHO, advocate important health benefits of eating fish, especially oily fish with their high EPA and DHA content.
Although oily fish have high levels of purines — and high purine foods are usually avoided by gout patients — they are THE source of extremely beneficial omega-3 polyunsaturated fatty acids.
This means they may be treated differently from other high purine foods such as organ meat, game, and red meat, as long as portion size and frequency of consumption are strictly controlled.
A 3.5 oz (100 g) serving of oily fish (not fried) once or twice a week will give you all the health benefits of omega-3 without negatively impacting your gout. And, according to the previous study, may even help reduce your risk of recurrent gout flares.
If you don’t eat fish then you could consider taking top quality fish oil supplements. But consult with your healthcare practitioner first that they’re appropriate for your particular health position.