Fish Oil

Low FODMAP

Typical portion

Any typical portion Low

Fish oil is Low FODMAP, a pure fat with essentially no carbohydrate for your gut to ferment.

As a pure fat, fish oil carries no FODMAPs, so any typical portion sits comfortably in the low range.

Whether you take it as a capsule or a spoonful of liquid, it's an easy one to keep in your routine.

Why fish oil is rated low

Fish oil is low FODMAP, and the rating is estimated from its composition rather than from a weighed dose: it is fat, and FODMAPs are carbohydrates, so there is nothing in plain fish oil for gut bacteria to ferment. The serving data is qualitative here and lists "Any typical portion" as low, which covers both a capsule and a spoonful of the liquid. The catch is that fish oil often does not arrive plain. Flavoured emulsions, chewable gummies and sweetened liquid blends are built around the oil with other ingredients, and those additions, not the oil, are what can carry a load. Plain oil is quiet. Anything sold as a treat to swallow deserves a look at the label first.

What changes your risk

Plain oil versus a sweetened product A capsule or plain liquid oil is just fat. Gummies, chewables and flavoured emulsions add sweeteners, syrups and gelling ingredients, and anything labelled sugar free is worth reading closely before it becomes a daily habit.
Serving size The data records "Any typical portion" as low, which is about the FODMAP question only. Fish oil is still a concentrated fat, and a large dose of any oil can upset a sensitive gut for reasons that have nothing to do with FODMAPs.
What it is taken with Low is a per serving rating and not a per meal one. Because fish oil contributes nothing to the total, the rest of the meal gets the full allowance, so judge the load of breakfast or dinner as a whole rather than counting the capsule.
Cooking with it Fish oil is not a cooking oil, but the same principle that makes garlic infused oil workable applies to oils generally: FODMAPs are water soluble and do not dissolve into fat, so a plain oil carries flavour without carrying them.

What else works

There is no need to swap fish oil out, and other plain oils sit in the same easy place: olive oil, canola oil, coconut oil, and plain fish oil in capsule form if the liquid is unpleasant. The versions worth being more careful with are the ones that look like a sweet: omega gummies, chewable capsules for children, flavoured emulsions and smoothie style blends, along with combination supplements that add fibre ingredients such as inulin or chicory root fibre, which is genuinely high FODMAP. If a supplement lists anything beyond oil, gelatin or glycerin and a vitamin, it is worth a second read.

How to keep it low

Choose a plain capsule or a plain liquid oil with a short ingredient list, and keep it in the fridge once opened so it does not go rancid, which is what causes the fishy aftertaste people complain about. If the burping is the problem, taking it with a meal helps more than switching to a flavoured version. When a practitioner has recommended a specific dose, follow that rather than adjusting it for FODMAP reasons, because the FODMAP answer here does not change with the amount.

Common questions

is fish oil low fodmap

Yes. Fish oil is rated low FODMAP, with "Any typical portion" recorded as low. The rating is estimated from its composition: it is pure fat, and FODMAPs are carbohydrates.

are omega 3 gummies low fodmap

The oil inside them is, but a gummy is a sweet as well as a supplement. Check the sweeteners and any added fibre ingredient on the label, because those are what can carry a FODMAP load, not the fish oil.

can i take fish oil during the elimination phase

Plain fish oil in capsule or liquid form fits the elimination phase. Supplement choices are worth raising with the dietitian or clinician who suggested them, since the FODMAP question is only one part of it.

does cod liver oil count the same as fish oil

For the FODMAP question, yes: it is another plain fish oil with no fermentable carbohydrate. The difference between the two is nutritional rather than anything to do with FODMAPs.

Learn more

Informational only, not medical advice. Individual tolerance varies. Talk to a healthcare professional or a dietitian for personal guidance.

Fish Oil is an estimated rating: it is inferred from the food's ingredients and composition and cross-checked, not measured directly in the papers below. The low, moderate and high cutoffs are still those of Varney et al. (2017).

References

Fructan and free fructose content of common Australian vegetables and fruit. Muir et al. (2007), J. Agricultural and Food Chemistry 55(16):6619-6627.
Measurement of short-chain carbohydrates in common Australian vegetables and fruits by HPLC. Muir et al. (2009), J. Agricultural and Food Chemistry 57(2):554-565.
Quantification of fructans, galacto-oligosaccharides and other short-chain carbohydrates in processed grains and cereals. Biesiekierski et al. (2011), J. Human Nutrition and Dietetics 24(2):154-176.
Dietary sorbitol and mannitol: food content and distinct absorption patterns. Yao et al. (2014), J. Human Nutrition and Dietetics 27(Suppl 2):263-275.
FODMAPs: food composition, defining cutoff values and international application. Varney et al. (2017), J. Gastroenterology and Hepatology 32(Suppl 1):53-61. Supplies the low, moderate and high cutoffs used on this page.