Oysters

Low FODMAP

Typical portion

Any typical portion Low

Oysters are Low FODMAP, a plain shellfish that's mostly protein with no fermentable carbohydrate to worry about.

Fresh oysters carry no FODMAP load at any typical portion, since they're essentially pure protein with negligible fermentable carbohydrate.

Enjoy them raw or gently cooked, and keep an eye on sauces or dressings, since garlic or onion-heavy toppings are what usually add FODMAPs to the plate.

Why oysters is rated low

Oysters are low FODMAP. Plain oysters are mostly protein with very little carbohydrate, so they hold a low rating at Any typical portion. That rating is estimated from what oysters are made of rather than a measured serving, and amounts beyond a typical portion are not covered by the rating. The things that change a plate of oysters are the toppings and preparations around them, many of which are built on shallot, garlic or wheat.

What changes your risk

Mignonette The classic raw oyster dressing is finely chopped shallot in vinegar. The oysters stay low, but shallot is not, and spooning it on changes the plate.
Baked and grilled toppings Oysters baked or grilled under garlic butter, breadcrumbs or a creamy spinach topping pick up garlic, wheat and dairy along the way.
Fried oysters A wheat flour or breadcrumb coating turns plain oysters into a battered food with wheat in it.
Stews and chowders Oyster stews and chowders are usually built on onion and milk or cream, so the dish carries far more than the oysters do.
Stacking the meal Plain oysters followed by garlic bread, a creamy pasta and a shallot dressing on the side all add up in one sitting, and that total is what matters.

What else works

Mussels, clams, scallops, prawns and plain white fish sit in the same place as oysters when served without onion or garlic. The lookalikes that are not the same are the prepared versions: oysters with mignonette, garlic-butter baked oysters, fried oysters in a wheat crumb, and oyster stew or chowder. For raw oysters, fresh lemon, a hot sauce checked for onion and garlic, or a vinegar dressing with chives instead of shallot keep the plate low.

How to keep it low

Buy oysters live and closed, or shucked and chilled from a trusted seafood counter, keep them cold, and eat them promptly. Serve raw oysters with fresh lemon and a dressing of vinegar, cracked pepper and finely chopped chives in place of shallot. For hot oysters, grill them with garlic-infused oil and a sprinkle of parmesan or a gluten free crumb. When ordering out, ask whether the dressing contains shallot and whether baked oysters are topped with garlic butter or breadcrumbs.

Common questions

are oysters low fodmap

Yes. Plain oysters are rated low FODMAP at Any typical portion, an estimate based on them being mostly protein with very little carbohydrate. Dressings and toppings are what usually add FODMAPs.

is mignonette sauce low fodmap

Classic mignonette is made with shallot, which is not low FODMAP, so it changes the plate. A vinegar and chive dressing gives a similar sharpness without the shallot.

are fried oysters low fodmap

The oysters stay low, but an ordinary wheat flour or breadcrumb coating adds wheat. A rice flour or gluten free crumb keeps fried oysters closer to the plain version.

can i eat oysters on the elimination phase

Plain oysters fit the elimination phase well. Serve them with lemon or a shallot-free dressing, and skip garlic butter, wheat breadcrumbs and onion-based stews.

Learn more

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

Oysters 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.