Walnuts

Food · Fat & Oil · Food, Typed Supps

The best plant omega-3 source — though a different type from fish.

Stage by stage

Intake (Dense nut structure): Thorough chewing matters for releasing nutrients from the dense nut structure.
Stomach (Fat & protein digestion): Fat and protein digestion begins.
Small intestine (ALA absorbed): ALA, a plant-based omega-3, is absorbed alongside the nut’s other fats.
Bloodstream (Low-rate conversion): The body converts a small percentage of ALA into EPA and DHA, the more active omega-3 forms found directly in fish.

Timing

A small handful (about an ounce) is the typical serving used in most studies.

Time to effect

Weeks: Regular intake contributes to ALA and, to a lesser extent, EPA/DHA status.

Allergens

Contains: Tree nuts. Derived from what this food is, not from a product label.

Eating patterns

Fits: Vegan, Vegetarian, Pescatarian, Halal, Kosher, Keto, Gluten-free. Depends on the product: Low-FODMAP.

Satiety

46 on the satiety index, where white bread is 100 — low. Modelled from the Holt et al. (1995) measurements.

Environmental footprint

0.4 kg CO2e and 4134 litres of freshwater per kg, matched to "Nuts" in Poore & Nemecek (2018), Science 360.

Cost band

Pricey — roughly £16 per kg, as a band midpoint rather than a price.

Key nutrients

ALA (plant omega-3)
Polyunsaturated fat
Fiber

Nutrition per 100g

Calories: 694.1
Protein: 14.4g
Carbohydrate: 3g
of which sugars: 2.7g
Fat: 69.2g
of which saturated: 4.4g
Fibre: 6.4g
Sodium: 3mg

Food vs. supplement

Walnuts provide ALA, which your body converts to EPA/DHA at a notably low rate — a fish oil supplement delivers EPA/DHA directly, which is why walnuts and fish oil aren’t fully interchangeable despite both being called "omega-3 sources."

Kitchen tip

Store them in the fridge or freezer - their high polyunsaturated fat content makes them go rancid faster than other nuts at room temperature.

Common myth

“Walnuts provide the same omega-3 benefit as fish oil.” In reality: The body converts plant-based ALA to the more active EPA/DHA forms at a low rate — typically under 10% — so they aren’t a direct substitute.

Recipes that use it

In the glossary

Absorption