Meet the Ingredient: Flax Seeds Explained, Nutrition and Uses Across Our Range

October 9, 2026

We sell flax as whole seed, milled seed and cold-pressed oil, and it is also part of our Omega Seed mix. It is the same plant in every case, Linum usitatissimum, but the products behave very differently in the kitchen and on the nutrition panel. This guide sets out the numbers side by side, explains why they differ, and helps you choose.

Flax nutrition at a glance (per 100g)

Brown flax seeds: 534 kcal, 18.3g protein, 27.3g fibre
Milled flax seeds: about 534 kcal, about 18g protein, about 27g fibre
Flax seed oil: 901 kcal, 50g ALA, no protein or fibre
Milled omega seeds (flax, chia, pumpkin, sunflower): about 520 kcal, about 21g protein, about 29g fibre

Why the numbers differ

Whole and milled seed match because milling only changes the particle size. It is the same seed, with its fat, fibre and protein, broken into a fine powder. The fat is a little over two-fifths of the weight (42.2g per 100g in the brown seed), and about two-thirds of it is polyunsaturated.

The oil has no fibre or protein because pressing separates the oil from the rest of the seed. What is left is almost pure fat, which is why it reads 901kcal per 100g, and about half of that fat is alpha-linolenic acid (ALA), the omega-3 fatty acid plants make. Published analyses of commercial linseed oils find ALA at roughly 47 to 54% of the oil, in line with our 50g.

The omega mix sits slightly apart because only part of it is flax. Blending in chia, pumpkin and sunflower seeds lifts the protein and fibre a little and trims the energy.

Label wording that applies

Under the rules retained in Great Britain, a food can be called a source of protein if protein supplies at least 12% of its energy, and high in fibre if it has at least 6g of fibre per 100g. Flax seeds meet both: protein supplies about 14% of the energy in brown flax, and the fibre is more than four times the threshold. The oil is high in ALA, which needs at least 0.6g per 100g. The authorised wording (Regulation (EC) No 1924/2006 and Regulation (EU) No 432/2012, as retained in Great Britain) is: "Alpha-linolenic acid contributes to the maintenance of normal blood cholesterol levels. The beneficial effect is obtained with a daily intake of 2g of ALA." That wording may be used only on foods that are at least a source of ALA.

Which to choose

Brown flax seeds: crunch in bread, granola and toppings.
Milled flax: egg replacer, smoothies, porridge. One tablespoon mixed with three tablespoons of water makes a gel that binds like an egg in cookies and breads.
Flax seed oil: cold dressings and drizzling.
Milled omega seeds: a four-seed blend for stirring into breakfast and baking.

Why flax gels

Flax seeds have a hard, glossy coat, and its outer layer holds a gum-like mucilage that makes up about 6% of the seed. A 2022 review notes that it binds a great deal of water, which is why milled flax thickens a smoothie and why a flax egg holds a biscuit mixture together. It is a binder rather than a riser: egg also traps air and sets a foam, which flax gel does not do, so it suits cookies and dense loaves better than whipped sponges.

Keeping each form

Oil: the most fragile. A 2022 study of 30 commercial cold-pressed flaxseed oils found clear deterioration after a month at room temperature in the light, and a 2020 study found oxidation far faster when linseed oil was heated. Keep it cool and dark, ideally in the fridge, use within 3 months of opening, and use it cold.
Milled seed: a 2000 trial found no significant rise in peroxide value over 128 days at about 23°C, but once opened we treat it as a fresh ingredient: keep it closed and cool and use it within a few weeks.
Whole seed: the sturdiest. A Flax Council of Canada summary reports whole and coarsely ground flaxseed stable for 308 days at 22°C in a laboratory test. Keep the pouch closed, cool and dark.

An old plant

Flax is among the oldest crops in the world. Wild flax fibres, some spun and knotted, have been found in a Georgian cave in layers about 36,000 to 24,000 years old, and enlarged seeds that may mark early farming turned up at Tell Ramad in Syria, dated to around 8,000 to 9,000 years ago. In Britain the seed is usually called linseed. The AHDB describes linseed as the short form grown for oil and flax as the tall form grown for fibre.