Lentils

Food · Legume · Food, Typed Supps

A plant iron source without the oxalates that block spinach’s iron.

Stage by stage

Intake (Cooking softens structure): Cooking is essential — raw legumes are difficult to digest and contain compounds cooking neutralizes.
Stomach (Protein & starch digestion): Protein and complex carbohydrate digestion begins.
Small intestine (Iron & fibre absorbed): Non-heme iron and soluble fibre are absorbed; the fibre also slows sugar absorption.
Blood cells & gut (Iron use & fibre fermentation): Absorbed iron supports red blood cell production, while unabsorbed fibre feeds gut bacteria in the colon.

Timing

Pairing with a vitamin C source improves how much of the non-heme iron is absorbed.

Time to effect

Weeks: Regular intake contributes to iron and fibre status over time.

Allergens

None of the fourteen major allergens. Derived from what this food is, not from a product label.

Eating patterns

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

Satiety

133 on the satiety index, where white bread is 100 — moderate. Measured by Holt et al. (1995).

Environmental footprint

1 kg CO2e and 397 litres of freshwater per kg, matched to "Peas" in Poore & Nemecek (2018), Science 360.

Cost band

Cheap — roughly £2.2 per kg, as a band midpoint rather than a price.

Key nutrients

Non-heme iron
Plant protein
Soluble fibre
Folate

Nutrition per 100g

Calories: 92
Protein: 7.3g
Carbohydrate: 11.9g
of which sugars: 0.5g
Fat: 0.5g
of which saturated: 0.1g
Fibre: 4.1g
Sodium: 1mg

Food vs. supplement

Lentils’ iron is non-heme like spinach’s, but lentils lack spinach’s oxalates — pairing lentils with a vitamin C source (like tomatoes) meaningfully boosts absorption, the same principle behind why iron supplements are often paired with vitamin C.

Kitchen tip

No soaking required - they cook in 20 to 30 minutes, making them one of the fastest legumes to prepare from dry.

Common myth

“Plant-based iron sources are basically useless.” In reality: Non-heme iron absorbs less efficiently than heme (animal) iron, but pairing it with vitamin C narrows much of that gap.