Red Lentils

Food · Legume · Food, Typed Supps

Red lentils are a cheap, fast-cooking way to get iron, fiber, and protein — pair them with vitamin C to help your body absorb more of the iron.

Stage by stage

Chewing & Starch Breakdown (Mouth): Chewing and salivary amylase begin breaking down the lentils' starch as soon as they enter the mouth.
Acid Digestion (Stomach): Stomach acid unfolds lentil storage proteins and begins releasing bound folate for later absorption.
Nutrient Absorption (Small Intestine): In the small intestine, non-heme iron, folate, fiber, and amino acids cross into the bloodstream, with iron uptake boosted by co-ingested vitamin C and inhibited by tea, coffee, or calcium eaten at the same meal.
Iron & Folate Use (Bone Marrow): Absorbed iron travels via transferrin to the bone marrow to support red blood cell production, while folate fuels DNA synthesis and cell division throughout the body.

Timing

Pairing red lentils with a vitamin C source, such as citrus, tomatoes, or bell peppers, and spacing them away from tea, coffee, or high-calcium foods, improves how much of their iron the body actually absorbs.

Time to effect

Weeks: Lentils' nutrients are digested and absorbed within a few hours of eating, but noticeable improvements in iron status typically take several weeks of consistent servings given the relatively low bioavailability of non-heme iron.

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

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

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
Folate
Dietary Fiber
Plant Protein
Potassium

Nutrition per 100g

Calories: 116
Protein: 9g
Carbohydrate: 20.1g
of which sugars: 1.8g
Fat: 0.4g
of which saturated: 0.1g
Fibre: 7.9g
Sodium: 2mg

Food vs. supplement

Cooked red lentils deliver iron and folate together with fiber and plant protein, a combination no isolated iron or folic acid supplement provides.

Kitchen tip

Red lentils need no soaking — rinse and simmer 15-20 minutes until soft; full cooking also neutralizes natural anti-nutrients like lectins and trypsin inhibitors found in raw legumes.

Common myth

"Lentils are just as good a source of iron as red meat." In reality: Lentils' iron is non-heme iron, absorbed at only about 2-20% efficiency compared with roughly 15-35% for the heme iron in meat, so gram for gram, iron from lentils reaches the bloodstream far less efficiently unless eaten with vitamin C and away from absorption inhibitors like tea, coffee, and calcium-rich foods.