Iron supplementation

There are different ways of supplementing with iron: inorganic salts, such as ferrous phosphate, or organic iron salts, such as iron bisglycinate.

In supplements, it is preferable to use iron in organic form and the heme form (Fe2+) for better absorption with fewer gastric effects.

Foods with iron

Foods with and without iron

There are two types of iron: heme iron (Fe 2+), which comes from the hemoglobin and myoglobin of animals, and non-heme iron (Fe 3+), which comes from plants.

Heme iron (from animals) is well absorbed, but non-heme iron (plant-based) depends on the associated foods: foods with vitamin C, meat, and fish improve its absorption, while high-fiber foods, legumes, tofu, coffee, and tea inhibit this. Calcium supplements reduce iron absorption.

The foods that contain the most iron are the following:

• Meat, organ meats, and processed meat products.
• Whole eggs and yolks.
• Oily fish, mainly, anchovies and sardines.
• Seafood, all types. The following are rich in iron: clams, canned cockles, periwinkles, mussels, and oysters.
• Legumes..
  Tofu.
• Chard and spinach.
• Nuts (all types). Sesame seeds.
• Nuts, all types.
• Quinoa.
• Whole oats.
• Breakfast cereals: granola and wholegrain cereals.

Foods that contain iron in moderate amounts include the following:

• Vegetables. Olives. Avocado. Wild mushrooms.
• Poultry.
• Rice.
• White bread, and wholegrain more.
• White fish.
• Dark chocolate.

The most bioavailable iron is found in foods of animal origin.

Information for professionals