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.

Intake and deficiencies

Deficiencies

The iron concentration depends on external inputs and absorption.

Iron deficiency. Iron deficit is one of the most prevalent nutritional deficiencies in the world, Average intake by men is higher than recommended.mainly affecting children, adolescents, and women in their childbearing years. The National Diet and Nutrition Survey (UK) found an iron deficiency in 30% of the population over the age of 65. The majority of women who menstruate do not consume the recommended amount of iron.

Deficient acid production, common in the elderly, reduces iron absorption.

The organic iron found in foods of animal origin is two to five times more easily absorbed than the inorganic iron (ferric hydroxide) found in plants. Iron of all types is best absorbed by eating meat.

Certain substances in grains, nuts, and vegetables bind with iron and reduce its absorption. Excess fiber (more than 35 g) reduces absorption. Substances like coffee and tea reduce absorption.

Calcium supplements reduce iron absorption. Iron deficiency is often associated with zinc deficiency.

Anemia can also be a sign of copper deficiency.

Drugs. NSAIDs, antacids, H2 antagonists (cimetidine, ranitidine, etc.) omeprazole, and antibiotics can accentuate an iron deficiency. In addition, drugs that affect vitamins A, B6 and B12, riboflavin, folates, and copper (NSAIDs, antacids, omeprazole, metformin, furosemide and thiazides) can help worsen the evolution of anemia.

Excess iron. An excess of iron is also a common alteration due to excessive absorption because of a genetic disorder that slightly increases iron absorption (hemochromatosis with two defective genes, but also carriers with just one defective gene), associated at times with eating red meat, taking supplements with iron, and/or using iron cooking utensils. High iron deposits occur mainly in men and also in post-menopausal women.

Reference values

VRN, IR, UL

The NRV is 14 mg. The PRI is 10 mg for men, 15 mg for adolescents, 18 mg for women in their childbearing years, and 10 mg for post-menopausal women.

There is no UL established currently, although it is known that iron does not have a broad safety profile because it accumulates and can be pro-oxidant.

Iron can accumulate and be toxic. Excess iron has pro-oxidant action.

NRV: Nutrient Reference Value. These are the daily amounts recommended for vitamins and minerals (micronutrients only) considered sufficient in the European Union to prevent a deficit in most healthy individuals in the population. They are the values used for labeling and claims.

PRI: Population Reference Intake. These are the reference values for a specific population group, defined as the amount of energy and/or nutrients (macronutrients and micronutrients) recommended to cover the nutritional needs of practically the entire population. They refer to healthy population groups. The values are expressed per person per day, as a 15-day average. To account for individual differences in digestive and metabolic processes, the PRI figure used for each nutrient is the average plus twice the standard deviation (except for energy, for which the average is used), thereby including almost all healthy individuals in the group (97.5%).

UL: Tolerable Upper Intake Level: the maximum level of total daily intake of a nutrient in a context of long-term or chronic consumption which does not pose a risk to health.

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.