Iron

Iron is a nutrient that is found in the body in very small quantities (trace element) and is vital to its proper functioning. It is found in all the body’s cells. Since the body cannot produce iron, it must obtain what it needs from food. The body has a mechanism to protect itself from the toxic effects of iron: the iron absorption rate increases when the body’s reserves have been depleted but decreases when reserves are high. Iron exists in two main forms: 

• Hematinic iron, which exists in animal-derived foods;
• Non-hematinic iron, which exists in plant-derived foods.

The tannins in vegetables make the non-hematinic form harder to absorb. Vitamin C and hematinic iron improve the absorption of non-hematinic iron.

Roles

What does iron do? 

• Transports oxygen to tissue and muscle cells;
• Facilitates reactions inside cells;
• Protects the body (indirectly) from infectious diseases.

Needs

Recommended Dietary Allowance for Iron:

Source: Food and Nutrition Board, Institute of Medicine, Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc, 2000.

This data reflects a consensus between Canadian and U.S. authorities.

*Lacking sufficient scientific evidence, authorities have established adequate intakes (AIs) rather than recommended dietary allowances (RDAs). Adequate iron intake is based on observed average intakes in North American babies in good health.

NOTE: Iron supplements must be taken only under the supervision of a healthcare professional. If iron supplements are advised (further to a test measuring ferritin and hemoglobin levels), they should be taken after a meal containing vitamin C sources to improve absorption.

Sources

The main food sources for both hematinic and non-hematinic iron are red meat, poultry, fish, and seafood. Dried fruit, molasses, whole grains, legumes, green vegetables, nuts, and seeds contain only non-hematinic iron. Wheat flour, breakfast cereals, precooked rice, and pasta are typically enriched with non-hematinic iron. 

NOTE: The calcium in dairy products may decrease iron absorption. 

Food Sources for Iron: 

Source: Health Protection Branch, Health Canada, Nutrient Value of Some Common Foods, 1999.

Deficiency

Iron deficiency is common. According to the World Health Organization, 80% of the world’s population is thought to be affected, with 30% of those suffering from anemia.

Insufficient iron intake, inadequate intestinal absorption, excessive blood loss, vitamin A deficiency, and/or increased iron requirements may lead to iron deficiency.

 The following people are at risk for iron deficiency: 

• Vegetarians;
• Elite athletes (especially women);
• Blood donors;
• Women with heavy menstrual periods;
• Pregnant women;
• Menopausal women who take hormones;
• Oral contraceptive users;
• Adolescents;
• Growing children (six months to four years);
• Nursing infants who are not breast fed;
• Premature newborns;
• People with kidney failure;
• People undergoing dialysis;
• Those who suffer from diseases causing malabsorption of iron or chronic blood loss (inflammatory or allergic diseases of the intestine, ulcers, benign polyps).

Signs of iron deficiency: 

• Anemia;
• Fatigue;
• Pale color;
• Weakness;
• Shortness of breath;
• Soft nails that split easily;
• Hair loss;
• Numbness in fingers and toes;
• Loss of intellectual productivity or performance;
• Difficulty regulating body temperature;
• Weakened immune system;
• Slowed cognitive and social development (in children).

Indications

Beneficial properties attributable to iron (in case of deficiency): 

• Fights fatigue (possible);
• Improves athletic performance (possible);
• Improves intellectual performance in children and adolescents (uncertain).

Other beneficial properties attributable to iron but that require medical monitoring: 

• Treats iron deficiency anemia;
• Prevents postsurgical anemia;
• Soothes dry cough, a side effect of certain medications;
• Prevents iron deficiency caused by menstruation in some women.

Adverse effects

The risk of iron poisoning through food is almost nonexistent, except in the case of certain diseases that lead to overabsorption of this mineral, such as hereditary hemachromatosis. 

On the other hand, an iron surplus may come from iron supplements. Before taking any type of supplements, consult your doctor or pharmacist. 

Signs of excess iron: 

• Nausea, vomiting, diarrhea or constipation;
• Cardiovascular complications;
• Renal complications;
• Liver complications;
• Hematologic (blood) complications;
• Nervous system disorders in the brain and spinal column;
• Spleen and pancreas damage.

Cons-indications

• Those suffering from ulcerative colitis or Crohn’s disease;
• People with gastroduodenal ulcers;
• People suffering from diseases that result in abnormal iron accumulation in the body should never take iron supplements:
  • Hereditary hemachromatosis (causes iron storage in various organs);
  • Chronic alcoholism;
  • Alcoholic cirrhosis and other liver diseases.

Interactions

Natural health products and vitamin supplements that decrease iron absorption (possible): 

• Coffee;
• Tea;
• Calcium;
• Red wine;
• Whole wheat flour;
• Tannins in dark green vegetables, legumes, and flat breads.

Natural health products and vitamin supplements that increase iron absorption: 

• Ascorbic acid (vitamin C);
• Meat, fish, and poultry.

Medications that increase iron absorption*: 

• Oral contraceptives.

Medications that decrease iron absorption*: 

• Various antibiotics;
• Non-steroid anti-inflammatories;
• Antacids;
• Proton pump inhibitors;
• Medications that reduce blood lipid levels;
• Anti-seizure medications;
• H2 blockers;
• Bisphosphonates (medications used to treat bone diseases).

Additional information

*Wait two hours between taking these medications and iron supplements. 

***Speak with your pharmacist if you plan to take iron supplements. Your pharmacist can help you choose the solution that’s best for you based on your health and any drugs you take. 

Other names

Iron, Ferrous carbonate, Ferrous fumarate, Ferrous gluconate, Ferrous sulfate, Ferrous citrate, Ferrous succinate, Fe