Iron

In adults, some of the common causes of iron deficiency include: 

• Not getting enough iron in your diet (also known as ‘inadequate dietary intake’).
  There are many reasons why someone’s dietary intake of iron could be too low, for example due to a poorly balanced vegetarian diet, chronic fad dieting or having limited access to a wide range of fresh foods. 
• Blood loss – iron deficiency easily occurs in situations of chronic (ongoing) blood loss. Common causes include heavy menstrual periods, regular blood donation, regular nosebleeds, other chronic conditions that involve bleeding (such as peptic ulcers, polyps or cancers in the large intestine), and certain medications, particularly aspirin. 
• Increased need for iron – if you are pregnant or breastfeeding your body needs more iron. If this increased need isn’t met, iron deficiency can quickly occur. 
• Exercise – athletes are prone to iron deficiency because regular exercise increases the body’s need for iron in several ways. For example, hard training promotes red blood cell production (which requires iron), and iron is lost through sweating. 
• Inability to absorb iron – healthy adults absorb about 10 to 15% of dietary iron, but some people’s bodies are unable to absorb or use iron from food.

Getting too little iron does not cause obvious symptoms. The body uses its stored iron in the muscles, liver, spleen, and bone marrow. However, when levels of iron stored in the body become low, iron deficiency anemia sets in. Red blood cells become smaller and contain less hemoglobin. As a result, blood carries less oxygen from the lungs throughout the body. 

Symptoms of iron deficiency include:

• anemia
• gastroIntestinal (GI) upset
• weakness, tiredness, lack of energy, and problems with concentration and memory.
• less able to fight off germs and infections
• to work and exercise
• control their body temperature

Iron may also be harmful if you get too much. In healthy people, taking high doses of iron supplements (especially on an empty stomach) can cause an upset stomach, constipation, nausea, abdominal pain, vomiting, and diarrhea. Large amounts of iron might also cause more serious effects, including inflammation of the stomach lining and ulcers. High doses of iron can also decrease zinc absorption. Extremely high doses of iron (in the hundreds or thousands of mg) can cause organ failure, coma, convulsions, and death. 

Foods that you should consider incorporating into your diet include: 

• Heme iron in the diet include lean meat and seafood. 
• Nonheme iron include:
  • nuts, beans, vegetables, and fortified grain products
  • bread, cereal, and other grain product

Heme iron has higher bioavailability than nonheme iron, and other dietary components have less effect on the bioavailability of heme than nonheme iron.

Iron supplements can interact or interfere with some medicines. Here are several examples: 

Levodopa: 
Some evidence indicates that in healthy people, iron supplements reduce the absorption of levodopa (found in Sinemet and Stalevo), used to treat Parkinson’s disease and restless leg syndrome, possibly through chelation [1-3]. In the United States, the labels for levodopa warn that iron-containing dietary supplements might reduce the amount of levodopa available to the body and, thus, diminish its clinical effectiveness [4,5]. 

Levothyroxine:
Levothyroxine (Levothroid, Levoxyl, Synthroid, Tirosint, and Unithroid) is used to treat hypothyroidism, goiter, and thyroid cancer. The simultaneous ingestion of iron and levothyroxine can result in clinically significant reductions in levothyroxine efficacy in some patients [6]. The labels for some of these products [7,8] warn that iron supplements can reduce the absorption of levothyroxine tablets and advise against administering levothyroxine within 4 hours of iron supplements. 

Proton pump inhibitors: 
Gastric acid plays an important role in the absorption of nonheme iron from the diet. Because proton pump inhibitors, such as lansoprazole (Prevacid) and omeprazole (Prilosec), reduce the acidity of stomach contents, they can reduce iron absorption [3]. Treatment with proton pump inhibitors for up to 10 years is not associated with iron depletion or anemia in people with normal iron stores [9] but patients with iron deficiency taking proton pump inhibitors can have suboptimal responses to iron supplementation [11].

References:

1. Campbell NR, Hasinoff B. Ferrous sulfate reduces levodopa bioavailability: chelation as a possible mechanism. Clin Pharmacol Ther 1989;45:220-5. [PubMed abstract]
2. Campbell RR, Hasinoff B, Chernenko G, Barrowman J, Campbell NR. The effect of ferrous sulfate and pH on L-dopa absorption. Can J Physiol Pharmacol 1990;68:603-7. [PubMed abstract]
3. Greene RJ, Hall AD, Hider RC. The interaction of orally administered iron with levodopa and methyldopa therapy. J Pharm Pharmacol 1990;42:502-4. [PubMed abstract]
4. Novartis. Stalevo Package Insert . 2010.
5. Merck & Co. I. Sinemet Package Insert . 2011.
6. Campbell NR, Hasinoff BB, Stalts H, Rao B, Wong NC. Ferrous sulfate reduces thyroxine efficacy in patients with hypothyroidism. Ann Intern Med 1992;117:1010-3. [PubMed abstract]
7. Forest Laboratories I. Levothroid Package Insert . 2011.
8. Abbvie Inc. Synthroid Package Insert . 2012.
9. Stewart CA, Termanini B, Sutliff VE, Serrano J, Yu F, Gibril F, et al. Iron absorption in patients with Zollinger-Ellison syndrome treated with long-term gastric acid antisecretory therapy. Aliment Pharmacol Ther 1998;12:83-98. [PubMed abstract]
10. Ajmera AV, Shastri GS, Gajera MJ, Judge TA. Suboptimal response to ferrous sulfate in iron-deficient patients taking omeprazole. Am J Ther 2012;19:185-9. [PubMed abstract]

Always read the label. Follow the directions for use. If symptoms persist, consult your healthcare professional. Vitamin supplements should not replace a balanced diet. If you have any pre-existing conditions, or are on any medications always talk to your health professional before use. Store your daily packs below 25°C in a cool, dry place, away from humidity and direct sunlight.