We have found that many of our clients or someone they know has experienced iron deficiency. Have you ever wondered what role iron plays in the body? Do you know what factors contribute to iron deficiency? Are you aware of what foods provide excellent sources of iron?
Iron is a mineral that is needed for all body functions, and every cell in the body contains and requires iron. The most significant role iron plays in the body is oxygen transport and storage. Roughly 75% of our iron is found in the blood in the form of hemoglobin and about 5% in the form of myoglobin. Hemoglobin is a protein-iron compound responsible for carrying the oxygen from our lungs to the rest of our body. Myoglobin is a form of hemoglobin that is found in the muscles and is responsible for carrying and storing oxygen for the muscles, specifically the skeletal and cardiac muscles. The less iron we have, the less hemoglobin is produced, and therefore less oxygen is delivered to our tissues. Iron also has a role in energy production and is present in a variety of enzymes that aid in chemical. In addition, iron aids the immune system in maintaining its function.
The largest factor that contributes to iron deficiency is the inability to adequately obtain appropriate levels from the diet. Iron is the most common single nutrition deficiency in our population, with the most significant deficiencies found in menstruating women. Men have a reserve of about 1000mg and a loss of about 1mg a day. Menstruating women on the other hand have a reserve of 200-400mg with a loss of 1.5-2.4mg per day. Other factors that contribute to iron deficiencies include low stomach acid, removal of a part of the stomach, malabsorption syndromes, calcium phosphate salts, tannic acids, antacids, and phytates.
Hypochromic microcytic anemia, also known as iron deficiency anemia, is the most common deficiency. The red blood cells are smaller than normal, and they are paler in color due to decreased levels of hemoglobin. The decreased hemoglobin results in oxygen starved tissues which then present symptoms including listlessness, difficulty swallowing, paleness, heart palpitations with exertion, and a general lack of well being. Even with the absence of anemia, decreased levels of iron are detrimental to your health. Symptoms include decreased learning ability, decreased endurance, fatigue, decreased tolerance to cold, depression, hair loss, brittle nails, headaches, and a craving for salt.
Iron in food comes from two different forms: heme iron and non-heme iron. Heme iron comes from animal flesh, while non-heme iron is found in plant food and dairy products. The absorbability of iron in different food varies according to the source. Organic iron found in red meat is the most absorbable at about 10-30%. Inorganic iron found in plant products is only absorbable at about 2-10%. The best 6 sources of iron are high in other nutrients that help aid iron absorption. For example, iron rich green vegetables are also high in vitamin C, copper, and manganese which all aid iron absorption. Shrimp, venison, and beef are also high in absorption boosting amino acids. Cooking in cast iron cookware has also been shown to enhance absorption. Some of the best food sources other than meat include spinach, Swiss chard, tofu, soybeans, pumpkin seeds, shrimp, lentils, olives, and herbs.
There are numerous guidelines that quantify the amount of nutrients that we need on a daily basis. The RDA is 18mg for women under the age of 51 and 8mg for men and women over the age of 51. The ODI for iron is 15-25mg for men and 18-30mg for women. While supplementation can be helpful, it is important to consume our minerals and vitamins through a whole food diet. Track your food for a week and calculate the mineral and vitamin intake to identify deficiencies in your diet.
By Pamela Geisel
References
Lieberman, S & Bruning, N. (2007). The Real Vitamin & Mineral Book. (4th edition). New York: Avery.
Mateljan, G. (2007). The World’s Healthiest Foods: Essential Guide for the Healthiest Way of Eating. (1st edition). Washington: GMF Publishing.
McGuire, M & Beerman, K. (2013). Nutritional Sciences from Fundamentals to Food. (3rd edition). California: Woodsworth.
