Iron is an important mineral that is present in the blood, the muscles, organ tissues and other parts of the body. Lately, a study has found out that iron can improve exercise performance in women.
What Is Iron?
Iron is an essential mineral in the body that can be derived from the food that we eat. Iron may be naturally present in foods such as fruits and vegetables or it may be available in supplement form. Iron is often incorporated in hemoglobin, the red pigment in blood that is responsible for the transport of oxygen from the lungs to the tissues. It also composes myoglobin, a protein that also provides oxygen to the muscles. Iron has essential functions in growth, metabolism, development, cellular function and the production of muscles, connective tissues and hormones.
Iron is available in food in two forms: heme and nonheme. Non-heme iron is often found in plants and foods which are iron-fortified while meat, poultry and fish may contain both heme and non-heme iron. Heme iron is formed when iron combines with protoporphyrin IX; this type of iron is commonly found in food.
Iron is present in haemoglobin at concentrations of 3 to 4 grams. Most of the iron in the body is stored as ferritin or hemosiderin in the bone marrow, liver and spleen. It is also present in muscle tissue as myoglobin. Iron may be lost through menstrual periods, feces, urine or the gastrointestinal tract.
The richest sources of iron include seafood and lean meat. Non-heme iron may be present in beans, nuts, grains and vegetables. Iron may also come from bread, cereals, and grain products. Breast milk may contain some amounts of iron for babies however these amounts are not often adequate to meet the needs of the growing child aged more than 6 months.
Iron is often mixed with other vitamins and minerals such as ascorbic acid in foods such as meat, poultry and fish. While these foods can enhance iron absorption, foods such as grains, beans and polyphenols in cereals and legumes can in fact inhibit iron absorption. Foods with calcium can also reduce the effect of iron on the body and its bioavailability to the tissues. Iron is also available in dietary supplements such as multivitamin or multimineral preparations. These preparations may contain ferrous and ferric salts such as ferrous sulphate, ferrous fumarate, ferrous gluconate and ferric citrate. However, doses of supplemental iron greater than 45 milligrams per day can cause gastrointestinal upset such as constipation and nausea. These iron supplements are widely used by children, pregnant women and lactating women. Calcium supplements should not be given along with iron supplements as the former may inhibit the absorption of the latter.
Children, teenage girls, pregnant women and premenopausal women are at risk of having iron deficiency. Iron deficiency is often associated with poor diet, blood loss and malabsorption. There are several stages that a person may pass through when he or she has iron deficiency. Initially, there may be decreased serum ferritin concentrations or abnormal erythropoisesis. Then, the haemoglobin and hematocrit levels may decrease and microcytic and hypochromic anemia may develop.
Iron and Exercise Performance in Women
A recent study has shown that women who take iron supplements often have improved exercise performance. This study, done by researchers from the University of Melbourne, was a systematic review and analysis of the effect of iron supplementation to the exercise performance of women in child-bearing years. The study gathered data from previous studies that have shown how iron has benefits on exercise performance. This is the first study to demonstrate that iron may have beneficial effects on exercise. The authors remarked that the findings of this study may be used to guide nutritionists in supplementing the diet of athletes, especially women athletes.
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