Published May 03, 2009 05:01
Why do I need iron?
Iron is an essential mineral that is part of a blood protein called hemoglobin. Iron's job in the body is to carry oxygen to every cell in your body including muscle cells and brain cells. The three key functions it is involved in are:
1. Transport and storage of oxygen.
2. Energy production and cell diffusion.
3. Immune and central nervous system (brain) function.
Iron deficiency has adverse consequences on aerobic work performance, immune function and psychomotor development.
What causes iron deficiency?
Iron deficiency can result from low dietary intake (iron and overall energy/calories), poor iron absorption, excessive iron loss (blood loss from menstruation, injury or disease), long term use of anti-inflammatory medication and disproportionate exercise. Iron requirements vary according to age, gender, and stage of life. Greater needs for iron occur during growth phases (children, adolescents, pregnancy), during hard training and when living at altitude.
What are the stages of iron deficiency?
The fall in iron status normally passes through 3 stages. These consist of:
Stage 1 lowered iron stores (ferritin).
Stage 2 iron depletion (ferritin and transferin are reduced)
Stage 3 iron deficiency anemia (ferritin, transferring and hemoglobin are reduced)
What are the symptoms of iron deficiency?
People with first stage of iron deficiency are generally symptom free. However iron deficiency with anemia symptoms include: feeling tired, pale, breathless, unusually rapid heart rate, decreased motivation to train, and poor exercise tolerance. Iron deficiency anemia is a concern to athletes as it can takes months to recover from being anemic.
How much iron do I need?
Menstruating women (19-50yrs) 18 mg/day
Active menstruating women 18 to 23 mg/day
Active non-menstruating women 8 mg/day
Where can I get iron in foods?
Iron occurs in two forms in foods:
1. Heme iron is found in animal foods like meat, poultry and fish. This type of iron is highly absorbed by the body. Athletes who consume animal products are advised to eat red meats 2-3 times per week depending on iron status.
2. Non-Heme iron is found in plant foods like legumes, dark leafy vegetables, dried fruit, enriched grains, fortified cereals and sport bars. This type of iron is poorly absorbed by the body. To increase the iron absorption of these products combine them with a vitamin C rich source (e.g. pineapple, orange, grapefruit and their juices; strawberries, peppers, tomato). In addition, consuming a heme iron-rich food at the same time as non-heme can also enhances its iron absorption. Tea, coffee and certain types of fiber (e.g. phytates) can inhibit the absorption of iron.
Foods with Heme Iron
Oysters (3 oz) 7.82 mg
Beef liver (3.5 oz) 6.77 mg
Ground beef, extra lean (3.5 oz) 2.35 mg
Lean steak, eye-of-round (3.5 oz) 1.95 mg
Lean ham (3.5 oz) 1.48 mg
Chicken, dark meat (3.5 oz) 1.33 mg
Tuna, light, canned in water (3 oz) 1.30 mg
Turkey slices, fat free Louis Rich (4 slices) 1.08 mg
Chicken breast (3.5 oz) 1.06 mg
Salmon, wild* (3 oz) 0.88 mg (*only 0.29 mg farmed salmon)
Pork, loin chop (3.5 oz) 0.85 mg
Fish fillet, lightly battered, Mrs. Paul's (1) 0.70 mg
Egg (1 whole) 0.59 mg
Cod fish (3 oz) 0.42 mg
Foods with Non-Heme Iron
Fortified cereal (1 oz) 4.5–18 mg
Tofu, raw (1/2 cup) 6.65 mg
PowerBar and other fortified bars (1) 6.30 mg
Oatmeal, instant (1 packet) 6.30 mg
Lentils (1 cup) 6.59 mg
Kidney beans (1 cup) 5.20 mg
Garbanzo beans (1 cup) 4.74 mg
Black beans (1 cup) 3.61 mg
Spinach, boiled (1/2 cup) 3.21 mg
Enriched white rice or pasta, cooked (1 cup) 1.90 mg
Peas, green (1/2 cup) 1.26 mg
Dried figs (4) 1.67 mg
Dried apricots (10 halves) 1.65 mg
Raisins (1/3 cup) 1.04 mg
Prunes (5) 1.04 mg
Wheat bread (1 slice) 0.9 mg
Mustard greens, boiled (1/2 cup) 0.49 mg
Should I take a supplement?
It is highly recommended for athletes to monitor their iron status on a yearly basis via laboratory investigations (CBC, ferritin, transferring saturation, serum iron, TIBC). If you ever experience clinical symptoms of fatigue, weakness, paleness, and impaired exercise capacity then have your doctor assess your health including iron status.
If your iron status is low then you should supplement with iron in combination with an iron-rich diet. Iron supplement treatment should last for three months with a subsequent blood test and clinical and dietary follow-up. The potential side effects of iron supplementation are constipation and decreased zinc and copper absorption.
Thanks to Susie Parker-Simmons M.S., R.D. and Carol Otis M.D.
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