Good sources of heme iron include lean meat, especially beef, dark poultry meat, clams, oysters, mussels and sardines.Juefrateam/Getty Images
It’s easy to blame fatigue, brain fog and lower than usual energy for workouts on poor sleep, stress or hormonal shifts.
But these common symptoms can also be connected to iron deficiency, especially if you’re a woman.
According to Health Canada, one in four women between the ages of 14 and 50 have low iron.
Here’s what to know about iron deficiency – why it matters, how to screen for it and how to treat and prevent it.
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The importance of iron
Iron is used to make hemoglobin, a protein in red blood cells that binds oxygen from your lungs and transports it to the rest of the body.
The mineral also supports energy production, helping your muscles, brain and other tissues function efficiently.
As well, iron plays a role in immune function, thyroid health, DNA synthesis and cognition.
Iron deficiency vs. iron deficiency anemia
Iron deficiency develops over time, progressing through stages, when your body doesn’t get enough – or absorb enough – iron.
Early iron deficiency occurs when iron stores, measured by a ferritin blood test, become depleted.
While a low ferritin level indicates iron deficiency, it doesn’t necessarily mean you have anemia.
Iron deficiency anemia occurs when iron levels are too low to support the production of oxygen-carrying hemoglobin.
It’s diagnosed using a complete blood count (CBC), which measures hemoglobin in red blood cells.
Symptoms of iron deficiency and iron deficiency anemia often overlap.
In the early stages, when iron stores are low, fatigue, mental fog, reduced exercise capacity and low mood are common.
As iron deficiency progresses and anemia develops, symptoms become more pronounced and include increased fatigue, shortness of breath (especially on exertion), dizziness, headaches and reduced stamina.
Other symptoms may include pale skin, cold hands and feet, brittle nails and restless leg syndrome.
Who’s at increased risk?
The main causes of iron deficiency are blood loss, inadequate iron intake, iron malabsorption and increased daily iron needs.
Menstruation puts women of childbearing age at greater risk of iron deficiency.
Pregnant women, infants and young children, are also greater risk because of increased iron requirements.
People who follow vegetarian or vegan diets may be more likely to become deficient, since they rely on harder to absorb non-heme iron sources.
Gastrointestinal disorders that impair iron absorption, such as celiac disease and inflammatory bowel disease, also increase the likelihood of iron deficiency.
Treating iron deficiency
Increasing your intake of foods high in iron can help, particularly in mild deficiency. (More on iron-rich foods to follow.)
But often, diet alone isn’t enough – and iron supplements are needed. This is especially true for iron deficiency anemia.
The most common iron supplements are ones made from ferrous salts (e.g., ferrous sulfate, ferrous gluconate, ferrous fumarate).
Taken in high doses, ferrous salts can cause gastrointestinal upset. Unabsorbed iron can irritate the gut, leading to nausea, constipation and diarrhea.
Other types of iron supplements, such as iron bisglycinate and heme iron polypeptide, are generally better tolerated and tend to cause fewer gastrointestinal side effects.
Sucrosomial iron, a newer iron formulation, has few GI side effects likely because it’s encapsulated in a way that reduces direct contact with the gut lining.
It also appears to be well absorbed and has been shown to raise hemoglobin levels similarly to intravenous iron in people with mild and moderate iron deficiency anemia.
If you are deficient in iron, speak to your doctor about which iron supplement is right for you.
Iron supplements can interact with certain medications; consult your pharmacist for guidance.
Diet strategies to maintain prevent iron deficiency
Preventing iron deficiency involves consuming enough dietary iron and optimizing its absorption.
Women between the ages of 19 and 50 require 18 mg of iron each day; during pregnancy daily iron requirements increase to 27 mg. Adult men and postmenopausal women need 8 mg.
Heme iron, found in animal foods, is easily absorbed by the body. Good sources include lean meat, especially beef, dark poultry meat, clams, oysters, mussels and sardines.
Non-heme iron in plant foods is less readily absorbed than heme iron because it must first be converted to a more absorbable form and is more affected by other foods in a meal.
Good sources include soybeans, tofu, lentils, chickpeas, black beans, red kidney beans, lima beans, pumpkin seeds, cooked spinach, cooked Swiss chard and quinoa.
Enhancing iron absorption
Vitamin C can enhance non-heme iron absorption by as much as threefold. Add a source to every plant-based meal – sweet bell pepper, broccoli, cauliflower, strawberries, mango, pineapple, orange segments and tomato sauce, for example.
Cooking (vegetables), sprouting (breads, grains, beans, lentils), soaking (nuts) and fermenting (tempeh) release iron from phytates, natural compounds in plants that bind iron.
Drink tea and coffee between, rather than with, meals. Compounds in these beverages, including tannins, can inhibit non-heme iron absorption.
Separate calcium – dairy foods and supplements – from iron-rich meals by at least two hours. Consuming them together can reduce absorption of heme and non-heme iron.
Consider a multivitamin with iron
Menstruating women may benefit from taking a multivitamin supplement that provides 10 to 18 mg of iron.
During pregnancy, people should take a prenatal multivitamin with 27 mg of iron.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan.
