Iron is a vital mineral that plays a crucial role in numerous bodily functions, including oxygen transport, energy production, and DNA synthesis. While it's often associated with meat consumption, obtaining sufficient iron on a vegan diet is not only possible but can also be quite straightforward with the right knowledge and planning. This article aims to provide a comprehensive guide to iron intake for vegans, covering everything from the types of iron to the best plant-based sources and strategies for optimizing absorption.
Why is Iron Important?
Iron is essential for proper growth and development. Your body uses it to make hemoglobin and myoglobin, proteins that carry and store oxygen. Hemoglobin, found in red blood cells, is responsible for transporting oxygen from the lungs to all parts of the body. Myoglobin, present in muscle cells, helps muscles accept, store, and transport oxygen. Iron is also a component of many important enzymes, which are substances that speed up chemical reactions in the body.
Iron plays an important part in proper bodily functions, including:
- Blood Production: Iron is a key component of hemoglobin in red blood cells, which carries oxygen in your blood from your lungs to your tissues. This improves your heart health, respiratory functions, and immune function.
- Physical Health: Iron is needed for the synthesis of collagen, a protein essential for joint and skin health, leading to stronger and healthier skin, hair, and nails. Myoglobin in muscle cells helps muscles accept, store, and transport oxygen.
- Mental Health: Iron is essential for energy metabolism. Adequate iron levels improve general energy and increase focus.
Types of Iron: Heme vs. Non-Heme
Iron is found in food in two forms: heme and non-heme iron. Heme iron is derived from animal-derived foods, while non-heme iron is found in plant-based foods. Heme iron, contained in animal products, is more easily absorbed into the body, whereas non-heme iron is not as efficiently absorbed. Meat is the only natural source of heme iron. The average heme iron content of various cooked meats is 65% for beef, 39% for pork, and 26% for chicken and fish. Heme iron is absorbed at a rate of about 25%.
Non-heme iron absorption ranges from approximately 0.7-23%. However, the body can adapt to solely relying on non-heme iron. Serum ferritin is the main determinant of non-heme iron absorption: as ferritin decreases, non-heme iron absorption increases. Despite the difference in absorption rates, vegans can still meet their iron needs by consuming a variety of iron-rich plant foods and employing strategies to enhance absorption.
Read also: Vegetarian Iron Sources: A Complete List
Iron Needs for Vegans
The average amount of iron a vegan needs is 1.8 times more than people who eat meat. The Institute of Medicine recommends 18 mg/day for pre-menopausal women and 8 mg/day for men. The increased requirement for vegans is due to the lower bioavailability of non-heme iron.
The average requirement for iron may be 30-70% higher for those who engage in regular, intense endurance exercise, especially running. This can be due to periods of rapid growth, training at high altitudes, menstrual blood loss, foot-strike hemolysis, intravascular hemolysis, injury, and increased losses in sweat, urine, and feces.
Top Vegan Sources of Iron
Vegans can obtain iron from a variety of plant foods, often in amounts that rival or even exceed those found in animal products on a per-calorie basis. Here are some excellent vegan sources of iron:
- Legumes: Lentils, beans, and peas are excellent sources of iron. One cup of lentils contains 6.6 milligrams of iron. Kidney beans, soybeans, and lima beans also have high iron content.
- Dark Leafy Greens: Spinach and Swiss chard are packed with iron. One cup of cooked spinach contains 6.4 milligrams of iron. Swiss chard is a green leafy vegetable rich in vitamins and minerals.
- Tofu and Tempeh: These soy-based products are integral to a vegan diet and good sources of iron. Tofu has a higher iron content of 6.6 milligrams per half-cup, while one cup of tempeh has 4.5 milligrams of iron.
- Blackstrap Molasses: This is an excellent source of non-heme iron. Only 2 tablespoons contain 7.2 milligrams of iron. However, molasses contains higher amounts of sugar, so intake should be limited.
- Nuts and Seeds: Certain nuts and seeds contain notable amounts of iron.
- Fortified Foods: Many breakfast cereals, plant-based milks, and other products are fortified with iron, making them a convenient way to boost your intake.
Examples of Iron-Rich Vegan Meals
To give you an idea of how to incorporate these foods into your diet, here are some meal examples:
- Breakfast: Oatmeal with orange juice (provides iron from the oats and vitamin C from the juice)
- Lunch: Tempeh/Rice Pocket Sandwich
- Dinner: Black-Eyed Peas and Collards or Creamy Lentil Soup
- Snack: Corn Bread or Spicy Sautéed Tofu with Peas
Enhancing Iron Absorption
Since non-heme iron is not as readily absorbed as heme iron, vegans need to employ strategies to enhance its absorption. Here are some effective techniques:
Read also: Delicious Skillet Meals
1. Vitamin C
Eating foods high in vitamin C with meals significantly increases the absorption of non-heme iron. Vitamin C-rich foods are abundant in vegan diets, including bell peppers, broccoli, cabbage, Brussels sprouts, kiwi fruits, oranges, strawberries, pineapples, grapefruits, and orange juice. A high percentage of Indian children were cured of anemia using 100 mg of vitamin C at two daily meals for 60 days.
2. Avoid Iron Inhibitors
Certain substances can hinder iron absorption. These include:
- Tea and Coffee: Tea, coffee and a component of our diets called phytates can all reduce iron absorption. Avoiding herbal tea within an hour of a meal can ameliorate the impact.
- Phytates: Phytates, found in legumes and whole grains, can inhibit iron absorption. Soaking, sprouting, and fermenting these foods can reduce their phytate content and improve iron absorption.
- Calcium: Different distributions of daily calcium intake.
3. Cooking Methods
- Cast Iron Cookware: Cooking tomato sauce in an iron skillet increased the amount of iron in the sauce and improved iron status among Brazilian teenagers and young adult lacto-ovo-vegetarians.
- Lysine-Rich Foods: Plant foods like legumes and quinoa are good sources of protein, which are rich in several amino acids that may help increase iron absorption.
4. Other Enhancers
- Beta Carotene: Beta carotene reduces the inhibitory effects of polyphenols and phytates in iron-rich grains.
- Garlic and Onion: Higher bioaccessibility of iron and zinc from food grains in the presence of garlic and onion.
Iron Deficiency and Anemia
Iron deficiency anemia (too little iron) is a common problem. Low levels of iron can lead to an iron deficiency called anemia. The symptoms of anemia include:
- Fatigue
- Weakness
- Pale or yellowish skin
- Shortness of breath
- Dizziness or lightheadedness
- Chest pain
- Cold hands and feet
- Headaches
Vegans are no more likely to develop iron deficiency anemia than the general population. However, it's essential to be aware of the risk factors and symptoms, especially for women, long-distance runners, and those with a history of iron deficiency.
Assessing Iron Status
Iron status is easily assessed through blood tests ordered by a physician. Due to concerns with both iron deficiency from menstruation and hemochromatosis (especially among men), it’s prudent to speak to a physician about having iron levels tested at least once during early adulthood.
Read also: The Vegetarian's Guide to Iron
Low iron stores are marked by serum ferritin of 15-30 μg/l with a transferrin saturation of >20%. Iron deficiency is marked by a transferrin saturation of < 20% and low reticulocyte hemoglobin. Iron deficiency anemia is marked by a reduced mean cell volume (MCV) and hemoglobin concentration.
Addressing Iron Deficiency
Vegans with milder forms of iron deficiency should add high-iron foods and vitamin C to meals while avoiding tea, and possibly coffee, red wine, and cocoa within an hour of meals. More serious cases of iron deficiency are treated with high-dose oral or parenteral iron which is normally effective but should be administered only under the supervision of a physician.
Potential Risks of Excessive Iron Intake
Iron is a pro-oxidant molecule. In high amounts, it could be a contributor to chronic disease. The tolerable upper limit (UL) for iron is 40 mg for ages ≤ 13 and 45 mg for ages >13. The UL is based on gastrointestinal distress. The UL is not intended for medically supervised iron therapy.
- Mortality: A 9-year prospective analysis of the United States National Health and Nutrition Examination Study (NHANES) data found significant trends between higher heme iron intake and an increased risk of all-cause and cardiovascular mortality.
- Type 2 Diabetes: A meta-analysis of prospective studies found that higher intakes of heme iron and iron stores were strongly associated with a higher risk of type 2 diabetes.
- Cardiovascular Disease: A meta-analysis of prospective studies found an increased risk of cardiovascular mortality when comparing highest versus lowest heme iron intake and for each 1 mg increase in heme iron intake.
- Cancer: A 9-year prospective analysis of the United States National Health and Nutrition Examination Study (NHANES) data found significant trends between higher non-heme iron intake and a lower risk for cancer mortality.
Hemochromatosis is a genetic disorder in which someone absorbs abnormally large amounts of iron, resulting in serum ferritin levels of >300 ng/ml in men, 200-300 ng/ml in postmenopausal women, and >200 ng/ml in premenopausal women.
Dispelling Common Misconceptions
It’s a common misconception that vegetarians and vegans, since they do not consume meat, are unable to get enough iron in their diets to safely donate blood. However, vegans typically consume an adequate amount of iron because their diet is high in vitamin C, which improves absorption of nonheme iron.