Jessica Cording, MS, RD, CDN, INHC is a registered dietitian, health coach, and author with a passion for helping people simplify their wellness routine and build healthy habits. Through her writing, consulting, public speaking, and counseling, she works with individuals, corporations, and the media to help make drama-free healthy living approachable and enjoyable.
She is a part of the mindbodygreen Collective and author of The Little Book of Game-Changers: 50 Healthy Habits For Managing Stress & Anxiety and the upcoming The Farewell Tour: A Caregiver's Guide To Stress Management, Sane Nutrition, and Better Sleep (Viva Editions, 10/11/22). A big believer in the mental and physical benefits of exercise, she is also a certified Pilates instructor. You can find her work in numerous print and digital publications, and she is a regularly featured nutrition expert. She has created video courses for CARAVAN Wellness and guided meditations for Simple Habit.
You probably hear a lot about the macronutrients — protein, fat, and carbs — but it's also important to make sure you're covering your bases with other nutrients your body needs. Exhibit A: Iron is a mineral that is important for growth and development and proper body functioning. Iron deficiency also happens to be one of the most common nutritional deficiencies worldwide, so you may want to start keeping tabs on your consumption of the micronutrient.
Below, your complete guide to iron, including more details on iron benefits, the best food sources of iron, and how to make sure you're getting a proper amount of the mineral.
You might notice a variety of iron benefits when you're consuming an adequate amount of the mineral. Here are a few highlights.
Your body uses iron to make hemoglobin, a protein in red blood cells which helps transport oxygen in your blood from your lungs throughout your body, and myoglobin, a protein that carries oxygen to your muscles, according to the National Institutes of Health (NIH). This is key for efficient day to day body processes, energy, immune system function, and more, according to the NIH.
Iron also plays a role in the production of certain hormones via supporting healthy function of the thyroid gland, which is responsible for the production and regulation of many hormones in your body, according to an article published in the International Journal of Research In Medical Sciences.
Another iron benefit, the mineral is important for the synthesis of connective tissue. This is why having healthy iron status is important for healthy hair, skin, and nails. If you're noticing your hair or nails are brittle or your skin is dull, you may want to check in on your iron levels. Remember how iron plays a role in the production of hemoglobin and transporting oxygen through your body? When that process is not efficient enough due to low iron levels, your body's cells may not get sufficient oxygen, which could result in brittle nails, hair loss, or sallow skin, according to the American Society of Hematology.
Iron may also support athletic performance. Your iron levels may factor into your aerobic capacity due to iron's role in energy production and the transport of oxygen to your body's cells. Put simply, when oxygen is not able to circulate through your body quickly enough, this can cause you to feel fatigued and weak — not helpful when you're running a race, swimming laps, or hitting the gym.
Your body stores iron as a protein called ferritin in your bone marrow, muscle tissue, liver, and spleen. If your iron intake is low for a short period of time, your body can use those stores to cover its needs for daily functioning. That's thanks to transferrin, a blood protein that binds to iron and delivers it to where it needs to go in your body. However, if you don't consume enough iron for a longer period, over time those stores become depleted and iron deficiency anemia (a condition in which you lack healthy red blood cells) can set in. You then have less healthy red blood cells available to carry oxygen through your body.
Some common iron deficiency symptoms include fatigue, dizziness, cold hands and feet, and pale skin, according to the National Heart, Lung, and Blood Institute (NHLBI). More severe cases may lead to tiredness, shortness of breath, or chest pain, according to NHLBI. Pica (unusual cravings for ice and non-food substances such as paper or dirt) is also a telltale symptom of iron deficiency anemia.
How much iron you need per day changes throughout your life. The U.S. Food and Nutrition Board's Recommended Dietary Allowance (RDA) for teen girls ages 14 to 18 is 15mg per day. Women over 18 need 18mg. The RDA jumps to 28mg during pregnancy, and then down to 9mg while breastfeeding. After menopause, women need 8mg of iron per day.
There are also certain medical conditions and medications that can impact your iron needs. For instance, if someone experiences gastrointestinal bleeding from overuse of non-steroidal anti-inflammatory drugs (NSAIDs), that iron loss in the blood impacts their levels, according to an article published in the Clinical Medicine Journal. Or if you lose a lot of blood during surgery, you may need extra iron to get back to a healthy level. People who experience heavy periods may also find they need to pay attention to their iron status.
If a doctor suspects you have an iron deficiency, they will typically test your ferritin and transferrin levels to check for iron deficiency anemia. Something to keep in mind is that "normal" does not always mean "optimal" when it comes to lab values. If your lab results are within the normal reference range but you're still having symptoms associated with low intake of iron, talk to your doctor for further investigation or consult with a registered dietitian for guidance on making sure you're consuming enough, and potentially, iron deficiency treatment.
"There are two types of iron: heme and non-heme," explains Keri Gans, R.D.N., author of The Small Change Diet and host of The Keri Report podcast. "Heme comes from animal products and non-heme from plant-based foods." Some foods high in iron include "beans, red meat, poultry, seafood (especially oysters), fortified breakfast cereals, dark green leafy vegetables (such as spinach, kale, and collard greens), eggs, and tofu," she says.
While someone can certainly meet their iron needs on a plant-based diet, it may require being extra intentional about it, as non-heme iron tends to be less easily absorbed by your body. Another thing to keep in mind is that vitamin C enhances iron absorption, which can be especially helpful when eating primarily non-heme sources. Fortified foods such as cereals and breads can also be sources of iron in your diet, though it's important to read labels and limit ultra-processed items or products high in added sugar, excess sodium, and trans fats.
A few things that can impair non-heme iron absorption are excessive amounts of bran fiber, large amounts of calcium (mostly from supplements), and certain plant compounds such as phytates/ phytic acid and tannins. A few examples of foods high in phytates include beans, seeds, nuts, and grains, but soaking beans or nuts and sprouting grains before cooking can help reduce phytates significantly. Tannins are found in high amounts in coffee, tea, wine, beer, some fruit (e.g. grapes and pomegranates) and juices.
In cases where meeting your daily iron needs through food isn't possible, supplements are available. "Some individuals who are following a 100 percent vegan diet, or even a vegetarian diet, may find it difficult to meet their iron needs and a supplement may be indicated," explains Gans. "I would, however, suggest getting their iron levels checked by their doctor first to see if it's necessary. This would be especially important for women of childbearing-age," because they're losing blood during menstruation. "Taking iron supplements may cause constipation, so I would highly suggest drinking plenty of water and consuming high-fiber foods, such as fruits, veggies, legumes, and whole grains," adds Gans. Talk to your doctor about whether you need to avoid taking iron with certain foods, other supplements, or medications.
Too much of a good thing is definitely possible with iron, as levels can build up your body, resulting in toxicity. The U.S. Food and Nutrition Board's Tolerable Upper Intake Limit (aka UL, or the maximum daily amount that's unlikely to have negative health implications) for iron is 45mg per day for those age 14 and over and 40mg for those 13 and under. In healthy adults, high-dose iron supplements (especially if taken on an empty stomach) may cause abdominal discomfort, constipation, nausea, vomiting, or diarrhea, according to the NIH. More serious effects are also possible with large amounts of iron, including ulcers, inflammation of the stomach lining, and decrease in zinc absorption. Extremely high doses (think: hundreds of milligrams) can lead to organ failure, coma, and death, according to the NIH.
Iron is widely available through a variety of foods. However, if you're having a hard time meeting your needs through food or experiencing symptoms of iron deficiency, talk to your doctor about whether a supplement would benefit you.