Iron is a micronutrient that is essential for many physiological functions, such as synthesis of hemoglobin, DNA, collagen, hormones, and neurotransmitters.
With that introduction I am going to guess that you can understand why it is essential you consume enough iron day to day, to achieve adequate iron stores.
How Much Iron Do You Need?
- Infants and Children
Infants from birth to 6 months need a fractional amount of iron as a result of the storage of iron they are born with but as they age, both males and females need between 8-11 milligrams (mg) per day.
- Adolescents and adults
As a general rule male, iron needs don’t change over the lifetime, continuing to remain at 8 mg per day. Females, however, have varying iron needs, needing 15-18 mg per day during the years of menstruation. These needs go up to 27 mg per day if pregnant to support the growing fetus. Past the years of menstruation, female needs reduce to no more than 8 mg per day.
The Best Iron-Rich Foods
To ensure we are meeting our minimum iron needs we will obviously turn towards a variety of plant or animal food sources.
- Plant based
- Broccoli, spinach, kale, collard greens and Swiss chard all offer iron when cooked. Of all these plentiful plant-based foods, spinach does provide the most, serving up 6.4 mg per cup.
- Legumes such as lentils, kidney beans, garbanzo beans, and pinto beans all offer a healthy serving of iron. Lentils, however, yield 6.6 mg per cup which is the highest of the legumes.
- Black strap Molasses is unique because for only 2 tablespoons it provides 3.8 mg, a particularly substantial amount .
- Raisins, dried figs, oatmeal, nuts, seeds, soymilk, tempeh, sweet potatoes, tomatoes, and many other foods also provide plenty of plant-based iron, just at a lesser quantity.
- Animal based 
- Cooked organ meat such as liver or giblets definitely provide the most generous source, the yield is 5-33 mg of iron for every 3 ounces.
- Oysters, when cooked with wet steam offer 8 mg for every 3 ounces.
- Bone broth provides about 0.5 mg per cup.
- Cooked meat, seafood, dark poultry and eggs are also going to yield iron. Yet, 3 ounces of beef only offer 2-4 mg of iron, 3 ounces of chicken thighs only provides 0.5-1 mg.
What Are the Types of Iron?
There are two types of iron: Heme and Non-Heme.
Animal products contain both the heme and non-heme form and only about 15% of what we eat is absorbed.
Plants contain the non-heme elemental form and only 3% to 8% of what we eat is absorbed.
It may seem odd but it is true that comparing oysters and organ meat to plant-based foods, we see that plant-based foods contain a much more substantial dose of iron.
However, the most noteworthy difference really is the rate of absorption of the two sources of iron.
The body more easily absorbs heme iron, this is not to say that non-heme iron is lacking entirely, in fact, both types of iron benefit from assistance to maximize absorption.
How to Increase Iron Absorption?
Foods that contain carbonates, oxalates, phytates, tannins, phosvitin, and fiber can bind to iron and prevent absorption. It may seem like an appealing option to limit these foods in our diet but many of the foods we commonly eat for other healthful reasons, even those with iron have these compounds. So, rather than focusing on what to eliminate, let’s look at what we can add to maximize on absorption.
Cooking in cast iron, combining heme iron with non-heme iron foods and adding foods rich in vitamin C to meals containing iron, can all promote iron absorption. In a nutshell, fruits and vegetables are rich in vitamin C.
Iron Deficiency and Iron Overload
In the setting of low rates of absorption and the commonality of deficiency, many people turn to supplements to prevent iron deficiency.
Supplementation is, at times a necessary solution, however, due to the fact that the body cannot rid itself of excess iron, it gets accumulates in our joints, pancreas, heart and other tissue.
- Iron deficiency
- People at risk for deficiency: runners, plant-based eaters, people who have had bariatric surgery, people with an inflammatory bowel disease, those who chronically use medications classified as proton pump inhibitors.
- Risks associated with deficiency include but are not limited to fatigue, chronic gastritis, spoon-shaped fingernails, shortness of breath, headaches, dizziness, dry skin and restless leg. A less commonly discussed risk of iron deficiency is increased toxic heavy metal absorption. To reduce your risk of absorbing heavy metals, ensure you are eating a variety of food sources replete with essential minerals. Despite being less common it is of importance, as our environmental exposure is to toxins is increasing. If you think you may be deficient, reach out to your medical team and schedule a CBC (complete blood count), this simple and routine blood test can provide the answer.
- Iron overload
- Symptoms of iron overload are extensive: Fatigue, joint pain, stomach pain, irregular heart rhythm, hair loss, depression, polycythemia, elevated blood sugar, elevated liver enzymes, and many other severe consequences. As these symptoms can also indicate other health issues, it is essential to contact your medical team for the CBC to rule out iron overload as the cause.
- Iron overload is typically related to taking a multivitamin or multimineral that contains iron, without the need for supplementation. Which begs the question, can you get your iron needs met by food alone or should you supplement? The answer is yes, one should be able to get their needs met by food alone. Unless they are at risk for low iron stores, and if that is the case, the best thing to do is first determine if they are in fact deficient and then discuss the right strategy for supplementation with their health care team.
- The upper limit for children up to the age of 13 is 40mg per day and 45mg per day for adults. For this reason, adult males and postmenopausal women should avoid taking iron supplements.
The Main Takeaway
In order to not get bogged down in the details, it is important to look at the big picture and remember these main points.
- Regularly eat a mixture of animal and plant based foods that are rich in iron.
- Iron increases in availability when the food source is cooked.
- If you think you are low, then get a blood test to determine if you need supplementation.
- Combine vitamin C rich foods with iron rich foods to maximize absorption.
- Cook in cast iron.
Iron and Vitamin C Rich Meal Ideas
Have fun and experiment like a food scientist by combining foods for a synthesizing experience!
- Oatmeal with Blackstrap Molasses, raisins, and nuts.
- Two hard boiled eggs and an orange.
- Lentils topped with spinach braised in lemon juice and water.
- Salmon baked with some fresh orange slices on top.
- Roasted chicken thighs, braised spinach, and mixed fruit.
- Steak, roasted fingerling potatoes, and braised chard.
2. Iron. (2017, May 05). Retrieved January 4, 2020, from http://lpi.oregonstate.edu/mic/minerals/iron#food-sources
3. Ask the Expert: What's the Deal With Bone Broth? - Today's Dietitian Magazine. (n.d.). Retrieved January 15, 2020, from https://www.todaysdietitian.com/newarchives/0516p10.shtml
4. Mahan, L. K., & Raymond, J. L. (2017). Krauses food & the nutrition care process. St. Louis, MO: Elsevier.
5. Ems, T. (2019, April 21). Biochemistry, Iron Absorption. Retrieved January 15, 2020, from https://www.ncbi.nlm.nih.gov/books/NBK448204/
6. Iron Deficiency After Gastric Bypass Surgery. (n.d.). Retrieved January 15, 2020, from https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=134&ContentID=108
7. Thielecke, F., & Nugent, A. P. (2018, September 2). Contaminants in Grain-A Major Risk for Whole Grain Safety? Retrieved January 15, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6163171/