Iron Benefits: Is Iron Supplementation Good for Your Health?

Iron isn't just a metallic element used for building skyscrapers and the frames of cars; it's also a critical micronutrient used throughout the body in essential functions. Iron is required for proper physical growth, neurological development, the function of your cells, the synthesis of some hormones, and the creation of hemoglobin (and, thus, the transport of oxygen through the blood.)

As is so often the case with essential vitamins and minerals, there's a market for supplements that give you more, often more than you need. The question is, is supplementing additional iron beneficial to your health, or are there risks that outweigh any possible benefit?

What is the Recommended Daily Intake of Iron?

There are two different forms of iron you can get from food and supplements: heme and nonheme iron. Heme iron comes from animal-based protein sources like red meats, poultry, and seafood. Nonheme iron is also present in meats but can be found in plant foods like beans, nuts, legumes, greens, and grains.

This is important because heme iron is better absorbed by the body and can be used more readily. Nonheme iron is less well-absorbed. Around 25% of the dietary heme iron you consume is absorbed, while only around 17% of nonheme iron is absorbed. Bioavailability numbers are even lower, at 14-18% for heme iron and 5-12% for nonheme iron.

What this means is that iron recommended intakes vary depending on your lifestyle. If you eat a mixed omnivorous diet, you will need less dietary iron in general than if you're a vegetarian or vegan and don't consume heme iron.

Recommended daily intake numbers are based on omnivorous diets. That means everything from the numbers you see on product packaging to the chart below is based on people who eat red meat, poultry, and fish on a regular basis. If you're vegetarian or vegan, you will need to increase those numbers by around 1.8x.

The amount of iron you need varies throughout your life but is highest when you're younger. It's also higher for women than for men; this is because menstruation typically causes a significant loss in bodily iron.

Women who are pregnant will also need significantly more iron to support all of the bodily processes that go into developing a fetus, so the amount required is nearly double what they would need normally.

Again, these recommendations are for people eating a diet mixed with both heme and nonheme iron; for vegetarians and vegans who solely eat sources of nonheme iron, increase these numbers by nearly two times.

The USDA and FDA have also determined that the tolerable upper limit of iron intake – combining both dietary and supplement sources – is 40 mg for anyone under the age of 14 and 45 mg for anyone over 14. This is the point at which side effects begin.

Where Does Iron Usually Come From?

Iron comes from the food we eat. Heme iron comes from animal sources, primarily lean meats and seafood. Nonheme iron is found throughout plant matter, including nuts, beans, vegetables of all kinds, and fortified grain products. Many cereal products, such as breakfast cereals, are fortified to include 100% of your recommended daily iron intake per serving, specifically because they are aimed at children, and children need iron to support growth. Infant formulas are also typically fortified with enough iron for a newborn.

Common sources of dietary iron include:

• Beef, with 33 mg per 3 ounces.
• White beans, with 8 mg per serving.
• Lentils, with 3 mg per serving.
• Spinach, with 3 mg per serving.
• Sardines, with 2 mg per serving.
• Potatoes, with 2 mg per serving.

The USDA also maintains a comprehensive list of products and food items, as well as their iron content, which you can find here.

What Happens if You're Deficient in Iron?

Unfortunately, despite how common iron-fortified foods are, iron deficiency is relatively common in both the United States and around the world. It's especially prominent among people with food insecurity, people with poor diets, people with malabsorption disorders, and people who lose blood for any reason.

Iron deficiency progresses through multiple stages and gets worse the longer iron is deficient. The first stage is a depletion of stored bodily iron. The second stage is a marginal deficiency, where the iron deficiency starts to affect erythrocyte production, but blood hemoglobin levels are still within normal ranges. The third stage is full deficiency, where iron stores are fully exhausted, hemoglobin levels decline, and anemia takes hold.

The World Health Organization has identified the third stage of iron deficiency, iron deficiency anemia or IDA, as one of the ten leading factors for disease globally.

What are the symptoms of iron deficiency anemia?

• Gastrointestinal disturbances and issues.
• Weakness.
• Fatigue.
• Difficulty concentrating.
• Impaired cognitive function.
• Impaired immune function.
• Decreased exercise and work performance.
• Disrupted body temperature regulation.
• Pale skin.
• Chest pain.
• Fast heartbeat.
• Headache.
• Poor circulation and feeling cold.
• Strange food cravings.
• Restless legs.

In infants and children, iron deficiency can lead to psychomotor and cognitive impairment that can lead to learning difficulties, and may persist throughout life even if the iron deficiency is treated.

On top of all of this, iron deficiency is commonly associated with other dietary nutrient deficiencies, so these symptoms are often muddled with symptoms of other deficiencies.

Who is most at risk of iron deficiency?

Anyone can be deficient in iron, but some groups of people have a greater risk due to biological, lifestyle, or other factors.

These groups include:

• Pregnant women. During pregnancy, many biological changes occur, including the mass production of red blood cells to fuel the development of the fetus and placenta and ferry nutrients; iron is critical in more significant amounts to account for this.
• Infants and children. Iron is critical for growth, neurological development, and bodily performance, and a deficiency can lead to long-term issues.
• Women, especially those with heavy menstrual bleeding. Scientifically known as menorrhagia, heavy bleeding means a loss of a more significant amount of blood each month and, thus, a loss of more blood-carried iron. There's some evidence suggesting that menorrhagia is responsible for over a third of all iron anemia cases in women of reproductive age.
• Frequent blood donors. Again, any reason you lose blood, willingly or otherwise, is a reason why you can have low iron levels. Frequently donating blood is likely to lead to longer-term iron problems.
• Cancer patients. Some cancers can inhibit the absorption of iron, such as colon cancer. Other cancers can cause iron anemia for other reasons. Additionally, many chemotherapy drugs can inhibit iron absorption. The disease and the treatment both frequently reduce appetite, leading to deficiencies as well.
• People with gastrointestinal disorders. Disorders such as celiac disease, ulcerative colitis, and Crohn's disease all impact the performance of the small intestines, where the majority of your dietary iron is absorbed. They can also cause blood loss in the gastrointestinal tract, further leading to loss of iron.

While these groups of people are at the highest risk, there are also lifestyle factors to consider. As mentioned, maintaining a poor diet, or maintaining a vegetarian or vegan diet, can mean you get less iron in your diet than you actually need to remain healthy.

Are There Benefits to Supplementing Iron?

A dietary supplement is best used in one of two cases.

The first is when you have a specific nutritional deficiency, and you want to address that deficiency. In cases where an individual has an iron deficiency, supplementing additional iron is a way to address the problem in the short term. Over time, other lifestyle adjustments and dietary changes can be made to get more iron from your diet naturally, and the iron supplement can be dropped.

The second is when you have a balanced diet and healthy lifestyle, but there’s a medical reason affecting your ability to absorb nutrients properly. For example, someone might be iron deficient not only because of dietary factors, like being vegetarian, but also due to conditions like gut health issues or medical conditions that interfere with absorption. It’s really important to talk to a doctor about this because if you’re low in iron, you need to find out why. Supplementing with iron could just cover up a more serious problem if the root cause isn't addressed. This is also the concept behind my MicroVitamin, which I developed to help address nutritional issues I see in my own diet.

It's worth mentioning that the majority of iron supplements on the market are going to be nonheme iron because iron from plant sources is both easier to produce and more common, and it allows those products to be taken by vegetarians and vegans who otherwise might avoid them.

Iron supplements, in general, are not recommended unless you have a specific reason to take them. There is such a thing as "too much of a good thing," and iron definitely falls into this category.

Are There Risks to Supplementing Iron?

In general, unless you are deficient in iron and instructed to take an iron supplement by your doctor, you should probably avoid taking iron supplements. This is especially true if you're over the age of 50.

First of all, iron supplements frequently cause gastrointestinal problems. Taking moderate to high-dose supplements can cause constipation, nausea, abdominal pain, vomiting, and diarrhea. Taking even higher doses can cause more serious side effects, including gastritis and gastric lesions. This can actually loop back around and cause anemia through internal bleeding. In extreme cases – more than 1,300 mg of iron per day – iron supplements have been observed to cause corrosive necrosis of the intestines. Obviously, you aren't going to reach this level without doing something very wrong, but it goes to show how the impact gets worse the more you take.

That's not all. Taking excess iron supplements can inhibit the body's ability to absorb other nutrients, such as zinc. Treating one deficiency and causing another is a real risk when addressing deficiencies with supplements rather than dietary and lifestyle changes.

Over time, excess iron can build up in your organs. This iron build-up can, over time, damage your liver, pancreas, and even your heart. This is especially true in people over the age of 50.

In general, it's not a good idea to take iron supplements, either as a stand-alone supplement or as part of a multivitamin, unless you've been instructed to do so by your doctor.

As always, consult with your own medical professionals about your own health circumstances rather than taking generic advice from the internet. Meanwhile, if you want to stay current with new developments in medical science, supplement news, and more, follow this blog or my YouTube channel.

Sources:

1. National Institutes of Health Office of Dietary Supplements Iron Fact Sheet for Health Professionals: https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/
2. National Institutes of Health Library of Medicine StatPearls Dietary Iron Review: https://www.ncbi.nlm.nih.gov/books/NBK540969/
3. Review on iron and its importance for human health: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3999603/
4. The American Red Cross - The Importance of Iron in Your Body: https://www.redcrossblood.org/local-homepage/news/article/iron-in-blood.html
5. Cleveland Clinic Iron Supplement (Ferrous Sulfate) Fact Sheet: https://my.clevelandclinic.org/health/drugs/14568-iron-oral-supplements-for-anemia
6. USDA National Nutrient Database for Standard Reference, Iron: https://ods.od.nih.gov/pubs/usdandb/Iron-Content.pdf
7. Age and the prevalence of bleeding disorders in women with menorrhagia: https://pubmed.ncbi.nlm.nih.gov/15625143/
8. Iron pill induced gastritis causing severe anemia: https://pubmed.ncbi.nlm.nih.gov/32468501/