Everything You Need to Know About Iron Supplements

Iron is one of the most common elements in existence, and none of us would live long without it. But why do we need iron in the first place, and does anyone really need to take iron supplements?

By Stephen C. George; Medically Reviewed by Dr. Ahmad Talha Azam
Feb 12, 2024 9:15 PMFeb 13, 2024 6:55 PM
Close Up Of Girl holding Red Pill and glass of water.With Iron of tummy or pregnant. Nutritional Supplements.Sport,pregnancy Concept.Capsules Vitamin And Dietary Supplements.
Who really needs iron supplements? (Credit: MIA Studio/Shutterstock)


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It is the most abundant metal in the universe. By mass, it is the most common element on our planet, making up much of Earth’s core and some of its crust.

As minerals go, humans — indeed, most living things — can’t make it themselves and don’t need very much of it. But without even that little bit, we’d all be dead. That’s the irony of iron.

What Is Iron?

How hemoglobin works. (Credit: Designua/Shutterstock)

Iron is one of several essential nutrients (meaning we have to get it from the foods we eat) that humans need to maintain good health and the proper functioning of many of the body’s critical operations.

Why Do We Need Iron?

In iron’s case, we use it to make a few hormones; it’s also important for our immune and reproductive systems and overall growth and development.

What Does Iron Do for the Body?

But where you really need iron is in your blood. The mineral is a crucial ingredient in the production of hemoglobin, a protein in red blood cells that transports oxygen from your lungs to everywhere else in your body. Without iron, you’d have no hemoglobin. Without hemoglobin, your body would get no oxygen. Without oxygen, you’d die. (Iron is also important in the making of another protein, myoglobin, which stores oxygen for use in muscle tissues.)

Read More: What Do Your Blood Test Results Mean?

How Much Iron Do We Need Daily?

The good news is that the average healthy human body doesn’t require very much iron at all — mere milligrams, in fact. According to current FDA guidelines, the daily value for iron is 7 milligrams per day for kids between the ages of 1 and 3 and 18 milligrams daily for adults and kids aged 4 and above. The National Institutes of Health provides more specific doses by age categories.

What Are the Best Sources of Iron?

(Credit: Tatjana Baibakova/Shutterstock)

For most of us, and as with most minerals, our bodies get all the iron we need through a regular healthy diet. Iron is abundant in most animal meats, as well as seafood and poultry. You’ll also find it in spinach, peas, most beans, nuts, and even some dried fruits, such as raisins.

Plenty of modern convenience foods are also fortified with iron, especially cereal and bread. And, of course, you can get iron through nutritional supplements, although this method of delivery has been checkered by some controversy over the decades. Because unless they have an underlying health issue, most people really do not need iron supplements.

Read More: 4 Science-Backed Diets to Improve Your Health

How Long Have Iron Pills Been Around?

Vintage ad for Carter's Iron Pills. (Credit: Boston Public Library/Wikimedia Commons/CC-BY SA 2.0)

Supplementary iron has been available in various formulations since ancient times. The Greeks were aware of its uses and benefits, and proper iron supplements of some kind have been available since the 17th century. By the 1800s, certain medical entrepreneurs were marketing iron pills to the masses — Carter’s Iron Pills (later known as Carter’s Little Liver Pills) was one such popular example.

By the 20th century, one of the most eagerly sought supplements of all time came to prominence in American popular culture: Geritol, an iron and B vitamin supplement (available in both pills and alcohol-infused liquids). Their marketing campaign famously — or perhaps infamously — touted this supplement as a cure-all for what was frequently called “iron-poor blood.”

By the 1950s and 60s, Geritol was everywhere, a major advertiser in magazines and a sponsor, especially in TV game shows of the era. You could not escape it or the promise that a good jolt of iron was all that one needed to boost energy levels and turbocharge that sluggish bloodstream of yours.

Eventually, the company that produced Geritol was slapped with a cease-and-desist order and fined for deceptive claims about Geritol’s benefits. Although the product waned in popularity from then on, Geritol is still available today, and as a supplement, it actually does have certain benefits ... but only for some people.

Read More: Strange Side Effects From Supplements and What You Need to Know

What Are the Risks of Iron Deficiency?

Pregnancy is just one of several possible conditions requiring supplementary iron. (Credit: FotoDuets/Shutterstock)

Having a low iron count is one of the most common nutritional deficiencies in the world and affects as many as 5 million Americans. Low iron is a common cause of another health problem — iron deficiency anemia, in which sufferers lack sufficient red blood cells to effectively deliver oxygen throughout the body.

This form of anemia affects more than a billion people worldwide. Having said that, taking supplementary iron can be downright beneficial if you suffer from iron deficiency.

Read More: Eating Paper in Search of Missing Nutrients

What Are the Causes of Iron Deficiency?

Causes for iron deficiency can vary. Children and the elderly can be at risk for low iron, as can people who suffer from nutritional malabsorption issues. For people who are pregnant or tend to have heavy menstrual periods, iron deficiency can also be a problem.

How to Treat Iron Deficiency

For these conditions and others, iron supplementation (in the form of pills, liquid, or intravenous infusion) can help and even save lives. However, the exact form of iron and the dosage required are factors that should be determined by a doctor.

If you’re just feeling tired and sluggish, and you haven’t been diagnosed with iron deficiency or a condition that could cause it, there is no guarantee that increasing your daily intake of iron will boost your physical or cognitive functions.

Read More: Is It Bad to Take Pills on an Empty Stomach?

What Happens If You Take Too Much Iron?

(Credit: Innovative Creation/Shutterstock)

To be clear: The average person doesn’t need iron supplements; we get plenty from our diets. If you take more iron than your body needs, your system might store some of it, but not all of it. And if you take excessive amounts, you might find yourself very sick.

What Are the Symptoms of Iron Toxicity?

Iron toxicity is a serious issue that affects thousands of people per year. As a form of accidental medicine overdose, it was for years the leading cause of death in children under 6, and adults have suffered from it as well.

If you take too much — for most adults, that’s more than 45 milligrams of elemental iron per day — you may find yourself with mild symptoms such as dizziness or nausea, possibly with stomach upset, cramps, and diarrhea.

What Are the Symptoms of Iron Poisoning?

Daily doses above 60 milligrams per kilogram of body weight can be fatal, especially in children. If you take even more than that, your symptoms are likely to be much worse than an upset stomach. Serious symptoms of iron poisoning can include fluid in the lungs, vomiting of blood, seizures, coma, liver failure — and, of course, death.

Read More: Can Healthy Foods Be Toxic?

Should You Take Iron Supplements?

So, iron supplements are definitely helpful in the right circumstances, but they are by no means the miracle elixir that supplement gurus and entrepreneurs have claimed over the years. In fact, as we’ve seen, there is plenty of evidence to show that too much iron can be a really bad thing for you.

Think about that the next time you’re in the vitamin and mineral aisle, and if a certain metallic element suggests itself to you as a perfect cure-all for whatever ails you, exercise some critical thinking — and, if necessary, an iron will to resist the temptation to take more of it than you really need.

Read More: Dietary Supplements Are No Substitute For a Healthy Lifestyle

Frequently Asked Questions About Iron Supplements

When Should You Take Iron Supplements?

For maximum absorption, iron supplements should be taken without food. This is because lower gastric pH facilitates better iron absorption. 

Do Iron Supplements Cause Constipation?

Iron supplements can cause constipation and other gastrointestinal side effects, including nausea, vomiting, and in rare cases, bowel obstruction.

Do Iron Supplements Make You Gain Weight?

Weight gain is not commonly reported as a side effect of iron supplementation. In fact, one study showed that iron deficiency anemia patients treated with iron supplements lost weight compared to those who did not take supplements.

Why Is My Body Not Absorbing Iron Supplements?

Poor absorption of iron supplements can be attributed to several factors, including the type of iron, dietary inhibitors like calcium, the timing and dosage of intake, and overall intestinal health.

How Long Do Iron Supplements Take to Work?

A study that analyzed pooled data from 5 randomized trials (comparing oral and intravenous iron-replacement therapy for iron-deficiency anemia) showed improvement in hemoglobin levels in 14 days. Improvement in symptoms of iron deficiency typically begins within 2 to 4 weeks of starting supplementation, while it may take up to 2 months for your hemoglobin levels to normalize.

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

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