Brain Development, Liver Detoxification, and Other Key Iron Functions

Facts about iron absorption and too much or too little of a good thing

By Roberta H. Anding, MS, Baylor College of Medicine and Texas Children’s Hospital
Edited by Kate Findley and proofread by Angela Shoemaker, Wondrium Daily

You may know that vegetarians run a risk of being iron deficient, but thankfully there’s an easy fix! Professor Anding explores iron facts and functions, including unusual sources.

Foods high in Iron
Having a deficiency or an excess of iron affects our health since iron plays an important role in many functions of our bodies. Photo By Tatjana Baibakova

Functions of Iron

Among its many important functions, iron is a component of hemoglobin, myoglobin, and many enzymes within the body.

Hemoglobin is the protein on red blood cells that’s responsible for oxygen transport. Its partner, myoglobin, is the protein found in muscle tissue. 

Since iron has an integral role in brain development, it is absolutely critical to have it in the first two years of life. It is also vital in the production of the protective membrane in the central nervous system, called the myelin sheath. And, iron is involved in the production of neurotransmitters, which are chemicals that carry signals between nerve cells.

Iron for Infants

Infant formula contains iron. Breast milk has very biologically available iron, but cow’s milk is devoid of iron. This is one of the reasons why the American Academy of Pediatrics recommends either infant formula or breastfeeding for newborns and infants for the first years of life. 

“I was in a San Jose clinic there in Houston, and I had a woman come in with what appeared to be strawberry milk,” Professor Anding said. “When I asked her what this was because her baby was profoundly iron deficient, it was cornstarch with strawberry flavoring in it.”

It looked like milk, but it wasn’t milk. It was a milk surrogate, as the woman described it. “It was pretend milk, infinitely less expensive than cow’s milk, and certainly much less expensive than infant formula,” Professor Anding said. This was the cause of anemia or iron deficiency in her infant.

Bioavailability and Dangers of Excess

Iron is a structural part of many enzymes that have a multitude of metabolic functions, including, again, neurotransmitter production and function as well as the synthesis of DNA and collagen. It helps the liver’s detoxification system.

Although detox diets are very trendy these days, the liver does a more than sufficient job. Just make sure that you have adequate amounts of iron in your diet. 

Iron is also integral in the maintenance of a functioning immune system, but bacteria also require iron for growth. Thus, if you’re taking lots of supplemental iron, keep in mind that bacteria can grow in the presence of extra iron. This is why many nutrition support products that might be given to you intravenously in the hospital are iron-free. 

Additionally, iron is not bioavailable. On average, only about 10% of dietary iron that you consume is absorbed by the body. Generally, women absorb about 13% of dietary iron, and men absorb about 6%. The reason men absorb less than women depends on biological need. 

Absorption can range from as little as 1% to over 50%, depending on your state of deficiency. Absorption is more effective during times of deficiency; so if you are deficient, your body actually ramps up the absorption.

Tips for Vegetarians

Dietary iron comes in two distinct forms: heme iron (from the word “hemoglobin”) and non-heme iron. Heme iron is found mainly in animal products and is absorbed much more effectively than non-heme iron, which is found in grains and plants. 

Thus, if you’re vegetarian and not eating any sources of animal protein, your absorption of iron might be compromised. The presence of free amino acids, a broken down product of protein metabolism and the acidic pH of your stomach, will enhance the absorption of non-heme iron. Thus, many of us think the acidic environment in our stomach is not physiologically normal, but it’s actually physiologically essential.

According to Professor Anding, you can take steps to increase the absorption of iron, and your grandmother probably had the best answer. Cooking with a black iron skillet can increase the iron content of a meal from anywhere from 30- to 100-fold. 

“In my work at the Houston Ballet, I always recommend to my ballerinas to go out and get a black iron skillet, because they are trying to manage their calories, and oftentimes they’re vegetarian; and, I want to enhance that iron absorption,” Professor Anding said.

Iron absorption can also be decreased by antacids. That should make sense, as the antacids’ job is to alter the pH of the stomach. Keep in mind that iron loves acid. Other things in the diet can influence the amount of iron that you absorb. Calcium, zinc, magnesium, and phosphorus can all reduce the absorption of iron. In the environment, lead exposure will reduce the absorption of iron.

In terms of dietary intake, if you take calcium, in any form, for the prevention of osteoporosis, don’t take it with iron. Think of dominoes. If you knock down one, you’re going to knock down others.

Tomorrow’s article will go into more detail on bioavailability and deficiency. 

This article was edited by Kate Findley, Writer for Wondrium Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for Wondrium Daily.

Professor Roberta H. Anding is a registered dietitian and Director of Sports Nutrition and a clinical dietitian at Baylor College of Medicine and Texas Children’s Hospital. She also teaches and lectures in the Baylor College of Medicine’s Department of Pediatrics, Section of Adolescent Medicine and Sports Medicine, and in the Department of Kinesiology at Rice University.