What Causes a Person to Have Low Iron?

Iron is a mineral that humans need to function. Causes of low iron include colon cancer, IBD, heavy periods, traumatic injury, and other causes.

Iron is a mineral that humans need to function. It is an important part of hemoglobin, which is found in red blood cells. Hemoglobin carries oxygen from the lungs to all the cells of the body. Low iron means that hemoglobin can't do its job well. 

Low iron can progress in stages to iron deficiency anemia, one of several types of anemia that can affect humans. Iron deficiency anemia is a global health problem that affects from 4 to 5 million Americans each year. 

Common signs of iron deficiency include:

• Paleness
• Fatigue
• Shortness of breath
• Headache

Low iron affects cells that grow rapidly, like hair and skin. With iron deficiency, you may have:

• Rough, dry skin
• Hair that appears dry or damaged
• Hair loss

You may develop low iron for several reasons, including:

• Not getting enough iron in your food
• Not absorbing the iron you have taken in
• Losing red blood cells, which contain iron

In addition, you may have unhealthily deficient iron if your need for iron rises, such as when a woman becomes pregnant. 

Blood loss is the most common cause of iron deficiency: 

If you have low iron, you may be losing blood from the gastrointestinal (GI) system. Causes include: 

• Colon cancer
• Inflammatory bowel disease
• Ulcers
• Celiac disease or other GI disorder

Blood loss can also occur from: 

• Heavy menstrual periods
• Traumatic injuries or surgery
• Bleeding during childbirth
• Long-term use of nonsteroidal anti-inflammatory drugs (NSAIDS), such as aspirin and ibuprofen 
• Urinary tract bleeding

If one of these conditions is causing blood loss, you will need to be treated for the underlying cause. You may need to see a specialist. 

Some people develop iron deficiency because they don't absorb iron well. 

Common causes of this include:

Celiac disease. If you have celiac disease, you react to gluten, a protein found in some grains. Celiac disease damages the small intestine, where iron is absorbed. In fact, iron deficiency is often the first symptom of celiac disease. If you remove gluten from your diet and allow the intestine to heal, your iron levels should return to normal levels. This can take up to 18 months. 

Gastric bypass surgery. After this type of surgery, food bypasses the first part of the small intestine, where iron is absorbed. You'll need to have your iron checked six months after bypass surgery and annually after that. You may get enough iron by changing your diet, or you may need iron supplements.

Infection with helicobacter pylori. Some studies suggest that low iron is associated with helicobacter pylori, the bacteria that causes stomach ulcers. Those with h. pylori infections often have low levels of ascorbic acid (vitamin C) in their stomach. Vitamin C aids in the absorption of iron, so its lack could cause low iron. 

You may have low iron because you're not getting enough in your diet. The iron in your food comes in two forms: heme and non-heme. Heme iron occurs only in meat. Non-heme iron is found in plant foods like nuts, seeds, legumes, and leafy greens. Meat can also contain non-heme iron due to the plants that most animals consume. In the United States and many other countries, food manufacturers add non-heme iron to some grain products, especially bread and cereal.

The body uses heme iron more readily than non-heme iron. Typical meat-eaters might get from 10% to 15% of their iron intake from heme iron, but because it's better absorbed, it could make up about 40% of the iron that is used by the body. 

Many factors, however, affect how well iron is absorbed. Absorption of non-heme iron is higher when the body's stores are lower. The same isn't true for heme iron or for iron used to fortify foods. 

Other factors affect the absorption of iron. Your body uses non-heme iron more readily when you consume it along with heme iron. Ascorbic acid (vitamin C) enhances the absorption of iron. 

Substances that can interfere with the absorption of iron include:

Calcium. This mineral found in dairy products may interfere with the absorption of both heme and non-heme iron.

Animal proteins. Although meat tissues enhance iron absorption, the proteins in animal products like eggs and milk reduce absorption.

Polyphenols. These substances have beneficial antioxidant properties but can lower iron absorption. They're present in many plant foods, including tea, coffee, and wine.

Phytates. Sometimes called anti-nutrients, phytates occur in legumes, seeds, and nuts. They decrease the body's use of several minerals, including iron.

People who do not eat meat may be at risk of iron deficiency since they don't get the more easily absorbed heme iron. However, experts say that the human body can increase its absorption of iron when needed. Several studies found vegetarians are no more likely than meat-eaters to have iron-deficiency anemia. Vegetarians may, however, have lower stored iron.  

A well-planned vegetarian or vegan diet should provide enough iron. Many foods that vegetarians eat also contain vitamin C, which helps with iron absorption. Those eating a plant-based diet should be sure to include iron-rich foods, including:

• Whole grains
• Legumes
• Nuts and seeds
• Dried fruits
• Green leafy vegetables
• Iron-fortified cereals

Iron needs vary by age and gender. Newborn babies usually have stores of iron that will last up to 6 months. After that age, recommended amounts for children are:

• 7 to 12 months old: 11 milligrams
• 1 to 3 years old: 7 milligrams
• 4 to 8 years old: 10 milligrams
• 9 to 13 years old: 8 milligrams

From ages 14 to 50, men and women have different needs because of the female reproductive system. Recommended amounts are:

• Men aged 14 to 18: 11 milligrams
• Women aged 14 to 18: 15 milligrams
• Men aged 19 to 50: 8 milligrams
• Women aged 19 to 50: 18 milligrams
• Pregnant women: 27 milligrams
• Lactating women: 9 to 10 milligrams
• Men and women aged 51 and older: 8 milligrams

Low iron levels require treatment, as iron deficiency anemia can be dangerous. The most common treatment is iron supplements. 

It's rare to get too much iron from your diet, but it can happen if you take supplements. High-dose supplements can cause gastrointestinal distress. Very high-dose supplements can be toxic. 

Always follow your doctor's directions when using supplements.