What is Iron Deficiency Anemia?

Iron is an essential mineral which surprisingly many people could be lacking. Learn about iron's core functions, symptoms and causes of its deficiency, as well as what high-iron foods to consume.

Core functions

Iron combines with other nutrients to form blood proteins which are necessary components of hemoglobin, a part of red blood cells (RBCs). The primary role of RBCs is to transport oxygen from the lungs to bodily tissues and carbon dioxide from the tissues back to the lungs.

Iron is also involved in food metabolism and is a cofactor and activator for some enzymes. In other words, iron influences enzymes which play key roles in energy production and metabolism, including DNA synthesis.

Deficiency symptoms

The main symptoms of iron deficiency are linked to the reduced delivery of oxygen to bodily tissues and the impaired function of iron-containing enzymes in various tissues.

Iron-deficiency anemia, characterized by very small RBCs, is the most common form of anemia. It must, however, be noted that anemia is the last stage of iron deficiency. Before anemia takes place, iron-dependent enzymes which play roles in metabolism and energy production would first be impacted by low iron levels. In other words, even before anemia sets in, a person who is deficient in iron could already be constantly feeling tired.

Symptoms of iron deficiency include:

• Anemia
• Excessive menstrual blood loss (ironically, also a cause of deficiency)
• Impaired immunity
• Reduced energy levels, fatigue, can't sustain prolonged activities
• Lowered physical performance
• Learning disabilities
• Poor memory and concentration
• Paleness

Common causes

People most vulnerable to iron deficiency are infants under two, teenage girls, pregnant ladies and the elderly. Research suggests as much as 30 to 50 percent of people in these groups could be iron-deficient.

Common causes of iron deficiency include:

• Increased iron needs - infancy, adolescence, pregnancy, lactation
• Insufficient dietary intake - quite common around the world. Diets typically fed to infants in developed countries, high in cereals and milk, tend to be low-iron. People, especially teens, who consume lots of junk processed foods are also susceptible.
• Reduced body absorption and/or utilization of iron - e.g. chronic diarrhea or malabsorption, removal of stomach, antacid use, lack of hydrochloric acid secretion in stomach
• Blood loss - excessive menstrual bleeding, peptic ulcers, hemorrhoids

Research also suggests the low-income elderly are most at risk of iron deficiency. Decreased absorption among this group is very common.

Children

In developing children, even slight iron deficiency can cause learning disabilities. This is because a developing nervous system uses significantly more energy than a mature one, and sufficient iron is critical in providing the energy needed for healthy development and growth.

Symptoms of iron deficiency in children include:

• Delayed physical growth
• Slow mental development - lower IQ, poor short-term memory
• Behavioral issues - hyperactivity, poor social interactions

Research suggests about 9 percent of US children aged 12-36 months have iron-deficiency anemia.

High-iron foods

These include:

• Beef
• Organ meats
• Clams
• Shrimp
• Black beans
• Black-eyed peas
• Blackstrap molasses
• Brewer's yeast
• Chickpeas
• Green leafy vegetables
• Kelp
• Kidney beans
• Legumes
• Lentils
• Lima beans
• Nuts
• Pinto beans
• Prune juice
• Pumpkin
• Quinoa
• Soybeans
• Spinach
• Swiss chard
• Tempeh
• Tofu
• Turnip greens
• Whole grains

Broadly speaking, heme iron (from animals) is better absorbed by the body than nonheme iron (from plants).

Iron levels in the body need to be carefully balanced as iron overload is linked to higher risks of heart disease, infections and even cancer. It can also harm the liver and pancreas. Iron excess is more common in men and, as such, some practitioners restrict iron supplementation only to persons with iron deficiency and women who are menstruating, pregnant or lactating.