What Causes Dietary
Iron Deficiency Anaemia?

What Is Iron?

Iron is a mineral that is crucial to various bodily functions, including the transportation of oxygen via the blood to all parts of the body. Without iron, your body’s ability to transport blood decreases, making iron a critical mineral for your very survival. Even when your iron levels dip just a bit, you may notice it in decreased energy levels, weakness, coldness in the hands and feet, brittle nails and other weird but not necessarily alarming symptoms.

Iron is a naturally occurring mineral that is found in everything from fruits and vegetables to dirt and rocks to stars in outer space. However, humans and other animals typically get iron from the foods they eat, such as broccoli, beans, nuts, leafy greens and red meat.

Iron does not stay in the body. It is lost through sweat, the shedding of intestinal cells and blood loss. In fact, because iron loss is so normal, approximately one-third of the world’s population has an iron deficiency. Menstruating women are more at risk of experiencing iron deficiency than postmenopausal women or men.

The Role of Iron in the Body

Iron supports four main functions within the body:

• Oxygen Transportation: Red blood cells contain haemoglobin, which is a complex protein that transports oxygen from the lungs to the rest of the body. Partly made from iron, haemoglobin accounts for approximately two-thirds of the body’s total iron content.
• Oxygen Storage: Myoglobin also contains iron, but instead of using the iron to transport oxygen, it uses the mineral to store it in muscle cells. Myoglobin is what causes muscles to take on their red hue.
• Energy Production: Iron is also present in several enzymes throughout the body, including those responsible for energy production. Enzymes are the catalysts of many cell functions.
• Immune System Function: The immune system, which helps the body fight off infection, relies heavily on sufficient iron. When iron levels dip, so, too, does immune system function.

The Recommended Dietary Iron Intakes

Technically speaking, humans need to only absorb a small amount of iron each day to remain healthy. A small amount is truly a small amount, at approximately 1 mg for adult males and 1.5 mg for menstruating females each day. However, to achieve this small absorption amount, healthy adults must consume anywhere from eight to 27 times the absorption amount, as our bodies can only absorb a small amount of iron from the foods we consume. Below are a few intake guidelines for select groups of people:

• Breastfed babies between 0 and 6 months of age = 0.2 mg
• Infants between 7 and 12 months = 11 mg
• Children between 1 and 3 years = 9 mg
• Children between 4 and 8 years = 10 mg
• Adolescents between 9 and 13 years = 8 mg
• Boys between 14 and 18 years of age = 11 mg
• Girls between 14 and 18 years of age = 15 mg
• Women between 19 and 50 years of age = 18 mg
• Men aged 19 and over = 8 mg
• Pregnant women = 27 mg
• Women 51 years of age and older = 8 mg

As you can see, women of menstruating age — meaning, between 14 and 51 years of age — need to consume exponentially more iron than men of similar ages. This is because women lose a substantial amount of blood each month, compared to most men, who do not.

How much do we absorb?

When you compare the amount of iron your body needs to how much you must consume to meet that goal, you can see that the human body does not metabolize iron very efficiently. That said, how much your body can absorb depends on how much it can store at any given time.

A healthy body is able to store approximately 18% of the iron consumed from a western diet and 10% iron consumed via a vegetarian diet. However, even if your diet contains substantial amounts of iron-rich foods, your body may absorb far less than that. When this happens, it is likely because your iron stores are either already full or near capacity. Conversely, when your iron stores are low, your body’s storing capacity increases. That said, how much iron your body can absorb — and, therefore, how much you need to consume — fluctuates on an ongoing basis.

What Affects Iron Absorption?

Though a few factors may affect your body’s iron-storing capacity, the most influential factor is your diet. Certain foods can either boost or reduce your body’s ability to store the mineral. Foods that can do the former include the following:

• Vitamin C
• A combination of animal protein and plant sources of iron
• Cooked vegetables (for example, the body absorbs 6% of the non-haem iron in raw broccoli compared to 30% from cooked broccoli)

Foods and beverages that may reduce your body’s ability to absorb iron are as follows:

• Tea, coffee, wine and other beverages that contain tannins, which bind to iron consumed and carry it out of the body; though you should not necessarily avoid these beverages altogether, you should avoid drinking them directly before or after eating iron-rich foods
• Soy proteins, which can reduce absorption from plant sources
• Fibres and phytates found in whole grains, which can reduce the absorption rate of iron and other minerals
• Phosphorous and calcium, both of which reduce the absorption rate of plant-sourced iron

If you are deficient in vitamin A, your body may also struggle to absorb iron, as vitamin A helps to release stored iron.

What Causes Iron Deficiency?

In adults, there are five main causes of iron deficiency: nutritional deficits, blood loss, exercise, the increased need for iron and the inability to absorb iron.

• Nutritional Deficits: Your diet may be lacking in iron for several reasons, including a poorly balanced vegetarian diet, limited access to a wide range of fresh foods and fad dieting.
• Blood Loss: Chronic blood loss can quickly lead to iron deficiency. Chronic blood loss entails monthly menstrual cycles, chronic nose bleeds, regular blood donations and other conditions that cause frequent bleeding. Additionally, certain medications, such as aspirin, can also cause chronic blood loss.
• Exercise: Regular exercise increases the body’s need for iron, as it promotes red cell production and induces sweating. For this reason, athletes are prone to iron deficiencies and tend to crave red meat.
• Increased Need for Iron: When you are feeding for two (literally), your vitamin and mineral needs nearly, if not wholly, double. If you fail to up your nutritional intake while pregnant or breastfeeding, you may become deficient in several areas.
• Inability To Absorb Iron: Healthy adults typically absorb 10% to 15% of iron from a well-rounded diet. However, due to underlying health conditions and other factors, some bodies are unable to absorb even that, leading to an iron deficiency.

Causes of Iron Deficiency in Babies and Children

For infants and toddlers, the causes of iron deficiency are slightly different. If your child was diagnosed with dietary iron deficiency anaemia, it may be due to one or more of the following reasons:

• Premature birth or low birth weight
• Exclusive breastfeeding beyond six months
• High intake of cow’s milk before the age of 2
• Vegetarian and vegan eating
• Low or no meat intake
• Poor diet in the second and subsequent years of life
• Lead poisoning
• Possible gastrointestinal illnesses

It is worth noting that babies and children experience rapid growth spurts, which can drastically and quickly increase their need for iron. If you are a parent, be prepared to meet these needs with each passing phase.

Risk Factors for Iron Deficiency

Some people are more prone to develop iron deficiency anaemia than others. Below are the top four groups most prone to this condition:

• Women: Because most women lose blood on a monthly basis due to menstruation, they are at a greater risk of developing iron deficiency anaemia than any other group.
• Vegetarians: Vegetarians who are unable to find suitable replacements for meat are also at an increased risk for developing anaemia.
• Infants and Children: Infants who were born prematurely, were born at a low birth weight, or who do not get enough breast or formula milk have a heightened risk of developing iron deficiency.
• Frequent Blood Donors: Regularly donating blood can deplete iron stores and, therefore, puts regular donors at an increased risk for iron deficiency. That said, you should be able to restore your iron stores with an iron-rich meal after donating. If you are unable to, talk to your doctor about other possible causes.