Low Haemoglobin Levels-Things we need to know

Introduction

If a blood test report tells you that your haemoglobin level is lower than normal, it means you have a low red blood cell count. Haemoglobin (Hb) is a protein found in the red blood cells that carry oxygen in your body and give blood its red colour. 

It is a metalloprotein (protein –globin; haem – iron-containing porphyrin). Our body needs iron to produce haemoglobin. Without enough iron, it is unable to produce enough of this substance in red blood cells.

An irritated child, a pale looking adolescent girl with significant hair fall, a woman experiencing dizziness, fatigue or light-headedness, therefore,  might all signal towards the lack of iron in their body. Some other complaints noted in case of low iron levels are – faster heart rates or palpitations, brittle or pale nails, shortness of breath.

What is iron and how important is it?

Iron is a mineral that our body needs for blood production, growth and development. Our body uses iron to make haemoglobin, a protein in red blood cells that carries oxygen from the lungs to different parts of the body, and myoglobin, another protein that provides oxygen, iron supports muscle metabolism and healthy connective tissue.  Our body also needs iron to make some hormones.

Iron deficiency is the world’s most common nutritional deficiency and is associated with

• developmental delay,
• impaired behavior,
• diminished intellectual performance, and
• decreased resistance to infection

Iron deficiency leads to decreased haemoglobin and the production of red blood cells leading to anaemia. Among the known causes of anaemia, the most common cause is iron deficiency. Iron deficiency anaemia (IDA) in children has been associated with retardation in growth and cognitive development (5, 6). Several studies have established the relationship between iron deficiency and hair loss (5).

Mild iron deficiency anaemia usually does not cause complications. However, left untreated, iron deficiency anaemia can become severe and lead to health problems, including heart problems. Iron deficiency anaemia may lead to a rapid or irregular heartbeat. Fatigue is the most common symptom of anaemia, but many people have mild anaemia without knowing it. Some other indications of anaemia can be:

• weakness.
• shortness of breath.
• dizziness.
• fast, irregular heartbeat.
• pounding in the ears.
• headache.
• cold hands and feet.
• pale or yellow skin.
• rapid heart beat
• pallor

In premenopausal women, the most common causes of iron deficiency anaemia are menstrual blood loss and pregnancy. In men and postmenopausal women, the most common causes of iron deficiency anaemia are gastrointestinal blood loss and malabsorption.

How to know whether we are iron deficient or not?

Testing the blood haemoglobin levels is a common way of screening iron deficiency. The haemoglobin count is an indirect measurement of the number of red blood cells in your body. It depends on many factors, including age, ethnicity, gender and the general health of the person. (1) A higher or lower haemoglobin count than normal, may be a sign of an impending health problem. According to the World Health Organization (WHO),

• Normal haemoglobin counts are 14 to 17 gm/dL (grams per deciliter) for men and
• 12 to 15 gm/dL for women.
• <12.0 g/dL in women and <13.0 g/dL in men, indicates anaemia.

Serum ferritin concentration can be used to confirm an iron deficiency. Serum ferritin levels closely correlate with total body iron stores. Normal ferritin concentrations vary by age and gender (3).

The commonly recommended Serum ferritin cut off level of  <15 μg/L is specific to determine iron deficiency (7). However, the range normally followed by most laboratories are:

• Normal- 30 to 300 ng/mL (67.4 to 674.1 pmol/L),
• Men-  88 ng/mL (197.7 pmol/L) and
• Women- 49 ng/mL (110.1 pmol/L)
• Iron deficient- < 12 ng/mL (27 pmol/L)

It is noteworthy that the serum ferritin levels may be raised in patients with infectious, inflammatory, and neoplastic conditions. In pregnant women, serum ferritin test has limited usefulness in diagnosing iron deficiency, as concentrations normally fall during late pregnancy  (3).

Other tests may be needed, such as free erythrocyte protoporphyrin concentration, transferrin concentration, serum and plasma iron concentration, and transferrin saturation to identify the cause of the iron deficiency.

In the case of men, postmenopausal women, or someone with risk factors for blood loss,  they should be evaluated for sources of blood loss.

Iron in our diet

It is necessary that we understand the factors contributing to maintaining optimal iron status.

Iron is the most abundant metal in the human body; one adult human body needs 3–4 g of iron. Our body re-utilises most of the iron and deposits the rest in the liver and spleen.

Depending on the gender and the physiological status, our body needs to absorb a relatively small amount of iron from our daily diet, about 1-3 mg. Therefore our diet should contain 10-25 folds of the daily iron requirement.

Diets vary extensively in the bioavailability of their iron. We can categorise iron in our food into two forms, heme and non-heme iron(8).

• Heme iron is found in animal foods namely -meat, poultry, and fish etc . Heme iron has higher bioavailability . Our body absorbs it well. Meat and fish based diets permit 10-20% absorption of iron (9).  
• Non-heme iron is found in plant foods — is less well absorbed but  our body can still use it, just not as easily. Plant based diets permit only a low level of absorption (1-2%) of iron.

The bioavailability of iron is approximately 14% to 18% from mixed diets that include substantial amounts of meat, seafood, and vitamin C (ascorbic acid, which enhances the bioavailability of nonheme iron) and 5% to 12% from vegetarian diets [2,4]. In addition to ascorbic acid,  meat, poultry, and seafood can enhance nonheme iron absorption, whereas phytate (present in grains and beans) and certain polyphenols in some non-animal foods (such as cereals and legumes) have the opposite effect [4]. Calcium might reduce the bioavailability of both nonheme and heme iron.

Sources of iron

• Meat
• Fish and other sea foods
• Poultry
• Cereals-millets, rice flakes, bajra, Iron-fortified breakfast cereals and breads
• Pulses-Chickpea, soybean, lentil, peas.
• Green leafy vegetables-spinach and all green coloured leaves
• Vegetables-lotus stem, cowpea pods, onion stalks, plantain green, beans.
• Nuts and some dried fruits, such as raisins.
• Jaggery

Factors that affect absorbtion of iron from foods

Some factors hinder the absorption of iron from foods.  These are:

• Phytates present in cereals and legumes
•  Fiber present in cereals and legumes
• Tanins in tea, coffee
• Heavy metals such as calcium, zinc and magnesium
• Low altitude –
•  Antacids –

Enhancers of iron absorption –

• Ascorbic acid present in jucies, fruits help in iron absorption from diet.
• Amino acids present in meat, fish, chicken.
• High altitudes 
• Deficient body stores of iron .

So, our body absorbs more iron from plant sources better when we consume it with meat, poultry, seafood, and foods that contain ascorbic acids, such as citrus fruits, strawberries, sweet peppers, tomatoes, and broccoli.

Remember

• Haemoglobin carries oxygen from lungs to different parts of our body.
• Characteristic symptoms of low haemoglobin include:  weakness, shortness of breath, dizziness ,fast, irregular heartbeat, pallor.
• Our body needs iron to make haemoglobin .
•  Iron deficiency typically causes low serum iron, high iron-binding capacity, and low serum ferritin levels.
• Iron is naturally present in many foods and is added to some fortified food products.
•  Iron in food comes in two forms: heme iron and non-heme iron. Non-heme iron is found in plant foods . Heme iron is more easily absorbed by our body.
• Meat, fish, sea-foods, millets, green leafy vegetables, lentils, chickpea, beans , raisins, sesame, jaggery etc., are good sources of iron.
• Our body absorbs more iron from plant sources better when we consume it with meat, poultry, seafood, and foods that contain ascorbic acid, such as citrus fruits, strawberries, sweet peppers, tomatoes, and broccoli.

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References