What is anemia?
Over 1.6 billion people worldwide are anemic. Anemia
is a condition by which red blood cells do not carry and deliver enough oxygen
to the rest of the body. This is either because there are not enough red blood
cells or because the red blood cells available do not function properly. The
four major types of anemias include iron-deficiency anemia, megaoloblastic
anemia, pernicious anemia and sickle cell anemia. Of these, the most common is
iron-deficiency anemia.
Iron-deficiency anemia is a condition that occurs when
there is a lack of iron in the body. Iron is essential to make hemoglobin, an
iron-rich protein, which binds to oxygen to carry and deliver it throughout the
body.
Without sufficient iron, the body cannot produce enough hemoglobin for
red blood cells, thus leaving the body with insufficient oxygen supply.
Megaloblsatic and pernicious anemia occur when there
is a deficiency in vitamin B12 or B9 (commonly known as folate). These two
micronutrients are required for red blood cell replication and synthesis. Vitamin
B12 is required for the body to make a usable form of folate. Therefore, the
root cause of these types of anemia are either due to B12 deficiency (which leads
to folate deficiency) or folate deficiency.
Sickle cell anemia is an inherited genetic condition
that cannot be prevented. In this condition, the red blood cells are
crescent-shaped and can stick together and get stuck in blood vessels. This
sickling can lead to chest pain and eventual organ damage as a result of
insufficient oxygen.
What causes anemia?
Anemia commonly occurs as a result of poor diet, pregnancy,
intestinal disorders, chronic diseases, and infections. Only sickle cell anemia
is caused by a genetic mutation.
Iron-deficiency anemia is most commonly due to
inadequate dietary intake of iron, particularly in infants and children. This
is also seen during pregnancy and breastfeeding, which can deplete a woman’s
iron stores. Women already have low iron stores and when pregnant, existing
iron is taken to supply the fetus.
Megaloblsatic and pernicious anemia are also commonly
seen during pregnancy, in vegetarians or vegans, or conditions where there is
reduced absorption of B12 from the gastrointestinal tract due to certain
diseases. B12 or folate deficiency during pregnancy can lead to serious
complications for the fetus so they are often supplemented during this time.
Can anemia be prevented?
The three major types of non-genetic anemia are caused
by inadequate intake, excessive losses, or impaired absorption of iron.
Anemia caused by inadequate intake can be prevented to
some extent by eating an iron-rich balanced diet. Foods that are high in iron
include beef, dark leafy greens, dried fruits and nuts. Vitamin B12 and folate
can also be supplemented if enough is not obtained through diet.
Anemia caused by excessive blood loss occurs from
menstruation, intestinal parasites or blood loss due to clotting disorders
(vitamin K deficiency). These cannot necessarily be prevented but can be
monitored.
Anemia caused by impaired absorption tends to be due
to chronic conditions that may inhibit the uptake of iron, even if there is
enough in the body. These chronic diseases increase your risk for developing
anemia – rheumatoid arthritis, kidney disease, cancer, liver disease, thyroid
disease and inflammatory bowel disease (IBD). For instance, disorders of the gastrointestinal
tract such as IBD can significantly reduce B12 absorption even when it is
present in the body.
References
American Society of Hematology. (2016). Anemia.
Kazal LA. (2002). Prevention of iron deficiency in
infants and toddlers. American Family
Physician.
de Benoist B et al. (2008). Global anaemia prevalence
and number of individuals affected. World Health Organization.
What is sickle cell disease? (2015). National
Institute of Health: National Heart, Lung and Blood Institute.
How Can Iron-Deficient Anemia Be Prevented? (2014).
National Institute of Health: National Heart, Lung and Blood Institute.
