NHD clinical - - anaemia
Emma Matthews has four years’ experience as a rotational dietitian
and experience of covering specialist head and neck oncology
post. Her most recent appointment is as a Macmillan Dietitian.
by Emma Matthews
Professional interests include surgery, oncology – nutritional
Dietitian support.
Classification and nutritional considerations of anaemia
Anaemia may be defined as a reduction in the number of red blood cells and haemoglobin in the blood (1) and can be caused by a num-
ber of factors such as increased nutritional requirements, increased losses/impaired absorption or reduced nutrient intake.
Although the term ‘anaemia’ is often associated
Anaemia Type Characteristics of Effect on lab Comments
with iron deficiency, it is important to consider
aetiologies such as those due to folate or vitamin
red blood cell values
B12 deficiency, as well as anaemia of chronic
Hypochromic, Small in size
↓ferritin levels
Normal ferritin may not
disease. Less commonly, anaemia may also be
microcytic anaemia Pale in colour
↓serum iron
exclude anaemia, and
caused by a deficiency of vitamin E and K in in-
(Iron deficiency)
↓total iron binding
can be raised due to other
fants (haemolytic anaemia), and can also have
capacity
clinical factors
a genetic component - sickle cell anaemia.
Transferrin saturation
↓Transferrin saturation
represents saturation of
Diagnosis and Classification of Anaemia
↓mean corpuscular
transferrin with iron
volume (MCV)
MCV measures size of RBC
Anaemia is often classified according to the
size, colour and shape of the red blood cell, all
Megaloblastic, Large in size
↑ MCV
Consider MCV with
of which vary according to the type of anae-
macrocytic anaemia
Normal B12 (Cobalamin)
other measures as
mia diagnosed. Haemoglobin is often consid-
(Folate deficiency)
↓ Serum folate
increase can be due
ered when diagnosing anaemia and the World ↑ Serum homocysteine
to clinical condition
Health Organisation provides specific ranges
Megaloblastic, Large in size
↑MCV
Increased homocysteine
for haemoglobin thresholds according to age
pernicious anaemia
and gender, as outlined in Table 1. As anaemia
↓Serum B12 (Cobalamin)
can be seen in both
( Vitamin B12 deficiency)
progresses, haemoglobin levels can become
Normal or↑Serum Folate
vitamin B12 and folate
deficiency therefore is
reduced, although may not appear low until
↑Serum homocysteine
non specific
the later stages of deficiency. It is therefore im-
portant to consider other lab values alongside
Table 2 – Classification of common anaemias (3)
glossitis, confusion, peripheral neuropathy and
haemoglobin levels, which may also become
neurological symptoms (3). Food sources of vi-
increasingly affected as anaemia progresses.
haem sources). The bioavaliablillity of non haem
tamin B12 include meat, milk, cheese and eggs.
Analysis of these lab values can provide clarifi-
iron can be increased by including vitamin C con-
Even with a limited intake of these foods, defi-
cation as to the specific type and cause of anae-
taining food or drink, or complimenting with other
ciency may take several years to develop due to
mia diagnosed, as outlined in Table 2.
haem sources. The presence of inhibitors which
the body’s ability to recycle vitamin B12.
When looking at biochemistry, it is important
may reduce the absorption of iron should also be
As vitamin B12 is required for the conver-
to consider results on an individual basis, taking
considered and include the following:
sion of folate into a more active form, pernicious
into consideration other factors such as clinical
• Phytates - cereals and some grains
anaemia and B12 deficiency can therefore lead
status and presence of other diseases, which
• Tannins - tea and grains
to a deficiency of folate and macrocytic anae-
may affect lab values. Ranges for individual
• Oxalates - green vegetables, spinach, rhu-
mia. Folate deficiency may also be caused by
measures should also be considered according
barb beetroot, sweet potatoes and chocolate
an inadequate folate intake, increased losses,
to local reference values.
• Presence of other minerals such as calcium,
chronic alcoholism as well as drug nutrient in-
which may compete for absorption
teractions. Another cause may be an increase
Iron deficiency Anaemia
in cell multiplication for example as in cancer or
Iron deficiency is the most common cause
Megaloblastic – Pernicious and
gastro intestinal (GI) tract damage. Deficiency
of anaemia worldwide (3), resulting in blood Macrocytic Anaemia
can therefore result in GI symptoms, tiredness,
cells that become small (microcytic) and pale Pernicious anaemia is usually caused by a
weakness or weight loss. Folate sources include
(hypochromic). Deficiency can result from an lack of intrinsic factor, following injury to the stom-
fruit and vegetables, particularly green leafy type
increased loss of blood, impaired absorption or ach, gastric surgery, gastric bypass or auto im-
as well as beans and fortified food products.
reduced nutritional intake. Signs of deficiency mune conditions. Lack of intrinsic factor reduces
It is important to distinguish between folate
may include lethargy, pallor, shortness of breath, the absorption of vitamin B12 causing deficiency.
and vitamin B12 deficiency, as treating B12
palpitations and pica. In such cases, an injection of B12 is required. De-
deficiency with folate may improve lab values,
Iron sources to encourage include fortified prod- ficiency may also be caused by long-term vegan
however will not treat the deficiency symptoms.
ucts, meat, poultry and fish (haem sources) as well diets, AIDS as well as drug nutrient interactions
This article has provided an overview of
as leafy green vegetables, legumes and grains (non – with deficiency symptoms including tiredness,
main classifications of anaemia - iron, vitamin
B12 and folate - including possible causes and
Age range Haemoglobin threshold (g/dl)
clinical symptoms. Having an understanding of
the effect of deficiency on lab values is essen-
Children 0.5-5 years 11
tial and can provide further clarification as to the
Children 5-12 11.5
type of anaemia present.
Children 12-15 12
References
Women (>15) - pregnant 11
1 Wikipedia Encyclopedia, ‘Anemia’, at www. en.wikipedia.org/wiki/Anemia,
visited 23rd October 2009
Women (>15) 12
2 World Health Organisation (2008). Worldwide prevalence of anaemia
1993-2005. Geneva: World Health Organisation. ISBN 9789241596657.
http://whqlibdoc.who.int/publications/2008/
Men (>15) 13
9789241596657_eng.pdf. Retrieved 2009-03-25
3 Charney P, Maole A (2004) ADA Pocket Guide to Nutrition Assessment,
Table 1 – Haemoglobin values (1,2) American Dietetic Association
26 NHDmag.com Mar '10 - issue 52
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