Nutritional vitamin defi ciency

In countries where diets are unbalanced and inadequate,
or where there are particular dietary customs,
certain typical disease patterns have been shown to
be due to vitamin defi ciency. Examples of the most
commonly observed diseases are xerophthalmia, rickets,
beriberi, pellagra and scurvy, which result from
defi ciencies of vitamin A, vitamin D, thiamin, niacin
and vitamin C, respectively. Defi ciency of a single
member of the vitamin B group is rare in humans
because these vitamins are largely found together in
nature, and foodstuffs lacking in one member of the
complex are likely to be poor in the others. Moreover,
the overt manifestations of defi ciency of this group
overlap to some extent.
Nutritional aspects of vitamins 9
Subclinical defi ciency and marginal defi ciency are
synonymous terms used to describe conditions in
individuals who are not clinically nutrient defi cient,
but who appear to be close to it. An alternative and
perhaps better term proposed by Victor Herbert in
1990 is ‘early negative nutrient balance’, which is
used when laboratory measurements indicate that an
individual is losing more of a nutrient than is being
absorbed.
By reference to the sequence of events in the development
of vitamin defi ciency, Pietrzik (1985)
emphasized the importance of preventing functional
metabolic disturbances that can evolve into overt
clinical symptoms. This sequence can be subdivided
into six stages as follows.
• Stage 1 Body stores of the vitamin are progressively
depleted. A decreased vitamin excretion in the
urine is often the fi rst sign. Normal blood levels are
maintained by homeostatic mechanisms in the very
early stages of defi ciency.
• Stage 2 The urinary excretion of the vitamin is further
decreased and vitamin concentrations in the
blood and other tissues are lowered. A diminished
concentration of vitamin metabolites might also be
observed.
• Stage 3 There are changes in biochemical parameters
such as low concentrations of the vitamin in
blood, urine and tissues, and a low activity of vitamin-
dependent enzymes or hormones. Immune
response might also be reduced. Non-specifi c subclinical
symptoms such as general malaise, loss of
appetite and other mental changes appear.
• Stage 4 The biochemical changes become more
severe and morphological or functional disturbances
are observed. These disturbances might
be corrected by vitamin dosing in therapeutic
amounts within a relatively short time or vitamin
supplementation in amounts of (or exceeding) the
recommended dietary allowances over a longer
period. Malformation of cells is reversible at this
stage.
• Stage 5 The classical clinical symptoms of vitamin
defi ciency will appear. Anatomical alterations characterized
by reversible damage of tissues might be
cured in general by hospitalization of the patient. In
most cases there are defi ciencies of several nutrients
and a complicated dietetic and therapeutic regimen
has to be followed.
• Stage 6 The morphological and functional disturbances
will become irreversible, fi nally leading to
death in extreme cases.
From the health point of view, Pietrzik (1985) proposed
that the borderline vitamin defi ciency is represented
by the transition from the third to the fourth
stage.

The causes of nutritional vitamin deficiency are
any one or combination of the following: inadequate
ingestion, poor absorption, inadequate utilization,
increased requirement, increased excretion and increased
destruction in the body. The capacity to store
vitamins in the body is another aspect to be considered:
humans can store thiamin for only about two
weeks, whereas vitamin B12 can be stored for several
years.