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The Role of Vitamin C in Collagen
Formation and Hip Dysplasia
In recent years major advances have been achieved in
ou runderstanding of the metabolism' and of the important
part played by vitamin Cin this process -e.g. the research
of Wegger and colleagues (1984). Studies have shown
that the biosynthesis', and amount, of vitamin C stored,
and used, in the body depends on man y factors.
In various nutritional deficiencies, and in many
diseases, the biosynthesis of vitamin C is reduced and
consequently the amount stored in the blood plasma
drops. At the same time a reduction occurs in the
concentration of vitamin C in the body's cells and this
results in a slowing down of many biochemical reactions
with the perfonmance of various cell types being impaired
. reduced energy metabolization in the mitochondria, is
an example.
Studies, particularly those carried out over the
past decade, have clearly shown that even those animals
that are able to sythesize vitamin Ccannot make enough
for all their metabolic requirements. This is especially
important if they are ill and this is aggravated further when
the animal is subjected to stress. As biosynthesis of
vitamin Cin the liver and absorbtion of vitamin Cfrom the
gut is impaired in the presence of astressor, vitamin Cis,
for this and other reasons, a most important vitamin and
the one which is most likely to be insufficiently available
unless provided, by dietary supplementation, for the dog.
The presence of this much-ignored vitamin is
necessary forthe absorbtion of dietary iron, for example,
as well as playing a vital, life-supporting role in other
biochemical functions such as the production of
antibodies, the fonmation of collagen (important to the
strength of ligaments and tendons), the efficient
metabolization of bone (through its influence on vitamin
D) and the efficient metabolization of amino acids and
carbohydrates.
These are a few examples of how vitamin C
supportsthe biochemical functions of the body, there are
many others. We should remind ourselves here that
vitamin C is largely destroyed through any processing
that involves heat, moisture, or pressure. The raw
materials that make up so-called 'complete diets' are
subjected to atl three I
Administration of vitamin C has been found
beneficial in the treatment regimes of various infectious
diseases, hip dysplasia, etc. As has been mentioned
above, the list of biochemical functions involving vitamin
C is very ex1ensive.
Hip Dysplasia
In large breedsof dogs,hip dysplasia was long considered
to be an inherited birth defect (ie. it is generally passed
12 The Service Dog
on). Recent research , however, suggests that it may be
an easily controlled biochemical condition. The onset of
the lesion in hip dysplasia appears to be due merely to
poor quality, low strength collagen in the affected
ligaments. In litters from dysplastic German Shepherd
parents or parents that produced dysplastic offspring,
there have been no signs of hip dysplasia when the
bitches were given higher than normal doses of vitamin
Cduring pregnancy and the pups were given daily doses
of vitamin C until they reached young adulthood .
In potentially dysplastic pups of large breeds, the first
year or two of life is fraught with high metab olic and
phYSiological stress. Therefore, the demands on the
body are great and the demands for large quantities of
vitamin C and other micro-nutrients even greater.
The laxity, or looseness of the hip ligament and the
changes in the pectieus muscle and tend on, are as a
result of the absence of high quality, strengthening
collagen. Weak collagen in the ligaments causes them to
stretch or loosen, resulting in joint laxity, which allows the
young femoral head to separate from the acetabulum
(hip socket). After separation an inflammatory process
(arthritis) ensues and varying amounts of scar tissue
form in the acetabulum, preventing the head of the femur
from returning to its nonmal position. This results in
coxfemoral subluxation (hip dysplasia).
Simultaneously, poor quality collagen in the pectieus
muscles and ligaments retards their growth and
development. The impaired growth and development of
tendon and muscle, together with the rapid growth of the
femur, contributes furtherto the severity of the dislocation.
In the trials, mentioned above, none of the pups which
were maintained on high doses of vitamin C have, to
date, shown evidence of hip dysplasia.
The recommended management regime consists in giving
the pregnant bitch high doses of vitamin C in the daily
ration. At birth, the pups are given 50 to 200mg of vitamin
C oral ly. When the pups reach three weeks of age, the
daily amount is increased to 500mg until th epups are four
months old. At that time, the dosage is increased to 1 or
2gm daily and maintained at that level until the pups are
18 months to two years of age.
, Metabolism - the total chemical and physical changes
that occur within the body to sustain life especially
through the release of energyforthe production of tissue,
etc.
, Biosynthesis - to produce inside a living organism (the
body).