Dietary Intolerance in Pets

Dietary Intolerance

Adverse reactions to ingredients in the diet may well be one of
the commonest yet least recognised causes of ill-health in pets
and humans.

In theory, any dietary ingredient can cause an intolerance. In
practice, protein (e.g. beef, milk) or carbohydrate (e.g. wheat,
lactose) sources are the most likely causes although it is
possible that chemical additives such as food colourings and
preservatives could cause a reaction.

Understanding and recognising dietary intolerance is not helped
by pet food legislation which allows pet food manufacturers to
declare ingredients such as “animal derivatives and cereals”
rather than naming the actual ingredients. This means that one
cannot know precisely what one is feeding and the ingredients
can be changed at will.

In general, adverse reactions to food can be divided into those
which act through the immune system (allergy) and those which do
not (intolerance). Although the mechanisms of the two are
different, the symptoms are indistinguishable.

Signs of intolerance (symptoms) vary widely and are not well
understood or documented.

A reaction can be instantaneous or delayed, even for several
days. It can be mild and ill-defined causing non-specific signs
of ill-health such as lethargy, loss of appetite, abdominal
pain, stiffness, unthriftiness, unpleasant body odours, bad
breath, discharge from orifices and so on.

At the other extreme an adverse reaction can be severe and
unmistakeable. An anaphylactic reaction can cause shock and
death. Some people with an allergy to nuts are affected in this
way.

In theory, any organ or system can be affected and this can give
rise to a wide range of symptoms.

In dogs dietary intolerance most commonly affects the skin or
digestive system causing disease/disorders related to these
organs. This might be eczema, itchy skin, dermatitis, otitis
(ear inflammation), vomiting, diarrhoea, colitis,
gastroenteritis, pancreatitis, hepatitis, abdominal discomfort
etc.

Other organ systems can also be affected e.g. immune system,
musculoskeletal system, nervous system, endocrine (hormonal)
system. Any symptom or disease affecting any of these organ
systems could be caused by a dietary intolerance. This would
include arthritis, convulsions (epilepsy), abnormal behaviour,
allergic (pollen, house dust mite) and inflammatory reactions
(pancreatitis, hepatitis), susceptibility to infection,
Cushing’s, Addison’s, under- and over-active thyroid etc.

Long-term unrecognised dietary intolerance may be the underlying
cause of degenerative diseases such as heart or kidney failure
and cancer.

It is probably true that dietary intolerance is much more
prevalent than pet owners and veterinary surgeons realise. There
are diagnostic tests but these are only possible for the
minority which involve the immune system. In any case they are
inaccurate and even misleading in that they produce both
false-positive and false-negative results. Any symptom of
ill-health which persists despite treatment or which recurs
after treatment should arouse suspicion of food intolerance.

A feeding (elimination) trial is the only reliable method of
diagnosis. This is the rationale of the Burns Health Management
Programme. This involves eliminating the existing food from the
diet and replacing it with a food which is new to the animal.
Home-made food allows more control over ingredients but a
commercial food like Burns may be more suitable for long-term
use. If symptoms improve when the suspect food is eliminated
then it can be presumed that a dietary intolerance was
responsible. Confirmation would require the re-introduction of
the suspect food to see if the symptoms recur but, of course
most pet-owners will be understandably reluctant to take that
step.

Disorders of the digestive system which are due to dietary
intolerance often disappear within a few days of eliminating the
food which is responsible but most disorders will take 3-4 weeks
to respond to removal of the offending food.

Most cases of dietary intolerance (those where the immune system
is not involved) are dose-sensitive. This means that the amount
of food can determine whether or not signs of intolerance will
disappear. This is why it is important that whatever food is
given, it should be fed sparingly.

It is likely that many people suffer from undiagnosed dietary
intolerance with similar consequences except that the
respiratory system is more commonly affected than the skin. see

http://www.burns-pet-nutrition.co.uk