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A cat food label
may simply state "artificial color" or
may list a series of E-numbers or names. Colors derived from coal-tar derivatives are possible
carcinogens or may interfere with the immune
system. The red color Sodium nitrite (also used
as a preservative) contains toxic nitrosamines.
Pets may be eating more color in their diet than
would be allowed in the human diet.
Cat foods must be
preserved to keep them fresh and tasty. Canning is
a preserving process, so canned foods need fewer
preservatives than dry food. Some preservatives
are added to ingredients or raw materials by the
suppliers; others are added by the cat food
manufacturer. Dry foods require a long shelf life;
the fats in them require antioxidants, but there
is relatively little information on their toxicity
over a long period of time. Rancid fats, an
ingredient in pet food, are often preserved with
BHT/BHA and ethoxyquin, to prevent further
deterioration. BHT/BHA may be carcinogenic (cause
cancer). The preservative propylene glycol has a
drying effect on stools and can increase
constipation.
Some
"harmless" chemicals are toxic to cats
due to the way their livers work. The preservative
ethoxyquin used in dog food has never been tested
for safety in cats, one more reason cats should
not raid the dog's bowl. Ethoxyquin was developed
as a rubber stabilizer and herbicide similar to
Agent Orange. It is no longer used in human foods.
In humans, exposure to ethoxyquin may cause
liver/kidney damage, skin cancers and leukemia,
hair-loss, sight loss, fetal abnormalities and
chronic diarrhea. In animals it may additionally
cause immune deficiencies, spleen, stomach and
liver cancer.
When moist foods
which required no refrigeration first appeared,
vets knew they must contain a strong preservative.
The preservative was formalin - an embalming agent
used by undertakers and for pickling animal
specimens in the laboratory (e.g. the pickled
animal fetus in its jar in school science class).
Nowadays, some "natural" or
"organic" products use natural
preservatives; as with flavors, these natural
preservatives may be made in the laboratory, not
harvested from plants. Foods with natural
preservatives have a shorter shelf life than those
with artificial preservatives.
Cats have limited
ability to taste sweetness, but sweeteners in cat
food masquerade under a variety of names: beet
pulp sugar, glucose, sucrose (regular sugar), corn
syrup or molasses. They are not necessarily used
to make the food taste sweet. Corn syrup is a
"humectant and plasticizer" i.e. gives
the product dampness and flexibility or chewiness.
Diabetes is increasing in cats - this may be
linked to the consumption of sugar by a creature
which does not require it in such great amounts.
Added sugar can affect the absorption of other
nutrients and can affect bowel fauna. Artificial
sweeteners may be linked to aggression and
hyperactivity. It is alleged that (unidentified)
US cat food manufacturers rely on sweeteners to
help "addict" cats to dry foods. This
may simply be an urban legend as there was a
similar scare about a cat food company adding
amphetamines to addict cats to its brand of canned
food.
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