Most diets contain a certain percentage of carbohydrates although
they are not considered essential nutrients for dogs. Sugars
and starches, which formulate the class of digestible carbohydrates,
are metabolized during digestion into glucose. Glucose provides
energy, dispenses amino acids and helps synthesize fats. Healthy
dogs can easily digest cooked starches, while raw starches
are more difficult on their systems. Carbohydrates are stored
in the body as glycogen, or animal starch and fat. This excess
stored food is often the cause of obesity. Carbohydrates provide
an inexpensive alternative to protein and fats. Most commercial
dog foods contain a large percentage of digestible carbohydrates.
Although fiber is not essential in a dog's diet, soluble fibers
such as fruit or oat bran play a role in helping maintain
proper hydration, in regulating nutrient absorption, and in
preserving a healthy intestinal tract. Insoluble fibers, such
as wheat bran or cellulose are commonly added to dog foods
to add bulk without adding calories. The same effect may be
obtained by adding fresh, raw vegetables such as carrots,
broccoli or cauliflower to your dog's diet.
Dogs can digest and digest high levels of dietary fat, which
is considered an excellent and concentrated source of energy.
Fats are also highly palatable (tasty!) and break down slowly,
satisfying the appetite between meals. However, fats should
not constitute more than 20% of the average dog's diet.
Fats provide essential fatty acids and carry the fat-soluble
vitamins, A, D, E and K, throughout the dog's system. The
essential fatty acids help regulate such functions as muscle
contractions, blood clotting, allergic reactions and add luster
to the coat. A deficiency in essential fatty acids results
in a rough, dry coat, dandruff, and retarded growth of puppies,
reproduction problems, chronic pancreatitis, gall bladder
disease, liver disease, and general poor health.
Fortunately dogs do not suffer from heart disease caused by
fats or cholesterol, but a diet high in fats can contribute
to another dangerous condition, obesity. High fat diets may
also deplete the body's store of fat-soluble vitamins such
as Vitamin E. Such diets increase the risk of gall bladder
disease, pancreatitis and diarrhea. Fatty acid supplements,
if used, should always be fortified with Vitamin E. A diet
high in fats should only be fed to very active working dogs,
puppies or lactating bitches and only under the advice of
Since dogs vary so much in size and activity level, it is
difficult to give a generalized statement as to the protein
requirements of dogs. However, the higher the activity level,
the greater the need for protein. Amino acids is the nitrogen-containing
main components of protein. The essential amino acids required
by dogs are arginine, leucine, methionine, histidine, isoleucine,
lysine, phenylalaline, tryptophan, valine and threonine. Foods
and proteins that contain all these nutrients in ideal proportions
are called "high quality". The digestibility (ease of digestion)
of a protein also affects how the body will absorb the protein.
Generally speaking, meat proteins are more digestible than
vegetable protein, and thus are a more efficient and valuable
source of amino acid.
A diet deficient in either individual amino acids or insufficient
quantity of protein can result in poor growth, weight loss,
loss of appetite, loss of muscle tone, dull, brittle or rough
coat, impaired immune system, blood protein depletion or even
death. Dogs with kidney failure or a tendency toward kidney
disease may be advised to stay away from protein-rich diets.
There are two kinds of vitamins, fat-soluble (A, D, E and
K) or water-soluble (C and B vitamins). Vitamin supplements,
except when recommended by your veterinarian during periods
of illness, are generally unnecessary and can be detrimental.
The best way to meet vitamin requirements is through a carefully
Vitamin A is necessary for normal growth, reproduction, mucous
membranes, skin cell surface lining, immune functions and
vision. Vitamin A-rich foods, such as liver or other organ
meats, must be included in limited quantity in a dog's diet.
However, both excess and a deficiency of Vitamin A can cause
very serious problems. Deficiency symptoms include lack of
appetite, stunted growth, skeletal abnormalities, weight loss,
night blindness, skin lesions and brain damage. Excess (such
as a diet mainly of liver) can cause a degenerative disease
of the vertebrae and loss of teeth.
Vitamin D helps metabolize calcium and phosphorus. It is necessary
for maintaining blood calcium levels and for the formation
of bones. In puppies, a deficiency of this vitamin causes
the bone-deforming disease called rickets. Dogs require controlled
doses of Vitamin D added to their diets. Excess dose of vitamin
D causes heavy calcium deposits to form on the organs such
as kidneys, heart and blood vessels, which can result in death
if not corrected in time. Calcium deposits on the kidneys
are usually irreversible.
Vitamin E functions as an antioxidant, protecting fats present
in the body from oxidation and maintaining the structure of
muscle cells. Vitamin E is found in good quantity in egg yolk,
wheat germ, soybeans, vegetable oils, whole grain cereals
Vitamin K, necessary for blood clotting, is generally found
in sufficient quantity in the intestinal bacteria of the dog's
body. Taken in very large quantities, Vitamin K can cause
toxic conditions such as blood abnormalities and anemia.
Water Soluble Vitamins: Vitamin B1 (thiamine) helps
metabolize carbohydrates for energy. When there is a thiamine
deficiency, neurological disorders may develop. Such deficiency
disorders are treated by dosages of thiamine. Sources of thiamine
include: chicken, beef, kidney, liver, egg yolk, peas, potatoes,
milk and whole-grain cereals.
Riboflavin (Vitamin B2) deficiency does not usually occur
except in periods of great demand on the body, such as lactation,
or severe illness in puppies. Deficiency problems can include
weight or hair loss, loss of appetite, reduced fertility or
cataracts on the eyes.
Pyridoxine, Vitamin B6, helps enzymes metabolize protein and
is necessary for normal immune system functions. B6 deficiency
causes symptoms that include weight loss, convulsions, kidney
disease and anemia. Foods rich in B6 are fish, liver, legumes,
wheat germ, whole wheat, brewer's yeast and milk.
Vitamin B12 contributes to red blood cell production and the
synthesis of nucleic acids (genetic components). Feeding dogs
raw egg whites impairs absorption of an important component
of this vitamin called biotin. Cooking eggs and their whites
avoids this problem. Vitamin B12 deficiency can also be a
concern for dogs fed an exclusively vegetarian diet, although
with care and appropriate supplementation, dogs can do well
on this diet. B12 deficiency causes anemia (low red blood
cell count), which is easily reversible through injections
of Vitamin B12.
Vitamin C is normally synthesized in the liver from glucose,
but in conditions of illness or for active, working dogs,
supplements are often given. Vitamin C is water soluble and
quickly eliminated in the urine.