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Pet Nutrition
         Diet and the Skin
      By Wendy C. Brooks, DVM, DipABVP
    Educational Director, VeterinaryPartner.com

Diet and the Skin

Did you know that skin diseases account for as much as 25% of the cases seen by small
animal veterinarians? Skin problems typically faced by pets and their owners include:

itching
dandruff
blackheads
odor
crusting
redness
rashes
oiliness

The nutritional aspect of skin disease is a very broad topic, too broad to address in this
small article. There are true nutritional deficiencies which affect the skin and other skin
diseases that can be made dramatically better through the use of supplementation.

It is helpful to know that because a condition responds to a nutrient, this does not
necessarily mean that a deficiency of that nutrient is present.

Everyone wants their pet to have a lustrous beautiful coat and would like to do what is
nutritionally possible to ensure this. Recently essential fatty acids have received a great
deal of press. A brief primer follows.

WHAT IS A FATTY ACID?

Biochemically, a fatty acid is what we colloquially refer to as fat. When we talk about
different types of fatty acids we are talking about different types of fat. A fatty acid
consists of a long carbon chain (say 20 or so carbons in length) with a biochemical acid
group at one end.

SATURATED VS. UNSATURATED

Each carbon has four binding sites. In the carbon chain, two sites will be taken up by
other carbons (i.e., the two adjacent carbons on the chain). In a saturated fat, the
other two sites are taken up by hydrogen atoms.

Saturated fats are typically solid at room temperature (like lard and butter) and are
generally of animal origin.
Saturated fats are generally burned as fuel by our bodies.

Unsaturated fats have two adjacent carbons held together by a biochemical double
bond. These fats are generally liquid at room temperature and are of plant origin (olive oil,
corn oil etc.).

Unsaturated fats can be classified as omega three fatty acids or omega 6 fatty acids,
depending on the location of the double bond relative to the end of the chain. These
types of fatty acids are essential, meaning that our bodies cannot make them; instead, in
order to get them we must eat them in our diet. These fats are not burned for fuel.
Instead they are used as structural components. The omega 6 fatty acids are used as the
main structural components in our cells. Omega 3s are used in the structure of the retina
and central nervous system.

For healthy skin and coat, the diet must contain adequate omega 6 fatty acids,
as these make up the very surface of the skin.

Examples of omega six fatty acids (also called n-6 fatty acids): Linoleic acid, gamma
linolenic acid, and arachidonic acid

An excellent source would be evening primrose oil

Examples of omega three fatty acids (also called n-3 fatty acids): Alpha linolenic acid,
eicosapentaenoic acid, docosahexanoic acid

An excellent source would be cold water fish oils

SHOULD WE SUPPLEMENT ESSENTIAL FATTY ACIDS?

There is no question that a diet must contain adequate omega 6 fatty acids to maintain
optimal skin and coat quality. A complete and balanced diet has an amount of omega 6
fatty acids that should be optimal for a normal animal.

But there's more. Research has shown that dogs with seborrhea (oily, dandruffy skin)
have depleted amounts of omega 6 fatty acids in their skin despite eating a diet that
should be optimal. When omega 6 fatty acids are supplemented, the seborrhea improves.
This finding supports the old time remedy of adding a spoonful of corn oil to the diet to
ensure a glossy coat. It should be realized that seborrhea is complex condition but animals
with seborrhea may need more omega 6 fatty acids.

And still more. Omega 6 fatty acids constitute our cell membranes. During assorted
biochemical situations it becomes necessary to produce hormone-like substances called
prostaglandins and leukotrienes. These substances are actually made from omega 6 fatty
acids and the prostaglandins and leukotrienes that result are not necessarily good for us.
In fact, these substances are responsible for itching, and inflammation leading to the
clinical skin problems listed above. One way to address this, is to supplement omega 3
fatty acids which become incorporated into cell membranes along with the omega 6's.
After a couple of months of supplementation, omega 3 fatty acids have infiltrated cell
membranes significantly. When it comes time to make prostaglandins, the omega 3's are
mobilized instead of the omega 6's only in this case, the prostaglandins that result are not
inflammatory. When omega 3 fatty acids are supplemented, itching can be substantially
reduced.

One problem with this is that no one really knows how much omega 3 fatty acid to
supplement. There is some evidence that a ratio of omega 6 to omega 3 fatty acids in
the supplement is crucial. If this is so, clinical research becomes hugely complicated as the
diets of pets cannot be standardized easily for study. If pets in a study eat different diets,
then it is impossible to tell what overall omega 6: omega 3 ratio each is receiving.
Essential fatty acids are being pursued as treatment for diseases of virtually every organ
system; watch for new research developments in this area.

It should also be noted that extra essential fatty acids or even certain omega 6:omega 3
ratios have become advertising points for different pet foods based on the above
theories and findings.

Date Published: 1/1/2001
Reprinted from
VeterinaryPartner.com
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