Dietary shortcomings may be associated with dogs and cats developing skin problems. Symptoms of skin problems include dull dry coat, scaling, erythema (skin redness), alopecia (absence of hair), greasy skin, seborrhoea (abnormalities in sebum production and / or keratinization), pruritus, poor wound healing and susceptibility to secondary infections. (Watson 1998, Ackerman 1987, Case et al 2011)

Diet may contribute to this condition if it is:

• nutritionally unbalanced,

• stored poorly resulting in loss or damage of nutrients, or

• if the animal is unable to digest the nutrients in it. (Lloyd & Marsh 1999)

There are several nutrients that, if unavailable to the animal or supplied in inappropriate ratio to other nutrients, will contribute to poor skin health. In this blog, I look briefly at the role of essential fatty acids (EFA), zinc, and vitamins A and E on maintaining skin health.

Essential fatty acids

Linoleic acid (omega 6) and alpha-linolenic acid (omega 3) are considered essential to dogs as they are unable to synthesize them and therefore require them to be supplied in their diet. (Bauer 2006)
Linoleic acid (omega 6) is essential for skin health as it is comprises a part of epidermal keratinocytes called ceramides. Ceramides are extruded from keratinocytes to enhance cell cohesion in the skin and create a water barrier to the epidermis. (Case et al 2011, Bauer 2006)

An important function of linoleic acid is to synthesize arachidonic acid. Arachidonic acid is a precursor of some eicosanoids. Eicosanoids are released into the cell membranes during times of trauma to affect the body’s inflammatory and allergic responses. (Case et al 2011)

Alpha-linolenic acid (omega 3) synthesizes eicosapentaenoic acid (EPA) which is also a precursor to eicosanoids.

The eicosanoids produced from EPA are more potent mediators of inflammation than those produced from arachidonic acid, so by ensuring omega 6 and omega 3 are provided in the appropriate balance, the body’s inflammatory response can be regulated.(Bauer 2006)

The ideal ratio of omega 6 to omega 3 is 3-5 to 1, however, in some commercial pet food the ratio can be a lot higher. The imbalance is likely caused by the destruction of omega 3 in the manufacturing process as it is highly unstable and prone to destruction from heat and exposure to light and oxygen. (Case et al 2011, Syme)

When the balance of omega 6: omega 3 is inappropriate, inflammatory skin symptoms appear because the eicosanoids produced from arachidonic acid are inflammatory and there is insufficient omega 3 to synthesize EPA to produce the less inflammatory eicosanoids. (Case et al 2011)

Feeding a raw food diet, omega 3 is less likely to be destroyed by heat and an appropriate balance of EFA can be reached. Raw food sources of omega 6 include vegetable oils (e.g. safflower, sunflower, soya bean, corn, cotton seed), and poultry and pork fat. Omega 3 is available in eggs, liver, rabbit, oats, vegetable oils (linseed, rapeseed, corn and soya bean) spinach, mushrooms, bananas, and marine sources (Billinghurst 1993, Bauer 2006)

Zinc

Zinc has a crucial role in cell metabolism in the body. It influences carbohydrate, lipid, protein and nucleic acid metabolism. It also has a key role in protein synthesis and is essential for immunity and reproductive functioning. Finally, it is a catalyst for RNA and DNA polymerase so it is important in the process of rapidly dividing cells, particularly in the epidermis. (Case et al 2011, Lloyd & Marsh 1999)

In cats and dogs, the first signs of a zinc deficiency are changes in the skin and coat. The coat becomes dull and skin lesions appear around the extremities, mucocutaneous junctions and pressure points of the limbs. (Case et al 2011, Kane et al 1981, Watson 1998)

The composition of pet foods can affect the bioavailability of zinc and the animal’s ability to absorb it internally. For example, excessive levels of calcium, iron and copper compete with zinc for intestinal absorption. (Watson 1998) Further, phytic acid from plant sources such as those found in cereal or soy based diets reduces the bioavailability of zinc to the animal. (Morris & Rogers 1994, Watson 1998)

Raw food sources of zinc, particularly those from animal sources are highly available to animals and readily absorbed. Meat and eggs are good sources of zinc. (Case et al 2011)

Vitamin A

Vitamin A or retinol and its derivatives are required to maintain healthy epithelial tissue including the skin. Vitamin A produces the mucoproteins in the mucous of some epithelial cells. These mucous secretions protect against bacterial invasion. Without Vitamin A, the conversion of squamous type cells to mucous producing cells fails to occur and they are replaced with dysfunctional keratinized cells. This leads to the development of lesions and susceptibility to infection. (Case et al 2011, Watson 1998, Billinghurst 1993)

Due to vitamin A’s susceptibility to being destroyed by heat, cooked pet foods may contain insufficient amounts of it. The levels of bioactive compounds in carotenoid from which Vitamin A originates is reduced when food is heated at temperatures as low as 60 degrees Celsius. (Rawson et al 2011)

Raw food therefore provides an excellent source of Vitamin A. Vitamin A originates from carotenoids which are synthesized from plant cells. Carotenoids are dark red pigments found in carrots, sweet potatoes and dark green vegetables. Other food sources include fish liver oils such as cod liver oil, milk, liver, and egg yolk. (Case et al 2011, Billinghurst 1993, Pitcairn & Pitcairn 2005)

Vitamin E

The principle role of vitamin E in the body is as an antioxidant. Polyunsaturated fatty acids in the body’s cells are prone to oxidative damage. Vitamin E interrupts the oxidation process and protects the body from highly reactive oxygen metabolites (free radicals). (Case et al 2011, Billinghurst 1993, Lloyd & Marsh 1999) Vitamin E, along with selenium, is therefore important for maintaining the cell membranes including those in the skin. (Watson 1998)

Pets fed a cooked diet may not consume sufficient vitamin E to maintain healthy skin as antioxidants are easily degraded by thermal processing. Further, antioxidants such as vitamin E are easily destroyed by exposure to oxygen such as when commercial pet foods are stored inappropriately. (Rawson et al 2011, Lloyd & Marsh 1999, Pitcairn & Pitcairn 2005)

Feeding an animal a high fat diet may also induce a Vitamin E deficiency as lipid metabolism is the major source of free radicals thus potentially depleting Vitamin E stores in the body. (Lloyd & Marsh 1999, Watson 1998)
Good raw food sources of vitamin E include vegetable oils such as wheat germ, cottonseed, safflower, soya bean and peanut oil, eggs, whole grains, liver, legumes and green plants. (Billinghurst 1993, Pitcairn & Pitcairn 2005)

Nutritional shortcomings may be associated with inflammatory skin problems in dogs and cats. A change to a diet with sufficient EFA, zinc and vitamins A and E may assist in healing skin problems in your cat or dog.

*Full Stride provides nutrition consultations to assess your pet’s existing diet and to formulate a customised diet plan to suit you and your pet. For more information please contact me at jlconlon@fullstride.com.au.

You can also stay up to date by following Full Stride on Facebook – https://www.facebook.com/FullStrideCanineMassageTherapy/

Until next time, enjoy your dogs.

Sources:

Ackerman, L, 1987 “Nutritional supplements in canine dermatoses” Canadian Veterinary Journal 28:1-2: 29 – 32

Bauer, J.W 2006, “Facilitative and functional fats in diets of cats and dogs”, Journal of the American Veterinary Medical Association. Vol.229, No.5 680 – 684

Billinghurst, I (1993), Give your dog a bone:the practical common sense way to feed dogs for a long and healthy life, Warrigal Publishing, Bathurst NSW.

Case, L.P, Daristotle, L, Hayek, M & Raasch, M.F, (2011), Canine and feline nutrition (3rd ed), Mosby Elsevier, Missouri.

Kane, E, Morris, J, Rogers, Q, Ihrke, P.J. & Cupps, P.T. 1981, “Zinc deficiency in the cat”, The Journal of Nutrition, April 1981, 488-495

Lloyd, D.H. & Marsh, K.A. 1999 “Optimizing skin and coat condition in the dog” Waltham Focus, Vol 9, No 2:2 – 7

Morris, J & Rogers, Q 1994, “Assessment of the nutritional adequacy of pet foods through the lifecycles”, The Journal of Nutrition (124), 2520S – 2534S

Pitcairn, R.H & Pitcairn, S. H. (2005) Dr Pitcairn’s complete guide to natural health for dogs and cats, Rodale Inc, USA

Rawson, A, Patras, A, Tiwari, B.K, Noci, F, Koutchma, T, & Brunton, N (2011) “Effect of thermal and non thermal processing technologies on the bioactive content of exotic fruits and their products: Review of recent advances”, Food Research International, 44:1875-1887

Syme, B. n.d. Scientific guide to natural nutrition. Available: www.vetsallnatural.com.au

Watson, T,D,G 1998 “Diet and skin disease in dogs and cats” Journal of Nutrition 128:2783S – 2789S