A healthy diet for all mammals—especially humans and dogs—contains a balance of two types of polyunsaturated fatty acids (PUFA), the omega-6 and omega-3 series. Omega-6 and omega-3 are not interchangeable. Both are needed in a roughly 1:1 to 5:1 ratio. PUFA are essential because mammals don’t manufacture them, so they must come from the diet. The 18 carbon PUFA omega-6 linoleic acid (LA 18:2n-6) and omega-3 alpha-linolenic acid (ALA 18:3n-3) are found naturally in plant foods. In theory, they are converted to longer chain PUFA that are critically essential, but in practice these conversions on the omega-3 side are only about 1 to 5% efficient. 

The best choice for a canine essential fatty acid supplement is one that contains both fish oil and borage or evening primrose oil.

Our human epidemic of obesity and inflammation statistically correlates well with a single food:  soybean oil.  Since 1900 our consumption of soybean oil has increased over 1000-fold: it’s our fourth biggest source of calories after grains, sugar, and dairy. All this soybean oil is flooding us with LA.Other high LA oils include cottonseed, safflower, sunflower, and corn. Typical diets in the U.S. and Canada have omega-6 to omega-3 ratios of 50:1, not 5:1! fin

Commercial dog foods generally contain an acceptable, healthy amount of LA, and moist dog foods (especially with liver and egg) also contain the longer chain omega-6 PUFA arachidonic acid (AA). In any event, dogs are fairly good at converting LA to AA.  However, dogs eating human table scraps are also getting too much LA, which can contribute to allergies, atopic dermatitis, arthritis, obesity, and diabetes. There’s a huge difference between feeding your dogs unwanted foods (plate scrapings, overcooked meals, leftovers, etc.) and purposefully preparing home-cooked pet meals. Are your dogs eating PB&J and pizza crusts, or green beans mixed with chopped chicken giblets and sardines? The problem for both dogs and humans is not LA per se, but the lack of balance. All mammals need LA, but they need other PUFA—especially DHA, EPA and and omega 6 gamma-linoleic acid GLA just as much. 

For more detail, please keep reading. 

Fish Oil is Anti-inflammatory

The main reason why soybean oil increases inflammatory and allergic conditions is that the same enzyme systems are used to convert omega-3 and omega-6 fatty acids. The omega-3 fats EPA and DHA, and the biochemicals derived from them, are generally anti-inflammatory, while some biochemicals derived from AA are pro-inflammatory. But the raging torrent of dietary soybean LA shuts conversions down on the omega-3 side, while forcing more conversion all the way to AA, which itself is hardly ever lacking in human or dog diets. 

Further, dogs (like humans) have very limited abilities to convert ALA to DHA. The only practical means to quickly shut down the production of proinflammatory biochemicals is to make sure the dog gets high-quality fish oil.  Do not rely on flaxseed oil to resolve itching!  If your pet suffers from pruritis (excessive itching) hot spots, atopic dermatitis, flea bite allergies, excessive shedding, skin sores, dry skin, coarse unmanageable coat etc. the first priority is to stop the damaging scratching.  Omega 3 PUFA take the lead here.

Borage or Evening Primrose Oil Rebuild and Repair

Skin is your dog’s largest organ and the first line of defense against infection and contamination. Skin cells and hair follicles secrete an oily/waxy sebum that protects the skin and coats the hair.  Sebum is antibacterial, antifungal, anti-inflammatory and coats the body surface to prevent excessive water loss. Dog coat oils make the hair shiny and supple. Extra sebum on the coat of water retrievers gives them a special ability to do the opposite—they shed water off their coats and do not absorb excess water in their skin while immersed. 

After you stop the damaging scratching, the second priority is to build new skin and hair cells that are healthy and functional. Omega-6 PUFA take the lead here. Also use an oil with GLA if your dog doesn’t have a skin or coat condition, and you’d like to keep it that way! 

In order to produce sebum skin and hair follicles need LA and GLA. Skin also incorporates these PUFA (and derivatives) right into the skin cells. Without adequate omega-6 PUFA, repair and rebuilding of the skin and coat damaged by chronic scratching, biting, and dermatitis are slow and compromised. Although itching is reduced, the skin may remain reddened and the coat dull and patchy. Long-haired dogs may have coarse, unmanageable coats with hair that sheds and breaks. 

If the sebum barrier layer is suboptimal your pet has a greater risk of having a pruritis or dermatitis relapse. In some cases, the condition itself was caused by too little dietary fat;for example, in larger long-haired breeds fed inadequately, dogs with gastrointestinal problems, or pets fed dry foods stored too long, where the LA becomes rancid. Keep this in mind if you rescue an animal that is underweight and itchy.