Omega 3 balance and fish oil

I have read most of the scientific arguments over the ratio of Omega 6 to 3 and it is something I am addressing in my own diet. I decided to seriously reduce grain in my dogs’ diet after losing two youngish dogs with cancer and taking a canine nutrition course. The thing that I am wondering about now is the place for fish oil in dog’s diet (not to mention in my donkeys’!) There is some doubt over how useful the plant sources of O3 are, especially to dogs, so fish oil is usually recommended. I just can’t imagine that the ancestral dogs caught a lot of fish. I have seen the grizzly bears fishing but dogs must have been getting sufficient O3 and a lot less O6 from dry land sources. Is it just that we humans have mucked things up so much that dogs and even horses should be asking Father Christmas for a fishing rod?

Thank you for bringing this subject up Chris. I too have been thinking about this recently because one of my lot had her coat stripped back in August. Since then, it has failed to regrow and looked dull and lifeless. She was on a complete raw food diet. Long story short, about 6 weeks ago I put her back on the fish based dry diet that she had as a puppy (she had a beautiful coat then) and it is already showing a marked improvement. It is now growing, thickening up and has developed a shine that wasn’t there before. I’ve concluded that it’s a good thing to include fish (hence omega oils) in a dog’s diet.

I’m a bit puzzled about supplementing with salmon oil or similar because a lot of the good quality foods already have added omega oils and you don’t want to overdose if the dog’s food doesn’t have it in already.

According to this article not all omega 3 is the same and the correct ratio 6 to 3 is important. Also, not all omega 3 is the same:

[i]It is the DHA and EPA forms – found mainly from marine sources, which are beneficial. The ALA form of Omega 3 found in vegetable sources such as Flaxseed oil or Linseed oil must first be converted to EPA & DHA for it to benefit, and dogs lack the enzymes to do that efficiently.[/i]
As for ancestral dogs, I don't consider it because our domestic dogs have evolved and have much longer lifespans. I'm not sure we should use it as a yardstick for a dog's nutrition but I know lots of folk disagree. However, my breed, which originated in the Highlands of Scotland would indeed have been fed a crofter's diet of lots of fish, plus oatmeal, potatoes and vegetable/table scraps as available. Oddly enough, I've tried lots of products on my lot and found that a plain, fish diet works best for them.


I have had my dog on salmon and salmon oil for a little while now, and like you i wondered about it being ‘natural’ (and also got myself concerned about PCB’s etc).

However i dont think dogs ‘natural’ diets can be compared directly to wolves personally, they have evolved to live with humans and be fed by humans …so throughout the ages i imagine lots of dogs have been fed on fish scraps.

From a personal point of view- salmon oil, salmon food and glucosamine/green lipped mussel have been a life saver in that they have given my 18 year old a new lease of life (he is now running around again and jumping on the bed etc which he couldn’t do before i started the supplementation)

However i am not sure what the LONG term affects might be - and while 5 year effects are not a great concern for me, they would be if i had a young dog.

The only issues i am aware of are

  1. Concerns over contaminants in farmed salmon (does this apply to fish oil?)
  2. I seem to recall a study showed that excessive omega 3 can deplete vitamin E

Developing the comments re Omega 3 levels relative to Omega 6

An article that can be viewed by clicking here has certainly caused me to consider Omega ratios in what I am feeding mine (& also on back of prior genuine dog health issue)

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Thanks for that Coaster. I have read a little about ratios in the human diet and unsurprisingly, people tend to have a high omega 6 intake but often not omega 3. From what I have read, it also seems that it is harder for the body to utilise omega 3 from seeds for humans too.

It can get a bit mind boggling looking at safe levels and how the nutrient groups need balance to work well. This is one of the reasons I keep coming back to a varied diet and hoping for the best.