1. Coconut or coconut oil- commonly used as a cure all for yeast, skin, etc. This is high in omega 6, so inflammatory as opposed to fish oil which is omega 3 and anti-inflammatory. It is also plant based vs animal based and dogs often cannot use plant based oils effectively and can be allergic as well.
2. Alfalfa- often a GMO ingredient and allergen. I find our breed in particular reactive to this. Watery eyes and sneezing.
3. Flax seed- for pregnant dogs, has been shown in animal studies to reduce litter size, cause resorption, and reduced birth weights. Flax has to be changed into a usable state in the body. Humans do it well, dogs not so well. So can be an allergen. Fish oil is a much better omega 3 source.
4. Brewers yeast- or any kind of yeast addition can be a popular allergen and a cheap filler.
5. Peas- too starchy and popular allergen. They are replacing grains in holistic dog foods, but appear to be creating as much intolerance. Not an easily assimilated item in the diet by dogs. Can create anal sac issues. They are also protein rich so its a cheap way to bolster protein in kibble.
6. Canola Oil or Sunflower oil(any vegetable oil really is not optimal)- another GMO product to look out for. Pro-flammatory item. Fish oil and chicken fat are better fat sources. Canola etc is a cheaper filler.
7. Eggs- just a popular allergen for dogs. In the top 5 food allergens for dogs. Fish, beef, grains, eggs, chicken are typically the most common issues for dogs these days. Since beef, chicken and eggs are most often grain fed, that's the likely correlation.
8. Potatoes- some dogs do not fair well because of the higher sugar content (starch). They can create a yeasty environment. Sweet potatoes are a lower glycemic choice.
***These items can pop up in supplements as fast as dog food too. So read labels. Fish oils often have soy added as a cheap filler as well. Not good!