Some nutritional requirements are difficult to meet from natural sources. Levels of vitamins D and E, iodine, zinc and the ω-3 and ω-6 fatty acids all need specific attention and are often supplemented in raw dog foods (note that ALL these key nutrients have to be supplemented in processed food). We use sea kelp to provide the iodine required for proper thyroid function, wheatgerm oil provides vitamin E, beef liver and free-range eggs contain cholecalciferol (vitamin D). Recommended zinc levels are met by the high (80%) meat content in raw food although certain Northern breeds with a genetic inability to metabolise zinc may need supplementation. However, check with your vet before using any supplements. Finally, the correct amounts and ratio of the essential fatty acids are achieved through the use of grass-fed beef meat sources, the addition of natural flax seed and no grain.
Some requirements are dangerously easy to exceed. Whereas humans manufacture vitamin D by the action of sunlight on their skins, dogs struggle to do likewise and many raw dog foods are supplemented by the addition of cholecalciferol. However, vitamin D can be toxic (it is used as rat poison) and is fat soluble, building up in the body. Supplementing with an appropriate amount of (good quality) cod liver oil may solve a vitamin D deficiency but will almost certainly drive levels of another fat-soluble vitamin (Vit A) too high, potentially dangerously so.
Cotswold RAW recipes provide all the nutrients your dog requires without using any artificial supplements. However, we positively recommended giving a juicy raw bone occasionally (supervised) and have no issue with adding a little variety to your dog’s diet by providing some oily fish once a week. Fresh salmon is particularly good but sardines, mackerel or herring will all boost Vitamin D and ω-3 levels without causing any adverse side effects