Vitamin E is an important nutrient which has been shown to have a number of physiologic and pharmacologic effects. It in a potent antioxidant and reduces fat oxidation and increases the production of HDL cholesterol. At higher doses, it also reduces cyclooxygenase and lipooxygenase activities, decreasing production of prostaglandins and leukotreines. As such, it is a potent anti-inflammatory drug. It will reduce platelet function and prolong the bleeding time slightly in healthy individuals. There is no known side-effects to vitamin E at levels less than 4000-6000 IU per day. I recommend that vitamin E be given to all dogs. For dogs under 2 years of age, give 400 IU of vitamin E daily. For dogs over 2 years of age, give 800 IU of vitamin E daily.
Vitamin C works with vitamin E and helps regenerate vitamin E, potentiating its antioxidant effect. Vitamin C supplementation does no harm, since the excess is excreted through the kidney. While dogs produce vitamin C in their bodies (unlike human beings and guinea pigs who must have it in their diet), under stress or disease, they may need vitamin C in excess of their manufacturing capacity. In excessive dose, vitamin C can cause flatulence and diarrhea. This intestinal tolerance level varies among dogs, but is generally around 3000 mg per day in an adult German Shepherd. I recommend this be given to all dogs. For dogs under 2 years of age, give 250 mg vitamin C twice a day. For dogs over 2 years of age, give 500 mg of vitamin C twice a day.