A method for inhibiting a decline in learning and/or memory in an animalcomprising maintaining the animal on an antioxidant-fortified diet for aperiod of at least about 3 years. The diet comprises at least one antioxidantin a total antioxidant amount effective to achieve such inhibition. Suitableantioxidants include vitamin E, vitamin C, .alpha.-lipoic acid and antioxidant-containing plant meals. The methods are particularly useful for young adultcanines such as dogs.
