As they age, dogs may suffer from a decline in cognitive function, becoming disoriented, anxious, and irritable as well as exhibiting alterations in the sleep-wake cycle and house training. SAMe, an endogenous molecule found in every living cell but in particular abundance in the liver and brain, is a donor of methyl groups in many reactions catalyzed by methyltransferase enzymes. Some studies have suggested that a lack of methyl groups in the central nervous system may play a role in the etiology of Alzheimer's disease in humans, and there are similarities between canine cognitive dysfunction and Alzheimer's disease. In this study, an oral S-adenosylmethionine (SAMe) tosylate supplement (Novifit tablets, was evaluated as a dietary aid for the management of age-related mental impairment in dogs. To participate in the study, dogs had to be older than 8 years and have displayed signs of cognitive dysfunction for at least 1 month. A standardized questionnaire evaluating behavior and locomotion difficulties was employed. Dogs were given 18 mg/kg SAMe tosylate or an identical placebo tablet for 2 months. The aggregate mental impairment score was reduced by more than 50% in 41.2% (n = 17) of treated dogs and 15.8% (n = 19) in the dogs given placebo. The authors conclude that SAMe appears to be a safe and effective agent for improving signs of mental decline caused by aging in dogs.

COMMENTARY: It's hard for owners to see pets age and show signs of cognitive dysfunction. Several nutritional and supplemental aids have been shown to be beneficial in decreasing some of the clinical signs associated with aging. Since this was a double-blind placebo-controlled study, it adds high-grade research findings to the evidence that SAMe is beneficial for canine patients with signs of brain aging.

Effect of S-adenosylmethionine tablets on the production of age-related mental decline in dogs: A double-blinded, placebo-controlled study. Rème CA, Dramard V, Kern L, et al. VET THER 9:69-82, 2008.