By Fiona Robertson, Cert A.C.N.
Please read part 1 of this series, which talks about weight gain and osteoarthritis: Feeding Senior Dogs: Part 1
While standardized diagnostic guidelines are yet to be defined, Canine Cognitive Dysfunction Syndrome (CCDS) is diagnosed with increasing frequency in modern veterinary practices. Early dietary intervention with or without concurrent medication, may help improve cognitive function in our aging dogs with CCDS. Therapy may include the use of dietary antioxidants, MCT oil, DHA, SAMe, L-arginine and B-vitamin supplementation, which may be implemented under the supervision of your dog’s professional care team.
Oxidative Stress
CCDS resembles human Alzheimer’s disease or Dementia, disrupting brain signals affecting cognition and behavior. Oxidative stress – the damage of cells by ROS or “Free Radicals” - is considered a primary contributor to the disease, and much of the current research is focused on the use of antioxidants to help lessen damage to brain cells. Dietary antioxidants for dogs might include mixtures of vitamin E, Vitamin C and Selenium, with or without Coenzyme Q10, L-carnitine and others. Dosing should be dependent on the individual dog’s diet to ensure optimal levels are reached overall.
Glucose Metabolism
Poor brain glucose metabolism, resulting in less fuel available for neuro functions, is also implicated in increased risk of age-related cognitive dysfunction. Providing the brain with alternate fuel source in the form of ketones has been shown to improve mental function in cognitively impaired individuals.
Medium Chain Triglycerides (MCT) can help the body produce ketones for energy and MCT oil has shown promise as a supplement in the treatment of CCDS. A standard dose is not yet available, but common recommendations call for replacing 5.5 to 9% of total calories with MCT oil. MCT oil containing only c8 (caprylic acid, sometimes called octanoic acid) and c10 (capric acid, sometimes called decanoic acid) appears to be the most favored, but ideal ratios of c8:c10 are yet to be defined for CCDS.
Omega 3 Fatty Acids
Docosahexaenoic acid (DHA) is an omega-3 fatty acid present in large amounts in the human and canine brain. It is depleted in the aging process, affecting how the brain communicates, promoting inflammation and leading to neurotoxic plaque formation. Increasing amounts of this DHA through dietary supplementation may or may not increase DHA levels in the brain, but supplementation of omega 3 fatty acids such as fish oils is considered protective against cognitive decline and/or improve cognitive function in animals and people.
To date, no standardized dose has been defined, but lower doses may be more beneficial when used in combination with other components. Marine source supplements containing at least 600 mg DHA + EPA may be a reasonable and easily attainable starting point, but overall dosing will be dependent on the amounts already present in the animal’s diet and the dog’s tolerance. Higher doses may provide more benefits for dogs suffering from CCDS, but there is a specified Safe Upper Limit for these nutrients ; diet + supplement totals for EPA + DHA should not exceed 175 mg/kg of bodyweight.
Remember that dietary fat, including MCT and fish oil, displaces other nutrients, so be sure the base (balanced) diet can still be fed within the guidelines on the package even after reducing portions to “make room” for added fats, as their may not be much wiggle room based on a recent study by De Andrade Príncipe et al. (2025).
Additionally, considerations should be made if your senior dog is prone to pancreatitis or other fat-metabolizing disorders; in these cases especially, adding any dietary fats should be done under the guidance of your veterinarian.
Other considerations
SAMe, L-arginine and B-vitamins, particularly when used with DHA and/or MCT oil may also benefit the senior dog with CCDS.
- Senior dogs treated with S-adenosylmethionine (SAMe) may see improved activity and awareness and decreased mental impairment (5). A suggested dose may be 18 mg/kg bodyweight, based on the literature, but accurate dosing may be obtained from your veterinarian.
- L-arginine, an amino acid, is involved in the learning and memory processes and may provide benefits in CCDS when used as part of a “cocktail” including various antioxidants, B-vitamins and DHA (2).
- An adequate supply of dietary B-vitamins in combination with omega-3 fatty acids may help improve memory and cognition (5). Properly formulated commercial diets, when fed as directed, should provide all the B-vitamins in adequate amounts, but conservative supplementation for seniors may be beneficial and is generally not harmful, as excess B-vitamins are excreted in urine.
Gut Microbiome and Gut/Brain Axis
The gut-brain axis is a relatively new and exciting area of study in both human and animals and there is a growing consensus that the gut microbiota plays an important role in age-related cognitive decline. Very generally, a diverse microbiome is linked with neuroprotection and overall good health (6). Through regulation of tryptophan (an amino acid provided in the diet) the gut microbiota affects the amount of serotonin produced in the brain. Specific strains of the bacteria Bifidobacterium longum, available in some canine probiotic supplements, have been associated in the improvement of anxiety in dogs and may prove to be helpful in senior dogs with CCDS.
Conclusion
Nutritional support for our aging seniors experiencing cognitive decline is important. Of course, the best protection is to ensure our dogs eat an optimized diet right from puppyhood, but dietary interventions, supplements and nutraceuticals are available. A “cocktail” may provide more benefits than single components.
References
Ashton, J. S., Roberts, J. W., Wakefield, C. J., MacLaren, D. P., Marwood, S., & Malone, J. J. (2023). Medium chain triglycerides with a C8:C10 ratio of 30:70 enhances cognitive performance and mitigates the cognitive decline associated with prolonged exercise in young and healthy adults. Physiology & Behavior, 269, 114284.
https://doi.org/10.1016/j.physbeh.2023.114284
Bhadoriya, P., Jatley, A., Singh, A., Mehrotra, R., Jain, M., Mohammed, A., Hamzah, Z., & Bukke, S. P. N. (2025). Exploring gut microbiota’s influence on cognitive health and neurodegenerative disorders: mechanistic insights and therapeutic approaches. Discover Immunity., 2(1). https://doi.org/10.1007/s44368-025-00010-x
Kim, S. H., & Hao, J. (2025). Recent advances in diagnostic and therapeutic strategies for canine cognitive dysfunction. American Journal of Veterinary Research, 86(8), Article ajvr.25.02.0053, ajvr.25.02.0053. Retrieved Mar 27, 2026, from https://doi.org/10.2460/ajvr.25.02.0053
Klievik, B. J., Fu, Y., Tyrrell, A. D., Chen, C. T., Metherel, A. H., & Bazinet, R. P. (2025). Dietary phospholipid carriers of DHA do not increase brain DHA levels: a replication study. Journal of Lipid Research, 66(11), 100913. https://doi.org/10.1016/j.jlr.2025.100913
May, K. A., & Laflamme, D. P. (2019). Nutrition and the aging brain of dogs and cats. Journal of the American Veterinary Medical Association, 255(11), 1245–1254. https://doi.org/10.2460/javma.255.11.1245
Olby, N. J., Araujo, J. A., Gruen, M. E., Johnson, P., Kubinyi, E., Landsberg, G., Latimer, C. S., McGrath, S., McKenzie, B., Moreno, J. A., Tarantino, M., & Volk, H. (2026). The Canine Cognitive Dysfunction Syndrome Working Group guidelines for diagnosis and monitoring of canine cognitive dysfunction syndrome. Journal of the American Veterinary
Medical Association, 264(4), 498-505. Retrieved Mar 27, 2026, from https://doi.org/10.2460/javma.25.10.0668
Príncipe, L. d. A., Marchi, P. H., Amaral, A. R., Pedrinelli, V., Zafalon, R. V. A., Romano, F. S., Balieiro, J. C. d. C., & Vendramini, T. H. A. (2025). Assessment of the Nutritional Impact of the 10% Snack Recommendation in Pet Diets. Veterinary Sciences, 12(3), 282. https://doi.org/10.3390/vetsci12030282