Medium Chain Triglycerides (MCT)

Medium-chain triglycerides (MCTs) may serve as an alternative energy substrate for the aging canine brain. With cognitive dysfunction, or age-related mental decline, glucose is not able to be utilized as effectively by cells within the brain. As glucose utilization declines, this can create a deficit in energy available to neurons. However, these cells are also able to utilize ketones as an alternate energy source, and this pathway appears to remain intact. MCTs are able to bypass traditional long-chain fatty acid pathways by being transported directly to the liver. There, they undergo rapid hepatic β-oxidation to produce ketone bodies like β-hydroxybutyrate (βHB), which cross the blood-brain barrier to provide a secondary fuel source. 

Beyond simple energetics, MCT metabolites may exert direct neuroprotective effects by modulating neurotransmission and supporting antioxidant responses.

Pharmacologically, MCT supplementation is distinguished by its ability to induce intermittent ketosis even in a well-fed state, unlike the strict carbohydrate restriction required for a traditional ketogenic diet. Clinical evidence in aged Beagle dogs and those with Canine Cognitive Dysfunction (CCD) have demonstrated that diets supplemented with 5.5% to 9% MCT can improve visuospatial function, learning, and attention. Interestingly, these procognitive benefits have been observed even when plasma βHB levels remain relatively low (0.3–0.6 mM), suggesting that the therapeutic effect may be mediated by direct actions of medium-chain fatty acids (MCFAs) in the brain or specific regional increases in ketone utilization rather than high systemic ketosis alone. MCTs are generally considered safe and are likely to be most effective when initiated during the early stages of cognitive impairment to support neuronal health before irreversible damage occurs.

There also appears to be a mild effect on palatability with some dogs, though this was most often seen at higher percentages of MCT in the diet (>6%).

Currently, supplementation appears to be primarily achieved through prescription diets and to a lesser degree supplements.