Disease Management Diet Guide

Heart Disease — The Role and Limits of Dietary Management

• ✓The most common cardiac disease in dogs is myxomatous mitral valve disease (MMVD), which is prevalent in small breeds in their senior years. Dietary management contributes to symptom relief and reducing cardiac workload, but does not replace prescribed medication as a treatment.
• ✓Sodium restriction: excess sodium leads to fluid retention → increased cardiac preload. Hand et al. (2010): sodium restriction is adjusted stepwise according to disease stage (moderate restriction in early stages, strict restriction in advanced disease). However, excessive sodium restriction can cause appetite loss and electrolyte imbalance.
• ✓Taurine and dilated cardiomyopathy (DCM): Freeman et al. (2018): DCM has been reported in dogs fed grain-free diets, with taurine deficiency proposed as a contributing factor. However, the causal relationship has not been fully established. Long-term feeding of diets where legumes or tuberous vegetables (peas, potatoes) form the primary ingredients warrants caution.
• ✓Omega-3 (EPA+DHA): used in dogs with cardiac disease for anti-inflammatory effects and to prevent cardiac cachexia (muscle wasting). Note that excessive doses can affect blood clotting — dosage should be determined under veterinary guidance.

Joint Disease — Nutrition and Weight Management Are Central

• ✓Osteoarthritis (OA) is the most common musculoskeletal disease in middle-aged and senior dogs, characterized by cartilage damage and chronic joint inflammation. Johnston (1997): obesity directly increases joint load — weight loss alone can significantly improve joint symptoms.
• ✓Glucosamine & chondroitin: supply the building blocks of cartilage components, inhibiting cartilage breakdown and supporting synovial fluid production. Hand et al. (2010): clinical efficacy requires at least approximately 500 mg glucosamine and 400 mg chondroitin per 10 kg body weight.
• ✓Omega-3 (EPA+DHA): inhibits prostaglandin synthesis within joints, reducing the inflammatory response. Fish oil-derived omega-3 is more bioavailable and effective than plant-based sources (ALA).
• ✓Weight management: every 1 kg of weight lost reduces front leg joint load by approximately 5-fold. In many cases of joint disease management, weight loss takes priority over any dietary prescription.

Kidney Disease — Stage-Specific Strict Dietary Management Required

• ✓Chronic kidney disease (CKD) is classified into stages 1–4 by IRIS (International Renal Interest Society) criteria, with dietary restrictions becoming more stringent at higher stages. IRIS (2019): from stage 2 onward, low-phosphorus food has been shown to effectively preserve kidney function.
• ✓Phosphorus restriction is the most important measure: when kidney function declines, the ability to excrete phosphorus decreases, leading to phosphorus accumulation in the blood → additional kidney tissue damage → secondary hyperparathyroidism. Renal prescription diets contain approximately 50–70% of the phosphorus found in standard foods.
• ✓Protein adjustment: historically, low-protein diets were universally recommended, but current guidelines favor stage-appropriate protein levels. Excessively low protein accelerates muscle loss. IRIS (2019): standard food is acceptable in stage 1; transition to a renal prescription diet should be considered from stages 2–3.
• ✓Increased hydration: water intake is critically important for dogs with CKD. Wet food (70–80% moisture) or adding water to dry food reduces kidney workload and promotes diuresis. Selecting a renal prescription diet without veterinary prescription is dangerous.