It is a water-soluble vitamin and a strong antioxidant. It supports the immune system and is necessary for the synthesis of collagen (the building material of joints, bones and vessels). Unlike humans, dogs and cats produce it themselves in the liver, in large amounts from glucose. Therefore, it is not an essential vitamin in their diet [1].
What it contains: Offal (liver, kidneys, adrenal glands). If necessary (joint problems, growth of giant breeds, convalescence, severe stress), a safe, natural supplement in the form of rosehip meal is used.
Deficiency: Does not occur in healthy animals. It may appear in severe liver diseases or in sporting/working dogs (sledding, agility) and during severe infections, when the body uses more antioxidants than the liver can produce [2].
Excess: Excessive supplementation with synthetic vitamin C may increase the risk of painful oxalate-calcium urolithiasis in the bladder, especially in predisposed animals (ascorbic acid is metabolized, among others, to oxalates), and cause violent osmotic diarrhea [3].
Sources
- National Research Council (2006). Nutrient Requirements of Dogs and Cats - vitamin C is not necessary in the diet of dogs and cats (endogenous synthesis). National Academies Press. https://nap.nationalacademies.org/catalog/10668/nutrient-requirements-of-dogs-and-cats
- Hand MS, Thatcher CD, Remillard RL, Roudebush P, Novotny BJ (2010). Small Animal Clinical Nutrition, 5th Edition. https://www.markmorrisinstitute.org/sacn5.html
- Lulich JP, Osborne CA. Calcium Oxalate Urolithiasis - increased dietary supply of oxalates (including vitamin C) increases the risk of calcium oxalate urolithiasis in dogs. Clinician’s Brief. https://www.cliniciansbrief.com/article/calcium-oxalate-urolithiasis