Dietary Supplements for Dogs and Cats – When Are They Useful?

Joints and Musculoskeletal System

Very common for osteoarthritis, HD, spondylosis, etc.:

• Omega-3 fatty acids (EPA/DHA, mostly from fish oil or algae oil)
  • Effect: anti-inflammatory, Pain-relieving, supportive for osteoarthritis.
  • Important: sufficiently high dosage, good quality (purity, oxidation protection).
• Glucosamine and Chondroitin Sulfate
  • Building blocks of cartilage, intended to support cartilage metabolism.
  • Evidence: mixed study results, but widely used clinically and often included in “joint packages.”
• Green-lipped mussel (Perna canaliculus)
  • Contains glycosaminoglycans, Omega-3 fatty acids, and other components.
  • Often used for osteoarthritis, quality highly dependent on the manufacturer.
• MSM (Methylsulfonylmethane)
  • Organic sulfur, said to have anti-inflammatory and Pain-relieving effects.
  • Clinical data limited, but often used in combination products.

Skin and Coat, Allergies

• Essential fatty acids (Omega-3 and Omega-6)
  • e.g., fish oil, borage oil, evening primrose oil.
  • Used for atopy, dry skin, dull coat, seborrhea.
  • Important: Omega-3/Omega-6 ratio, patience (effect often takes weeks to appear).
• Biotin, Zinc, B-vitamins
  • Often combined in skin/coat preparations.
  • Useful for proven deficiency or during convalescence.

Digestion and Gut Health

• Probiotics
  • e.g., Enterococcus faecium, Lactobacillus spp.
  • Used for acute and chronic diarrhea, after antibiotic administration, IBD support.
  • Important: prefer veterinary preparations, ensure sufficient germ count.
• Prebiotics
  • e.g., FOS, MOS, inulin.
  • Food for “good” gut bacteria, often in diet feeds and supplementary preparations.
• Fiber
  • e.g., psyllium husks, beet pulp, cellulose.
  • For colitis, constipation, anal gland problems, IBD (depending on the case).
• Digestive Enzymes (Pancreatic enzymes)
  • Strictly speaking, a medicine/dietetic, but often perceived as a “supplement.”
  • Especially for exocrine pancreatic insufficiency (EPI).

Liver, Kidneys, and Metabolism

• Liver-supporting supplements
  • S-Adenosylmethionine (SAMe)
  • Silymarin/Milk Thistle
  • Vitamin E (Antioxidant)
  • Often used for liver diseases (elevated liver values, chronic hepatitis).
• Kidney support
  • Phosphate binders (e.g., calcium carbonate, lanthanum carbonate) – legally more of a dietetic/medicine, but perceived as a supplement in everyday use.
  • Omega-3 fatty acids
  • B-vitamins (increased renal losses).
• Antioxidants in general
  • Vitamin E, Vitamin C, Selenium, among others.
  • Used for chronic Inflammatory conditions, geriatric patients, heart/kidney diseases.

Cardiovascular

• Taurine and L-Carnitine
  • Especially for feline cardiomyopathies (taurine deficiency was common earlier, less so today), for some dogs (certain DCM cases).
  • Always use in consultation with a cardiologist.
• Omega-3 fatty acids
  • Also here for inflammation modulation and possibly arrhythmia reduction.

Immune System, Convalescence, Seniors

• Multivitamin/Mineral preparations
  • Often useful for homemade rations, BARF, or severely unbalanced feeding.
  • Usually not necessary with commercial complete feeds – oversupply is possible.
• Beta-glucans (e.g., from yeast)
  • Immunomodulatory effects, often used for animals prone to infection.
• Yeast preparations (brewer’s yeast)
  • B-vitamins, trace elements, used for skin/coat, convalescence.
• Geriatric supplements
  • Combinations of antioxidants, Omega-3, B-vitamins, L-Carnitine, phosphatidylserine, etc.
  • Goal: support brain function, muscles, metabolism in old age.

Joint and Bone Development in Young Animals

• Calcium and Mineral Supplements
  • Especially for BARF/homemade food if rations are not precisely calculated.
  • Caution: overdose of Ca/P in puppies → developmental disorders (HD, OCD, etc.).
• Special Puppy/Junior Dog Preparations
  • Often with Vitamin D, trace elements, GPS (glucosamine/chondroitin), Omega-3.
  • Only useful if there is a nutritional gap.

Calming, Stress, Behavior

• L-Tryptophan
  • Serotonin precursor, in some “calming” products.
• Alpha-casozepine (milk protein hydrolysate)
  • Slight anxiolytic effect described, used for anxiety/stress patients.
• Pheromones (e.g., D.A.P. for dogs, Feliway for cats)
  • Formally not classic dietary supplements, but often used in the same context.
• B-vitamins, magnesium, plant extracts (valerian, passionflower, etc.)
  • In various combination preparations for “nerve strengthening.”

Dietary Supplements for Cats

General information about cats:

• Strict carnivore.
• Significantly more sensitive to liver and kidney strain, also to some plant substances.
• Many preparations must be available in a feline-appropriate dosage form (taste, volume), otherwise poor acceptance.

Musculoskeletal System (Osteoarthritis, especially in older cats)

• Omega-3 fatty acids (EPA/DHA)
  • Use: osteoarthritis, CKD, inflammatory processes.
  • Often requires products that are as tasteless as possible.
• Glucosamine, Chondroitin, Green-lipped mussel
  • As with dogs, but consider feline-specific dosages and acceptance.

Skin and Coat

• Omega-3/6 fatty acids
  • Use: atopy, Itching, dry skin, seborrheic changes.
• Biotin, Zinc, B-vitamins
  • For skin problems, convalescence; often in combination preparations.
• Hairball prophylaxis
  • Malt pastes, fiber (e.g., cellulose, psyllium husks).
  • For long-haired cats and cats with intensive grooming.

Digestion and Intestines

• Probiotics
  • Use: acute/chronic diarrhea, food changes, antibiotic therapy.
• Prebiotics and Fiber
  • Dose with caution, as cats are sensitive to fiber content.
  • Used for colitis, constipation, hairball problems, among others.

Liver & Metabolism

• SAMe, Silymarin, Vitamin E
  • Use: hepatic lipidosis, chronic hepatitis, non-specific elevated liver values.
  • Cats with liver disease are very sensitive → precise dosing and follow-up checks are important.

Kidneys (CKD – common in older cats)

• Phosphate binders
  • Standard additive for CKD cats with elevated phosphate, in addition to renal diet.
• Omega-3 fatty acids
  • Complementary to the renal diet.
• B-complex
  • Compensation for increased renal losses, appetite stimulation.

Cardiovascular

• Taurine
  • Essential for cats – industrial food contains it, but must be supplemented for homemade/BARF rations.
  • Additional administration may be useful for cardiomyopathies (after diagnosis).
• L-Carnitine, Omega-3
  • As with dogs, as a supplement for heart patients.

Feline Lower Urinary Tract Diseases (FLUTD, FIC)

• Glycosaminoglycans preparations
  • Goal: support the glycosaminoglycans layer of the bladder mucosa.
• Cranberry extract
  • Complementary, especially for bacterial urinary tract problems (rather rare in cats).
• DL-Methionine (urine acidification)
  • Only with precisely matching indication and under control (e.g., struvite), usually regulated via diet food.

These preparations are always only supplementary to adequate diet feeds and management (stress reduction, water intake).

Seniors and cognitive dysfunction

• Omega-3 fatty acids (especially DHA)
• Antioxidants, B-vitamins
  • Use: geriatric cat with cognitive changes, general weakness.
  • Dosage adjusted to body weight and organ function.

Behavior / Stress (indoor cats, multi-cat households)

• Alpha-casozepine, L-Tryptophan
• • Use: stress, increased marking, anxiety, social tensions.
• Pheromones (e.g., Feliway)
  • Not a dietary supplement, but practically used in the same context.
• Plant extracts
  • With cats, be particularly cautious with plant substances (liver sensitivity).

Taurine – a special case for cats

• Taurine
  • Essential nutrient, especially for heart, retina, bile acid.
  • Already added to complete feeds, additional administration especially for:
    • BARF or homemade ration
    • unclear food quality
  • In case of deficiency: risk of cardiomyopathy, retinal damage, reproductive disorders.

Trend and “Lifestyle” Preparations for Cats

• CBD products
  • Similar problems as with dogs: unclear quality, dosage, legal situation; cats are additionally liver-sensitive.
• “Superfoods”
  • Cats are significantly more sensitive to many plant ingredients; such additives should only be used very selectively and with caution.

Important Differences Between Dogs and Cats

• Taurine:
  • Dog: not essential, only relevant in special cases.
  • Cat: essential, especially important for homemade/BARF feeding.
• Plant substances and “herbs”:
  • Dog: usually better tolerated (still consider interactions).
  • Cat: significantly more sensitive, liver strain and acceptance problem.
• Hairballs and FLUTD:
  • Rather cat-specific areas for supplementary feeds.
• Dosing window:
  • Cats often have a narrower therapeutic range (e.g., for fat-soluble vitamins, trace elements, plant substances).

“Trend” Areas (frequently requested, sometimes limited evidence)

• CBD products
  • Use for Pain, epilepsy, anxiety – legal situation, dosages, and product quality are tricky; evidence-based data still limited.
• “Superfoods”/Plant extracts
  • Turmeric, spirulina, rosehip, ginger, etc.
  • Predominantly in combination preparations; observe safe dosage and interactions.
• Prophylaxis preparations for “healthy” animals
  • “Immune system boosters,” “detox,” “liver cleanse” without concrete indication – rather to be viewed critically.

Important Principles for the Use of Dietary Supplements

1. Check indication
   • Is there a specific problem or a proven deficiency?
   • Or is it just to supplement “on suspicion”?
2. Dietetics first
   • Complete feed from the manufacturer usually covers requirements.
   • BARF/cooked rations require calculated mineral/vitamin provision.
3. Quality and Declaration
   • Prefer veterinary preparations with clear dosage instructions.
   • Beware of “miracle cure promises” and very opaque internet products.
4. Dosage and Interactions
   • Especially with fat-soluble vitamins (A, D, E, K), iodine, selenium, etc., there is a risk of overdose.
   • Observe interactions with medications (e.g., Omega-3 and coagulation, herbal preparations and liver metabolism).
5. Monitoring and Progress Assessment
   • Critically evaluate the effect after a defined period (e.g., 4–8 weeks).
   • Blood tests/ration review for long-term administration