The topic of L-Carnitine came up on an online forum for diabetic caregivers recently. L-Carnitine is grouped among the amino acids (like Taurine), and is also known as Vitamin Bt. I’d known of the link of carnitine to weight loss and the recommendation to supplement carnitine for cats suffering hepatic lipidosis (fatty liver disease). I also knew that carnitine levels were higher in raw meat than in cooked meat – but I didn’t realize how MUCH higher.
I stumbled across a patent from 1989, for carnitine supplementation in pet food. It lists carnitine content for some typical foods and here was the shocker (for me) – dry cat food samples had less than 10% of the carnitine as raw hamburger, canned food still had less than 20%. Assuming raw chicken contains 3% to 5% of the carnitine as raw hamburger (based on cooked values), the picture’s less grim – but obviously cats in the wild wouldn’t eat only chicken… or beef… and so far I’ve found no information on the values in rabbit, rodents, or small birds.
The present invention is for a method of preventing diet-induced carnitine deficiency in domesticated dogs and cats using a dietary supplement containing a prophylactic amount of L-Carnitine.- The invention is useful in preventing L-Carnitine deficiencies which can lead to a multitude of conditions, including myopathic heart disease, ischemic heart disease, hyperlipidemia, ketosis, muscle weakness and premature aging. Pets, particularly the carnivores, are at great risk for developing L-Carnitine deficiencies. As Table 1 indicates, dog and cat foods are extremely low in free L- Carnitine levels as compared with that found in raw ground beef. Most pets are maintained strictly on commercial pet food diets and are thus kept chronically deficient in L- Carnitine. This results in a diet-induced carnitine deficiency.
So, of course that sent me on more internet searches:
..these results demonstrate the protective effect of a dietary L-carnitine supplement against fasting ketosis during obesity induction. Increasing the L-carnitine level of diets in cats with low energy requirements, such as after neutering, and a high risk of obesity could therefore be recommended.
Your Cat May Need Supplemental Carnitine
• A new study shows that the amount of L-carnitine in commercial cat food is insufficient to protect the liver. Researchers gave obese cats approximately 150 mg of L-carnitine per quarter pound of food versus the approximate 5 mg approved for commercial cat food. The higher amount approaches what cats would get from a natural diet. The added carnitine had significant effects on liver function, specifically the utilization of fatty acids. For obese cats, supplemental carnitine is essential. They are prone to developing anorexia, which leads to the life-threatening condition, hepatic lipidosis, where fat builds up in the liver. Cats with this condition have drastic alterations in fatty acids, with liver triglycerides off the chart. Cats given adequate amounts of L-carnitine have a much better ability to weather this metabolic crisis. Supplement L-carnitine suppresses these drastic alterations in lipids.
• L-carnitine also maintains good metabolic function during obesity. When cats become obese on a commercial diet, carnitine levels shoot up drastically in the liver. This is apparently because the amino acid is not being utilized: normally it carries fat for fuel. But cats maintained on natural high levels of L-carnitine everyday in their diet don’t have drastic increases of unused carnitine in their liver when they become obese. Their carnitine levels remain steady, indicating less stress on the system, and better metabolism.
The Benefits of Carnitine and DHEA for Fat Metabolism INFLUENCE OF 1-CARNITINE ON METABOLIC RATE, FATTY ACID OXIDATION, BODY CONDITION, AND WEIGHT LOSS IN OBESE CATS The Clinical and Metabolic Effects of Rapid Weight Loss in Obese Pet Cats and the Influence of Supplemental Oral L-Carnitine CARDIOVASCULAR – Veterinary Institute of Integrative Medicine
Red meats are the best sources of carnitine (50 to 120 mg/100 g). Fish, chicken and milk are good sources (1.6 to 6.4 mg/100 g).
Carnitine boosts energy by stimulating the body’s burning of tryglycerides as fuel, and sparing the supply of glycogen stored in the liver for heavier exertion. During exercise, the body will burn fat at a rate of 75-80% of maximum exertion, thus less glycogen from carbohydrates is burned. L-carnitine allows the body to burn more fat, save more glycogen, and ultimately boost stamina and endurance. By providing more fat to the muscles, carnitine makes accessible an otherwise unavailable energy source.
FAT + OXYGEN + L-CARNITINE = ENERGY
So, I’m still intrigued… and convinced feeding my cats a diet that most closely replicates their natural diet is the best way for them to avoid suffering for our lack of complete knowledge of feline nutrition.