A new study published in the Journal of Nutritional Science has shown that by adding L-Carnitine (an amino acid) to the diet of our dogs will help prevent the loss of muscle in older dogs and will also cause an increase in muscle mass in otherwise healthy dogs.
Almost all dogs (especially Labs) exhibit a loss of thigh muscle as they age, and here is the "fix".
Here are some key points from the article.
A recent study published in the Journal of Nutritional Science suggests that supplemental L-carnitine (an amino acid) is beneficial to both performance and recovery in working dogs, and contributes to a higher percentage of lean muscle mass, enhanced muscle recovery and less oxidative stress during vigorous exercise.
96 dogs were in this study. In the experiments the dogs were divided into two groups. All the dogs were fed a low L-carnitine commercial diet, but one group was supplemented with 250 mg/day of L-carnitine powder for up to 14 weeks; the other dogs (the control group) did not receive the supplement.
The study authors observed that the dogs whose diets were supplemented with L-carnitine were “significantly more active” than the control group during both sprints and endurance runs.
The supplemented dogs gained 0.74 kg (about 1.63 pounds) in total body weight during the study, while the control group lost 0.12 kg (about a quarter of a pound). The weight gain was the result of an increase in lean mass of 0.68 kg. The control dogs lost an average of 0.41 kg of lean mass, even though they were eating the same amount of calories as the supplemented dogs.

The L-carnitine dogs also had a significantly lower level of creatine kinase, which is a marker for muscle damage. Plasma myoglobin, which is another indicator of muscle damage, was also much lower in the supplemented dogs, both an hour after a run, and 24 hours later. Oxidative stress was also improved in the L-carnitine dogs, who had significant decreases in thiobarbituric acid reactive substances (TBARS), and significant increases in total antioxidant capacity. The study authors concluded:

“Supplementing L-carnitine had positive benefits in Labrador retrievers for activity intensity, body composition, muscle recovery and oxidative capacity.”

The first experiment evaluated 56 dogs who completed one endurance run and two sprint runs per week. The second experiment included 40 dogs who completed two endurance runs per week. The researchers analyzed the dogs’ performance with running programs, activity monitoring measured by accelerometer collars, body composition scans and evaluation of muscle recovery using biomarkers.

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Doc E