Research Paper Discussion: Dose-Titration Effects of Fish Oil in Osteoarthritic Dogs

This study showed that increasing Omega-3 intake improved signs of arthritis in dogs

Using Omega-3s for their anti-inflammatory effects is a key part of joint health, and something that we strongly recommend at The Vet Equation.

Here we review a research study published in the Journal of Veterinary Internal Medicine, carried out on 117 dogs that had stable chronic osteoarthritis of hip or stifle (knee) joints, that showed that by increasing the amount of EPA and DHA Omega-3s in the diet of dogs with osteoarthritis (in this study 3x the amount compared to the baseline diet was effective), improvements in lameness and weightbearing of affected limbs were noted. The Study:

It was a prospective, randomized clinical trial. Dogs were randomly assigned to receive baseline therapeutic food containing 0.8% eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) or experimental foods with approximately 2- and 3-fold higher EPA+DHA concentrations. Both veterinarians and owners were blinded to the specific food the dogs received. Serum fatty acid concentrations were measured on days 0, 21, 45, and 90, and veterinarians assessed the severity of 5 clinical signs of OA. At the end of the study (day 90), veterinarians scored overall arthritic condition and progression of arthritis based on clinical signs and an owner interview.

The results showed that serum concentrations of EPA and DHA increased in parallel with the concentration of fish oil in the food. There was a significant improvement in two out of five clinical signs (lameness and weight bearing) as well as overall arthritic condition and progression of arthritis in dogs fed with food containing 3-fold higher EPA+DHA concentrations, compared to the baseline food. However, there was no significant improvement observed with the 2-fold higher EPA+DHA food.

Thoughts about the study:

• Prospective, Randomized Clinical Trial - this is good as it makes it as fair a test as possible.

• Relatively large sample size (117 dogs) - this is a good thing as the larger the sample size, the more chance there is to detect trends, side effects, it reduces sampling error, or the risk that results are occurring due to random chance.

• Random allocation to baseline vs. therapeutic foods - this is good as it makes it as fair a test as possible.

• Blinded study (both veterinarians and owners did not know which diet the dogs were receiving) which helps to remove bias in assessment.

• Adverse events were also reported - which in this case were 1 case of gastrointestinal upset for the baseline diet and the diet with 2x higher EPA+DHA food.

• EPA and DHA levels in this study are reported in relation to baseline diet levels, so this can be difficult to interpret in relation to how much exact EPA and DHA to add to your own dog's diet based on the study.

• The study was funded by Hill's, and the baseline diet used in this study was a joint diet manufactured by Hill's, but since the study is focusing on the addition of the Omega-3 (fish oil) supplement (which was an unbranded product), not on the baseline diet, and the study was designed as a blinded, randomized controlled trial, this would remove the risk of conflict of interest having an impact on results, which is good.

Take-home points:

• Increasing the fish oil ingredient in the diet led to measurable increases in serum (blood level) EPA and DHA (Omega-3) concentrations - this means that dogs are absorbing it from the diet.

• Modest improvements to osteoarthritis clinical signs were seen by adding Omega-3s EPA and DHA to the diet.

• These findings suggest that fish oil supplementation can provide additional symptomatic benefits for dogs with osteoarthritis, supporting its use as a therapeutic approach in managing this condition in canine patients.

Reference

Fritsch, D., Allen, T.A., Dodd, C.E., Jewell, D.E., Sixby, K.A., Leventhal, P.S. and Hahn, K.A. (2010), Dose-Titration Effects of Fish Oil in Osteoarthritic Dogs. Journal of Veterinary Internal Medicine, 24: 1020-1026. https://doi.org/10.1111/j.1939-1676.2010.0572.x