of course it works- but it’s just a high dose of fish oil, which anyone can supplement any diet with, and even grocery-store foods might have better ingredients and give better results if supplemented with a high enough dose of fish oil. You should probably put your dog back on the cosequin- the glucosamine encourages the joint to heal itself over time, so it may prevent the condition from worsening. Most people see the best results if they use a multi-modal approach.
This is one of Hill’s studies on fish oil:
J Vet Intern Med. 2010 Sep-Oct;24(5):1020-6. doi: 10.1111/j.1939-1676.2010.0572.x. Epub 2010 Aug 12.
Dose-titration effects of fish oil in osteoarthritic dogs.
Fritsch D, Allen TA, Dodd CE, Jewell DE, Sixby KA, Leventhal PS, Hahn KA.
Source
Hill’s Pet Nutrition Inc, Topeka, KS 4Clinics, Paris, France. dale_fritsch@hills.pet.com
Erratum in
J Vet Intern Med. 2011 Jan-Feb;25(1):167.
Abstract
BACKGROUND:
Food supplemented with fish oil improves clinical signs and weight bearing in dogs with osteoarthritis (OA).
OBJECTIVE:
Determine whether increasing the amount of fish oil in food provides additional symptomatic improvements in OA.
ANIMALS:
One hundred and seventy-seven client-owned dogs with stable chronic OA of the hip or stifle.
METHODS:
Prospective, randomized clinical trial using pet dogs. Dogs were randomly assigned to receive the baseline therapeutic food (0.8% eicosopentanoic acid [EPA] + docosahexaenoic acid [DHA]) or experimental foods containing approximately 2- and 3-fold higher EPA+DHA concentrations. Both veterinarians and owners were blinded as to which food the dog received. On days 0, 21, 45, and 90, serum fatty acid concentrations were measured 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 their clinical signs and an owner interview.
RESULTS:
Serum concentrations of EPA and DHA rose in parallel with food concentrations. For 2 of 5 clinical signs (lameness and weight bearing) and for overall arthritic condition and progression of arthritis, there was a significant improvement between the baseline and 3X EPA+DHA foods (P=.04, .03, .001, .0008, respectively) but not between the baseline and the 2X EPA+DHA foods.
CONCLUSIONS AND CLINICAL IMPORTANCE:
Increasing the amount of fish oil beyond that in the baseline food results in dose-dependent increases in serum EPA and DHA concentrations and modest improvements in the clinical signs of OA in pet dogs.
Copyright © 2010 by the American College of Veterinary Internal Medicine.
this is from the discussion section of another study on fish oil, one not conducted by Hill’s, about doses of fish oil:
The Hill’s studies give the ω-3 dose as % of food on a dry-matter basis and conclude that the test food had 3.47% ω-3 s and the placebo food 0.11%, meaning that the test food had an over 31-fold higher amount of total ω-3 s, compared to the control [13]. Hall used 6.2 g ω-3 fatty acids per kg of food [23]. As we do not know how much the dogs ate in that study we can, however, not calculate the mg/kg BW daily doses. Blonk showed that, in humans, doses over ~1.2 g DHA/day (given as fish oil) saturates the plasma DHA concentration and further increase of given DHA increase the plasma concentration only incrementally [40]. This has not to our knowledge been studied in dogs. Hall concluded that 175 mg of DHA/kg BW/day was needed to attain maximum plasma levels of DHA in dogs [23]. As EPA will change into DHA in the EPA cascade, it is however unclear how much of EPA and DHA combined is needed to achieve maximum plasma levels. In fish oil the EPA concentration is usually about 60% and the DHA 40% [41]. In the product we used the DHA was about 22% of the EPA amount. Although we had a significant increase in both DHA and EPA in our end-of-trial samples in the fish oil group, it is possible that we did not come up to the maximum plasma levels. Therefore we cannot say if a bigger dose still would have benefitted the outcome. However, as our oil contained only fish derived EPA and DHA and as there was a big difference in the ω-6:ω-3 ratio between the fish oil and the placebo, we think that our dose and ratio used led to at least some positive results. As EPA, DHA and other EFAs from the EPA cascade have been shown to have anti-inflammatory properties, this supports the clinically positive, although mild, results seen in our treatment group and not in the placebo group.
It makes a lot more sense to dose dogs by body weight instead of by percent of diet, because dogs eat varying amounts, and an older inactive dog may eat very small amounts and yet still need lots of fish oil. From this info, you’d want to feed somewhere around 200 mg of fish oil per pound of dog. Trying to compare to the Hill’s, which has fish oil as % of diet, if we follow their feeding instructions, we can estimate their food is supplying about 300 mg per pound of dog. This is much more than the amount usually suggested for general dog health, so if you thought you already tried fish oil, and didn’t like the results, check your dose.
Purina PM is only supplying about 85 mg of fish oils per pound of dog and has only 1 mg of glucosamine per pound of dog- the usual suggested dose for glucosamine is 25 mg per pound of dog.
