Nutritional interventions for osteoarthritis management

Nutritional supplements can help dogs with osteoarthritis, but reaching or maintaining a healthy weight and lean body mass is important as well. (Getty/Terry J. Alcorn)

Osteoarthritis is best described as an end-stage disease resulting from many potential causes. The hallmark features of the disease are inflammation of the synovium and changes in cartilage metabolism resulting in breakdown of matrix. Synovial mediation of inflammation is seen very early in osteoarthritis and may precede cartilage degeneration. 

Inflammatory cytokines produced by cells in the synovium (and also by chondrocytes) are top candidates for therapeutic intervention. These cytokines cause two main adverse effects: they act directly to decrease matrix synthesis by chondrocytes, and they induce expression and secretion of matrix-degrading protease enzymes. 

Nutritional therapies aimed at targeting inflammation

Arachidonic acid from cell membranes is a precursor to the proinflammatory cytokines prostaglandins and leukotrienes, the concentrations of which are increased in osteoarthritis. A diet rich in omega-3 fatty acids (specifically eicosapentaenoic acid, or EPA) alters the fatty makeup of cell membranes and reduces the presence of arachidonic acid as an inflammatory precursor.1

Incubation of chondrocytes with omega-3 fatty acids has resulted in decreased production of proinflammatory cytokines.2 Dogs fed a diet rich in omega-3 fats and vitamin E have showed objective improvements in lameness secondary to osteoarthritis.3,4

The recommended intake of EPA is between 40 and 100 mg/kg in order to achieve systemic anti-inflammatory effects. Supplementing the diet with the precursor molecule of omega-3 fatty acids, alpha-linolenic acid, does not show the same anti-inflammatory and analgesic benefit for dogs since dogs have limited ability to synthesize omega-3s from the precursor molecule.5

Evidence for anti-inflammatory or disease-modifying effects of oral glucosamine and chondroitin sulfate is equivocal in dogs and cats,6 but chondroitin sulfate has been demonstrated in other species and in vitro to control aspects of synovial membrane inflammation-cell infiltration and activity and mediator release.7,8 Glucosamine is also active on both cellular and molecular aspects of the inflammatory reaction.7,8

Human studies emphasize the importance of the quality of tested compounds for achieving high-quality clinical trials, and this needs to be pursued in veterinary research.7 Avocado and soybean unsaponifiables have been shown to reduce prostaglandin production in inflammation-stimulated chondrocytes when combined with glucosamine and low-molecular-weight chondroitin sulfate.9-11

Green-lipped mussel is rich in omega-3 fatty acids and also contains chondroitin sulfate. In one study, feeding arthritic dogs a diet enriched with green-lipped mussel (which also contained glucosamine) elevated blood concentrations of the omega-3 fats along with improving lameness based on force-plate analysis.12 In another study, elk velvet antler (which contains chondroitin sulfate) was shown to improve subjective and objective signs of osteoarthritis in dogs.13

The resin from Boswellia serrata has been shown to inhibit leukotriene biosynthesis from endogenous arachidonic acid in intact peripheral mononuclear neutrophils through the inhibition of 5-lipooxygenase (LOX) and to inhibit tumor necrosis factor alpha production.14 An appropriate dosage has not been fully established in dogs or cats, but a clinical trial giving 40 mg/kg of a resin extract to dogs with osteoarthritis had a positive subjective effect on pain and lameness.15

Getty Images/DelectusWeight modulation

Management of obesity is part of managing the pain of existing arthritis, but overnutrition as a cause of arthritis may be overlooked. About 22 to 40 percent of dogs and cats are reportedly overweight or obese.16 In a lifespan study of Labrador retrievers, dogs that had increased body condition score (overweight) at the age of 2 years had a 25 percent prevalence of hip arthritis compared with 4 percent of restricted-fed dogs (ideal body condition score).17 By 6 years of age, the overweight dogs had 1.5 times the incidence of shoulder arthritis compared with restricted-fed dogs.18 Adipose tissue can produce systemic mediators of inflammation, and this may be part of the pathogenesis of osteoarthritis in obese individuals.19

Building muscle to support an arthritic joint can help to improve mobility and comfort. Therapeutic exercises provide stimulus for improvement in muscle strength and mass,20 but adequate protein intake is important for muscle building. This is especially true for older pets because they lose muscle as they age and actually require increased protein in their diets to offset this loss (or to build muscle). Restricted-protein diets are no longer recommended in senior diets for pets with healthy kidneys.21

Conclusion

Nutritional supplements can help modulate the inflammatory aspect of osteoarthritis and may also help improve cartilage metabolism, but the impact of reaching or maintaining a healthy weight and lean body mass on ameliorating clinical signs of osteoarthritis should not be underestimated.

References

1. LeBlanc CJ, Horohov DW, Bauer JE, et al. Effects of dietary supplementation with fish oil on in vivo production of inflammatory mediators in clinically normal dogs. Am J Vet Res 2008;69(4):486-493.

2. Sakata S, Hayashi S, Fujishiro T, et al. Oxidative stress-induced apoptosis and matrix loss of chondrocytes is inhibited by eicosapentaenoic acid. J Orthop Res 2015;33(3):359-365.

3. Roush JK, Cross AR, Renberg WC, et al. Evaluation of the effects of dietary supplementation with fish oil omega-3 fatty acids on weight bearing in dogs with osteoarthritis. J Am Vet Med Assoc 2010;236(1):67-73.

4. Fritsch DA, Allen TA, Dodd CE, et al. A multicenter study of the effect of dietary supplementation with fish oil omega-3 fatty acids on carprofen dosage in dogs with osteoarthritis. J Am Vet Med Assoc 2010;236(5):535-539.

5. Heinemann KM, Waldron MK, Bigley KE, et al. Long-chain (n-3) polyunsaturated fatty acids are more efficient than alpha-linolenic acid in improving electroretinogram responses of puppies exposed during gestation, lactation, and weaning. J Nutr 2005;135(8):1960-1966.

6. Canapp SO Jr, McLaughlin RM Jr, Hoskinson JJ, et al. Scintigraphic evaluation of dogs with acute synovitis after treatment with glucosamine hydrochloride and chondroitin sulfate. Am J Vet Res 1999;60(12):1552-1557.

7. Richy F, Bruyere O, Ethgen O, et al. Structural and symptomatic efficacy of glucosamine and chondroitin in knee osteoarthritis: a comprehensive meta-analysis. Arch Intern Med 2003;163(13):1514-1522.

8. Martel-Pelletier J, Wildi LM, Pelletier JP. Future therapeutics for osteoarthritis. Bone 2012;51(2):297–311.

9. Mauviel A, Daireaux M, Hartmann DJ, et al. Effects of unsaponifiable extracts of avocado/soy beans (PIAS) on the production of collagen by cultures of synoviocytes, articular chondrocytes and skin fibroblasts [article in French]. Rev Rhum Mal Osteoartic 1989;56(2):207-211.

10. Cake MA, Read RA, Guillou, et al. Modification of articular cartilage and subchondral bone pathology in an ovine meniscectomy model of osteoarthritis by avocado and soya unsaponifiables (ASU). Osteoarthritis Cartilage 2000;8(6):404-411.

11. Lippiello L, Nardo JV, Harlan R, et al. Metabolic effects of avocado/soy unsaponifiables on articular chondrocytes. Evid Based Complement Alternat Med 2008;5(2):191-197.

12. Rialland P, Bichot S, Lussier B, et al. Effect of a diet enriched with green-lipped mussel on pain behavior and functioning in dogs with clinical osteoarthritis. Can J Vet Res 2013;77(1):66-74.

13. Moreau M, Dupuis J, Bonneau NH, et al. Clinical evaluation of a powder of quality elk velvet antler for the treatment of osteoarthrosis in dogs. Can Vet J 2004;45(2):133-139.

14. Safayhi H, Sailer ER, Ammon HP. Mechanism of 5-lipoxygenase inhibition by acetyl-11-keto-beta-boswellic acid. Mol Pharmacol 1995;47(6):1212-1216.

15. Reichling J, Schmökel H, Fitzi J, et al. Dietary support with Boswellia resin in canine inflammatory joint and spinal disease. Schweiz Arch Tierheilkd 2004;146(2):71-79.

16. O Neill DG, Church DB, McGreevy PD, et al. Prevalence of disorders recorded in dogs attending primary-care veterinary practices in England. PLoS One 2014;9(3):e90501.

17. Smith GK, Paster ER, Powers MY, et al. Lifelong diet restriction and radiographic evidence of osteoarthritis of the hip joint in dogs. J Am Vet Med Assoc 2006;229(5):690-693.

18. Runge JJ, Biery DN, Lawler DF, et al. The effects of lifetime food restriction on the development of osteoarthritis in the canine shoulder. Vet Surg 2008;37(1):102-107.

19. Bertola A, Bonnafous S, Anty R, et al. Hepatic expression patterns of inflammatory and immune response genes associated with obesity and NASH in morbidly obese patients. PLoS One 2010;5(10):e13577.

20. Henriksen M, Klokker L, Graven-Nielsen T, et al. Association of exercise therapy and reduction of pain sensitivity in patients with knee osteoarthritis: a randomized controlled trial. Arthritis Care Res (Hoboken) 2014;66(12):1836-1843.

21. Larsen JA, Farcas A. Nutrition of aging dogs. Vet Clin North Am Small Anim Pract 2014;44(4):741-759.

Dr. Julia Tomlinson is a board-certified specialist in surgery as well as rehabilitation and sports medicine at Twin Cities Animal Rehab and Sports Medicine in Burnsville, Minnesota. She founded the American Association of Rehabilitation Veterinarians in 2007 and is an active member of the Canine Sports Medicine Association and the International Veterinary Academy of Pain Management.