In dogs with cardiac cachexia and congestive heart failure, does administration of fish oil result in measurable improvement in clinical status?
Author:
Joe Student, V’08
Endorsed By:
Dr. John Rush
1. Search Process
Ovid Medline
CAB abstracts
2. Key Sources and Detail
Source 1:
a. Donaldson MT, LaMonte BH, Morresey P, Smith GJB. Treatment with pergolide or cyproheptadine of pituitary pars intermedia dysfunction (equine Cushing’s disease) J Vet Intern Med. 2002;16:742–746.
b. http://www.ncbi.nlm.nih.gov.ezproxy.library.tufts.edu/pubmed/12465775
c. Retrospective review of medical records
d. This article reviewed the records of horses with pituitary pars intermedia dysfunction that had been treated with Pergolide or cyproheptadine. Horses treated with Pergolide showed improved ACTH levels and clinical signs as compared to horses treated with cyproheptadine.
Source 2:
a. Mehra MR, Lavie CJ, Ventura HO, Milani RV. Fish oils produce anti-inflammatory effects and improve body weight in severe heart failure. J Heart Lung Transplant 2006; 25: 834-838.
c. Blinded, randomized, controlled trial
d. 14 human patients with CHF (New York Heart Association III-IV) were randomized to receive fish oil or placebo for 18 weeks. The group receiving fish oil had significant reductions in TNF and IL-1 concentrations. Fat mass, as assessed by skin fold thickness, increased significantly in the fish oil group although lean body/muscle mass was not assessed.
3. Comments and Caveats
a. Are there significant financial costs associated with the treatment?
No
Fish oil is relatively inexpensive.
b. Are there common or possible side effects?
No
Significant side effects are uncommon with fish oil although mild gastrointestinal signs can occur. Some people receiving fish oil complain of the fishy taste or smell.
c. Are there complimentary tests that should be considered or performed?
Yes
Weight loss (particularly loss of muscle or lean body mass) is very common in dogs and cats with heart failure so body weight and body composition should be carefully monitored. Since this muscle loss is a multifactorial problem (reduced appetite, medication toxicity, increased cytokine production), animals with heart failure should be carefully monitored to avoid drug toxicities and to ensure adequate food intake. Fish oil supplementation should be considered in heart failure, especially if weight loss, muscle loss, or reduced appetite are present.
d. Are there special treatment outcomes, expectations, or alternatives that should be discussed with the owner?
Yes
Nutritional management is an important component of optimal medical therapy for dogs and cats with heart failure.
e. Are there supporting data from other species that might be applicable?
Yes
There are other potential benefits of fish oil supplementation in heart failure that have been demonstrated in people, rodent models, and dogs. These include antiarrhythmic effects, correction of a relative deficiency of n-3 fatty acids, and reduction in inflammatory mediations (eg, inflammatory cytokines, eicosanoids).
f. Are there study design issues that might weaken the strength of evidence?
Yes
Both studies had some limitations, including small sample size, relatively short duration of treatment, suboptimal techniques for direct measurement of lean body mass, and the inability (at least in the human study) to perform a double-blinded study (people are easily able to determine whether they are receiving fish oil or placebo supplements). Also, the two studies used different doses of n-3 fatty acids (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)).
g. Are there any other comments or caveats that are relevant?
Yes
Fish oil, which is high in the n-3 fatty acids, EPA and DHA, was used in both studies. The optimal dose of EPA and DHA for dogs with CHF is not known although a commonly recommended dose in the literature is 40 mg/kg EPA and 25 mg/kg DHA. Also, because commercial fish oil products contain varying levels of EPA and DHA, owners must be given specific recommendations for brand and dose to avoid over- or under-supplementation. Cod liver oil and flax seed oil should be avoided as sources of n-3 fatty acids for dogs and cats. Also, because of the lack of regulation for dietary supplements, careful attention should be paid to recommending specific brands that provide good quality control (eg, amount of EPA and DHA in capsule meets label claim, lack of contamination, etc).
4. Clinical bottom lines
1. Weight and muscle loss (cachexia) is common in heart failure.
2. Fish oil, which is high in n-3 fatty acids (EPA and DHA), may reduce cachexia in heart failure.
3. Attention to nutrition is an important aspect of optimal medical management for animals with heart failure.