It has long been known that deficiencies of taurine, and/or L-carnitine, have been associated with Dilated Cardiomyopathy (DCM) in dogs (Paulson, 1998; Keene at al., 1991; Costa and Lubac, 1994; Keene at al., 1989; Fascetti et al., 2003; Backus et al., 2003) and some breeds of dogs (e.g. Boxer, Golden retriever, Newfoundland and American Cocker Spaniels), have shown dramatic improvement in myocardial function after supplementation with one or both nutrients (Gompf, 2005; Sanderson, 2006). As large dog breeds are more predisposed to developing DCM than small dog breeds (Ko et al., 2007) it is best practice to include additional taurine and/or L-carnitine in foods designed for large and giant breeds and also in diets designed for certain specific dog breeds previously identified as at risk. The advice has also been that supplemental taurine and/or L-carnitine should also be considered in dogs with DCM fed on lamb and/or rice diets, vegetarian diets or protein restricted diets (Gompf, 2005; Torres et al., 2003). However, a recent observation made by the FDA raises the question if this advice should also be extended to ‘grain-free’ diets.
A small number of clinical cases of atypical DCM in dogs, with or without low whole blood taurine levels, have been reported to the FDA. Some of the recent reports are from Golden retrievers and these cases all had low whole blood taurine levels; this has already been identified as a breed at risk of DCM where blood taurine status is impaired so in my view these cases are characteristic of a known effect in this breed specifically. However other recent reports are from more atypical dog breeds although in a recent statement from the FDA all but one case in a Labrador retriever (three Labrador retrievers in total, one Shih Tzu and one Miniature Schnauzer) were found to have normal whole blood taurine levels. Veterinary advice has been that whilst most dogs diagnosed with DCM do not have a documented taurine or L-carnitine deficiency, they may still benefit from supplementation (Sanderson, 2006; Fascetti et al., 2003).
Whilst the number of cases reported by the FDA is currently very small, it appears that in these cases a correlative factor is a ‘grain-free’ (high potato and legume content) diet. To date no causative link between ‘grain-free’ diets and DCM has been made so it may be that the recent observations are a function of the widespread popularity of ‘grain-free’ diets rather than a direct link between these diets and canine DCM it is a topic that should be closely monitored by the industry as it develops and action taken should it be deemed necessary.
Please do not hesitate to contact any of the Premier Nutrition pet team if you wish to discuss this further.