FOOD ALLERGY AND HYPOALLERGENIC

Q: How does James Wellbeloved fare as a hypoallergenic food trial?

To my mind there are 3 levels of diets which are currently marketed as ‘hypoallergenic’: 1)The naturally-sourced or named-protein products (such as James Wellbeloved) – they take their proteins from ingredients which aren’t normally associated with adverse reactions to food but are not manufactured to the same standards as elimination diets 2) The exclusively select (novel) protein diet such as Sensitivity Control which are manufactured with very stringent internal controls on production and quality assurance and 3) the truly hypoallergenic diet; these are produced more specifically for the purposes of elimination trials (with pre-digested proteins or ‘hydrolysates’).These are best suited to food elimination trials.

Q: Can feeding the dog’s ‘normal’ diet at the same time as a hypoallergenic diet (i.e. while transitioning from one to another) cause sensitisation to

We recommend immediate removal of a diet with allergenic properties without a transition period so concurrent feeding of a normal and hypoallergenic diet should not occur.

Q: you mention that food allergic dogs are often less than 6 months old -many of the hypo allergenic diets are unsuitable for young dogs – which diets can you recommend that avoid the ubiquitous poultry in such youngsters?

To be clear and re-iterate what we said in our webinar, Hypoallergenic is formulated such that it is fully complete and balanced for a growing puppy (and kitten). You can feed a young dog confidently with this product using the feeding guides found in our product books or available through our helpline. This way you can go one step beyond avoiding poultry, and feed a hydrolysate instead.

Q: are all hydrolysate diets effective?

Great question. The effectiveness of hydrolysate diets are very much dependent upon the individual animal and the quality of the hydrolysate in question. This is why it’s so difficult to paint all diets with the same (‘efficacious’ or ‘non-efficacious’) brush. The premise of a hydrolysate diet is to reduce (ideally completely eliminate) allergenicity such that the typical type-1 hypersensitivity reactions to food proteins don’t occur. Where this becomes a problem is where an animal displays an allergy which is NOT IgE-mediated (i.e. not type-1; a concept suggested but not yet explored in the veterinary world) or displays multiple allergies, sometimes to multiple proteins or very select amino acids which somehow make their way into the digestive tract. This is the very small population (5%of food adverse patients – Biourge et al 2003) of dogs that are refractory to currently available hydrolysed diets. Manufacturers such as Royal Canin are doing all they can to help these patients further by improving contaminant-controls (to reduce the incidence of ancillary proteins making their way into the food) and exploring the best protein sources to tackle adverse reactions. – What about the fact that there tends to be a wider span of protein sizes in some diets compared to others?

Q: if you suggest fish and potato for dogs, what would you suggest for cats as a homemade hypoallergenic diet?

My suggested answer: We would not suggest homemade diets for food elimination trials, unless trials with the commercially available diets had proved unsuccessful and a food allergy were still strongly suspected, in which case there is no other option. Good sources of protein for Feline elimination diets can include duck, goat, horse, pheasant, rabbit and even venison. Your owner should be guided by availability of these ingredients but more so by their cat’s dietary history. In order to be truly effective as an elimination diet the cat must not have had any prior dietary exposure to this ‘novel’ protein source. The owner should also be made aware that a homemade diet of this sort is unlikely to be nutritionally balanced.

Q: I have such a problem with food trials – the clients I have with pruritic animals can never afford to feed the hypoallergenic prescription diets -can you offer any suggestions?

I’d be sure the owner is completely aware of the value of an elimination trial (after all without a trial there is no confirmed diagnosis!) and then also the actual cost to feed (per day) a diet such as Hypoallergenic. In fact, feeding a 15kg dog from a 7kg bag, sold at our SSP, will only cost them around £1.53 per day if they’re feeding according to our guidelines. If they cut out all other food sources (chews, rewards, supplements..) they may even make a saving. Because diet isn’t perceived be as valuable as a ‘medicine’ it’s always going to be difficult… what I think we need to make owners aware of is that in the case of true food allergy, the food IS often the be all and end all of management of that dog or cat; if the owner can be consistent in their feeding, this is a MUCH better option than having to repeat-visit for symptomatic treatments for the rest of their dog’s life.

Q: What about gluten allergy?

Canine allergies to gluten are in fact rare. Apart from the breed idiosyncrasy we’ve seen in Irish Setters (the original line of affected individuals has now been bred out) literature supporting sensitivities in the general Canine population is difficult to come by. These proteins have been extensively investigated (and are often thought of negatively) due to their allergy-inducing abilities in humans. Wheat gluten is in fact an exceptional protein source as it’s highly concentrated (with protein), free of biogenic amines (histamine for example) and has a low fibre level meaning it’s highly digestible (99%). This is why we use wheat gluten in our Skin Care product. It’s also high in glutamine (important in maintaining digestive integrity and supplemented in human gastro-enteral cases) and relatively available and sustainable.. So watch this protein source! Having said all of the above, if an animal is confirmed gluten-sensitive (by means of not only serological tests but a dietary challenge) then a hydrolysed protein diet such as Hypoallergenic is currently our 1st choice in

Recommendation. Hall, E.J. (2004) Breed specific intestinal disease, In Waltham Focus, 15(2) pp36-

37.

Q: How long does it take for a dog to become food allergic if it’s been on the same diet for 2.5 years and then starts to have skin lesions as you described in your first food allergic slide?

Seeing as a true food allergy is dependent upon the affected individual going through a period of sensitisation whereby the immune system is being ‘primed’ to react to that unique dietary allergen it’s almost impossible to put a definite figure on how long it takes for the clinical signs of an allergy to kick in. Texts I’ve read have mentioned allergies developing after as short a feeding period as 2months through to 3 years… very frustrating obviously when an owner insists that ‘everything was completely fine and consistent until now’. In a slow-developing allergy we’ll still have to change the diet.

Q: what is the difference between food allergy and food intolerance? Some of the subtleties in these terms are dependent on the source of your information.

From my reading I see it as thus: Food allergies, food intolerance and food intoxications are all part of the larger ADVERSE FOOD REACTION (AFR) group. An intolerance is a lot more common than an allergy and entails metabolic, pharmacologic and idiosyncratic reactions to ingesta (for example enzyme deficiencies, histamine consumption in spoiled fish and gluten-enteropathies in Irish Setters respectively). True food allergies are the ones that involve the immune system, are unique to the individual and entail a period of sensitisation (much the same as a reaction to a vaccine) during which time the animal develops an unhealthy bodily reaction to an allergen. The vast majority of these are proposed to be type 1 (IgE-mediated) hypersensitivity reactions however type III and I have also been proposed. An intolerance case will need a low-residue highly digestible diet, an allergic one will need one that avoids the offending allergen at all costs. There is still a lot we can learn in the area of small animal AFRs and only further investigation will disclose exactly what is happening in our truly ‘food allergic’ cases, however clinical signs and our approach to management are usually consistent across the entire AFR group; identification and avoidance of the offending foodstuff is key.

Case Studies in Feline Dermatology