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  • Writer's pictureDr Meredith Wall

No more itchy eyes ... Purina develops new diet for allergic cat lovers

An interesting paper was published recently in the journal Immunity, Inflammation and Disease by

Satyaraj et al. from Nestle Purina Research. The title of the paper is 'Reduction of active Fel d1 from cats using an antiFel d1 egg IgY antibody', and the study was conducted to evaluate a new dietary approach to reduce the exposure of cat owners to the allergenic glycoprotein, Fel d1 .

Fel d1 protein model
3D printed model of the Fel d1 protein, available from

Fel d1, in cats, is encoded by the CH1 (chain 1/Fel d 1-A) and CH2 (chain 2/Fel d 1-B) genes. It is the primary allergen that causes symptoms in sensitive people, and it is produced by the salivary and sebaceous glands of the cat. Fel d1 from saliva is spread over the coat during grooming, and then all over your house as your cat sheds hair and dander. Even better, the very small size of the Fel d1 protein, and its molecular structure, mean that it can remain airborne for a long time, allowing you ample opportunity to inhale it. It can also adhere to furniture, carpet, clothes ... and is pretty difficult to remove.

Anyway, the objective of this particular study was to test the efficacy of the anti-Fel d1 IgY in reducing immunologically active Fel d1, when fed to cats as a dietary component. The authors' hypothesis was that hair taken from cats fed a diet containing anti-Fel d1 IgY would show a significant reduction in active Fel d1 (aFel d1), which they measured via ELISA binding.

The paper provides good detail on the experimental method used; essentially the authors collected hair from 105 cats four times, during a baseline period of two weeks, which was evaluated for aFel d1 via ELISA. Hair was then collected weekly during the 10 week treatment period, during which cats consumed an AAFCO-formulated diet containing the anti-Fel d1 IgY (8 ppm).

The results were interesting and encouraging. Baseline aFel d1 varied greatly among the cats in this study – no surprises here, as this has been shown before. From week 3 of the treatment period, there was a significant reduction in mean aFel d1, with an overall average decrease of 47% by week 10 (the range was a 33– 71% decrease, compared with baseline). Half the cats showed a reduction of at least 50%, and cats with the highest aFel d1 during the baseline period showed the greatest decrease in aFel d1. Therefore, the authors concluded that feeding cats a diet containing anti-Fel d1- IgY from chicken eggs was able to significantly reduce the active Fel d1 on the cats’ hair.

Change in aFel d1 (μg/g hair) means over the treatment period, based on initial concentrations.

It's pretty exciting research, as this kind of dietary modification to reduce or prevent allergies o cats has never been trialled before. It's also worth keeping in mind that the development of owner allergies is an important reason why many cats are surrendered, re-homed or returned to breeders, and a diet that decreases the number of homeless cats would be very welcome indeed. It's difficult to know how long it will be until Purina make the diet available; we will certainly keep an eye out for any updates.

Read the full paper by Satyaraj et al. here:

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