Sue's Blog

ADHD and autism in dogs


50 years ago, most people had never heard of autism or ADHD in children, let alone dogs.

Now, studies show that dogs can have symptoms resembling either of those conditions. Called CDB (Canine Dysfunctional Behaviour), the condition is considered to be idiopathic – that is, experts don’t know what causes it.

Autism in rodents

However, scientists have already shown that propionate preservatives can cause autistic type behaviours in laboratory rats (1), as you can see for yourself in the following video:

Vautism (From Autism Enigma; 3:00min)

Propionate preservatives were introduced in Australian bread in the 1990s and are now used in nearly all mass-produced breads as well as an expanding range of foods, including mayonnaise, processed meats, and … wait for it … dog food!!!

If propionate preservatives can cause autism in rats, WHY would you give it to dogs???? (or to children, for that matter!)

Good question. For human foods, such as most commercial breads, the food industry has taken to describing propionate preservatives as “natural” so they can claim “No artificial preservatives” on their products while hiding the propionates under ingredient names such as “cultured dextrose” or “fermented wheat flour”.

We haven’t yet seen propionates listed on dog food because they don’t have to list all ingredients, so we wrote to a pet food manufacturer to find out whether the “natural preservative” listed in their product was, in fact, propionates.

Their answer: “Our puppy rewards are labelled with the ingredients included, and do not contain any artificial colours, flavours or preservatives. To ensure our products are safe and nutritious for our customers’ pets, we only include ingredients that have been approved as safe for use in pet foods by AAFCO (Association of American Feed Control Officials). Unfortunately we are unable to share further details of our confidential formulation.”

In other words: We’re not saying. We were NOT reassured. If AAFCO is anything like our food regulators FSANZ, we are in fact alarmed. VERY alarmed.

So then I wrote to Ivory Coat (food sold in pet shops) and was reassured by their answer:

“Thank you for reaching out to us and for your interest in our Ivory Coat foods … We can confirm our Ivory Coat dry foods will not contain propionate preservatives”

According to latest research, behaviour caused by dietary propionates can be reversed by sticking to a propionate-free diet BUT autism caused by propionates in the mother’s diet while pregnant is NOT reversible (2). Of course, not all dogs are affected by nasty additives, just as only about 50% of children are affected (3). But the increasing number of rescue dogs makes you wonder…


The kennel warned us that our new puppy, Buster (pictured above) was at age 6 months the most “boisterous, destructive and hyperactive” puppy they had ever encountered. Jack Russells are listed as one of the breeds most likely to exhibit ADHD type symptoms, but he’s our third Jack, and much more overactive than the previous two.

So we are currently doing everything we can to give him additive free food: plain meats sold for humans, dog treats that are dried meat with nothing added, and additive free biscuits: Hills Science Diet sensitive food that gives a very full list of all the ingredients and sounds OK.

We are also doing an online dog training course, daily long walks, playdates with a compatible dog, and regular socialisation sessions at a local dog park. He’s now aged two and he has improved (phew!) – but still needs work.

More info

Symptoms of hyperactivity in dogs

Can dogs be autistic?

Further reading

Harm from bread preservative confirmed

Caution cultured dextrose

Our factsheet about diet for dogs


1. MacFabe DF et al. Neurobiological effects of intraventricular propionic acid in rats: possible role of short chain fatty acids on the pathogenesis and characteristics of autism spectrum disorders (2007). Behav Brain Res, 2007,10;176(1):149-69.

2. Abdelli A et al, Propionic Acid Induces Gliosis and Neuro-inflammation through Modulation of PTEN/AKT Pathway in Autism Spectrum Disorder (2019). Sci Rep, 2019,19;9(1):8824. Also reported in Medical News Today: Could processed foods explain why autism is on the rise? For the first time, scientists have found a molecular connection between a common food preservative, neuronal disruption, and autism spectrum disorder. The findings suggest that there may be a link between the consumption of processed foods during pregnancy and the rise of autism.

3. McCann D et al, Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial. Lancet. 2007;370(9598):1560-7.