Can dogs really digest Starches? - Amylase Study considerations

Westie Feeding Science - including the starch Amalase study round up!

Did you know that the Westie is one of a handful of breeds proven to have the least chance of coping with starches, cereals and grain in their diets?
The Westie has been shown to have less copies, if many at all, of an important gene variance between dogs and wolves that allows for dogs to better digest starches.
We all knew it, the Westie is just that little bit different to your average canine, now we know it’s not just about chunky cute paws tapping at your leg for attention or their inquisitive button noses, they are different in their diet requirements too.
Something, I feel, needs to be understood by Westie owners everywhere.
The story begins in with a study from 2013 (1) which highlighted a genetic adaption to the breakdown of starches in the dog, proposed in the study to have arisen as dogs were domesticated and began eating more human leftovers, including our dietary inclusion of grain.
The genes of the adaption known as : AMY2B (MGAM and SGLT1) or Maltase-glucoamylase appeared in many breeds but were much lower in others. Westies, alongside Chinese Crested Chihuahuas, and Huskies and were the lowest with some Westies not showing the gene adaption at all, described in the study as ‘lacking it’.

Maltose-glucoamylase is responsible for the second step in the breakdown of starch, maltose to glucose, known as catalysing the hydrolysis of maltose to glucose.
Proponents of a commercial processed food diet have cited this study many times to provide an understanding into how dogs may cope with cereals or grains in their diets. Yet they currently do not often share the evidence that our little besties, the Westie, were much less able to perform the secondary starch breakdown steps.

Veterinary researchers however have noted the Westie as a dog who is likely to suffer skin, yeast or digestive ailments. Specifically choosing Westies for studies into skin health, and describing them as a high-risk breed . One such study including Westies shows that Westies fed home-made real meat diets, were less likely to suffer Canine Atopic Dermatitis (CAD) than those fed a commercial processed diet (2).
The study also specifically highlighted that pregnant bitches fed a home-made diet give birth to puppies less likely to suffer these ailments. Prevention is indeed better than cure.
Choosing a breeder who recognises the value of real fresh meat diets, either raw or lightly cooked affords you a better chance of avoiding atopic dermatitis in your pet Westie.

The story is not about grain though, the above genetic amylase study only holds true for the type of grains early man included in his diet, ancient grains such as Spelt flour which have a different nutrient and molecular profile than todays’ very refined grains, and for the most part did not include rice either. There is also no evidence to show dogs of any breed do well on a consistent, repetitive amount of cereal or starches in their diets.(3)
If grain was the only possible issue for our Westies in a processed diet you could be forgiven for simply switching your dog to a grain free commercial, processed food and hoping that would be the answer.
Usually due to the change in microbiome such a dietary switch would afford your Westie you may very well see initial improvements. However, unless the switch is to a real meat fresh diet the changes will not be as significant. Studies have only shown vast differences in canine microbiome when the dogs are switched between a dry processed food and a fresh meat diet.(4)
A full switch away from processed foods is more likely to create the beneficial change needed.

Interestingly the profile of the microbiome shown in dogs fed real meat diets is also much closer to the profile of healthy external skin microbiome.
Your Westies skin is directly related to the health of the gut microbiome. Both the skin and the gut lining continually renew themselves, shedding old cells and forming new ones. Both need a balanced healthy microbiota to do so. The same bacteria in both cases (5).
Studies show that less diversity of bacteria on the skin and gut lining plays a role in skin ailments (6) . A diversity that includes the bacteria found in soil has shown to be pivotal to encourage in the healing of skin issues(7).
Soil based probiotics are fast becoming a highly recommend factor in a dogs gut healing and skin health protocol, FidoSpore (8) is one brand with evidence to show the difference the supplements can make alongside dietary changes.

Another often overlooked factor in processed foods and huge influencer of skin conditions is the lack of hydration that a processed diet, even tins, foil packs, white tray foods too.
This includes both traditional water hydration and hydration from fatty acids, lipid hydration
Firstly your dog’s body is set up to produce histamine as a response to being dehydrated, even if subtly over a period of time. Unfortunately drinking water does not provide the same kind of hydration as water found in food. Fresh meat is around 70% water, even when lightly cooked. Following a lack of hydration in the body histamine is produced by the hypothalamus gland to act as a buffer to cells, a useful response the dogs (and our) bodies have evolved to protect cells.
With a persistent daily lack of hydration the body can accumulate too much histamine and certain histamine responses can show up, skin issues, itching and respiratory issues for instance.
Secondly, fat or lipid hydration. The second vital form of hydration comes from the fatty acids. Currently the fatty acids humans need as an essential part of their diet ‘essential fatty acids’, are not considered essential for dogs. This is due to a specific set of enzymes dogs have called Esterases which should act to provide needed fatty acids such as the well-known Omega 3 (alpha-linolenic acid) to the dog’s body. However certain conditions can either mean not enough is converted or that much more is needed than the average dog. Stress and anxiety play a role in the requirements, as does internal inflammation, healing of injuries and skin wound healing. Your dog’s kidneys are also reliant on fatty acids like omega 3, for optimal function, especially if they are already dealing with a diet lacking in moisture content.
From what I can determine the esterase assumption is the reason fatty acids such as the omegas are not included in adult commercial pet food guidelines, no processed food has to include them to be labelled Complete. Yet when supplements of omega oils are added to the diet dramatic changes in skin issues or joint inflammation occur. Clearly an adult dogs body needs them too.(9) Perhaps we now live in a world that sees dogs needing more nutrients to stay healthy, than the nutrient guidelines set up for processed pet food.

All in all the feeding of a fresh diet high in moisture content, microbiome balancing ingredients and the correct fatty acids we can see that our Westies will do better.

Westies were also included in a study that showed the individual dog is the strongest determining factor in skin issues. Stronger than the site of the issue, the location on the body, or the breed predisposition. In other words no matter the higher chances of Westie’s getting skin issues as a breed, or the higher chance of skin issues showing up in specific places such as the ears or paws for instance, the dominant factor in the skin issues was still the individual dogs state of health. Including the balance and diversity of internal and external skin microbiome.(10)
We can forgive ourselves for simply putting issues down the breed, or perhaps the regularity of ear, or paw yeasts in many breeds of dog. But ultimately we can see there is a lot we can do with diet to support our Westie as an individual, that goes beyond these commonly accepted explanations.
Perseverance will also be key, our final study link highlights that it takes only two hours of a single stressor point to significantly reduce microbiome diversity, and yet up to three weeks for the microbiome to re-balance on its own accord.(11)
We can support these changes with beneficial prebiotics, but also need to be patient, trust and persevere to fully support our dogs back to optimum health from a transition to a fresh food diet. It might not happen overnight, but as these studies show feeding fresh, grain free food offers the best chance of health for your best little Westie.

Caroline Griffith
Pet Industry Nutrition Consultant
Nutrition Specialist @nakeddograw


Refs
1. The genomic signature of dog domestication reveals adaptation to a starch-rich diet doi:10.1038/nature11837  201
2. A case-control study of risk factors for canine atopic dermatitis among boxer, bullterrier and West Highland white terrier dogs in Sweden. https://pubmed.ncbi.nlm.nih.gov/17845618/

3. https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/dietary-nutrient-profiles-of-wild-wolves-insights-for-optimal-dog-nutrition/6698A301900EEDF10E49B062A2BD9ED8 2014
Although the dog has been shown to have an increased digestive and absorptive capacity to cope with starch-containing foods compared to wolves, the impact of a consistent high amount of absorbed glucose on the dog's health and longevity remains to be determined.

4. The fecal microbiome and metabolome differs between dogs fed Bones and Raw Food (BARF) diets and dogs fed commercial diets
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0201279
5. ’’https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6351938/
2019 – ‘’what is a healthy gut microbiota composition
And defining canine skin microbiota https://doi.org/10.3389/fvets.2017.00006 ‘’
6 and 7 The Skin Microbiome in Healthy and Allergic Dogs
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3885435/
Published online 2014 Jan 8. doi:10.1371/journal .pone.0083197
8. microbiomelabs.com/home/products/fidospore/
9. https:// yumoveadvance360. com/
10. Front. Vet. Sci., 06 February 2017 | https://doi.org/10.3389/fvets.2017.00006
Individual Signatures Define Canine Skin Microbiota Composition and Variability
11. https:// bmcmicrobiol.biomedcentral.com/articles/10.1186/1471-2180-14-189