Fermentation fix: enhancing pet gut health

Among humans, eating fermented foods is now regarded as an essential part of taking care of one’s overall health.

This is backed by significant evidence, so it’s no wonder there is a growing interest in how these foods might benefit pet companions.

Effects on gastrointestinal health

Fermented food’s effects on humans have been well studied and shown to improve health in numerous ways, from the effects on microbiome and digestibility to enhancing mood.

Fermentation makes food more absorbable by pre-digesting certain components and reducing the presence of anti-nutritional factors that inhibit digestive enzymes, such as trypsin inhibitors.

This is particularly relevant for dogs and cats, as their digestive systems can benefit from the enhanced nutrient availability that fermentation provides.

For instance, the addition of fermented ingredients, such as fava beans and pea starch, has been shown to improve palatability and nutrient absorption in dogs and cats, leading to better overall digestive health.

Additionally, fermented foods can introduce beneficial microorganisms into the gut, which benefits the overall gut microbiota, and enhances immune function and nutrient assimilation.

Kefir in companion animals

One of the most popular and praised naturally fermented foods is kefir, a traditional fermented milk product containing more microorganisms such as lactic acid bacteria, yeast and acetic acid bacteria.

Its effect on dogs’ gut health has been investigated in several studies.

The most recent study, led by the University of Illinois, investigated how kefir affects macronutrient digestibility, fecal characteristics, microbiota composition and metabolite and immunoglobulin A concentrations in healthy adult dogs.

12 dogs were fed either traditional kefir, commercial kefir or a control milk-based product for 28 days. Kefir products differed in microbial density and profile.

Overall, kefir had a minor impact on gut microbiota and metabolites but did not significantly alter the dogs’ overall digestion or immune markers. Fecal microbiota populations were weakly impacted and the effect on nutrient digestibility was negligible.

Traditional kefir was found to increase beneficial bacteria such as Lactococcus, and commercial kefir increased Fusobacteriota levels.

This partially confirmed the findings of a previous South Korean study published in the Journal of Dairy Science.

The study evaluated the impact of kefir on gut bacteria in 6 healthy adult dogs. These dogs were given kefir for 2 weeks, and their gut microbiota was analyzed before and after the supplementation.

Results showed significant changes in the gut bacteria: the relative abundance of beneficial bacteria families, like Prevotellaceae, increased, while potentially harmful ones, such as Fusobacteriaceae, decreased.

Additionally, kefir increased the population of lactic acid bacteria, which are known for promoting gut health.

Importantly, no negative side effects were observed, suggesting kefir could be a promising probiotic supplement for improving dog gut health.

The authors concluded that “kefir may be applied as a novel functional pet food supplement to improve the quality of life of dogs, much to their owners’ satisfaction”.

Caution over labelling

Although evidence of the potential of kefir to improve the gut health of companion animals exists, there is a problem with variability and reproducibility.

A study evaluating the accuracy of labelling regarding probiotic content in 6 kefir products found that many of these products overstated the number of live microorganisms, often by a significant margin, and that the specific bacteria listed on the labels were often incorrect.

In fact, none of the products contained only the microorganisms listed, and all had additional bacterial species that weren’t disclosed. Some products made health claims that were unsupported by scientific evidence.

This highlights the need for stricter regulations and better labelling accuracy for probiotic products intended for pets.

Other fermented products

And how about fermented vegetable products, such as kimchi, sauerkraut and others?

There is simply not enough evidence of their health benefits in dogs and cats in the literature. Still, this doesn’t mean that these foods don’t provide any – only that more studies are needed.

However, there is evidence of the effects of fermented meat, such as Pediococcus spp.-fermented chicken meat as a snack for dogs.

Results showed that fermentation increased lactic acid bacteria levels, lowered pH and improved pepsin digestibility of the snack. Additionally, fermented snacks exhibited better preservability, with lower bacterial growth compared to non-fermented snacks.

These findings suggest that Pediococcus spp.- fermented chicken meat could enhance the nutritional value and shelf life of dog treats, making them a potentially beneficial option for canine diets.

Looking forwards

Recent studies have shown that the inclusion of fermented ingredients in pet food or feeding animals fermented foods like kefir, might be beneficial in terms of improving digestibility, nutrient availability and gut microbiota.

However, these effects are also variable, and more comprehensive research with larger numbers of animals is needed to confirm their overall efficacy and long-term benefits.

Until more robust data is available, claims about the widespread advantages of fermented foods for pets should be approached with caution.