Benefits of raw feeding: the science
One of the biggest arguments against raw feeding is that, supposedly, there are no scientifically proven benefits but only risks associated with it.
For a long time, I, myself, have believed that there weren't (yet) any studies on raw diets, as this idea was always claimed by strong proponents of evidence-based science.
I decided, then, that it was time to do some serious research by myself, and I was pleasantly surprised when I found much more scientific studies reporting the benefits of raw diets than I thought.
In this article, I will report my findings from the scientific literature, listing the proven benefits of raw diets.
A well-studied benefit of raw diets: increased digestibility
One of the benefits of a raw diet–which is also the most noticeable when you switch your cat to a raw diet–is that the stools are much smaller, with almost no smell. This benefit, often judged as anecdotal, is–in fact–reported in many studies and has a scientific explanation.
In fact, raw meat-based diets are highly digestible, significantly more than kibble or canned-based diets. This is something really important because it means that the cat assimilates almost all the nutrients that it is eating.
A higher digestibility also means less waste (smaller feces) as almost everything which is eaten is used by the body. Cats eating a raw diet always have better or equal fecal scores to cats eating commercial diets.
To give you an idea of the magnitude of the increase in digestibility, a commercial diet is considered of poor quality if its digestibility is below 75%, of moderate quality if the digestibility is between 75 and 82%, and of high quality if the digestibility is above 82%.
In most studies, the digestibility of raw diets was ranging between 90 and 95%, which not only classifies raw diets as highly digestible, but it also means that there is as much difference between a low-quality and a high-quality commercial diet as between a lower range high-quality commercial diet and a raw diet!
If you want to know more about digestibility, this article written by Linda Case–a prominent animal nutritionist–explains well its importance. You could also read the book "Dog Food Logic" by the same author to study the subject further.
Concerning the odor of the feces, their bad smell is caused by the presence of putrefactive compounds. These compounds are the result of the fermentation in the large intestine by the gut bacteria of the proteins that weren’t digested in the small intestine.
Even if raw diets have higher protein content than commercial diets, because of the higher quality and digestibility of the proteins found in raw meat, they result in less undigested proteins. This leads to less odor in the feces due to the presence of fewer putrefactive compounds.
On top of the smell factor, a high presence of odorous compounds is also linked–in humans–to gastrointestinal diseases or others, such as chronic kidney diseases.
The improvement of the stool quality suggests, therefore, that raw diets could be useful in the management of gastrointestinal diseases such as IBD in cats.
[1][5][8][11][12][13][14][16][17][18][19][27][28][32][34]
Gut health
The importance of our gut microbiota is more and more studied since it has proven consequences on our overall health.
For our companion animals, being fed a raw or a whole-prey diet results in very different gut bacteria when compared to the ones found in pets fed a commercial diet.
In dogs that are fed a raw diet, not only the bacteria were different, but they were also richer and more diverse. In humans, a higher diversity of gut bacteria is linked to better overall health, while lower diversity of bacteria is linked to obesity and unhealthy eating behavior.
As we still don’t know much about what is a healthy gut microbiota for our pets, it is not possible to conclude with certainty if the differences in gut bacteria are, in fact, beneficial for the pet or not. However, some studies on our pets' gut microbiota are starting to find results that could be linked with enhanced gastrointestinal health and an improved intestinal barrier. [6][9][10][31][33][34]
Non-nutritive benefits
Something that is often underestimated is the non-nutritive aspect of feeding our cats.
The studies on this are still in their infancy and have been carried out mainly on large felids living in zoos. Several studies have shown the mental enrichment provided by feeding partial carcasses or whole prey to large felids instead of ground meat, which resulted in reduced stress and improved well-being. [2][4]
In fact, feeding whole prey or carcasses fulfills the need to exercise the teeth, which prevent jaw and cranial malformations, as well as being sensory stimulating.
Similarly, feeding biologically relevant enrichment to cats, such as chicks or mice, should provide the same mental enrichment and benefits. [3]
Another non-nutritive aspect linked with feeding raw meaty bones is the improvement in the oral health of cats. The act of chewing and eating the bones, in fact, scraps and cleans the teeth. I personally experienced this benefit when I switched Néline to a raw diet. While there is still not a clear scientific claim made specifically for cats on this topic, the benefits of feeding bones have been studied in wild felids, and it is proven that it does indeed promote better oral health. [29][30]
Less studied/potential benefits
Early studies are starting to show benefits of raw diets for dogs such as anti-inflammatory effects, a decrease in oxidative stress, enhancement of immunity, improved metabolic health. This could have an effect on diseases such as atopic dermatitis and allergies.
Additionally, dogs eating a raw diet early in life or who had a mother fed a raw diet seem to be less likely to develop canine atopic dermatitis.
These effects are hypothesized to stem from the fact the diet is high in fat and non-processed. [20][21][22][23][26]
A case-control study indicates that feeding a raw diet to German shepherd puppies could be protective against hip dysplasia. This is the first time that this benefit has been reported, so more studies (and especially clinical ones) will be needed to confirm it. This is still promising as it suggests that raw diets seem to provide benefits in a wide range of health improvements. [24]
In another study, feeding a raw diet to dogs was protective against the parasite Toxocara canis. The hypothesized explanation is that since a raw diet isn't sterile–as opposed to a commercial diet (kibble or canned)–it resulted in enhanced immunity. [25]
To mitigate the widespread misinformation against raw diets, it's also worth mentioning that it has been proven that raw diets can indeed support a normal growth rate and pass a growth feeding trial as defined by the AAFCO, as well as maintaining body weight and normal health in adult pets. [1][15].
I wouldn't consider these as "benefits", but rather normal effects of a complete and balanced diet.
Whole food
Finally, an area of research that is promising for raw diets is the shift of the focus from nutrients to whole food. In fact, we don’t have a deep understanding of all the constituents of an ingredient, and whole food provides more than just the known nutrients. The health benefits of eating whole food are in general superior to the health benefits provided by the nutrients taken separately. Feeding a balanced diet made of minimally processed whole food to our pets should also promote better health in the same way that eating whole food promotes better health in humans. [35][36][37][38]
As raw diets have recently been growing in popularity, the research on them is still in its infancy, but there are already several proven benefits over commercial diets, and in particular over kibbles.
I can’t wait to see all the future research done on raw diets and in particular on all the health improvements that are linked to improved digestibility, the increased gut health, and the consumption of whole food.
To conclude, keep in mind that the benefits reported in this article are just the ones that are backed by science, but there are still many things that we don’t know!
In a future article, I will talk about the risks of a raw diet.
Other recommended readings
Sources
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