- The proposition to reduce reliance on livestock production invites the question as to the feasibility of utilising plant proteins as an alternative to, or alongside, insects. Recent research seems to suggest that plant-based diets are beneficial for our dogs and for the environment. Below, we look at the issues of plant-based diets for dogs as well as addressing the research into plant-based diets so far.
- The issue of plant proteins is two-fold. Firstly with regards to the environmental impact. Familiar, and suitable, plant proteins are: chickpeas, lentils, soy beans, and borlotti beans.
- Many of these plants are not a good match for the UK climate; they require a long growing season whilst being unable to cope with frost.[1] Equally, most R&D in the UK has gone into harvesting low-protein cereals rather than legumes which would be required to make up the high protein content required in dog food; UK farms are not structured to manufacture the required plant proteins. Thus, utilising plant protein would likely require the importation of dried plant protein powder which has a lower nutritional value than fresh produce. The most feasible plant protein to be used as a replacement would be soy protein. However, the environmental implications of farming soy are worrisome: one metre-squared of land can produce up to 0.5kg of soy feed per year, yet Insect farms can produce up to 750kg of feed in an equal space.[2] Importing plant proteins from halfway around the world could compromise much of the carbon emissions gained from eradicating livestock.
- The second issue, perhaps somewhat more pertinent, is the nutritional concerns of plant proteins in dog food.
- The nutritional problems with plant protein starts with the fact that most are incomplete, meaning that it can be difficult to get sufficient amounts of essential amino acids in a plant-based meal.[3] Equally, plant-proteins have relatively low digestibility compared to animal proteins[4] meaning that in some cases, even if a dog is fed a much higher volume of plant protein, it would still not receive all the amino acids that it requires.[5] Equally, whilst some plant oils do contain omega-3 fatty acids, they tend to be in the form of ALA (alpha-linoleic acid) which dogs cannot convert to a usable form of omega-3.[6]
- One study analysing the nutritional effects on dogs fed a vegetarian diet found that[7]:
- 1. Protein intake was inadequate for more than half of the dogs
- 2. Calcium requirements were not met in 62% of the dogs
- 3. Phosphorus requirements were not met in approximately half the dogs
- 4. 73% of dogs had an insufficient intake of sodium
- 5. 56% of dogs were not receiving sufficient vitamin B12
- Therefore one would conclude that there are some dangers of advocating for a meat-free diet as the potential nutritional deficiencies need to be considered.
- Nonetheless, a recent study on “Vegetarian versus Meat-Based Diets for Companion Dogs” argues that dogs maintained on a vegetarian diet may be healthy if the diets are nutritionally complete and reasonable balanced.[8] A further study analysed the protein digestibility of certain plants in dog food and found certain plant proteins including soy, corn and rice to be highly digestible by dogs.[9] Most recently, an research that was covered by the Guardian claimed that vegan diets are better for our dogs.[10]
- However, it should be noted that the first study, the dogs had only been fed a vegan diet for around 2-4 years, with nutritional values compared to that of dogs fed commercial dry dog food diets. Firstly, a study would need to be undertaken over a lifetime to conclude whether such a diet leads to health issues later in life. Secondly, commercial dry dog food does not provide a good comparison given the nutritional issues related to this type of food in the first place. Commercial dry dog food is void of fresh nutrition and tends to be inappropriately balanced with macronutrients. The manufacturing of this type of food can lead to cancer in dogs.[11]
- In the second study, although the protein digestibility was shown to be adequate, the study does not discuss the effect of feeding dogs plant-based foods on digestion as a whole, but rather as a concentrated protein source. In fact, the study notes that “it is not possible to describe the “healthiness” of a food based on only a knowledge of protein concentration and protein digestibility”. Equally, there is no consideration of supplements that would be required to ensure that a dog meets its nutritional requirements in the form of complete amino acids and the study concludes that “[plant proteins] provide a satisfactory source for the complementation of animal protein ingredients in meeting the amino acid needs of pets” rather than being the sole source of protein for canines. Therefore, whilst promising in the fact that there are alternatives that can, indeed, be of use to dogs, one must appreciate the importance of balancing the benefits of reducing livestock consumption with that of the dog’s nutritional requirements; so far, the evidence seems to suggest that plants do not offer a payoff worth taking.
- With regards to the study covered by The Guardian, the study tracked 2500 dogs over the course of a year and based the conclusion on how many times the dogs went to the vet and other health-related issues. However, an incredibly weak point of this study is the sample size – only 13% of the dogs studied were on a vegan diet with 54% on a ‘conventional meat’ diet and 33% on a raw diet. Interestingly, the dogs fed the raw diet were found to be healthier than dogs fed vegan food, with the study noting that dogs fed raw food were younger which, they stated, may have offset the results. There is no mention of how the unbalanced sample sized could have influenced the results. It is also unclear what a ‘conventional meat’ diet consists of, considering there are significant problems plaguing the dog food industry of cheap, processed, dry dog foods causing a myriad of health issues. Could it be that, in fact, the conclusion to be drawn is that processed food, full of cheap fillers, is causing health issues, rather than the fact that vegan food might be better for dogs? The article is misleading in that it does not highlight issues of sample sizes or the fact that most foods would prove better for dogs when compared to poor-quality, processed kibble.
- Nonetheless, it should be noted that a growing body of population studies and case reports have indicated that cats and dogs maintained on vegetarian diets may be healthy, and this is something that Tuggs will keep an open mind to in our research. What is vital is that such diets need to be fresh as well as nutritionally complete and reasonably balanced, which is the real issue of this topic.
- Furthermore, arguably of most importance is the quality of the food, especially in line with findings on how unhealthy current commercial dog foods can be. Tuggs stands for fresh food for dogs to help dogs thrive, and not just survive, without sacrificing the planet.
- [1] Kew.org. 2021. Plant proteins: Can they grow in the UK? | Kew. [online] Available at: <https://www.kew.org/read-and-watch/plant-proteins-grow-uk> [Accessed 20 July 2021].
- [2] Better Origin | Fixing the food chain. 2021. The Black Soldier Fly: everything you need to know.. [online] Available at: <https://betterorigin.co.uk/2021/05/black-soldier-fly-guide/> [Accessed 20 July 2021].
- [3] Healthine, “Are ‘incomplete’ proteins a myth?”. https://www.healthline.com/nutrition/incomplete-protein#vegetarian-and-vegan-diet
- [4] Wang, T et al, A review on plant-based proteins from soybean: Health benefits and soy product development, https://www.sciencedirect.com/science/article/pii/S2666154321001678
- [5] Olson, Lew. Raw and Natural Nutrition for Dogs. North Atlantic Books (2015) page 22
- [6] Ibid page 34
- [7] Ibid page 165
- [8] NCBI. 2016. Vegetarian versus Meat-Based Diets for Companion Animals. [online] Available at: <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5035952/> [Accessed 22 July 2021].
- [9] NCBI. 2020. Cats Have Increased Protein Digestibility as Compared to Dogs and Improve Their Ability to Absorb Protein as Dietary Protein Intake Shifts from Animal to Plant Sources. [online] Available at: <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7143243/> [Accessed 22 July 2021].
- [10] The Guardian, “Like a dog with a bean … vegan diets found to aid canine health”, https://www.theguardian.com/lifeandstyle/2022/apr/13/vegan-diets-are-healthier-and-safer-for-dogs-study-suggests
- [11] National Cancer Institute. 2021. Chemicals in Meat Cooked at High Temperatures and Cancer Risk. [online] Available: https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet
