It is so important in any scientific field to have true evidence based medicine. This helps you to make very careful decisions to choose the best care when treating a patient (dog or person).
In this instance, we finally have some evidence based medicine for choosing a vegan diet to feed our dogs over a standard meat-based diet thanks to the hard work of vet and recent Master’s student Lukas Kiemer. His choice of master’s topic after completing his degree was – ‘The vegan diet and its effects on the dog’s health’.
Being fluent in 5 languages, Lukas was able to work with a full range of top professionals including Dr’s Lisa Walther and Romberger who we work with to produce the balanced homemade recipes. He diligently sent out questionnaires to dog owners around the world, and was able to gather information from 250 fully completed forms from dog owners feeding a plant-based diet and he also had access to recent blood tests performed on the dogs sent in by the owners.
His completed thesis is fascinating as shown below:
Summary from the thesis
This research was conducted at the Department of Animal Husbandry in the Veterinary Academy of the Lithuanian University of Health Sciences in 2019. In this investigation, dogs in Scheer, Germany, were fed two different diets: vegan and meat-based.
The nutritional adequacy of a vegan diet was determined by analysis of blood samples from 40 dogs, 20 of which were fed a 100% plant-based vegan diet for an average of 2.15 years, and a control group of 20 were fed a meat-based diet. The results showed the same number of surpluses in both groups; however, the vegan group had only two nutritional deficiencies compared to 11 in the meat fed group. Statistically significant differences (p < 0.01) were found between the groups in iron, vitamin B12 and folic acid concentrations. Total protein, calcium and magnesium were not significantly different (p > 0.05).
To further evaluate the impact of a plant-based diet on dog health; eight dogs were put on a six-week feeding trial. The dogs were split into two groups of four dogs each; the control group was fed a meat-based diet, and the other group was fed a vegan diet. Blood analyses were performed prior to the start and at the end of the trial. The results showed that most of the values were not significantly changed. Some folic acid, B12 and iron deficiencies detected prior to the trial reached recommended healthy ranges during the trial on a vegan diet, although one dog experienced a folic acid surplus and another dog a folic acid deficiency.
All participants from all groups were determined to be in overall good health or in a condition that would not affect the blood chemistry parameters. These included total protein, vitamin B12, folic acid, calcium, magnesium, iron, taurine and L-carnitine. Laboratories analysing blood samples in Germany were Laboklin (seven samples), EasyLAB (two samples), IDEXX (37 samples), SYNLAB (one sample); in Australia, ASAP LABORATORY (two samples); and in England, AXIOM VETERINARY LABORATORIES (two samples). Veterinarians performed physical examinations during blood sample collection in various cities in Germany (including Stuttgart and Regensburg), England (Newton Abbot) and Australia (Melbourne).
To collect additional data from dog owners feeding a vegan or partially vegan diet, a questionnaire (initially presented to several thousand potential participants) was completed by 250 people.
Blood chemistry analyses and physical examinations of the vegan dogs in this study together clearly indicate that a vegan diet can be healthy and adequate for dogs, and in some cases, even improve overall health. The additional data collected from 250 dog owners feeding a plant-based diet strongly supported this conclusion.
Keywords: vegan, dog food, climate change, animal ethics, greenhouse gases, water usage
Digestion of carbohydrates in dogs
Digestion involves the mechanical breakdown of carbohydrate food source, with enzymatic processes and microbial processes. Dogs do not produce alpha-amylase in their saliva, meaning that the digestion of enzymes does not start in the oral cavity of a dog, however new research has proven that amylase is present in the dog’s saliva. In the stomach, little digestion of carbohydrates occurs, therefore the real digestion and absorption of simple carbohydrates and starches happens in the small intestine.
As several studies suggest; dogs do digest carbohydrates far better than wolves due to a drastic increase in copies of the gene that codes for the digestion of carbohydrates, produced in the pancreas, the AMY2B, which is the gene that has made it possible for dogs to thrive and be healthy on a starch-rich diet.
Dogs fed a diet containing 30-57% extruded barley, corn, oats and rice showed that these starches were almost 100% digested, as almost no starch passed from the small intestine into the colon .
Other studies compared uncooked to cooked starch digestibility in dogs and showed that some starches like rice starch are digested in its raw and cooked form by almost the same degree, however other starches such as potatoes when given raw were not digested at all. This therefore strongly indicates the increase in digestibility of cooked foods over raw food sources, again showing that the dog is of an omnivorous nature.
Grain-free or not Grain-free
34,4% of the surveyed dog owners didn´t know of any difference between grain-free and grain containing diets. However, 40% reported feeding a diet containing grains and 22,4% fed a grain- free diet while 3,2% of the participants did not provide any answer to this question.
When asked the grain-free feeders for reasons, amongst the most common were:
- Belief that a grain-free diet could be healthier (Most were unsure of the factuality of their claim)
- Allergies, intolerances
- The vegan dog food they chose happened to be grain-free
- Two participants reported fewer digestive issues without grains
- Two participants reported diarrhoea due to a gluten intolerance in their dogs
- One participant reported that she has been feeding grain-free diets for 25 years and her personal experience is that her dogs appear healthier without grains
When asked the grain-included feeders for reasons, amongst the most common were:
- Grain is very well tolerated and digested
- No evidence of grains being bad
- The need for grains in the diet for a dog’s overall health
- Feeding grains in moderation
- The belief that grain-free is unhealthy for dogs
- Some mentioned that everything that is unbalanced can be unhealthy, the key is balance in whatever we give the dogs
- One participant even mentioned a research study conducted in Sweden that showed the adaptability of dogs towards digestion of starches and therefore his knowledge that grains can be fed without any issues
- One participant finds the grain topic overhyped and believes it is necessary to feed grains, except in cases of allergies
The discussion about grains in a dog’s diet is very split between the surveyed participants and so are their feeding behaviours regarding this subject.
Assurance about the nutritional adequacy of the given plant-based food
The vast majority of owners, represented by 59,2%, are assured of the nutritional adequacy of feeding a plant-based diet to their dogs by trusting the package claim of the vegan dog food producer which says “Complete-diet.” The EU law defines a complete pet food as “Any food which, by reason of its composition, is sufficient for a daily ration” Regulation EU No. 767/2009 (57), therefore assuring the average total quantity of a specific pet food that is needed daily by a pet of a given species, age category and lifestyle or activity to satisfy all its energy and nutrient requirements.
24,8% reported to using the package claim and have had a blood test done for evaluation of adequacy, whilst 10,8% had nutrition counselling with a dietitian (professional advice). 5,6% did not provide an answer to this question.
Supplementation of dog´s food
Participants were asked if they are supplementing their dog´s food, with 50,4% reporting to supplement and 47,6% did not supplement. 2% did not provide an answer to this question. 58 participants reported using VegDog; 26 reported using nutritional yeast; 18 reported using V-Complete, 8 reported using single vitamins, 5 were using brewers´ yeast and 3 were supplementing with a mixture of herbs.
Several more reported to supplement with the following: seaweed, taurine, spirulina, L- carnitine, lupine powder, digestive enzymes, green mush, MSM, glucosamine, CBD oil, Hokamix powder, Boswellia powder, quercetin, algae, chlorella, Omega 3 oils, seaweed powder, flaxseeds, sunflower seeds, pumpkin seeds, desiccated coconut, Goji berries, chia seeds, hemp seeds, Vitamin C, calcium citrate, mineral nutrition mix, Augustine, Rose hip vitals, Cranium, Dorset greens, Nepani, Vegepup, moringa powder, medical mushrooms, D-mannose tablets, curcumin powder, turmeric, berries, psyllium husk, cinnamon and ginger. 120 participants did not provide any answer.
Is there any association between a vegan diet and lower urinary tract infection (LUTI)?
The question was asked how many of the dogs participating in the study were diagnosed with a UTI while on a vegan diet compared to the frequency to prevalence levels of meat-based fed dogs. 87,2% reported that no UTI have been diagnosed while feeding a vegan diet, with 13 participants (5,2%) reporting a diagnosed UTI while being fed a vegan diet. 7,6% did not provide an answer.
Comparing the prevalence of UTI in the study participants to meat-based fed dogs, it can be assumed that even when feeding a mostly vegan diet without an added acidifying agent, there is a decreased prevalence of UTI disease in the study participants. Studies have shown the prevalence of LUTI (lower urinary tract infection) to be around 26,6%, while the lifetime risk for LUTI is 14% (61; 62). The risk of a LUTI positive urine culture is 2,5 times higher in spayed female dogs over a neutered male and 1,5 times higher for an intact female over a neutered male (62). However, the highest risk group for LUTI are spayed females in the higher age group (63).
In this study the plant-based fed dogs had a LUTI prevalence of only 5,2% compared to 14% for meat-based fed dogs.
Experience on feeding a vegan diet
After having fed a vegan diet, the participants were asked if they would recommend a vegan diet for dogs to their friends and colleagues. 44,4% of all participants responded with “Yes, definitely” and that they do recommend it very often. 38% stated that they recommend a vegan diet for dogs but only if being asked by someone out of his/her own interest and 0,4% (1 participant) would not recommend a vegan diet for dogs.
Interestingly, 13,6% reported that they would like to recommend it but are afraid to be criticised and 8,8% stated that they never mentioned feeding a vegan diet in order to avoid negative comments. This clearly shows that society as a whole is approaching this topic with a strong prejudgement.
When asked if the participants find it easy talking to friends, colleagues or family members about a vegan diet for dogs, 46% answered with “sometimes” and 37,6% answered that they did not find it easy, while 14% did find it easy talking about this topic. 2,4% did not provide an answer.
The participants were asked why they find it hard having a conversation about this topic, and the results are as follows:
- 41,2% say that most others have an immediate prejudice about this topic
- 23,2% say that most others believe dogs to be no different from wolves in terms of nutrition
- 11,6% say that most others don´t even want to listen to scientific research, and therefore their refusal towards this topic is hindering a constructive conversation
- 10,4% did not provide a specific answer
- 6,8% say that most believe they are experts on dog nutrition
- 3,6% say that most do not realise that commercially available dog food is already made up mainly of plants in order to produce a cheaper product and to increase profit
- 3,2% say that many are not keen to talk about the topic “vegan” in whatever context
Is a vegan diet for dogs cruel or unhealthy?
72,4% answered with “No, it is the opposite of cruel as it is an act of compassion. Dogs can even be healthier on a vegan diet”. 22% responded with “No, I don´t find it to be cruel or unhealthy for dogs” and 3,2% responded with “I am not sure. It needs more research”. Not one single participant found feeding a vegan diet to dogs cruel or unhealthy, however 2,4% of the participants did not provide an answer.
The biggest concerns of the participants feeding a vegan diet to dogs were:
34%: Not being taken seriously by their vet; 30%: Do not have any concerns; 28,8%: Nutritional inadequacy; 19,2% Being labelled an animal abuser; 15,6%: Health issues; 8,4%: Rejection of the food; 3,2%: Did not provide an answer.
This research has shown that the long-term vegan-fed dogs showed the same number of nutritional surpluses as the conventional meat-fed control group (all were detected for iron). The meat-based fed control group showed 11 deficiencies (four folic acid, four vitamin B12, two calcium and one iron), while the long-term vegan fed category presented only two deficiencies in total (lower than recommended folic acid values, explained by a Giardia infection during the blood collection). When comparing the groups (plant- and meat-based), the mean differences in protein, calcium and magnesium showed no statistically significant differences (p > 0.05); the results showed statistically significant differences in iron, vitamin B12 and folic acid (p < 0.01). The physical examinations did not raise any suspicion of nutrient-related issues. The results of the six-week vegan trial showed that most of the blood chemistry values remained steady during the trial. Three deficiencies detected before the trial in folic acid, vitamin B12 and iron reached recommended healthy ranges during the vegan diet. However, no statistically significant differences were observed between the vegan and meat-based control groups during the trial (p > 0.05), further strengthening the plausibility of feeding a vegan diet to dogs. The physical examinations did not raise any suspicion on nutrient resulting issues.
The 250 surveyed dog owners responded with defined reasons (ethical, environmental and health) for feeding a vegetarian or vegan diet to their dogs and themselves. Of the 250 surveyed, 54% of dog owners feeding plant-based food observed positive health changes while feeding a plant-based diet, and the great majority reported increased health and positive health changes. However, stool volume and frequency were reported by 31.6% to have increased. Out of 250 surveyed dog owners, only one would not recommend a vegan diet to others, which shows the great satisfaction felt by dog owners in being able to offer their dog a vegan diet.
The performed direct food ratio analyses with expert DMV Uwe Romberger also confirmed that a vegan diet, if well balanced, has an abundance of nutrients and proteins, supplying the dog with all required nutrients.
Feeding a vegan diet to dogs is shown to be possible, according to this research. The reasons behind such a practice are clear and well defined, as are the diet choices of the dog owners. Feeding a vegan diet to dogs is NOT A TREND BUT A SOLUTION to diminish the consequences of climate change and simultaneously raise the standards of animal ethics in 2020.
Be open to new ideas, even if they seem crazy at first glance, sometimes there is more truth to find than we might anticipate. If you might not agree with someone, inform yourself first before being judgemental. We can still turn the climate crisis around, let´s unite and if you have an idea yourself, go for it! Don´t wait for others to do it. I believe in you.
– Dr Lukas Kiemer
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