What does peer-reviewed research say about chews, fish oils, single-protein diets and rewarding with treats? On this page we line up the key studies, honestly and with full references, and show which Woef Woef products go with them.
At a glance
- Chewing helps teeth. In a study of 1,350 dogs, those with access to more types of chewing material had less tartar, less gum inflammation and less bone loss around the teeth.[2] Brushing remains the gold standard.
- Omega-3 from fish has proven effects on joints and skin, but at targeted, concentrated doses.[5][6]
- Beef, dairy, chicken and wheat are the most commonly reported food allergens in dogs.[7] Single-protein treats with a less common protein source (duck, venison, horse, rabbit, wild boar) make an elimination diet easier.
- Reward quality matters more than quantity. Dogs ran faster for a tastier reward, but not for more pieces.[9]
- Keep treats below 10% of daily energy intake.[11]
1. Chewing and dental health Evidence: moderate
Periodontitis (inflammation of the gums and jawbone) is one of the most common conditions in dogs. A visual check of a conscious dog picks it up in 9.3 to 18.2% of dogs, but a thorough examination under anaesthesia raises that to 44 to 100%. Small breeds and older dogs are at greater risk.[1]
A large North American study of 1,350 dogs found that dogs with access to more types of chewing material had progressively less tartar, less gum inflammation and less bone loss. Rawhide showed the strongest association, especially in dogs fed only dry food.[2]
Controlled studies in beagles back this up: a daily rawhide chew strip reduced plaque build-up compared with a control group,[3] and a soft rawhide chew resulted in 28% less tartar, 19% less plaque and 46% less gingivitis.[4]
What does this mean for your dog?
Chewing works mechanically: the teeth scrape along a tough surface. Our dried skins and chews work on the same principle. Please note: the studies mentioned tested specific chew products, not our own products. Chews complement tooth brushing and dental check-ups at the vet; they don't replace them.
2. Omega-3 and fish skin Evidence: moderate
Fish contains the omega-3 fatty acids EPA and DHA. In a randomised, double-blind study of 127 dogs with osteoarthritis across 18 veterinary practices, blood omega-3 levels rose after 24 weeks on an omega-3-enriched food, and owners saw improvement in getting up, playing and walking.[5]
In dogs with atopic dermatitis, clinical scores improved after 10 weeks of omega-3 fatty acid supplementation, but not in the placebo group.[6]
What does this mean for your dog?
Salmon and cod skin are a natural source of fish oils and also an easily digestible chew with a single protein source. Let's be realistic: the studies used concentrated doses via food or supplements. A treat contributes, but it isn't therapy. If your dog has joint or skin problems, discuss a targeted omega-3 dose with your vet.
3. Single protein and food allergy Evidence: strong
A systematic review of the scientific literature concludes that beef, dairy, chicken and wheat are the most likely causes of food allergy with skin symptoms in dogs.[7]
Food allergy is far from rare: among itchy dogs the proportion is between 9 and 40%, and among dogs with atopic dermatitis between 9 and 50%.[8] The most reliable way to diagnose it is an elimination diet with a single (ideally novel) protein source, followed by a provocation test.
What does this mean for your dog?
During an elimination diet your dog mustn't have anything that could disrupt the trial, so no mixed treats either. Single-protein products with one clear protein source mean you can still reward your dog. Choose a protein source your dog hasn't eaten before, such as duck, venison, horse, rabbit or wild boar, and talk to your vet.
4. Training and rewards Evidence: strong
Dogs trained with rewards show less stress behaviour than dogs trained with punishment and corrections. In a study of companion dogs, dogs from aversive training schools showed more stress signals during training, a greater rise in the stress hormone cortisol and a more ‘pessimistic’ outlook in a cognitive test.[10]
Which reward works best? Researchers had dogs run down a 20-metre runway to a reward. One or five pieces of kibble made no difference to speed, but the dogs ran noticeably faster for a tastier reward.[9]
What does this mean for your dog?
Use small, really tasty pieces: they motivate better than large portions and keep calorie intake low. Our training treats are dried meat or organ meat with nothing added, easy to break into small pieces and smelly enough for distracting environments.
5. How many treats per day? Guideline
The World Small Animal Veterinary Association (WSAVA) advises that treats should make up no more than 10% of your dog's daily calorie intake, so that the main meal continues to provide nutritional balance.[11] If you give lots of rewards on a given day, for example during training, reduce the main meal slightly.
Tip: break training treats into small pieces, and give large chews such as head skin or a bully stick a few times a week rather than every day.
6. Hygiene and food safety Evidence: strong
Dried animal treats are raw materials that need to be processed properly. In Canada in 1999, an outbreak of Salmonella in people was linked to pig ears sold as dog treats.[12] Since then, strict rules have applied in the EU to animal by-products used in pet food.[13]
What we do and what you can do
- Our treats come from producers who work in line with the EU regulations on animal by-products and animal feed.[13][14]
- Every batch has a batch number and best-before date, so its origin can be traced.
- Wash your hands after giving treats, store them dry and sealed, and always supervise your dog with chews.
7. Overview by product
| Product group | Relevant research | References |
|---|---|---|
| Skins, bully sticks, beef bone, yak chews | Chewing reduces plaque, tartar and gingivitis | 1, 2, 3, 4 |
| Salmon skin, cod skin | Omega-3 (EPA/DHA) for joints and skin | 5, 6 |
| Single-protein wet food, duck, venison, horse, rabbit, wild boar | Elimination diet for food allergy | 7, 8 |
| Training treats and puppy training treats | Reward-based training, quality over quantity | 9, 10 |
| All treats | No more than 10% of daily calories | 11 |
| Pig ears and other dried parts | Hygiene and EU regulations | 12, 13, 14 |
8. Frequently asked questions
Do chews make tooth brushing unnecessary?
No. Research shows that chews reduce plaque and tartar,[3][4] but tooth brushing remains the most effective method. Think of chews as a complement.
Which treat is suitable for a dog with a food allergy?
Choose a single-protein treat with a protein source your dog hasn't eaten before, such as duck, venison, horse, rabbit or wild boar. Beef, dairy, chicken and wheat are the most commonly reported allergens.[7] Always consult your vet about an elimination diet.
How many treats can my dog have per day?
No more than 10% of daily calorie intake, according to the WSAVA.[11] If you give lots of rewards, reduce the main meal.
Does fish skin help with itching or stiff joints?
Fish skin contains omega-3 fatty acids, which had beneficial effects on skin and joints in studies using concentrated doses.[5][6] A treat provides a smaller amount and is not a treatment.
What is the best reward for training?
A small, really tasty piece. Dogs work harder for a better reward, not for a bigger portion.[9]
Are pig ears safe?
Yes, provided they are processed properly in line with the EU rules on animal by-products.[13] Wash your hands after giving them and store them dry.
9. References
- Wallis C, Holcombe LJ. A review of the frequency and impact of periodontal disease in dogs. Journal of Small Animal Practice. 2020;61(9):529-540. doi:10.1111/jsap.13218
- Harvey CE, Shofer FS, Laster L. Correlation of diet, other chewing activities and periodontal disease in North American client-owned dogs. Journal of Veterinary Dentistry. 1996;13(3):101-105. doi:10.1177/089875649601300304
- Hennet P. Effectiveness of an enzymatic rawhide dental chew to reduce plaque in beagle dogs. Journal of Veterinary Dentistry. 2001;18(2):61-64. doi:10.1177/089875640101800201
- Stookey GK. Soft rawhide reduces calculus formation in dogs. Journal of Veterinary Dentistry. 2009;26(2):82-85. doi:10.1177/089875640902600202
- Roush JK, Dodd CE, Fritsch DA, et al. Multicenter veterinary practice assessment of the effects of omega-3 fatty acids on osteoarthritis in dogs. Journal of the American Veterinary Medical Association. 2010;236(1):59-66. doi:10.2460/javma.236.1.59
- Mueller RS, Fieseler KV, Fettman MJ, et al. Effect of omega-3 fatty acids on canine atopic dermatitis. Journal of Small Animal Practice. 2004;45(6):293-297. doi:10.1111/j.1748-5827.2004.tb00238.x
- Mueller RS, Olivry T, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Veterinary Research. 2016;12:9. doi:10.1186/s12917-016-0633-8
- Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (3): prevalence of cutaneous adverse food reactions in dogs and cats. BMC Veterinary Research. 2017;13:51. doi:10.1186/s12917-017-0973-z
- Riemer S, Ellis SLH, Thompson H, Burman OHP. Reinforcer effectiveness in dogs: the influence of quantity and quality. Applied Animal Behaviour Science. 2018;206:87-93. doi:10.1016/j.applanim.2018.05.016
- Vieira de Castro AC, Fuchs D, Morello GM, et al. Does training method matter? Evidence for the negative impact of aversive-based methods on companion dog welfare. PLOS ONE. 2020;15(12):e0225023. doi:10.1371/journal.pone.0225023
- WSAVA Global Nutrition Committee. Feeding treats to your dog. World Small Animal Veterinary Association, 2025. wsava.org (pdf)
- Clark C, Cunningham J, Ahmed R, et al. Characterization of Salmonella associated with pig ear dog treats in Canada. Journal of Clinical Microbiology. 2001;39(11):3962-3968. doi:10.1128/JCM.39.11.3962-3968.2001
- Regulation (EC) No 1069/2009 laying down health rules as regards animal by-products and derived products. EUR-Lex
- Regulation (EC) No 767/2009 on the placing on the market and use of feed. EUR-Lex