Are mealworm-based diets an option for pets with food sensitivities?

These can start at any age, and even if the cat or dog has been eating the same food for months or years¹. Like people, these allergic reactions can range from itchy and irritating dermatological or gastro-intestinal problems to severe and dangerous symptoms.    

Food allergies are involved in about 5% of all skin diseases and up to 25% of all allergic skin conditions in dogs². They happen when the immune system, that normally fights off harmful infections, wrongfully targets certain types of food. It tends to recognize and react mostly to proteins, causing allergic reactions. And indeed, the most common dietary allergens for dogs are proteins from beef, dairy, chicken, wheat and lamb; and for cats are proteins beef, fish and chicken³. 

It is crucial to find alternative dietary solutions to cater to and feed these animals. Mealworm-based ingredients could be one answer, as they are an alternative premium protein source with reduced allergenicity both in the short and the long term. 

Mealworms as a new protein source: the short-term answer

Dogs and cats can develop allergies and other adverse reactions to foods, triggered more specifically towards proteins in their diet. Shifting the protein source to one that is unfamiliar to the immune system can be a sturdy short-term solution to the problem. Because of their novelty, insect-based products can claim hypoallergenic properties in this first-time frame.

Mealworms are particularly interesting in that regards. Studies have shown that feeding mealworm-based protein diets can reduce dermatological symptoms and improve coat quality⁴. Brands are already including mealworms in recipes for dogs and cats allergic or with food adverse reactions to conventional animal proteins.

“Mealworm-based ingredients are novel to the pet food market. Dogs and cats have not consumed them before, so the risk of the immune system reacting to these proteins is minimized” adds Jeroen Schweitz, Pet Food Sales Director at Sprÿng.

This was true for a long time for lamb proteins. At first, vets prescribed them to pets with allergies because they were an uncommon food source and provoked fewer adverse reactions than beef or chicken. However, as lamb proteins grew more common, a small population of dogs and cats started developing allergic reactions⁵. 

For now, insects remain hypoallergenic because they are that novel source of protein. “Once mealworms become more widespread and abundant on the petfood market, this might change,” adds Lorena Sanchez, Scientific Project Manager at Sprÿng. “Like for any other protein, we expect some pets might develop reactions in the long run, but it could take years or decades before those manifests. In anticipation of such a phenomenon, at Sprÿng, we have developed a long-term hypoallergenic product, hydrolysate.”  

Cutting down proteins to reduce allergic reactions: the long-term hydrolysate solution

To reduce allergic reactions to proteins, it is possible to cut, or hydrolyse, them into smaller fragments. These short peptides exhibit reduced allergenicity compared to the longer protein chains⁶. The immune system is less likely to bind to them and trigger a response. 

Numerous pet food manufacturers already use this technique to create allergenic recipes. Sprÿng applied it to mealworm proteins to successfully create dry and liquid hydrolysates, Hydrolysate70 and Hydrolysate15. An internal study showed that 87,5% of the sera of people allergic to mealworms, but also shrimp and house dust mites, wasn’t recognized by the immune system corroborating a reduced allergenicity to Hydrolysate70 compared to the whole fresh larvae. An equivalent response in pets is expected since their immune system reacts to the same proteins as humans⁷.

“It’s not black or white. Some pets and humans will still react to those small peptides but the chances of it happening are drastically reduced,” details Sanchez. 

The mealworm proteins are not cleaved chemically but using enzymes. This denatures less the products retaining their nutritional properties.  Enzymatic scissors are very precise and ensure a high control over the size of the resulting peptides. Sprÿng ingredients contain peptides smaller than 12 kDa, of which 88% are less than 1.4 kDa. This is really small, which means that as well as being hypoallergenic, these hydrolysates are highly digestible.  Hydrolysate70 and Hydrolysate15 both have a peptic digestibility close to 90% and do not contain the chitin fraction, which is considered as an insoluble fibre. 

Does chitin cause allergenic reactions?

Besides proteins, another molecule found in insects seems to cause some concerns regarding allergenicity: chitin, a polymer of sugars that resembles cellulose. It is structurally important to insects and crustaceans because, in association with different proteins, it forms their shell or exoskeleton. 

“Chitin is often incriminated in allergic reactions because it is found in shrimp and shrimp can cause strong allergies. But this is a shortcut. In effect, the answer is much more nuanced and complicated,” cautions Sanchez. “It is more likely that the proteins associated to chitin are allergenic, rather than chitin itself.” 

Under some circumstances, chitin has been shown to activate innate and adaptive immune cells in vitro and in vivo and potentially promote hypersensitivity to allergens⁸. Nevertheless, the results need to be put into perspective. It seems that the route of administration (ingestion or inhalation), but also the size and the form (soluble or not) of the particles and molecules in contact could play a role in the ability of chitin to induce an allergic response. Some studies have even shown that chitin may have a protective anti-allergic effect⁹.

“It is not an easy topic and the question of the allergenic role of chitin is still very much an open one. More studies will be required to address its role in allergic reactions,” insists Sanchez. “Chitin remains quite misunderstood. It is important to remember that it is an insoluble fibre. And as for all fibres, it is considered good for the intestinal transit and faeces consistency, among other things, but can also be difficult to digest.” 

Allergies, whether in pets or humans, remain a complex topic. They are intrinsically built on intricate immunological processes that arise from an unknown combination of environmental and genetic factors. For now, pet food manufacturers have found in mealworms a short- and long-term solution to food sensitivities including allergy problems in dogs and cats. They fit consumer needs for hypoallergenic products while also providing a rich and premium nutritional profile with a low environmental impact. A win-win-win alternative diet.

1) https://www.dvm360.com/view/identifying-food-allergies-veterinary-elimination-diet-trial
2) Premrov Bajuk, B.; Zrimšek, P.; Kotnik, T.; Leonardi, A.; Križaj, I.; Jakovac Strajn, B. Insect Protein-Based Diet as Potential Risk of Allergy in Dogs. Animals 2021, 11 (7), 1942.
3) https://bmcvetres.biomedcentral.com/articles/10.1186/s12917-016-0633-8
4) Lee, K.-I.; Chae, Y.; Yun, T.; Koo, Y.; Lee, D.; Kim, H.; So, K.-M.; Cho, W. J.; Kim, H.-J.; Yang, M.-P.; Kang, B.-T. Clinical Application of Insect-Based Diet in Canine Allergic Dermatitis. Korean J Vet Res 2021, 61 (4), e36. 
5) https://www.dvm360.com/view/identifying-food-allergies-veterinary-elimination-diet-trial
6) Verlinden A, Hesta M, Millet S, Janssens GPJ. Food allergy in dogs and cats: a review. Crit Rev Food Sci Nutr. 2006;46:259–273. doi: 10.1080/10408390591001117.
7) Premrov Bajuk, B.; Zrimšek, P.; Kotnik, T.; Leonardi, A.; Križaj, I.; Jakovac Strajn, B. Insect Protein-Based Diet as Potential Risk of Allergy in Dogs. Animals 2021, 11 (7), 1942
8) Safety of dried yellow mealworm (Tenebrio molitor larva) as a novel food pursuant to Regulation (EU) 2015/2283 – https://doi.org/10.2903/j.efsa.2021.6343
9)Burton, O. T.; Zaccone, P. The Potential Role of Chitin in Allergic Reactions. Trends in Immunology 2007, 28 (10), 419–422. https://doi.org/10.1016/j.it.2007.08.005.