What is yellow, has ears and can be used to make food, coffee, fireworks and fuel? 

Yes, today we are going to talk about corn and the role it plays in dog diet. I know corn often gets bad press and has been dismissed by many pup parents because the grain is often presented as “the worst” ingredient in dog food. But is it really?

Let’s discuss a few curious facts today.

Corn isn’t just a “filler”. Corn is a nutrient-rich grain that adds proteins important for body’s growth and maintenance (the grain is 6.8-12% protein), carbohydrates for energy, fibre for healthy digestion and potentially reduced risk of GI cancers, antioxidants such as carotenoids to protect and strengthen the immune system and, importantly, linoleic acid that is essential for dogs. 

Based on the amino acid content, corn has a biological value of 74, almost the same as beef and chicken (both are 75). When combined with other sources of amino acids, corn can help create food with the gold standard value of 100.

Dogs can digest corn because they evolved and became omnivores that have a genome different to the wolf’s, particularly when it comes to digestion of carbohydrates. When fed a diet containing corn starch, dogs showed 99% digestibility of the starch and 87% of the protein (the highest digestibility compared to diets containing other grains). The diet containing corn flour showed 98% of carb digestibility. 

Corn is not going to cause an allergic reaction in every dog. I have talked about allergies in Perfect cocker spaniel in detail and dedicated a chapter to it in Beyond the Doughnut too. 

If I am to put it all in a (long) sentence – grains are least likely to cause allergies in dogs and corn is considered an “uncommon food source of allergens”, the type of corn used in food production plays a role (in a study dogs with potential allergy to corn were less likely to react to cornstarch than kernels and flour), there is always a small chance of a dog reacting to ANY food ingredient simply because dogs are unique and there are several diet, lifestyle, health and genetic factors that can contribute to the reaction, just because a dog had a reaction to some food where corn is an ingredient, it does not mean the dog reacted to corn, the only way to know for sure is through extensive and labour-intensive veterinary exam, months-long elimination trials under veterinary and nutritional supervision and a review and potentially complete overhaul of the environment the dog in question lives in. 

Corn may lower glycemic response in adult dogs meaning that dogs will not have insulin spikes following a meal.

Corn can be a very useful ingredient in a diet formulated for dogs with diagnosed health condition or dogs undergoing tests or treatment. If you vet prescribes a food made with corn, he is doing it to help your dog, not because he’s got an evil canning plan!

But before you rush and grab a bag of dog food made with corn, remember the following…

The corn used in pet food is often a hybrid type that may be higher in proteins and lower in phytates. This, however, means that corn used in dog food, may undergo genetic modification, which can put many people off for a number of reasons. The subject is controversial, especially when it comes to pet food industry because long-term studies of GM corn and its potential role in cancers are lacking. 

If you are concerned, look for UK and EU produced foods and check the label. By law “animal feed materials and compound feeds which contain GM or GM-derived material must be indicated on the label”. And even though many ingredients, including corn, are exported from the countries that allow genetic modification, the UK/EU rules will highlight this for the consumer.

Corn can be a source of aflatoxins and at the moment the official recommendations and safety limits differ greatly when it comes to grains used for human food and those used in animal feed. There have also been a few recalls due to aflatoxin contamination in pet food, however, not of them were necessarily caused by corn. 

It is worth remembering that pet food manufactures do test ingredients and have measured in place to ensure food safety. There have also been considerations for the use of special supplements such as Hydrated sodium calcium aluminosilicate, which is natural clay that coats the food and prevents potential aflatoxin poisoning even if the food is contaminated. 

However, according to the review by Maxwell Leung et al. published in 2006 “government regulations of mycotoxin contamination are often compromised by the analytical detection limits, regional prevalence, as well as trade relationships amongst different countries instead of fulfilling the scientific approach of risk assessment and safety determination”.

If you are concerned, buy the food produced by PFMA-registered members. Personally I would stick with bigger food manufacturers that have resources and facilities for testing ingredients and products and actually inform their customers of food recalls should the worst happen. 

Choose shops that are more likely to store the food with great care.

Check the label on the bag for best before date and keep the food in a cool, dark place, and use the bag the food came in – just remember to seal it well.

And if you choose to make treats with corn for your dog, shop in supermarkets for organic polenta or organic corn flour known as masa harina. 

References:
https://pubmed.ncbi.nlm.nih.gov/34078195/
https://bmcvetres.biomedcentral.com/articles/10.1186/s12917-018-1538-5
https://www.mdpi.com/2072-6643/5/8/3099/htm
https://academic.oup.com/jas/article-abstract/77/8/2180/4625546
https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1439-0396.2007.00794.x
https://www.food.gov.uk/business-guidance/gm-in-animal-feed
https://www.tandfonline.com/doi/full/10.1080/10408398.2021.1931020
https://pubs.acs.org/doi/10.1021/jf062363%2B
https://www.sciencedirect.com/science/article/abs/pii/S0278691504002121
https://link.springer.com/article/10.1007/s12550-018-00340-w