We last blogged about this issue back in 2018, when the headlines first appeared that certain kinds of dry food formulas could be causing heart problems in dogs. Not much has changed since then in terms of research and answers, but the pet food industry has made changes to eliminate the concern. Read on for an updated summary of the issue.

What is DCM?

Dilated cardiomyopathy (DCM) is a condition in which the heart’s ability to pump blood is decreased because the heart’s main pumping chamber, the left ventricle, is enlarged and weakened.

What causes DCM?

This is still being worked out and there are debates within the vet world about the factors involved:

• Often the cause is unknown, but overall it mainly affects large breeds.
• Genetic predisposition is the most common factor. This can be a predisposition to DCM in general or a predisposition to taurine-deficient DCM in particular.
• Infection or a toxin can damage the heart muscle but is uncommon.
• Nutritional deficiencies may be implicated when the dog cannot maintain normal amino acid levels, but most of these cases seem to have a genetic component.

What’s it got to do with grain-free dry food?

In 2018 there were reports of more cases of DCM where the development of the disease was unexpected, and vets were noticing a correlation with the dogs being fed grain-free dry food so they speculated that these diets were the cause. Subsequent analysis has found no evidence that grain-free dry food diets cause DCM.

Much of the public information on this topic is taking this speculation and jumping to a flawed conclusion – that grain-free dry food causes DCM. Here are the flaws:

• Some effected dogs were fed grain-based dry food
• Not all dogs had deficient blood levels of taurine (though this was why food was suspected)
• Most dogs eating grain-free diets remain unaffected
• These diets have been around for 20 years. They became popular for a reason; pets with skin problems and other allergy symptoms improved when they got off grain-based foods.

 What could be the problem with the food?

• All concerns are exclusively about dry food diets.
• There’s not enough meat in the food; meat is the natural source of the most easily absorbed amino acids dogs need.
• Protein from plants (whether grains, legumes, or potatoes) is hard for dogs to digest. Dry food diets have come to depend on these starch ingredients to enhance the amount of protein listed on the packaging.
• Excessively heat processed foods (like meat meals in kibble) are less digestible, and the amino acids are damaged by the production process.
• One possibility is that too much fiber from large amounts of legumes, potatoes, or grains could be carrying too much of the taurine and other nutrients out of the body (this is what they found with the cats in the 80s, as well as dog study that implicated beet pulp in dry food).
• The dogs could be eating less of the food than recommended (yep, that was something UC Davis found with many of the dogs they studied), this would lead to overall deficiencies because they weren’t consuming the nutritional values the food was designed to provide. If you are feeding less than is recommended to keep their weight in check you might want to take a look at whether your dog is getting enough exercise or consider having them tested for hypothyroidism.
• Foods that are low in meat and high in fiber could be the wrong diet for dogs that are susceptible to taurine deficiency due to their breed, size, and metabolism. (this was discovered by studying Newfoundland dogs many years ago, before grain-free diets existed).

How are dry food companies responding?

They are adding taurine to their current foods and adding grain-inclusive formulas to their lineup to retain the market of concerned consumers who have been told to switch.

What’s Taurine got to do with it?

Taurine is the main amino acid for heart health. It’s also necessary for normal bile acid function. Dogs create their own taurine from other amino acids, methionine and cysteine (whereas cats must consume it directly, which was discovered in the 1980s). When caught early, supplementing with taurine can reverse the disease, but only for those dogs that specifically had a taurine deficiency. Very large dogs with slower metabolisms may need more taurine in their body (and most dog feeding trials are done with beagles).

Do you need to add Taurine to your dog’s diet?

If your pet has not been diagnosed with low taurine levels or other heart abnormalities, you don’t need to add it. Dry foods now have added additional taurine, and while supplementing won’t hurt, the supplemental form is expensive; it’s better to simply feed a diet with more meat. Fresh meat, either raw or lightly cooked, retains the most nutrition and retains the most taurine when all juices are included in the meal (so don’t drain off the blood or cooking water).

THE MAIN TAKEAWAYS

• Grains aren’t the solution. More meat in the diet is the solution.
• If you’re concerned about DCM we strongly recommend adding fresh meat to your pet’s dry food diet because it is the richest source of taurine and all the other amino acids your pet needs, all naturally occurring and easily absorbed.
• Raw food diets that are high in meat provide all the naturally occurring amino acids needed. Even if you don’t feed a 100% raw diet to your pet you will improve their health by including more fresh meat.
• The meats with the most taurine are heart, organs, dark meat poultry, and mussels.