DCM #3 – The Problem with Grains in Pet Food

I wrote this as a three part blog series.

In part one, I share my personal experiences that led me to recommended Grain Free diets for my patients in the first place.

In part two, I will look at the differences between the companies that make the Grain Free brands vs the traditional Grain Inclusive brands.

In part three, we look at why grains could be a problem for dogs.

In the next series, I tackle the discussion of the cardiomyopathy more specifically.

I have also put together a PDF available for download that includes my recommendations on dog foods, supplements and what to feed your pets in light of these recent DCM controversies. (Coming soon!)

So what’s up with grains?

I believe that the problem with grains has little to do with them being “grains.” And I actually don’t believe that grains are even bad for dogs!

There are some troublesome ingredients going into grain-inclusive dog food, and three of them happen to be grains.

The majority of dog and cat food companies use these ingredients as carbohydrate sources in pet food:

  1. Corn
  2. Soy
  3. Wheat
  4. Beet pulp*
  5. Canola
  6. Potato
  7. Rice

I refer to these as “grain inclusive ingredients,” because three of them are not actually grains: canola, soy and sugar beet pulp.

*“Beet pulp” is a common fiber source in dog food. I always assumed this came from the big red beets you can buy at the supermarket that are highly nutritious. However, the “beet pulp” included in dog food actually comes from GMO sugar beets. After the sugar is extracted for processed food for people, the pulp goes into dog food.

Why are companies choosing these particular ingredients?

In our nutrition class in veterinary school, we learned about the unique characteristics of the “grain-inclusive ingredients.”

We discussed the digestibility and fermentability of each individual carbohydrate source as well as their vitamin content and various nutritional qualities.

Here is an example of a chart from one of our textbooks that shows how fermentable these fiber sources were relative to each other:

Hand, Thatcher, Remillard, Roudebush, Small Animal Clinical Nutrition, 4th Edition, p.43

We learned about how the fermentability and fiber levels affected an animal’s bowel movements.

Back when I was in veterinary school, I never stopped to ask: why were we choosing these particular ingredients in the first place?

Instead of choosing, say: pumpkin, oatmeal or flax seed? Which were also good sources of fiber.

I just assumed, based on what we were taught, that these ingredients were chosen because they were scientifically proven to be good for animals.

In the previous blog post, I quickly went over the historic trajectory of dog food. A lot of dog food ingredients were historically chosen because they were left over from human food manufacturing.

Science Diet, Purina, Royal Canin and Iams/Eukaneuba do a lot of nutritional research about dogs and cats. But they are not choosing ingredients like corn, soy, wheat, rice and (sugar) beet pulp for its nutritional value, for their fermentable properties, or for their unique nutritional value for dogs and cats.

They are choosing these ingredients because they are left over (in large quantities) from people food.

And in particular, processed people food.

Surplus corn at a plant in Colorado

For various complicated reasons, we have a MASSIVE production of corn, soy, wheat, sugar beets, canola and their various derivatives in the United States.

Michael Pollen talks about the case of corn specifically in his book, Omnivore’s Dilemma. Here’s a good quote from the book that summarizes this situation (p61-62):

“The immense pyramid of corn I stood before in Farnhamville is of course only a tiny part of an infinitely more immense mountain of corn dispersed over thousands of grain elevators across the American Corn Belt every autumn. That mountain is the product of the astounding efficiency of American corn farmers, who – with their technology, machinery, chemicals, hybrid genetics, and sheet skill – can coax five tons of corn from an acre of Iowa soil. All this you can see with your own eyes, hanging around during harvest. What is much harder to see is that all this corn is also the product of government policies, which have done more than anything to raise that mountain and shrink the price of each bushel in it…This is a system designed to keep production high and prices low.

Moving that mountain of cheap corn – finding the people and animals to consume it, the cars to burn it, the new products to absorb it, and the nations to import it – has become the principal task of the industrial food system, since the supply of corn vastly exceeds the demand.”

The reason we have such an oversupply of these ingredients is because most of them are GM (genetically modified) crops. The success of genetic modification along with specific farming practices and government funding have led to very large crop sizes.

And as Michael Pollen writes in the quote above: we don’t know what to do with all of it.

And so, a lot of it ends up in dog food.

But are these foods healthy for our animals be consuming every single day as part of their diets? What are the risks? Let’s take a look.

Genetically Modified Crops

Genetically modified foods, or GMOs (Genetically Modified Organisms), are one of those topics that make most people’s hair stand up.

One side believes it’s a scientific miracle that has been proven safe in hundreds of studies while the other side believes that Monsanto (the company that is behind many of these foods) is trying to poison us all.

And then there are the people that don’t know that much about it and prefer not to get too involved in conspiracy theories or heated debates on a topic they don’t think matter too much.

At the time when I started looking into this, I would have probably described myself using the last sentence.

But for the sake of our pets who are eating these ingredients every day as part of a scientifically-based, veterinary-recommended, healthy diet, it is worth looking at this topic.

What most people don’t know is that only a handful of foods right now are ACTUALLY genetically modified and approved for mass consumption.

Things we eat that are GMO:

  1. Corn (90% in 2013)
  2. Canola (93% in 2013)
  3. Soy (93% in 2013)
  4. Sugar beets (98% in 2013)
  5. Potato (unknown – went to market in 2015 so relatively new)
  6. Squash (11%)
  7. Papayas (60%)

Things we don’t eat that are GMO:

  1. Alfalfa
  2. Cotton
  3. Carnations (flowers)

There are NO OTHER FOODS on the market today that are GMO. These are it.

Not salmon, not peaches, not oatmeal, or any other food that you can think of.

Now, for comparison, let’s go back to our list of most common carbohydrate ingredients in “grain-inclusive” pet food:

  1. Corn
  2. Soy
  3. Wheat
  4. (Sugar) beet pulp
  5. Canola
  6. Potato
  7. Rice

I have emphasized in orange the ingredients that are found on both the GMO and grain-inclusive dog food ingredient lists.

So here’s the thing.

If your pet is eating a grain-inclusive diet, then they are consuming a diet that is largely genetically-modified. This doesn’t even take into account that the animal protein (cow or chickens) were likely also raised on GMO corn/soy diets.

And if they are eating a lot of genetically-modified food, then they are also likely consuming a lot of:


Image by zefe wu from Pixabay 
Spraying crops with Roundup or herbicide

Among the common grain-inclusive ingredients in pet food, four of them are specifically genetically engineered not to die when sprayed with the herbicide, Roundup.

Those four crops are:

  1. Corn
  2. Canola
  3. Soybean
  4. Sugar beets

The fact that they don’t die when sprayed with the herbicide means, ipsum factum, that these crops are sprayed with Roundup. And according to some scary first hand accounts from farmers, possibly sprayed with a lot of it.

So if your dog or cat is eating a diet that is Grain Inclusive, then your pet is likely consuming Roundup.*

Many of our pets eat the same food every day.

So their exposure to a contaminant like this is much greater than a person who might eat a variety of foods throughout the week or month.

In addition to being linked to cancer, Roundup has been shown in studies to be an endocrine disruptor, is linked to birth defects, liver disease, and can harm beneficial gut bacteria. 

Other studies have shown that even at low levels, Roundup in water can induce morphological changes in frogs.

In another study, Roundup destroyed the good bacteria Lactobacillus in the intestines of chickens, while Salmonella was highly resistant to it.

So regardless of what pet food companies may claim are the beneficial qualities of corn, more than 93% of corn in the US is genetically modified, and therefor sprayed with Roundup.

Besides being genetically modified, there are many other ways that we have altered corn today. The modern day industrial corn plant is almost a completely different species from the corn our ancestors ate. And who knows how this may be affecting our bodies?

*Because of cross contamination, Grain Free diets can also contain RoundUp. Also, I have seen more than one “Grain Free” diet still contain canola and beet pulp as an ingredient because these are not technically grains. So while there is no guarantee that a Grain Free diet doesn’t contain Roundup, you can be pretty sure that a Grain Inclusive diet that uses corn, soy or beet pulp as an ingredient, does.

The Case of the Fat Cat

This is not an image of the cat I treated, but another example of an overweight pet

I have been a veterinarian for over a decade now.

In this time period, I have witnessed both miraculous stories of healing that brought me so much joy, but also very sad and challenging cases that still haunt me to this day.

This story I am about to tell was unfortunately one of the latter.

A few years ago, an owner came to me in tears.

She had adopted her cat eleven years prior when he was just a little kitten.

At the time, she did some research and decided to feed him a raw meat diet. For the past 10 years of his life, he ate raw food, and was a healthy cat. The owner showed me videos of him just the year prior: a lithe, muscular, happy cat darting around the house in playful fits of joy.

This past year, the owner had to leave town for one month. She researched and found a well- reviewed cat boarding facility that agreed to take him. However, they required an updated health check. 

So the owner made an appointment with a local veterinarian.

The well-meaning veterinarian was horrified by the raw food diet.

She warned the owner of the various concerns with raw food: from food-borne illness to an imbalanced food source. This veterinarian did what most veterinarians would do, and what veterinarians are taught to do in veterinary school. And she had good intentions at heart: she wanted what was in the best interest of the cat. She highly recommended a veterinary formulated diet.

The owner admitted that she got a little scared by what the veterinarian told her. This, combined with the added convenience of dry food for the boarding facility, led her to go to the pet store and pick up a bag of Science Diet cat food. 

Her cat seemed to eat it with no problems, so she left him with the new food at the boarding facility, and went on her trip.

One month later, when the owner went to pick up her cat, she was shocked at what she saw. She didn’t recognize her cat. 

Upon leaving, he had barely weighed in at 9 pounds of weight. Now, he was closer to 20. He had more than doubled his weight in one month.

She began to inquire about his weight. The caretakers at the facility said they were equally concerned. They assured the owner that they encouraged him move around and that they fed him only limited amounts of the food. When they noticed the weight gain, they decreased the food as much as they could over the past few weeks. But none of their efforts seemed to help.

The owner took him home, and immediately tried to switch him back to his raw diet.

But he wouldn’t touch it.

It took her over five months to be able to switch him back to the raw food. And during this time, even with very limited portions of the dry food, the cat gained an additional 10 pounds of weight.

By the time she came to see me, we were looking at a 30-pound cat. Weight that was put on in less than 6 months even with limited portion sizes. And even back on the raw food now, he wasn’t able to lose the weight.

What I saw before me, in many ways resembled an obese human.

The cat could barely walk. His belly dragged on the floor and he tripped over it when he would attempt to move. And the bigger problem was that he couldn’t defecate. All of the extra fat, and loss of muscle mass made him unable to posture or be able to push out the stool.

We put the cat through weeks of enemas, laxatives, stool softeners, acupuncture, herbs, sedation and pulling out poop.

I lost track of this owner and she never came back for followup. However, given the fact that we tried every intervention imaginable: both pharmaceutical and holistic and nothing seemed to be working, I worry that the fate of this cat was not good.

This case haunts me to this day. What happened? What caused this?

Not every animal that eats Science diet or foods with grains in them becomes obese. Did the stress of being boarded for one month, combined with the high corn diet somehow create this?

And even though not every animal or person that eats these foods becomes obese, could there be a connection?

Obesity is on the rise in both the human and the pet populations. Approximately 54% of the dog population in the United States in 2018 was considered overweight or obese.

In people, obesity is closely linked with increased incidences of heart disease, diabetes and cancer.*

(It is worth pointing out here, that heart disease in people is different than heart disease in cats and dogs. People are most prone to heart attacks that come from blocked arteries, or arteriosclerosis. Arteriosclerosis appears to be related to saturated fats and high fat meals in people.

Dogs, likely because they are more carnivorous than people, have hearts that are more accustomed to high fat diets, and do not develop blocked arteries.

Dogs, however can develop taurine-deficient related heart disease. This is not recognized as a major problem for humans (whose diets don’t require meat protein), but can be a problem for carnivores, such as dogs and cats.

In that sense, if there is a connection between high fat diets and heart disease in people, this appears to be a less obvious connection in dogs and cats.)

Corn and Obesity

Let’s take a quick veer away from the topic of animals and look at the obesity epidemic in people.

Sadly, people serve as a model for what could be happening our animals and all species that eat modern day grains. In some ways, we are all part of this larger food experiment together.

Being obese appears to be very much related to poverty and socioeconomic status. The less money you have, the more likely you are to be obese.

The less money you have, the more likely you are to eat large amounts of (cheap and affordable) processed and fast food.

Some blame the high saturated fat and sugar content of processed food/fast food for the obesity crisis.

However, the question to look at is: If the people who eat large amounts of fast food and processed food were to substitute all their caloric and fat intake for an equivalent caloric and fat intake with foods such as avocado, nuts, salmon and even grass fed milk/ice cream and other natural high fat foods, would they still be obese? Or would they lose weight?

In other words, is it the fat and sugar content ITSELF, or is the problem more about where that fat and sugar is coming from?

Most of processed food and fast food is actually just corn.

I return once more to Michael Pollen’s book, Omnivore’s Dilemma. As part of his research, Pollen hired a biologist at Berkeley to analyze a McDonald’s meal using mass spectrometry in order to calculate how much of the food’s carbon atoms came from a corn plant (p.116-7).

Here were the results:

Soda: 100% corn

Milk Shake: 78% corn

Salad Dressing: 65% corn

Chicken nuggets: 56 % corn

Cheese burger: 52% corn

French Fries: 23% corn

So yes, the people who eat the most amounts of fast food are consuming large amounts of calories from fat and sugar, but they are also indirectly consuming a lot of modern-day corn.

Now let’s look at some other statistics.

The amount of people in the United States who are overweight has remained fairly consistent since measurements were started in 1960 (about 32% of the population is overweight now and were also overweight in 1960).

Obesity, and extreme obesity to a lesser degree, took a dramatic upswing which started in between the years of 1976 – 1980.

Chart was taken from this study

So to repeat, the first time we noticed the rates of obesity rising in the United States was between the years 1976-1980.

In 1976 soda companies all substituted sugar in soft drinks with High Fructose Corn syrup.*

A causal link between consuming high fructose corn syrup and the obesity crisis has been speculated by some scientists.

It is unclear if it is corn itself, genetic modifications, or RoundUp that is causing these changes in our bodies. To be clear, the corn used in high fructose corn syrup in 1976 was not genetically modified, nor was it sprayed with RoundUp.

However, it is unlikely that these changes (genetic modification and Roundup) have helped the in the situation of highly processed corn products.

When it comes to weight gain and GMOs, studies in rats, salmon and other species have shown that animals that were fed GMO food ate more and gained more weight than their non-GMO counterparts.

In this article I have focused mostly on corn.

However, similar health problems can be found to be associated with eating wheat, soy, canola and sugar beets.

In one study, hamsters were fed GMO soy for three generations. By the third generation, the hamsters eating GMO soy lost the ability to have babies, suffered slower growth, and even had hair growing out of their mouths.

Wheat, which is not genetically modified, but which has gone substantial genetic alterations through selective breeding practices over the years, can also cause problems. One theorized mechanism for wheat sensitivity (besides gluten) are a group of proteins called amylase-tripson inhibitors, which have been shown to create an immune reaction in the gut that can spread to other organs.

Canola, sugar beets and soy are also RoundUp ready, meaning, as we discussed before, they are sprayed with Roundup possibly many times prior to harvest.

And so you can have a back and forth argument about whether or not grains are good or bad for dogs, but the real question is: Is corn, soy and wheat, the way it is produced and farmed today, a healthy food ingredient for anyone? Human or animal?

Grains and Inflammation

The biggest problem with modern day grains are their inflammatory effects on the body.

One large scale study in people showed that the people who ate diets high in government subsidized grains (corn, soy, wheat) had a 37% increased chance of having inflammation in their bodies and a 34% increased chance of becoming obese.

Many diseases in the body begin with inflammation. Diseases such as skin disease, digestive disease, arthritis and cancer. These are very common illnesses that we see in our pet population. And while not all of it can be definitively linked with grains in the diet (dogs that eat Grain Free diets also develop these problems), we know from our human population that eating modern day grains only exacerbates these problems.

And, as I’ve said now a few times in these posts, this is exactly what I was seeing in my animal patients.

The dogs that ate Grain Inclusive diets have diseases that I see less often in my Grain Free fed patients. One of the most dramatic examples of this was diabetes, but I have since seen connections to other diseases as well.

These are all my anecdotal observations and, yes, studies are needed. But if we go by what we see in people, the effects of eating these processed grains are likely not good.

All of this being said, we now have a new problem in our midst: the increased incidence of dogs that eat Grain Free diets that are developing a type of heart disease called dilated cardiomyopathy, or DCM.

Let’s take a closer look at that in my next posts, here. (Coming soon!)

Disclaimer: These blog posts are based entirely on my personal opinions, experience and research. I am not involved with the FDA report in any way or affiliated with any of the brands of dog food discussed in these articles. My intention in writing these posts is to share my opinions how to best feed and care for your animals in light of this developing story.

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However, in order to support my ongoing effort to the public, I use affiliate links, which allow me to receive financial compensation for web traffic through the site. All proceeds go towards maintaining the site and blog. To find out more information about my affiliate links, see my disclosures here.

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