Just because you’re an omnivore or herbivore (vegan) that doesn’t mean your pet should be on the same diet. Their bodies work differently and those healthy vegetables and fruits may actually be bad for them.

You would die if you only ate meat. Your body can’t produce vitamin C, which is an essential nutrient for you. Without it, you would develop scurvy and succumb to some pretty nasty side effects. The only food sources of vitamin C are plants.

Dogs and cats don’t have that issue. Their livers make vitamin C from glucose, as do the vast majority of animals.

Humans and primates, like monkeys, can’t make L-gulonolactone oxidase (GLO). That’s needed for converting glucose to vitamin C (1).

Although not a primate, guinea pigs are another example of a mammal which can’t make C internally. Other furry critters can, including your pet rabbits, rats, mice, and hamsters.

Internal vitamin C production is just one of many differences between human and dog digestive systems.

A lot of people are starting to feed their dog the same superfoods they eat themselves. Often that’s okay and in fact, they’re often good for your cute Yorkie or Labrador. Other times, what’s healthy for you is bad for your puppy.

Labrador Retriever eating an apple core

What happens if a dog eats an apple? That depends on the form it’s eaten.

For something processed like applesauce, or cooked like filling from a pie slice, giving them a nibble under the kitchen table is harmless. Assuming the animal is non-diabetic, there will be no adverse reaction from these foods. Even if if the dog at a whole apple pie instead of a small slice, vomiting or diarrhea are probably the worst side effects that can occur. When it comes to raw fruit or apple cider vinegar, they can be bad and cause serious adverse reactions.

They are among the worst things you can feed your pet for the following 3 reasons.

1. Choking hazard

Starting with the most straightforward thing. Fruits are a much greater choking hazard for dogs and cats.

The food they eat — meat — is hardly chewed. Unlike plant-based foods, meats don’t have cell walls and therefore, can be digested even without chewing. That’s why dogs don’t have good molars like rabbits do.

Once something fits in their mouth, their instinct is to try swallowing it. This is why so many dogs get into trouble when we give them human food.

We have already had to scold people who give their K9 friends another superfood, burdock root. Like the cores and pits of fruit, a root vegetable can be a major choking hazard.

2. Cyanide poisoning risk

No, this has nothing to do with pesticides. Whether the fruit is conventional or USDA certified organic is irrelevant to this.

Most people are oblivious to the dark and dirty secret of this fruit… amygdalin is in the seeds. When metabolized, this compound creates hydrogen cyanide (HCN) in the body.

amygdalin molecule chemical structureEven though it’s of very low risk to humans, it’s still an issue that needs better awareness. Why? Because it is the apple seeds which contain the amygdalin. It is assumed that people don’t eat the core, and in turn, the medical community never publicizes this issue.

But how can we safely assume toddlers and young children know that?

Even if they do know they shouldn’t eat the core, are parents thoroughly explaining to them the need to spit out the seeds, too?

Probably not.

Plus with today’s nutritional emphasis on whole grains, seeds, and raw foods, even many adults are eating the parts of produce which their parents and grandparents would never fathom.

All of us loving pet owners have that very bad habit of throwing scraps from our plate, at least once in a while. It’s just too hard to resist that wrinkled French bulldog face, with those big eyeballs gazing at you while eating, right?

And often times it’s the unwanted portions of the food we throw to the dogs. Meat bones, crusts, and yes – the cores and rinds of fruit – for them to chew on.

What happens if a dog eats an apple core?

apple with sticker PLU 3283 for conventional HoneycrispIf they eat it, they will swallow the poisonous seeds inside. Even if they’re finicky with fresh plant-based foods, there’s a good chance they will at least gnaw on the core before spitting it out. While doing so, they may inadvertently swallow seeds. Apples are toxic to cats for this same reason.

Whether it’s a Red Delicious, Gala, Granny Smith, Fuji, Pink Lady, or Honey Crisp, all apples have a total of 5 seed pockets (carpels). Within each of those, the number of seeds can vary; from zero to two or more, depending on the plant’s health and maturity of the fruit. If you were to assume an average of 1.5 seeds per carpel, it would mean 7.5 seeds per fruit. Some have even more, as many as a dozen. (2)

So how much cyanide is your puppy ingesting if it were to eat an apple or its core containing just 7.5 seeds?

According to the NIH’s Toxicology Data Network (TOXNET) there is 0.60 mg of hydrogen cyanide per gram of moist apple seed. The average weight per seed is typically 0.75 gram. That means there is around 0.45 mg of cyanide in one seed. (3)

Based on an average of 7.5 seeds per fruit, that’s 3.38 mg of cyanide per apple core.

How much would it take to kill your dog or cat?

Turning to the National Institute for Occupational Safety and Health (NIOSH), they list several sources of lethal concentration data. There’s no data on canines, but for humans, cats and a couple other animals there is. (4)

Species Hydrogen Cyanide LCLo (lethal concentration low) Exposure Time Source
Human 107 ppm 10 min Dudley et al. 1942
Human 179 ppm 60 min WHO 1970
Human 357 ppm 2 min Izmerov et al. 1982
Cat 759 ppm 1 min Gates et al. 1946
Rabbit 759 ppm 1 min Gates et al. 1946
Unspecified Mammals 200 ppm 5 min AAPCO 1966

As you see, it takes very little!

In humans, it’s as little as 107 ppm (parts per million). The numbers for cats and rabbits may seem relatively high, but notice their exposure time was shorter.

Current limits by NIOSH for skin exposure in humans is just 4.7 ppm and their Immediately Dangerous to Life or Health Concentrations (IDLH) is 50 ppm.

Of course, knowing the PPMs isn’t very helpful here. Some of the above is related to skin exposure and gas.

Let’s go with the data from the EPA, which was calculated using case studies of intentional or accidental poisonings (5):

Per the EPA, the “average fatal dose” in humans is 1.52 mg of cyanide per kg (2.2 lbs) of body weight.

Using that same threshold for dogs, we calculated out how many apples the most popular breeds would have to eat to equal the “average fatal dose” for humans.

  1. For each breed, we calculated off of the lowest number in the weight range. Typically that was for the female.
  2. We used an average of 7.5 seeds per fruit.
  3. The 20 most popular dogs are according to the American Kennel Club’s rankings (6).
Breed Weight (lbs) Weight (kg) How Many Apples For Lethal Dosage
1. Labrador Retriever 55 to 80 25 to 36 11
2. German Shepherd 49 to 88 22 to 40 10
3. Golden Retriever 55 to 75 25 to 34 11
4. Bulldog 40 to 50 18 to 23 8
5. Beagle 20 to 25 9 to 11 4
6. French Bulldog 16 to 25 7 to 11 3
7. Yorkshire Terrier (excl. teacup Yorkie) 4 to 7 2 1
8. Poodle (Standard)** 45 to 65 20 to 29 9
9. Rottweiler 110 to 132 35 to 60 16
10. Boxer 55 to 71 25 to 32 11
11. German Shorthaired Pointer 45 to 70 20 to 32 9
12. Siberian Husky 35 to 60 16 to 27 7
13. Dachshund (excl. miniature) 16 to 33 7 to 15 3
14. Great Dane 99 to 200 45 to 90 20
15. Doberman Pinscher 60 to 100 27 to 45 12
16. Australian Shepherd 35 to 70 16 to 32 7
17. Miniature Schnauzer 12 to 20 5 to 9 2
18. Pembroke Welsh Corgis 22 to 31 10 to 14 5
19. Cavalier King Charles Spaniel 9 to 12 4 to 5 2
20. Shih Tzu 9 to 16 4 to 7 2

How many seeds it takes to produce a lethal dosage in a small breed or puppy is only a few. One apple contains enough cyanide to kill a Yorkie. For little kittens, just two seeds may be all it takes.

But wait, that’s only theoretical!

That lethal dosage from the EPA is based off of the free form of hydrogen cyanide. In the apple seeds, it is chemically attached to sugars which it must be separated from.

To cause the separation, the seeds need to be thoroughly crushed. To be exposed to 100% of the toxic poison, it would require pulverizing the seeds to a fine powder.

The good news is their canines, premolars, and molars are all designed for chewing meat. What happens if a dog eats apple seeds is probably nothing, because their teeth are not even crushing them open.

Animal cells don’t have walls, plant cells do have walls. For dog, cats, and even humans, our stomach acid is largely ineffective at breaking down these cell walls.

Not to get too graphic, but that’s why if you don’t chew your corn, it’s going to come out the other side intact.

Since a dog is not chewing the seeds, it’s unlikely they are being exposed to significant amounts of the poison.

Notice though we said significant. A little poison, or even the potential for it, is not healthy for your pet! Even if it doesn’t kill them, the adverse reactions can be serious and cause permanent damage (7).

sick Boxer with droopy eyesWhat happens if a dog eats an apple can include choking and if exposed to the amygdalin in the seeds, the following side effects:

  • Headache
  • Dizziness
  • Fever
  • Nausea and vomiting
  • Skin turning blue (fur may obscure this)
  • Eye lids drooping
  • Low blood pressure
  • Difficulty walking
  • Mental confusion
  • Liver damage
  • Coma
  • Death

Our advice? Under no circumstances should your dog or cat be allowed to eat whole apples or their cores. Never!

Also be aware of this danger if you have the trees growing in your backyard. Likewise for cherry, peaches, and pears, as their seeds and pits also contain the amygdalin, which is what degrades into cyanide. Obviously this issue is harder to address with cats since they may live outdoors, but the good news is they’re not inclined to eat fruit on their own.

3. Can I give my dog apple cider vinegar?

Many people consider a bottle of Bragg’s to be liquid gold for their health. That doesn’t mean the same is applicable to your pet!

Diluting a small amount in their bath water for fleas, dermatitis, and itchy paws are not proven remedies, but at least they’re not dangerous.

Nor do you have to worry about cyanide being in the vinegar.

tooth damage from using apple cider vinegarWhat you do have to worry about is that ACV is bad for dogs’ teeth. In humans, it has been linked to the permanent erosion of tooth enamel. The photo you see here is from the case study of a 15 year Dutch girl who was drinking a daily shot of vinegar for weight loss purposes. (8)

How it affects canines vs. human teeth hasn’t been studied, but the risk is comparable (best case) and possibly even worse for them.

Being omnivores, humans are designed to eat acidic fruits on occasion. Not the case with dogs. And even as a human, to avoid these side effects of ACV you need to always dilute it.

Plus, most people don’t let acidic food sit on their teeth for very long.

It may not be for dental health, but at least for the purpose of taste, most people will chase a vinegar flavor with sips of water or another beverage to wash it down. Are puppies doing the same? Unlikely.

Why do you even want to give it to them anyway?

Using it diluted in bathwater for skin issues may be relatively safe, but the same can’t be said about using apple cider vinegar to treat ear infection in dogs.

In humans, some research has suggested it might be effective against the following types of ear infections:

  • Otitis externa (swimmer’s ear)
  • Otitis media (inflammation of middle ear)
  • Granular myringitis (inflammation of the tympanic membrane)

The problem is that even if vinegar works, it may cause hearing damage in the process!

sensory hair cells in ear

sensory hair cells in ear

Even diluted vinegar (2% acetic acid solution at pH 2) can “damage cochlear outer hair cells” in humans (9). These act as sensory receptors for sound. Damage to them results in hearing loss and in extreme cases, going deaf.

Whether it’s for infections or removing ear wax, even diluted vinegar in the ears is extremely dangerous and may cause permanent damage.

Some have asked how much apple cider vinegar to give a dog for UTI. That’s a well-intentioned question, but the problem is that this remedy has literally zero scientific evidence of working. None of the 27,000,000+ pieces of medical literature in the PubMed database mention this vinegar in relation to urinary tract infections.

Therefore, the answer would be to give your dog zero. It’s not a proven remedy, so why give them something that doesn’t work and certainly isn’t pleasurable to their taste buds!

The takeaway?

Superfoods for humans aren’t always super for your pet!

Apples are OK for dogs if you give them small cut pieces, with the core and seeds already removed. But you need to make sure they are tiny enough to not be a choking hazard. Don’t assume yours will actually chew it. Our Shar Pei wouldn’t chew produce and our Siberian Husky would only chew inedible things, like flashlights and door molding! Save the apple cider vinegar for yourself.

So my dog ate apple seeds will he be OK?

Most likely yes. If he didn’t chew them, two or three probably won’t hurt. Just make sure it doesn’t happen again.

Better superfoods for dogs…

For meals, if you want to give them the best, try Wellness grain free made with 100% raw freeze dried wild game duck, lamb, and boar. You can get it on Amazon with free shipping.

For snacks, try all natural Blue Buffalo treats.