Foods Forbidden for Dogs

Dogs cannot eat every food we humans eat, since some of them contain toxins that are highly harmful to them. There are several toxic foods for dogs that we should avoid entirely.

And although they would happily eat anything given the chance, it is up to us to look out for their health. Here at Soyunperro we are going to show you which foods to avoid for your dog and why.

Chocolate Contains Theobromine

Chocolate is a highly harmful food for our dogs, in any of its forms. It makes no difference whether it is chocolate squares, chocolates, chocolate-flavoured yoghurt or any kind of sweet containing chocolate. All, absolutely all foods containing chocolate, cocoa or its derivatives, are highly harmful to our dogs.

Chocolate contains a toxin called theobromine, which is harmless to humans but highly harmful to other animals, such as dogs. It is a toxin already present in the cocoa bean itself, from which chocolate is obtained, so there is no type of chocolate free of this toxin.

Although dogs seem to love chocolate, it is genuinely harmful to their health. In the wrong amounts it can cause seizures, a racing heart, diarrhoea and vomiting, and even death.

Onion and Garlic Contain Sulfoxides

Both onion and garlic are highly toxic foods for our dogs, through similar mechanisms too. It makes no difference whether they are raw, cooked or powdered (as a seasoning); they are equally toxic to our dogs.

They contain sulfoxides that are harmful to dogs. These destroy red blood cells, leading to anaemia. In turn, they release the haemoglobin from these cells, which is toxic to the kidney and causes acute kidney failure.

Although it is true that large amounts need to be eaten to experience serious problems, individual susceptibility means some animals are more prone to severe forms of this poisoning.

When a dog eats onion or garlic, the symptoms are not immediate; instead, it takes four or five days for the first symptoms to appear. The most typical are tiredness or exercise intolerance, both consequences of the anaemia.

We may also notice their urine turning orange or reddish, because their red blood cells have burst and the pigments they contain have entered the bloodstream and been filtered by the kidney.

Generally dogs do not like either raw onion or garlic, but when a dog is fed leftovers containing cooked onion, we may unknowingly be giving them these toxins.

Dairy Containing Lactose

The vast majority of dairy products are harmful to our dogs, since they contain lactose. This is a sugar abundant in milk that is digested in the body thanks to the enzyme lactase.

Most dogs stop producing this enzyme a few months into life, once they finish feeding on their mother's milk, so they are unable to digest the lactose in milk or its derivatives, causing damage to their gastrointestinal system.

The most common symptoms from eating lactose are:

• Increased wind.
• Diarrhoea.
• Anal itching.
• Vomiting.

Milk becomes yoghurt or cheese through fermentation by specific bacteria. Each cheese and yoghurt is produced by fermentation from a particular set of bacteria. Every cheese has its own bacterial species, milk (from one animal or another) and special processing.

Broadly speaking, the longer the bacteria ferment it, the less lactose the dairy product will have, since this is the sugar the bacteria use to get energy. The longer they ferment, the more lactose they consume. (This is the same process that happens in the gut of a dog who cannot digest lactose, with the symptoms already mentioned.)

Because of this, not every dairy product is harmful, since the problem is not dairy itself, but the lactose. Plain yoghurts contain minimal amounts of it, since it has been consumed by the lactobacilli added to the milk to make the yoghurt. Plain yoghurts can be beneficial for our dogs; click the link to find out more.

On the other hand, fresh or briefly fermented cheeses will have higher amounts of lactose (since the bacteria will not have consumed much of it). Cheeses cured for longer will, in principle, be safer; even so, given how many foods our animals can eat, it is better to go for the safest ones.

Potato, Tomato and Avocado

Tomatoes and potatoes can be hugely nutritious foods for our dogs, as long as they are eaten properly ripe and, in the case of potatoes, properly cooked.

Eaten before their time, they contain glycoalkaloids in the case of tomato and solanine in the case of potato. With potatoes, it is advisable to give them boiled or microwave-roasted, since their starch is indigestible (in humans and dogs alike).

Once cooked it is entirely assimilable and a very interesting carbohydrate source. As for tomato, as well as being properly ripe, it should be given with no seeds, since these can cause unwanted effects in our pet. Given how fiddly it is to remove the seeds from this fruit, as a precaution it is advisable to avoid giving it altogether.

Grapes and Raisins

It is not known why grapes are so toxic to dogs; it is still being studied, but it has been clearly shown that they are highly harmful to them. Simply eating a few grapes can cause serious kidney failure in your dog, which could kill them.

It matters to stress that the dose at which this food is toxic is very low. Even a few can bring on the first symptoms, such as diarrhoea and abdominal pain, before kidney disease sets in.

In the past dogs were rewarded with raisins, the way "biscuits" or "sausage pieces" are used today, something that has since been clearly shown to be highly inappropriate. Even if your dog has eaten grapes with no problems, do not risk giving them again, since no dog is immune to the toxins in this fruit.

Obviously it is not advisable to give them raisins or grape derivatives either, since these contain the same toxins for our dogs. In raisins they are even more concentrated, so for the same dose, the effects can be far worse.

Fruit Seeds

The ways a seed can prove toxic range from chemical compounds it contains, as already mentioned with tomato, avocado or apple, to the mechanical, obstructive action of the seed itself, as with peach or plum.

The most representative case would be the apple, whose seeds contain a substance called amygdalin, which breaks down to produce cyanide, a highly toxic compound. A dog poisoned by cyanide-containing seeds can show serious symptoms such as hyperventilation, seizures, severe breathing problems and even death.

On another note, intestinal blockages cause persistent vomiting, abdominal pain and can even bring on gastric torsion-dilation, which if not treated and operated on as an emergency is fatal.

In this last case, eating these seeds is usually accidental, since almost nobody thinks to give them deliberately, simply because we do not eat them ourselves. With dogs who rummage through the household rubbish we should take special care, or when we are eating these fruits, watch that we do not drop the seed.

Liver Is Harmful in Large Amounts

Liver is a food with protein of high biological value, iron, copper, and B group vitamins and vitamin D. That is why it is widely used in formulating kibble, especially for puppies, or occasionally in home-made diets.

The problem is it contains a high amount of vitamin A; this vitamin is not harmful (indeed, it is needed) in the right doses, but our dogs cannot naturally handle amounts as high as those liver provides.

Even other micronutrients already mentioned, such as copper or vitamin D, can also build up with unwanted effects. In small portions it can be given to our dog, very occasionally; it should not become an everyday food.

It is used in natural food diets such as the BARF diet, though it is generally better served cooked than raw, since there is a large number of zoonotic parasites dogs can pick up from eating raw food.

Even so, it is not only whole liver that will prove problematic. Since vitamin A is a lipid, liver oil will carry these very high amounts of vitamin A and prove equally toxic. Another point to bear in mind is feeding fish livers or their oils (cod liver oil specifically).

A dog with excess vitamin A can suffer loss of appetite, deformation of the neck bones (very painful) and even death. Even so, treatment is based on feeding a balanced diet and removing vitamin A at those doses.

Cooked Bones

Plenty of people think bones are very healthy for dogs; they have eaten them all their lives and nothing ever happened… they could not be more wrong. The only bones a dog can eat are meaty and/or soft bones, such as chicken carcasses, wings, thighs, pork ribs and so on… and they should always be entirely raw, never cooked.

Cooked bones splinter when chewed and can get stuck in our dog's throat or gastrointestinal tract, which can even prove fatal. Other bones dogs can eat are large, hard, round ones, such as a beef or veal knee bone. Never give your dog cooked or unsuitable bones — only soft, meaty bones or a beef knee bone.

Alcohol

We don't know anyone in their right mind who would even consider giving their dog alcohol, but plenty of people are capable of joking about it. A little beer or wine for the dog to see if they like it, or get a bit drunk… These are jokes you should never act on, since alcohol is a highly potent poison for dogs.

In moderate doses, it can send our dog into a coma or kill them. This is no joke — dogs do not tolerate alcohol.

Other Toxic Foods for Dogs

• Walnuts are toxic for their high phosphorus content, not at all advisable for our dogs.
• Raw eggs: the shell can cause salmonellosis in our dogs, which can kill them. They should be given with no shell.
• Salmon and other raw fish can contain highly dangerous toxins and parasites. If you are going to give it entirely raw, freeze it for a few days first to kill parasites.
• Mushrooms: most mushrooms and fungi carry toxins highly dangerous to dogs. They can cause vomiting, diarrhoea, kidney problems…
• Coffee or tea: caffeine is pure poison for our dogs. They cannot have anything containing caffeine or its derivatives.
• Sweets, candy or confectionery usually contain sugar or xylitol, a sweetener highly harmful to our dogs, just like sugar itself.
• Salt disagrees terribly with dogs; it causes seizures and vomiting, and in serious cases even death.
• Bones from large fish are not at all advisable in your dog's diet. They can cause problems throughout the digestive system.
• Out-of-date food: some people give their dogs spoiled or mouldy food… highly inadvisable given the toxins it can carry.
• Chard or spinach, since they contain oxalic acid, harmful to our dogs' health.
• Yeast: if we are making bread or pastry dough we need to be careful around our dogs. Yeast is highly toxic to them and they should never eat it.
• Fat: dogs do of course eat fatty foods, but always in controlled amounts. Too much fat can cause serious pancreatic problems, diarrhoea and vomiting.

These are the most common everyday foods harmful to our dogs, though not the only ones. We need to make sure of what we give our dog, since as we have mentioned, what agrees with us does not necessarily agree with our dog.