Vitamins in pet food: helpful or harmful?

Vitamins and minerals have become somewhat of a bad-guy as of late so I think it’s time we cleared a few things up. Pet food ingredient labels can be confusing, and scary because they contain chemical sounding words we aren’t used to seeing – but that does not mean they are toxic for us or our pets.

Recently, a client told me they were told by a friend to immediately stop feeding the food I recommended because it contained “synthetic vitamins”. So let’s talk about that.

For a pet food to be complete and balanced, it must contain vitamins and minerals. Plain and simple. A synthetic vitamin just means it has been synthesized or ‘created’ in the lab. Often, these synthetic vitamins are extracted and then purified from a natural source (either plant or animal), other times it’s a chemically produced vitamin that is made to be identical to the real vitamin but it’s important to note, it’s actually very hard to create a vitamin from scratch so it’s usually preferred to extract it from a natural source or combine it with something else to make it more stable. In many cases, vitamins are used in a synthesized form because it is actually better absorbed and utilized by the animal eating the food or the right amount of that nutrient is impossible to get in the correct amount from a natural source without throwing the balance of the entire diet out.

Now if we compare this to our food, I often hear clients stating that they don’t need to take vitamins and the reason it’s added to pet food is because it’s overly processed. This isn’t necessarily true – did you know many of the things we eat and drink on a daily basis contain vitamin and/or mineral supplementation? Again, this is due to the fact that vitamins and minerals occurring nature aren’t usually in high enough amounts to meet our daily requirements, and also much of its natural vitamin content is destroyed through natural processes of storage, cooking, processing or exposure to light. Almost every variety of cow’s milk you drink will contain added calcium, breakfast cereals are usually fortified with iron or manganese. It’s also important to remember that when consuming a food, you aren’t consuming one vitamin in isolation, you are consuming multiple in combination with each other which is necessary for the correct combination of nutrients to be absorbed and provide a “balanced” diet, as many nutrients rely on the presence of others to ensure absorption.

In pet food, vitamins and minerals come in a powdered pre-mix; they are balanced and mixed to be in the correct ratios and to complement the absorption of each nutrient, so when they are added to the pet food it fills the nutritional gaps and provides a complete and balanced diet each time the pet eats their meal. This is quite different to the type of multivitamins we have in human health – a multivitamin pill typically contains a number of binders and fillers to get the pill to hold its shape whereas in pet food, the premix comes in its raw, powdered form so it’s actually a lot less “polluted” in that sense. So the thought that synthetic vitamins equals bad is more so referring to human multivitamins that contain fillers, not pet vitamin premixes.

So, getting back to vitamins and minerals in pet food; almost every pet food will contain synthetic vitamins. Even “natural” pet foods are legally allowed to contain synthetic vitamins, so the argument that feeding something other than kibble or canned food will avoid synthetic vitamins is simply not true – even if you feed a home-cooked, gently-cooked or even a raw diet, for the food to be complete, it will need to have a “balancer” or vitamin mix that is added to ensure its balanced and you can guarantee at least a few of the vitamins in there will be synthetic.

So what sort of vitamins and minerals are included in pet food, and what are those chemical sounding names? Just because a vitamin or mineral has a scientific name listed, does not mean it’s synthetic and, if a vitamin is synthetic, there is likely good reason for it. Looking at a handful of pet foods, I’ve listed the most common scary names you encounter when reading a pet food ingredient list, what they mean and what they are doing in pet food! Read on.


B-group vitamins:


Also known as vitamin B2, is a water soluble vitamin that is found naturally in many foods, but is often added to cereals as it is easily destroyed when exposed to light. Riboflavin plays a vital role in thyroid function, helps the body produce immune cells and also works in conjunction with iron to make red blood cells. It also converts B6, B3 (niacin) and folate into their active forms! Good sources of riboflavin are liver, beef, eggs and fish however due to its rapid degradation when exposed to light, it often needs to be supplemented in pet food.


It’s often common to see thiamine monohydrate, written on an ingredient list. Thiamine is B1, and was the first B group vitamin ever discovered. The body can only store a small amount of thiamine and stores generally only last around two weeks, so a deficiency can fairly rapidly take hold if it’s not in the diet. Thiamine is involved in carbohydrate metabolism, making DNA and brain function. Dietary thiamine in dog and cat foods can be supplied in raw ingredients or can be added as a synthetic supplement in the form of thiamine mononitrate or thiamine hydrochloride. A recent study looked into the prevalence of thiamine deficiency in cats and dogs, aswell as some recent recalls due to low levels of thiamine in pet food.


More commonly known as vitamin B6. Like thiamine, it is essential for life. Vitamin B6 comes in six forms but pyridoxine hydrochloride is the form used in most supplements and pet food. This vitamin, performs hundreds of functions in a day; it acts as a coenzyme to speed up reactions in cells, works with B12 & folic acid to prevent heart disease/vascular disorders and helps cells make proteins and neurotransmitters. Fish, poultry, chickpeas, brewer’s yeast, sunflower seeds, wheat germ, soybeans and potatoes are often used as a natural source in pet food. When kittens are deficient in B6, they appear to be more prone to calcium oxalate formation due to decreased excretion, so B6 seems to also play a role in urinary health.

Vitamin C

Pets can actually synthesize a small amount of their own vitamin C, however it’s often added to pet food to ensure they get the correct amount and also is used as a natural preservative! It can be included in many forms, but the most common in pet food is L-Ascorbyl-2-Polyphosphate or ascorbic acid. It has a number of benefits particularly collagen production, joint support and immune support. However, the amount of vitamin C in pet food is generally fairly low as pets can make their own, and excesses can happen.

Vitamin D

Cholecalciferol is vitamin D3 from animal sources, this is the type of Vitamin D you make when you are exposed to sunlight, or you eat vitamin D rich foods – this is a natural vitamin. Whereas ergocalciferol is vitamin D2 and is from plant sources, this is a synthetic supplement. Both are frequently used in pet food to ensure calcium is absorbed in the body. Without vitamin D, regardless of the amount of calcium ingested, you simply cannot absorb it or make use of it; eventually blood calcium levels drop so calcium is leached from bones which causes bone loss and fractures. This also leads to damage to the heart muscle and nerves.

Vitamin E

This fat-soluble vitamin is stored for long periods in the body, however it’s only found in a few very high fat foods. Alpha-tocopherol acetate is the most common form used in pet food as it is the most potent form, to replace the substantial amounts that are lost during cooking and storage. It can also be noted as mixed tocopherols on an ingredient list. DL-alpha-tocopherol is the synthetic form which isn’t as commonly used. Insufficient vitamin E can cause immune system abnormalities, neurological damage and anaemia. Pets prone to pancreatitis and fat sensitive disorders, may be more susceptible to deficiencies. Vitamin E also preserves food naturally.



We are all very familiar with the consequences of calcium deficiencies. In pet food, calcium is usually supplemented as it’s actually fairly difficult to get the amounts you need from food without it being fortified. There’s many forms which Calcium can be supplemented as, and the amounts it provides vary widely. Calcium phosphate or dicalcium phosphate is typically the form in which it’s found in pet food; it is in this form to ensure the correct calcium: phosphorus ratio is present in the food, as an unbalanced ratio can have detrimental effects especially in growing animals.


Zinc is usually included in the form of zinc oxide or zinc sulfate. In cats and dogs, zinc deficiencies result in poor skin and coat condition, lesions and poor growth. Seeds and some grains can interfere with the absorption, as well as high calcium levels. This is usually why it needs to be added into pet food. Some breeds also have a breed predisposition to deficiency as they have higher zinc requirements.

Vitamins and minerals are essential to life, whether they come in synthetic or a natural form. Our pet’s health is no different – if you are concerned about vitamins and minerals in your pet’s food, or aren’t sure what those scientific names are, why not reach out to a veterinary professional or the company itself and ask them what it is!

Are you alarmed by synthetic ingredients? Do you want to know more about vitamins and minerals and their role in the body? Post a comment below!

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Readers Digest (2010) Vitamins Minerals And Supplements: For Australia and New Zealand. ISBN: 9781921569555

McDonald, et al (2011) Animal Nutrition, 7th ed. ISBN: 9781408204238

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