Answers from Science Diet and Royal Canin:

Science Diet’s answers are this color
Royal Canin’s answers are in this color

Science Diet: We originally spoke with Ashley on Hills staff but she couldn't answer our questions so she transferred us to a Veterinarian on staff.

Royal Canin admitted that it is not required to have any background in nutrition to work for Royal Canin.


"What agency regulates and monitors veterinary prescription diets?"
Science Diet’s answer: “No one, the vets regulate it.” The veterinarian will determine who or what animal requires what diet and which is appropriate.” Ashley said, “nobody.”


Royal Canin’s answer: “The FDA regulates it – it’s only the package that makes it a prescription. So if we package something such as “anallergic” we are told it has to be labeled prescription since we are making medical claims on the package. There are no pharmaceuticals...Early cardiac formula has low sodium… other formulas also have low sodium but since low sodium levels in O.T.C. diets don’t SAY “cardiac” they aren’t labeled prescription.”


We also contacted Scott Ziehr at the Colorado Department of Agriculture and asked what the difference is between prescription pet food and pet foods that you purchase at the grocery store. To which he responded that the only difference is that one makes medical claims and one doesn't - "it's strictly a marketing term." You, as a consumer, can contact any department of agriculture and ask this question as well.


Another example is Renal and Liver Diets - they are for “Intermittent and Supplemental Feeding Only.” If fed to a healthy animal (or sick) long term it will cause muscle wasting… muscle wasting is also a symptom of having those diseases. It is not recommended that you feed these diets to healthy animals. A primary cause of muscle wasting (besides existing disease or injury) is malnutrition. Many pet parents are led to believe that kidney and liver disease lead to muscle wasting simply because their pets develop muscle wasting after months or years of being on prescription pet foods - neither are not listed as causes of muscle wasting.


The FDA and State Departments of Agriculture are the only “regulatory” agencies over pet food. They regulate labeling. They don’t care what’s in the ingredients as long as it has been defined by AAFCO. Other ingredients that are accepted by AAFCO include animal feces and litter, hydrolyzed leather, sludge, used restaurant grease/cooking oil, recycled and salvage pet food and much more. Ingredients that are not approved by AAFCO include Milk Thistle, Slippery Elm, Catnip, Mushrooms and Spirulina. To see this in person stop by Hero's Pets to see our AAFCO book that we keep in the store.


Are prescription foods regulated any differently than any other product out there?
Science Diet: “Nope”


Royal Canin: No Answer


If AAFCO standard for complete and balanced is what you abide by, and all companies are required to abide by equal AAFCO standards, what makes Royal Canin “more” complete or healthy than any other brand?
Royal Canin: “It does not. We are familiar only with our own practices, not other companies.”


Why are prescription foods allowed to make medical claims? Can any company do that? Why not?
Science Diet’s answer: In summary - They aren’t big and scary. “Larger companies that have done the appropriate research and have the data to back up their claims are the ones that do it." (Hero's Note: there are not official parameters or limitations to studies. For example, this vet also explained to us that he participated in the "research" that allowed them to manufacture their T/D (dental) diet - they got "some dogs" from a local rescue (obviously creating lots of room for variables) and fed half of them Pedigree for 2 weeks and half T/D for 2 weeks. At the end of 2 weeks they "compared tartar." This was the entire study)


Royal Canin’s answer: "Any food with similar or the same ingredients could be sold O.T.C. but not be labeled as a prescription food. However, they wouldn’t be sold O.T.C. because the prescription diets are for intermittent and supplemental feeding only and would make a pet sick if fed long term." E.g. According to Royal Canin treating a specific disease outweighs the harm done to the rest of the body.
Ultimately if the disease process doesn’t kill them first, the diet might.

What do you use L-Lysine and L-Threonine for in the food?
Science Diet’s answer: “They are essential amino acids.” They are “certainly synthetic” and they “have to add them to their food. “
Royal Canin’s answer: We didn’t ask Royal Canin this question because we didn’t know about why it’s added until after the call with them.

Long term feeding of several of the diets causes muscle wasting. Muscle wasting is “end stage starvation.” Excessively “Low protein” causes the body to eat its own protein. L-Lysine and L-Threonine are also added to decrease already low protein values even more.


This lists, on page 15, the purpose of L-Lysine and L-Threonine being added to food: “Supplementing diets with L-lysine and L-threonine, which reduces dietary crude protein, can also lower nitrogen excretion and improve nitrogen efficiency.” It is also, “primarily used in swine and poultry diets… dairy cattle diets can also benefit from L-lysine supplement.” No note is made of dogs and cats.


What form do you get your vitamins and minerals and amino acids? Are they individually added/purchased or do you use the FDA vitamin/mineral pre-mix pack?
Science Diet’s answer: They make their own pre-mix and each one is specific to each diet. They test individual ingredients in the food prior to releasing the final diet. Based on those test results they’ll determine what their pre-mix should be. But the test is only ever done once. “They (the vitamins and minerals) are individually added to the pre-mix.” “It might be a tiny bit off. It’s not perfect.” “It’s always the same pre-mix used though.” Here is an example of one of Hills Science Diets massive recalls caused by their synthetic vitamin/mineral premix that resulted in the deaths of hundreds of dogs and cats. When asked about using whole food sourcing they stated: “Corn has lots of vitamins” they also stated that they did not have any laboratory analysis to validate the claim.


A NOTE ON CORN: Note that RAW corn would NEVER be used in pet food… ever! Corn would not only be cooked but as listed in the ADM manual it is stripped, separated and cooked. So nutrient levels of those listed on NutritionData.com are incapable of determining the actual remaining vitamin/mineral values of a product that is as processed in as many ways and as many times as pet food. This is to compare that raw corn DOES have vitamins and minerals and that cooked corn has substantially less. Not to mention corn is generally high in phosphorus yet it is still used as a primary ingredient in the renal/urinary diets (even though it’s Royal Canin and Science Diet themselves that tell vets that phosphorus levels should be limited in such cases… even though research shows otherwise).


Nutritive values of a variety of corns:
White raw corn = 12% fat, 6% saturated fat, 41% carbohydrate, 31% protein, high in (35%=) thiamin, vitamin b6, omega 6, magnesium, phosphorus, manganese, selenium, moderate in (20-34%) riboflavin, niacin, iron, zinc, copper, low in (-20%) calcium, potassium, sodium, pantothenic acid.
White cooked corn: 2% fat, 1% saturated fat, 19% fiber, 5% protein, low levels (less than 15% but above 5%) of niacin, folate, magnesium, phosphorus, zinc, manganese.
Yellow raw corn: 3% fat, 1% saturated fat, 17% carbohydrates, 10% protein, low in (5-20%) vitamin c, thiamin, niacin, folate, pantothenic acid, magnesium, phosphorus, potassium, zinc, manganese.
Yellow corn cooked: 3% fat, 2% saturated fat, 14% carbohydrate, 18% fiber, 11% protein, 24% thiamine, low levels (5-20%) of vitamin a, vitamin c, riboflavin, niacin, vitamin b6, folate, pantothenic acid, magnesium, phosphorus, potassium, zinc, manganese.
Yellow corn flour: 7% fat, 3% saturated fat, 30% carbohydrate, 34% fiber, 16% protein, 25-32% phosphorus, magnesium, manganese and selenium, 15-24% thiamin, vitamin b6, iron and 5-14% vitamin a, riboflavin, folate, pantothenic acid, potassium, zinc and copper.
White corn flour: 7% fat, 3% saturated fat, 30% carbohydrate, 34% fiber, 16% protein, remaining levels are similar to those listed above with the low levels being even lower.

All corn products have no, to virtually no, vitamin d, vitamin e, vitamin k, vitamin b12, betaine, calcium, sodium, selenium and extremely low levels of niacin, folate, zinc and vitamin a.


Also you can see in AAFCO nutritional requirements for cats and dogs document that cats and dogs have ZERO nutritional requirement for carbohydrates/starches.
(we don't know where Science Diet or Royal Canin sources their synthetics - the links are examples of these ingredients).

Science Diet’s Vitamin Pre-Mix:
“vitamins (l-ascorbyl-2-polyphosphate (source of vitamin c), vitamin e supplement, niacin, thiamine mononitrate, vitamin a supplement, calcium pantothenate, biotin, vitamin b12 supplement, pyridoxine hydrochloride, riboflavin, folic acid, vitamin d3 supplement)”
Science Diet’s Mineral Pre-Mix:
“Minerals (ferrous sulfate, zinc oxide, copper sulfate, manganous oxide, calcium iodate, sodium selenite)”
Almost every Science Diet/Hills list of synthetics, not including “vitamins” and “minerals” pre-mixes:
Dicalcium phosphate, potassium chloride, calcium carbonate, choline chloride, DL-Methionine, vitamin E supplement, taurine, L-tryptophan, preserved with mixed tocopherols and citric acid, phosphoric acid, beta-carotene, rosemary extract.

Royal Canin’s answer: The majority of the diets do use those, not all of them. It is case dependent and “part of the recipe.”

Royal Canin’s Vitamin Pre-Mix:
“Vitamins [D-alpha tocopherol acetate (source of vitamin E), L-ascorbyl-2-polyphosphate (source of vitamin C), biotin, D-calcium pantothenate, vitamin A acetate, niacin supplement, pyridoxine hydrochloride (vitamin B6), thiamine mononitrate (vitamin B1), vitamin B12 supplement, riboflavin supplement, folic acid, vitamin D3 supplement]”
Royal Canin’s Mineral Pre-Mix:
“Trace minerals [zinc proteinate, zinc oxide, ferrous sulfate, manganese proteinate, manganous oxide, copper sulfate, calcium iodate, sodium selenite, copper proteinate]”
Almost every Royal Canin Diet’s list of synthetics, not including “vitamin” and “mineral” pre-mixes:
monocalcium phosphate, sodium silico aluminate, potassium chloride, calcium carbonate, taurine, choline chloride, DL-methionine, L-lysine, marigold extract (Tagetes erecta L.), rosemary extract, preserved with mixed tocopherols and citric acid

Additional differences in both Science Diet/Hills and Royal Canin formula’s:
There are additions in formulas of varying types of calcium, sometimes l-lysine and l-threonine (which, as listed, decrease protein in the diet) and L-methionine (according to pg 24 of the FEDIAF_Nutrition_Guideline2014 methionine values are based on a dog food containing a very low taurine content), also Vitamin K. According to page 30 of the FEDIAF_Nutrition_Guideline2014 “Vitamin K does not need to be added unless diet contains antimicrobial or anti-vitamin compounds.” Such as soy.
sodium selenite is 109 times more toxic than Arsenic but is added into these foods and advertised as immune boosting.


The most toxic of the synthetics are of primary note because they prove the necessity of careful moderation of the products and “an exact science” in handling. Additionally, use of multiple of the most toxic synthetics, with repeating chronic indications leads one to assume that it is, in fact, the supplements THEMSELVES that cause the illnesses that the food is trying to prevent by using non-nutritive and anti-nutritive ingredients in their products.


You talk a lot about the antioxidants in Science Diet. The vitamin E, C, Selenium and Beta-Carotene. Do you know how much of each of those is actually in the food? Are those from food sources or synthetic?
Science Diet’s answer:
When asked if they are synthetic: “My guess… yeah.” Those particular anti-oxidants are “Part of the pre-mix.” “The pre-mix is mixed in the blender. Then the pre-mix of synthetics goes in the mix.” “It’s not an exact Science” … and, as indicated above, Science Diet says no one monitors this… the “vets decide what’s appropriate."


Royal Canin’s answer: "Some of the raw ingredients are tested at a third party facility, then once they are combined they are retested and then they save a small amount from every batch and retest it at a later date for things like crunchiness." When asked about testing for aflotoxins she didn’t know what that was.


According to MSDS reports some of the synthetic vitamins and minerals used in Science Diet and Royal Canin blends are extraordinarily toxic in very low dose. Thus, utilizing an “exact science” seems a necessity in creating a safe product. This is proven by the number of recalls caused by Vitamin D toxicity.


Dr. Karen Beker from Mercola notes that, “Pet foods with plant-derived proteins may contain more harmful toxins than pet foods with traditional proteins.” The most common sources of aflatoxin poisoning include maize (corn), sorghum (wheat), pearl millet, rice, wheat cereals, peanuts, soybeans, sunflower seeds and a few types of nuts. According to Science Professor Trevor Smith at Guelph in Canada, who has spent over three decades researching mycotoxins, “Although we have no exact numbers, we can estimate that when half of the food is of vegetable origin, there will almost always be some degree of contamination. If the food is mainly of animal origins, the chances of contamination are greatly reduced.” Aflatoxicosis is more common in dogs than cats because commercial dog food formulas more often contain corn products. Aflatoxicosis is chiefly a disease of the liver, causing GI symptoms, reproductive issues, anemia and jaundice. Certain types of aflatoxins are linked to cancer in animals.


Aflatoxins are one of the single most common causes of pet food recalls.
Where do you source your ingredients? Do you know if your corn, soy and wheat are genetically modified? Do you know if your animals are all antibiotic and hormone free and free range? (Knowing it’s illegal to put antibiotics or hormones into chickens)

Science Diet’s answer:
80% of the world’s grain (including corn) is GMO. It’s very hard to get non-GMO. “They purchase Round-up ready corn”
Japan and Europe won’t import anything with GMO’s so they get non-GMO for foods that are exported. They don’t know if any of the non-GMO products get mixed into the American supply. If so it’s accidental because they have more than they made for the European or Japanese order."
Chicken is from Tyson = don’t ask about how they’re fed or raised.
They also stated that “all canned food (in the world) is made in Topeka, KS" (which is where Science Diet is made). This is absolutely not true - there are many, many canneries in the world that are not in Kansas.


Royal Canin’s answer: "No clue. Our venison is from New Zealand. Our meats are tested for dangerous levels of hormones and antibiotics prior to use.... No clue what the animals are fed." "We select our ingredients based on multiple factors, including the supplier’s compliance with our food safety and quality requirements, consistent availability and on nutrient contents that meet the dietary needs of the pet...Royal Canin is dedicated to sustainable development and attempts to source raw materials as close to each manufacturing facility as possible. In some cases, we use international suppliers, because only those suppliers can offer raw materials that comply with our quality and food safety standards."

Round-Up Ready Corn (Round-Up = glyphosate) - According to Monsanto, glyphosates were found to decrease pituitary size and function at as little as 20mg/kg/day in Beagles.


As far as health is concerned,” genetic engineering unleashes a host of unpredictable side effects. Moreover, irrespective of the type of genes that are inserted, the very process of creating an GM plant can result in massive collateral damage that produces new toxins, allergens, carcinogens, and nutritional deficiencies” states the Institute for Responsible Technology.


Raw-Wisdom offers an extensive article regarding the negative health effects of GMO products including 37 recorded deaths caused by GMO L-Tryptophan, near death effects caused by Brazil nuts that were spliced into soybeans, multiple studies showing evidence of allergenic reactions to GMO corn (combined with pork), potato (combined with Cod), peas (causing allergic lung damage in mice) and soy (listing it as being, “among the top ten allergenic foods.”). They also link GMOs directly to cancer (primarily colorectal, prostate and breast) and degenerative diseases such as inflammation, arthritis and lymphoma (a malignant blood disease). Additionally, allergic reactions are misguided defense reactions against incoming parasites and in GM food cases, the body senses an unnatural invasion. Cells in the body recognize this lack of vitality, producing antibodies and white cells in response. This is analogous to our brain’s cells recognizing and rejecting mechanically repeated thoughts – or thinking, “like a broken record.” Intuitively the body cells and the overall immune system seems to reject excess homogeneity (GMO foods… clones). Each new GMO food item products contains many new potentially allergenic proteins.

What type of scientific research do you do? Is it specific to beagles? Isn’t it mostly on WHAT and HOW pets eat? (Do you do your own scientific research or do you just use information from other places that have done studies on things? E.g. Selenium is a good anti-oxidant… do you test that YOUR selenium in the form and levels that YOU use it are a good anti-oxidant source?
Science Diet’s answer: “The kidney diet was developed 50 years ago. There’s been no new research done on that diet since then. No changes have been made and no new research regarding low protein in the kidney diet has been considered. That shit is so old.”
"Y/D (Iodine deficient thyroid formula) was developed 10 years ago and tested on 150 cats."
“Since 1979 numerous articles have investigated the link between commercial cat foods and the epidemic of hyperthyroidism in cats. To date every epidemiologic study investigating hyperthyroidism in cats has found that consumption of commercial cat foods is a risk factor for developing the disease [10-17]. Both canned and dry cat foods have been implicated as factors in the development of hyperthyroidism in cats [12, 13, 18].” “In a recent case-control study, cats consuming commercial foods without iodine supplementation, according to listed ingredients, were more than four times as likely to develop hyperthyroidism compared with cats that ate iodine-supplemented foods [17].” “It is easy to understand how Hill’s new iodine deficient diet y/d works to lower the circulating thyroid hormone levels in hyperthyroid cats. By starving the follicular cells of the thyroid for the iodine they need to make the thyroid hormones T3 and T4, any iodine deficient diet will lower circulating levels of these hormones.” “Minimally, we know that this diet does nothing to prevent the continued growth of the tumors responsible for hyperthyroidism in cats. Hill’s y/d includes at least two of the dietary factors that appear to contribute to the development of hyperthyroidism including overt iodine deficiency and soy isoflavins that act as goitrogens.” “While publicly acknowledging the potential risks of feeding an iodine deficient diet to cats without established thyroid disease, privately Hill’s representatives encourage veterinarians to recommend feeding y/d to all of the cats in multi-cat households as a means of overcoming this problem (iodine deficiency in healthy cats). They argue that supplementing the cats without hyperthyroidism with small amounts of other foods will overcome the deficiencies of the y/d product. In light of our current knowledge of pervasive iodine deficiencies in many commercially available cat foods, this logic seems flawed. Feeding y/d to every cat in a multi-cat household, just to ensure severe iodine deficiency in a single hyperthyroid cat seems sure to accomplish only one goal, namely increasing the sale of y/d.” “Soy has been shown to contain enzyme inhibitors that impeded normal protein digestion and soy is a known goitrogen suspected as a contributing factor in the development of hyperthyroidism in cats[18, 29-34].” “It is well established, however, that geriatric cats normally have total T4 levels in the lower half of the reference range that was utilized in Hill’s studies [35]. In Hill’s own studies, hyperthyroid cats fed exclusively y/d did not routinely achieve these levels, even after 12 weeks on the diet. Preliminary evaluation suggests that this therapy appears to be more effective in cats with mild to moderate elevations of T4 and is not as effective in cats with severe hyperthyroidism. Furthermore, as an iodine deficient diet does not prevent, and may even encourage growth of the thyroid adenomas responsible for hyperthyroidism in cats, use of an iodine deficient diet appears unlikely to successfully control the thyroid hormone elevations over time.” “As the thyroid adenoma(s) responsible for hyperthyroidism continue to grow, the number of autonomously functional thyroid cells increases and their combined efficiency for extracting iodine from the blood stream with which to make thyroid hormones increases.”
http://www.animalendocrine.com/yd/ Written by Dr. Mark E. Peterson, Ph.D. Specialist in animal endocrinology.
"J/D used force plates to determine how much pressure the dog was using when walking on the plates. If, after being on the diet, they applied more pressure to the plates when they walked it was considered to be working... Some of the animals in the study were on pain meds."
"We only study on animals that have a naturally occurring disease process… so we won’t induce illness. Science Diet has animals that we own and study on in a facility. We have very strict animal cruelty rules and guidelines that are followed very well."
T/D (this particular doctor was part of this actual study while he was in school) It was “Supposed to be double blind... we fed some of the dogs T/D and some of the dogs Purina Puppy Chow and then we
evaluated tarter. It was just a group of rescue dogs; no particular breeds were used." Leaving multiple variables in question.


Royal Canin’s answer: "We only test on animals that are “owned” … we have a contract in Europe with different veterinary practices … if a patient comes in with a disease through that facility Royal Canin will supply the food in exchange for being able to track the progress of that pet. It does not “cure” - it “slows the progression” of the disease."

Isn’t the scientific testing you do on the breed specific formulas mostly on WHAT and HOW pets eat, not what’s good for them?
Royal Canin's answer: We test kibble shape and size. We also test on higher levels of glucosamine and chondroitin for large breed dogs and low sodium for boxers because they are predisposed to heart disease" (like the “cardiac” diet).


How much of each ingredient that is touted as a “beneficial property” or ingredient in Science Diet is actually in each bite vs how much is necessary to be a therapeutic dose?
Science Diet’s answer:
“All the big companies do similar research so it’s just about whichever one you are more comfortable with." E.g. you could use baytril or another florquinolone and ultimately, you’ll get the same result but the mechanism of action may differ. “Most of the research we do is “ours” (though it may have been 50 years ago). Each company uses their own research to come to their own conclusions and that’s what applies to only their products."


The EPA levels in the J/D, if they’re feeding the recommended amounts a dog, would be getting about 50mg/kg/day (approximately). “The kibble is not uniform so there is no way to determine if each kibble has the same amount of a nutrient in it.”


Royal Canin’s answer: "We don't know if there is a therapeutic level. Three ingredients combined having a calming effect. If the dog were to get into too much it could be overdosed but we don’t know what a therapeutic dose would be."


Do you make your own food in your own facility? Do you make anyone else’s food or is anyone else’s food made there?
Science Diet’s answer: “No”
Royal Canin’s answer: No answer

I know that denaturing is mandatory. Do you know what you use to denature? Is it the FDA pre-mix, your own mix, or charcoal? Is it detergent or chemicals like carbolic acid?
Science Diet’s answer: “Not sure”
They rinse all of the cans with hot water prior to shipping. Because the food is cooked at such a high temperature, in the canning process it is “sterile.” He thinks that the sterilization is called, “Detort”
Royal Canin’s answer: No answer

What is powdered cellulose besides just a fiber? What is that sourced from? Like sawdust?
Science Diet’s answer:
"It's an insoluble fiber like Metamucil. It's typically food grade. It's like paper - from the poplar tree, I think."

Poplars are rapid-growing but relatively short-lived trees... the wood of poplars is relatively soft and hence is mostly used to make cardboard boxes, crates, paper and veneer.

Poplar wood is very flexible. It is widely used for paper and inexpensive hardwood timber. It is also used for pallets and plywood. Camembert cheese is usually sold in boxes made out of poplar. Poplar wood is great for snowboard core because it is flexible wood.

Poplar bark, sap and catkins contain moderately high levels of salicin, one of the components of aspirin, a natural reliever of pain. It also functions as a digestive cleanser and to relieve nausea. While poplar LEAF or “herb” is touted as having anti-aging effects for people, the bark (used in pet and animal feed), sap and catkins are not generally known as being nutritious or even edible. Only in books on living in the wild or third world countries are even minor uses, such as for severe stomach issues associated with diseases such as Malaria, is information even available regarding its use as a consumable product. Certain species of poplar may also be used for urinary concerns, however, with the numerous species of poplar available its hard to know if a “nutritionally beneficial” species is being used… additionally, no species is known for having “nutritive qualities.” Some simply have limited qualities for limit use for acute health conditions.

Royal Canin’s answer: No Answer


ISO … what’s that good for? How does that ensure you’re using good quality ingredients, not just that you have a clean facility?
Royal Canin’s answer: “It doesn’t. We do have third party laboratories that test our ingredients for toxins but not for pathogens or quality. We have no idea if it’s free range or grass fed … but it could be depending on the source at the time."

I thought a lot of animals with allergies were allergic to corn and soy and rice and chicken… why do you use those ingredients in the allergy foods?
Royal Canin: "We didn’t know that dogs could be allergic to soy or rice."
When asked, "why do you use hydrolyzed protein?" they said, "the same amino acids are in the food as there would be in a different meat source therefore its fine."

They also stated, "There are no negative effects to feeding soy long term." Research clearly shows that soy does damage health over time.

They claim that, "canines and felines don’t assimilate the phytoestrogens like humans do." Research clearly shows that they do.

Royal Canin uses "Poultry aggregate meal" which they admitted is “ground feathers from assorted birds.”

They state that "Natural flavors" are just a part of the recipe. Click here to see a list of "natural flavors" and their chemical sources.


… but people with allergies to peanuts can’t tolerate them even if they’re in small amounts. Why would that be different for a dog? Isn’t an allergy an allergy?
Royal Canin: "They wouldn’t be allergic to those things at all."

Back to blog
1 of 5
1 of 2