purina z d

By Isabella Storyclaire

last updated September 16, 2024

Contributions sourced from

z/d Food Sensitivities Dry Dog Food Original Bag

Food sensitivities and intolerance are potentially serious problems that can result in irritated skin, coat and ear conditions or even gastrointestinal upset. Dogs that have adverse food reactions due to a food allergy (typically to a protein in the food) or intolerance benefit from a food designed for food sensitivities. Hill's nutritionists and veterinarians developed Prescription Diet z/d clinical nutrition especially formulated to support your dog's food sensitivities. In fact, z/d is clinically proven nutrition to reduce skin & digestive signs from food intolerances.

Food sensitivities happen because proteins enter the skin and cross the digestive system to the body causing immune system to react. z/d is a specialized food with proteins that are gentle and broken into smaller pieces to help avoid detection by the immune system to help your dog feed better, prebiotics to create a healthy gut microbiome balance and fatty acids to build healthy skin.

z/d is nutrition clinically proven to reduce skin & digestive signs from food intolerances which are the outward signs you see. Rest assured this product is working inside the pet to avoid the core issue which is due to an overactive immune reaction to certain foods. With pre-digested animal proteins, antioxidants, prebiotic Fibre and skin nourishing nutrients.

Royal Canin Hydrolyzed Protein vs. Hills Z/D

When your furry friend has dietary sensitivities, finding the right food is more than a necessityits a priority. If youre wading through the myriad of options, you may have come across Royal Canin Hydrolyzed Protein and Hills Prescription Diet z/d. Both are top contenders for managing food sensitivities and allergies in dogs, but which one is best for your pet?

Key Takeaways for Quick Readers:

Main Ingredient: Royal Canin uses hydrolyzed soy protein, whereas Hills z/d uses hydrolyzed chicken.
Purpose: Both are designed for dogs with food sensitivities or allergies.
Availability: Prescription only.
Packaging Options: Both offer dry and canned food versions.
Veterinary Recommendation: Consult your vet before switching to a specialized diet.

What Are Hydrolyzed Protein Diets?

Hydrolyzed protein diets are designed for dogs with allergies or intolerances to common food proteins. In these diets, the protein is broken down into smaller pieces, which are less likely to trigger an allergic reaction. This makes them an excellent choice for managing diet-related skin and gastrointestinal issues.

Royal Canin Hydrolyzed Protein

Main Features:

Protein Source: Hydrolyzed soy protein.
Designed For: Dogs with severe allergies or intolerances.
Benefits: Promotes skin health and aids in digestive problems.
Veterinary Approval: Required.

Product Variants:

Adult HP Dry Dog Food
Small Dog HP Dry Food
Canine Hydrolyzed Protein Wet Dog Food

Hills Prescription Diet z/d

Main Features:

Protein Source: Hydrolyzed chicken.
Designed For: Dogs with food allergies and sensitivities.
Benefits: Highly digestible, improves skin and coat health.
Veterinary Approval: Required.

Product Variants:

Original Skin/Food Sensitivities Dry
Skin/Food Sensitivities Small Bites Dry
Original Wet Food

Comparing the Two

Feature	Royal Canin Hydrolyzed Protein	Hills Prescription Diet z/d
Protein Source	Hydrolyzed soy protein	Hydrolyzed chicken
Form	Dry and wet	Dry and wet
Specific Use	Severe allergies/intolerances	General allergies/sensitivities
Benefits	Aids digestion, promotes skin health	Highly digestible, improves skin and coat
Availability	Prescription only	Prescription only
Packaging Options	Small and standard kibble, cans	Small bites, standard kibble, cans

Critical Insights and Tips

Consult Your Veterinarian

Before switching your dogs diet, a thorough discussion with your veterinarian is crucial. They can help determine if a hydrolyzed protein diet is necessary and which brand might suit your dogs specific health needs.

Transition Gradually

When introducing a new food, especially one as specific as a hydrolyzed protein diet, transition your dog slowly to avoid gastrointestinal upset. Mix the new food with the old in increasing amounts over a week.

Monitor Your Dogs Response

Keep an eye on how your dog responds to their new diet. Improvements in skin condition or gastrointestinal symptoms can be a good sign, but any negative reactions should prompt a call to your vet.

Conclusion

Choosing between Royal Canin Hydrolyzed Protein and Hills Prescription Diet z/d depends on your dogs specific health needs and reactions to different protein sources. Both are excellent choices designed to manage food allergies effectively, so your decision should be guided by professional veterinary advice and your pets individual health.

Interview with Dr. Emily Norton, Veterinary Nutrition Specialist

Q: Dr. Norton, could you explain why hydrolyzed protein diets are recommended for dogs with food allergies?

Dr. Norton: Absolutely! When dogs have food allergies, their immune systems mistakenly identify certain protein molecules as threats, leading to adverse reactions. Hydrolyzed protein diets contain proteins that have been broken downchemically sliced into smaller pieces that are typically too small for the immune system to recognize. This significantly reduces the risk of triggering an allergic response, making these diets particularly beneficial for managing and mitigating food allergy symptoms in dogs.

Q: What are the most common signs that a dog might benefit from a hydrolyzed protein diet?

Dr. Norton: Great question! The signs can vary, but typically, you might notice chronic gastrointestinal issues such as diarrhea, vomiting, and excessive flatulence. Skin problems are also a common indicator, like persistent itching, redness, or hair loss that doesnt seem to resolve with typical treatments. If a dog exhibits these symptoms, its a cue that we might need to explore dietary changes, particularly if these symptoms persist despite other interventions.

Q: How do Royal Canin and Hills approach the formulation of their hydrolyzed protein diets differently?

Dr. Norton: Royal Canin and Hills both strive to meet the needs of sensitive pets, but their approach to hydrolyzed proteins differs subtly yet significantly. Royal Canin primarily uses hydrolyzed soy protein, which is an excellent choice for dogs with sensitivities to common meat proteins. Its about both the source and the process. Their hydrolyzation process ensures that the soy proteins are broken down into very small fragments.

Hills, on the other hand, uses hydrolyzed chicken. This can be particularly beneficial for dogs who may be allergic to beef or lamb but can tolerate chicken if its sufficiently processed to remove allergenic properties. Hills focuses on making their diets extremely digestible, which can aid in nutrient absorption and reduce the workload on the gastrointestinal tract.

Q: Is there a difference in how dogs might react to soy versus chicken as a protein source?

Dr. Norton: Definitely. The protein source can influence both the palatability and how well a dog tolerates the diet. Some dogs might find chicken more palatable, which is crucial for maintaining appetite, while others might react better to soy due to specific meat allergies. Its about finding a balance between a dogs individual allergies, their taste preferences, and their overall health. Each dog is unique, so while one might thrive on a soy-based diet, another might do better with chicken, even in its hydrolyzed form.

Q: For pet owners considering these diets, what should they keep in mind about long-term feeding?

Dr. Norton: When it comes to long-term feeding of specialized diets like these, the key is monitoring. Owners should watch for any changes in their dogs symptoms, weight, and overall behavior. Regular check-ups with the vet are crucial to ensure the diet continues to be appropriate for their health needs. Additionally, because these are specialized diets, they are often more expensive than regular dog food, so financial planning for pet care becomes even more important.

Q: Any final advice for dog owners navigating the choice between these two diets?

Dr. Norton: My biggest piece of advice is to work closely with your veterinarian. They can help you navigate the choice based on your dogs specific health profile. Also, be patient. Sometimes, finding the right diet involves some trial and error. And once you find a diet that works, sticking to it consistently is crucial for maintaining your dogs health.

HELP US PUT FOOD ON THE TABLE

Hill's Science Diet vs. Purina Pro Plan

In this comparison article for Hill's Science Diet vs Purina Pro Plan, we'll highlight the key differences between these two pet food brands. To properly compare Hill's Science Diet and Purina Pro Plan, we'll use up-to-date nutritional and price information.

There are many factors to consider when choosing the best pet food brand for your pet. Factors such as ingredient quality, guaranteed analysis, product safety, brand history, and cost are among the most important factors to consider.

Throughout this Purina Pro Plan vs Hill's Science Diet comparison, we've utilized average data to make general comparisons. If you'd like to see individual product reviews, visit our Hill's Science Diet Review Page or Purina Pro Plan Review Page.

Guaranteed Analysis: Purina Pro Plan vs. Hill's Science Diet

According to AAFCO, all pet food labels must provide a guaranteed analysis of nutrient content. The analysis must provide guaranteed minimum percentages of crude protein and crude fat, and maximum percentages of crude fiber and moisture.

All percentages used in this comparison are averages reported on a dry matter basis.

Hill's Science Diet Dog Food vs. Purina Pro Plan Dog Food

Dry Dog Food	Hill's Science Diet	Purina Pro Plan
Crude Protein	24.6%	32.1%
Crude Fat	14.7%	17.9%
Crude Fiber	3.7%	4.3%

Wet/Canned Dog Food	Hill's Science Diet	Purina Pro Plan
Crude Protein	25.7%	45.5%
Crude Fat	17.3%	19.5%
Crude Fiber	3.5%	7.0%

Crude Protein Comparison For Dog Food

Dogs require twenty-two amino acids to sustain life. Twelve of these amino acids are synthesized naturally, the remaining ten are consumed. Protein is the nutrient which provides some or all of these ten essential amino acids.

The table shows that Hill's Science Diet provides far less protein than Purina Pro Plan. The difference in protein content is roughly 7.49%. In addition, Purina Pro Plan wet dog foods also provide more protein than Hill's Science Diet wet foods.

Crude Fat Comparison For Dog Food

Like protein, fats are an essential part of a dog's body. Fats are needed for the proper development and function of the canine body.

If you look at the average percentages of crude fat, you'll notice that Purina Pro Plan typically guarantees 3.23% more fat. This is a fairly small difference between Purina Pro Plan and Hill's Science Diet, but still worth mentioning. In addition, Purina Pro Plan wet dog foods also provide more fat than Hill's Science Diet wet foods.

As you can see, Hill's Science Diet and Purina Pro Plan guarantee a similar amount of crude fiber. For wet dog foods, Purina Pro Plan typically provides a little more fiber (about 3.47% more).

Hill's Science Diet Cat Food vs. Purina Pro Plan Cat Food

Dry Cat Food	Hill's Science Diet	Purina Pro Plan
Crude Protein	35.0%	44.2%
Crude Fat	18.5%	17.0%
Crude Fiber	4.5%	3.8%

Wet/Canned Cat Food	Hill's Science Diet	Purina Pro Plan
Crude Protein	38.7%	49.8%
Crude Fat	21.5%	17.8%
Crude Fiber	3.6%	7.2%

Crude Protein Comparison For Cat Food

Cats require twenty-two amino acids to sustain life. Eleven of these amino acids are synthesized naturally, the remaining eleven are consumed. Protein is the nutrient which provides some or all of these eleven essential amino acids.

On average, Purina Pro Plan dry cat food recipes contain 9.19% more protein than Hill's Science Diet recipes. Clearly, there is a significant difference between the protein content of Hill's Science Diet and Purina Pro Plan. Similarly, Purina Pro Plan wet cat foods provide significantly more protein than Hill's Science Diet wet foods.

Crude Fat Comparison For Cat Food

There are many ways in which dietary fat contributes to the overall health of our feline friends. Here is a short list of benefits provided by fats (not exhaustive):

Help transport nutrients across cell membranes
Fats produce metabolites, which help control inflammation
Maintain healthy blood pressure
Slow the growth of yeast infections
Fats improve the taste/texture of food.

Purina Pro Plan and Hill's Science Diet both provide roughly the same amount of crude fat. For wet cat foods, Hill's Science Diet typically provides a little more fat (about 3.71% more).

There is a relatively insignificant difference between the crude fiber content of the two brands. For wet cat foods, Purina Pro Plan typically provides a little more fiber (about 3.53% more).

Hill's Science Diet Pet Food Ingredients vs. Purina Pro Plan Pet Food Ingredients

Hill's Science Diet and Purina Pro Plan both use the following controversial ingredients in many of their products:

Liver

Liver is a controversial ingredient because the source animal is not specified. Anonymous animal ingredients are typically very low quality and may contain almost any animal, including dogs and cats!

Pea Protein

Pea protein is produced by removing the starchy parts of peas. Pea protein is considered controversial because it provides a substantial plant based protein boost. This boost is undesirable because plant based protein is typically lower in biological value when compared to meat based proteins.

Brewers Rice

Brewer's rice is the small fragments of rice kernel that are separated from the larger kernels of milled rice. The fragments do not contain the same nutrition profile of the whole kernel and therefore brewer's rice is a lower quality grain. Brewer's rice is typically regarded as an inexpensive and low quality filler.

Wheat Gluten

Wheat gluten is the main protein of wheat. Although wheat gluten is mostly protein, wheat gluten is considered controversial because it significantly boosts the protein content of the product. This is undesirable because plant based protein does not provide the same amino acid profile as meat based protein.

Caramel Color

Caramel color is a concentrated form of caramel, a natural food colorant. Caramel color has been linked to cancer in laboratory animals. Since our pets do not care about food color, caramel color is an unnecessary addition with possible health risks.

Corn Gluten Meal

Corn gluten meal is a by-product from the production of various corn products (corn starch, corn syrup, etc). It's very high in protein (nearly 60% protein) and therefore can significant boost the protein content of the product. Because plant based proteins such as corn gluten meal are inferior to meat based proteins (lack many essential amino acids), they are not suitable substitutes.

Whole Grain Corn

Whole grain corn is the entire corn kernel (the germ, bran, and endosperm). Corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

In regards to digestibility, the claims of "highly digestible" are only true if corn is processed into a meal or flour and subsequently cooked. In regards to the protein contribution, we must note that corn is a plant based protein which does not contain all of the necessary amino acids required by pets to sustain life. Therefore substituting corn for meat is an unsuitable substitution and actually degrades the overall protein quality of the product.

Finally, we'll discuss the claims about vitamins and minerals in corn. Although corn does provide many vitamins and minerals, it not necessarily an exceptional ingredient in this regards. There are many other ingredients which are more complete and biologically appropriate. Therefore the usage of corn as the primary ingredient in pet food should certainly warrant further questioning.

Whole Grain Wheat

Whole grain wheat contains the entire grain of wheat (the germ, bran, and endosperm). Wheat is the second most-produced cereal grain in the world (corn is the first). Although wheat is a controversial ingredient, it is not necessarily undesirable because it provides dietary fiber and many other nutrients. However, wheat contains a notable amount of plant based protein, which is inferior to meat based protein and therefore an undesirable substitution.

Wheat is also one of the most common ingredients to cause food allergies or intolerance. However, grains such as wheat are typically low offenders in comparison to certain protein sources (such as beef).

Powdered Cellulose

Powdered cellulose is produced from minuscule pieces of wood pulp and plant fibers. Other than its fiber content, powdered cellulose lacks any nutritional contribution.

Soybean Protein Isolate

Soy protein isolate is a highly refined/purified form of soy bean protein. Roughly 90% of soy protein isolate is protein. The inclusion of non-meat protein typically degrades the overall quality of protein in the recipe. This degradation is due to the inferior amino acid profile of plant based proteins.

Here are some of the controversial ingredients used only by Hill's Science Diet.

Caramel

Caramel is a widely used natural food colorant. The concentrated form of caramel is typically listed as caramel color and has been linked to cancer in laboratory animals. Since our pets do not care about food color, caramel is an unnecessary addition with possible health risks.

Corn Flour

Corn flour a ground cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

Iron Oxide

Iron oxide is an FDA approved natural food coloring agent. It's commonly found in rusting metal and provides a reddish-brown color.

We believe food colorants are unnecessary ingredients in pet food. Other than potential harm, food colorants do not provide any nutritional value. These type of ingredients are used only to make the food look appealing to humans.

Pork Plasma

Pork plasma is the colorless fluid part of a pig's blood. It may sound disgusting, but it's actually very nutritious for pets. Regardless of the nutritional aspects, consumers are shocked by this ingredient, which is why pork plasma is considered a controversial ingredient.

Poultry Fat

Poultry fat is a by-product of poultry tissue rendering. Poultry fat is a controversial ingredient because the specific protein is not specified. Such ingredients are typically low-quality in comparison to named poultry fats (e.g. chicken fat, turkey fat).

Animal Liver

Animal liver is a controversial ingredient because the source animal is not specified. Anonymous animal ingredients are typically very low quality and may contain almost any animal, including dogs and cats!

Tomato Pomace

Tomato pomace is a by-product of tomato manufacturing. It's considered a controversial ingredient because many people believe it is an inexpensive low quality filler. However, tomato pomace provides a notable amount of dietary fiber, B vitamins, Lycopene, and vitamin A. Although it is a very inexpensive ingredient, it is not nutritionally empty.

Beef By-Products

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, beef by-products contain nearly all parts of the beef which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Like other meat by-products, beef by-products are considered controversial, mainly because they are inexpensive ingredients which consumers have equated with slaughterhouse waste. However, manufactures and many experts claim that animal by-products are unjustly criticized. Proponents state that "named" by-products, such as beef by-products, supply many important nutrients required by pets.

Pork By-Products

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, pork by-products contain nearly all parts of pork which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Like other meat by-products, pork by-products are considered controversial, mainly because they are inexpensive ingredients which consumers have equated with slaughterhouse waste. However, manufactures and many experts claim that animal by-products are unjustly criticized. Proponents state that "named" by-products, such as pork by-products, supply many important nutrients required by pets.

Dried Tomato Pomace

Dried tomato pomace is a by-product of tomato manufacturing. It's considered a controversial ingredient because many people believe it is an inexpensive low quality filler. However, tomato pomace provides a notable amount of dietary fiber, B vitamins, Lycopene, and vitamin A. Although it is a very inexpensive ingredient, it is not nutritionally empty.

Pea Protein Concentrate

Pea protein concentrate is produced by removing the starchy parts of peas. Pea protein concentrate is considered controversial because it provides a substantial plant based protein boost. This boost is undesirable because plant based protein is typically lower in biological value when compared to meat based proteins.

Here are some of the controversial ingredients used only by Purina Pro Plan.

Poultry

Poultry is a controversial ingredient because the source animal is not specified. Anonymous ingredients such as poultry are typically low-quality ingredients in comparison to named protein sources (e.g. chicken, turkey, duck).

Canola Oil

Canola oil is a plant-derived oil from the seeds of canola plants. Although fat is an essential component of any diet, canola oil is controversial in pet food. Proponents claim that canola oil provides a better fat profile in comparison to other plant based oils. However, opponents claim that canola oil is typically produced with genetically modified rapeseed and that rapeseed oil has multiple adverse health affects.

Corn Grits

Corn grits are made from ground corn. Corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

Canola Meal

Canola meal is a high protein by-product of canola oil production. This ingredient is marked controversial because it may be derived from genetically modified rapeseed, which is associated with multiple adverse health affects.

Ground Wheat

Ground wheat is regarded as an inexpensive and low-quality filler in pet food. However, wheat does provide plant-based protein and makes pet food more affordable for consumers. It's important to note that plant based protein does not provide the same amino acid profile as meat based protein.

Animal Digest

Animal digest is the result of undecomposed animal tissue after hydrolysis, a chemical reaction. It is typically used as flavoring to improve taste. Animal digest is considered by many as an undesirable low-quality ingredient. What's more, the source animal is not specified and therefore animal digest can contain almost any animal, including dogs and cats!

Garlic Powder

Garlic powder in very small quantities can be an acceptable addition, however, garlic can also be toxic. Therefore many pet owners choose to completely avoid garlic.

Soybean Flour

Soybean flour contains more than 50% protein. Therefore, soybean can significantly boost the protein content of the product. The inclusion of non-meat protein typically degrades the overall quality of protein in the recipe. This degradation is due to the inferior amino acid profile of plant based proteins.

Soybean Hulls

Soybean hulls are a by-product of soybean oil and meal processing. They are typically regarded as low quality and inexpensive fillers which lack any significant nutritional value.

Vegetable Oil

Specific vegetable oils are typically positive ingredients; however, this ingredient does not specify which vegetable(s) were used to produce the oil.

Without this information, it is impossible for us to make any specific statements. With any fat source, it is important to know the omega-3 to omega-6 fatty acid ratio, a property which cannot be determined with this ingredient. Thus, we have marked vegetable oil as a controversial ingredient.

Corn Germ Meal

Corn germ meal is a high protein by-product of the oil extraction process from corn (maize). It's considered controversial because plant based protein does not contain all of the necessary amino acids required by pets to sustain life. Therefore substituting corn germ meal protein for meat based protein is an unsuitable substitution and actually degrades the overall protein quality of the product.

Poultry Giblets

Poultry giblets includes the heart, liver, gizzards, and other internal organs of poultry. Organs are nutritiously dense ingredients which provide high quality protein and fat. However, this particular ingredient is considered an anonymous meat ingredient because the type of poultry is not specified. In order words, "named" giblets such as chicken giblets or turkey giblets are preferred over poultry giblets.

Meat By-Products

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, meat by-products contain nearly all parts of the animal which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

This ingredient is marked controversial because the meat source is not identified. Anonymous ingredients such as meat by-products are typically very low quality additions. The most unpleasing property of this ingredient is that the animal source can contain any mammal, even dogs & cats.

Ground Yellow Corn

Ground yellow corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

Chicken By-Products

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, chicken by-products contain nearly all parts of the chicken which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Like other meat by-products, chicken by-products are considered controversial, mainly because they are inexpensive ingredients which consumers have equated with slaughterhouse waste. However, manufactures and many experts claim that animal by-products are unjustly criticized. Proponents state that "named" by-products, such as chicken by-products, supply many important nutrients required by pets.

Poultry By-Products

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, poultry by-products contain nearly all parts of poultry which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Like other meat by-products, poultry by-products are considered controversial, mainly because they are inexpensive ingredients which consumers have equated with slaughterhouse waste. However, manufactures and many experts claim that animal by-products are unjustly criticized. Proponents state that by-products, such as poultry by-products, supply many important nutrients required by pets. Finally, we must also note that this ingredient is considered an anonymous meat ingredient because the specific type of poultry is not specified. By-products which are "named", such as chicken by-products are typically higher in quality when compared to the more general poultry by-products.

Chicken By-Product Meal

Chicken by-product meal is produced by cooking chicken by-products using a process called rendering. By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, chicken by-products contain nearly all parts of chickens which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Poultry By-Product Meal

Poultry by-product meal is a controversial ingredient because the source animal is not specified. Anonymous ingredients such as poultry by-product meal are typically low-quality ingredients in comparison to named protein by-product meals (e.g. chicken by-product meal, turkey by-product meal, duck by-product meal).

Soybean Protein Concentrate

Soybean protein concentrate is produced by removing the water soluble carbohydrates from soybeans. The inclusion of non-meat protein typically degrades the overall quality of protein in the recipe. This degradation is due to the inferior amino acid profile of plant based proteins.

Animal Fat (Preserved With Mixed Tocopherols)

Animal fat is a by-product of tissue rendering. The source animal is not specific and therefore we cannot be certain that the source does not include diseased animals or even euthanized dogs and cats.

We believe that certain pet food ingredients are linked to adverse health affects; these ingredients are classified as harmful.

Hill's Science Diet and Purina Pro Plan both use the following harmful ingredients in many of their products:

Menadione Sodium Bisulfite Complex

Menadione sodium bisulfite complex is a synthetic version of vitamin K that has been linked to many health concerns. Research has suggested possible toxic reactions in liver cells and red blood cells among other serious problems. In fact, one large chemical supplier warns, "The substance is toxic to kidneys, lungs, liver, mucous membranes. Repeated or prolonged exposure to the substance can produce target organs damage."

Here are some of the harmful ingredients used only by Purina Pro Plan.

Bha

Butylated hydroxyanisole (BHA) is an artificial preservative and possible cancer-causing agent. Studies have show that BHA can be linked to various tumors in laboratory animals.

Bht

Butylated hydroxytoluene (BHT) is an artificial preservative and possible cancer-causing agent. BHT is banned in several countries, but the FDA has classified BHT as "generally recognized as safe."

Corn Oil

Corn oil is extracted from the germ of corn kernels. It contains an omega-6 to omega-3 fatty acid ratio of 49:1. Corn oil's unfavorable omega-6 to omega-3 fatty acid ratio makes it an undesirable ingredient. Consumption of such ingredients can lead to an array of health problems in both animals and humans.

Yellow 5

Yellow 5 is an artificial dye which may be contaminated with several cancer-causing chemicals. Like other dyes, yellow 5 does not provide any nutritional value.

Added Color

The ingredient "added color" is ambiguous and may include various artificial dyes. Most artificial dyes have been linked to various chronic diseases.

Menadione Sodium Bisulfate Complex

Menadione sodium bisulfate complex is a synthetic version of vitamin K that has been linked to many health concerns. Research has suggested possible toxic reactions in liver cells and red blood cells among other serious problems. In fact, one large chemical supplier warns, "The substance is toxic to kidneys, lungs, liver, mucous membranes. Repeated or prolonged exposure to the substance can produce target organs damage."

Pork Fat (Preserved With Tbhq And Citric Acid)

Pork fat is typically collected while cooking pork using a process called rendering. Pork fat is a relatively high quality source of essential fatty acids. In particular, pork fat is high in linoleic acid, an important omega-6 fatty acid. Unfortunately, this ingredient is preserved with TBHQ, an artificial preservative.

Animal Fat (Preserved With Tbhq And Citric Acid)

Product Safety: Recall History of Hill's Science Diet & Purina Pro Plan?

Hill's Science Diet has been recalled 2 times.

Jan. 31, 2019: elevated levels of Vitamin D
March 20, 2019: elevated levels of Vitamin D

Purina Pro Plan has been recalled once.

March 9, 2016: Incorrect Vitamins and Minerals

Price Comparison: Which Brand Is More Expensive?

Dry Dog Food	Hill's Science Diet	Purina Pro Plan
Per Pound	$2.83	$3.10
Per Calorie	$0.0018	$0.0017

Dry Cat Food	Hill's Science Diet	Purina Pro Plan
Per Pound	$4.17	$4.67
Per Calorie	$0.0024	$0.0025

Wet Dog Food	Hill's Science Diet	Purina Pro Plan
Per Pound	$5.03	$3.85
Per Calorie	$0.0125	$0.0079

Wet Cat Food	Hill's Science Diet	Purina Pro Plan
Per Pound	$9.11	$8.25
Per Calorie	$0.0197	$0.0185

The average cost-per-lb is heavily influenced by the varying amounts of moisture present in each brand's food products (wet vs. dry food, dry vs. freeze-dried food, etc). However, the average cost-per-kcal eliminates the influence of moisture. Therefore, the average cost-per-kcal is the better metric to consider.

If you'd like to calculate the average cost-per-day or cost-pet-year of feeding Hill's Science Diet or Purina Pro Plan, input your pet's weight into our cost analyzer widget.

Averages price data can identify whether or not there exists a significant price difference between two brands. However, the actual price that you'll pay for Hill's Science Diet or Purina Pro Plan will depend on your shopping habits.

Pet owners who use our price comparison feature typically save more than 25% off retail prices for Hill's Science Diet and Purina Pro Plan. In addition, we currently have some great coupons for our readers.

Disclosure: PawDiet has an affiliate relationship with stores featured (or linked-to) in this article. We are compensated for referring customers. Thank you for shopping with our retail partners!

Where To Buy Hill's Science Diet Pet Foods

You can purchase Hill's Science Diet pet foods from the following stores:

125 Recipes In-Stock Today

123 Recipes In-Stock Today

100 Recipes In-Stock Today

Where To Buy Purina Pro Plan Pet Foods

You can purchase Purina Pro Plan pet food products from these retailers:

122 Recipes In-Stock Today

70 Recipes In-Stock Today

118 Recipes In-Stock Today

Type Of Pet Foods Available

Product	Hill's Science Diet	Purina Pro Plan
Dry Dog Food	48 Recipes	53 Recipes
Wet Dog Food	34 Recipes	43 Recipes
Dog Treats	18 Treats	None
Dry Cat Food	25 Recipes	31 Recipes
Wet Cat Food	48 Recipes	84 Recipes
Cat Treats	None	None