Rating: 
Hill’s Prescription Diet I/D Canine dry dog food gets the Advisor’s below-average rating of 2.5 stars.
The Hill’s Prescription Diet I/D Gastrointestinal Health product line includes only one dry dog food. Although the product appears to be designed to help manage dogs with digestive health issues, we found no AAFCO nutritional adequacy statements for this dog food on the Hill’s website.
Hill's Prescription Diet I/D Canine
Dry Dog Food
Estimated Dry Matter Nutrient Content
Ingredients: Ground whole grain corn, brewers rice, dried egg product, chicken by-product meal, corn gluten meal, pork fat (preserved with mixed tocopherols and citric acid), powdered cellulose, dicalcium phosphate, chicken liver flavor, iodized salt, potassium citrate, choline chloride, calcium carbonate, potassium chloride, dried beet pulp, soybean oil, vitamins (vitamin E supplement, niacin, thiamine mononitrate, vitamin a supplement, calcium pantothenate, biotin, vitamin B12 supplement, pyridoxine hydrochloride, riboflavin, vitamin D3 supplement, folic acid), taurine, minerals (ferrous sulfate, zinc oxide, copper sulfate, manganous oxide, calcium iodate, sodium selenite), phosphoric acid, preserved with mixed tocopherols & citric acid, rosemary extract
Fiber (estimated dry matter content) = 2.6%
Red items when present indicate controversial ingredients
The first ingredient in this dog food is corn. Corn is an inexpensive and controversial cereal grain of only modest nutritional value to a dog.
For this reason, we do not consider corn a preferred component in any dog food.
The second ingredient is brewers rice. Brewers rice represents the small grain fragments left over after milling whole rice.
This is an inexpensive cereal grain by-product and not considered a quality ingredient.
The third ingredient is dried egg product… a dehydrated form of shell-free eggs. Quality can vary significantly. Lower grade egg product can even come from commercial hatcheries… from eggs that have failed to hatch.
In any case, eggs are easy to digest and have an exceptionally high biological value.
The fourth item lists chicken by-product meal… a dry rendered product of slaughterhouse waste. It’s made from what’s left of a slaughtered chicken after all the prime cuts have been removed.
In a nutshell, chicken by-products are those unsavory leftovers usually considered “unfit for human consumption”.
This stuff can contain almost anything… feet, beaks, undeveloped eggs… anything (that is) but skeletal muscle (real meat).
On the brighter side, by-product meals are meat concentrates and contain nearly 300% more protein than fresh chicken.
The fifth item is corn gluten meal. Gluten is the rubbery residue remaining once corn has had most of its starchy carbohydrate (the good stuff) washed out of it.
Compared to meat, glutens are inferior grain-based proteins low in many of the essential amino acids dogs need to sustain life.
This inexpensive plant-based ingredient can significantly boost the total protein content reported in this dog food.
The sixth ingredient is pork fat. Commonly known as lard, pork fat can add significant flavor to any dog food. Though it can be high in saturated oils, in reasonable amounts, pork fat can be considered an acceptable ingredient.
The seventh ingredient is powdered cellulose… a non-digestible plant fiber usually made from cotton or sawdust. Cellulose is sometimes added to dilute the number of calories per serving and to give the feeling of fullness when it is eaten.
Except for the usual benefits of fiber, powdered cellulose provides no nutritional value to a dog.
From here, the list goes on to include a number of other items.
But to be realistic, ingredients located this far down the list (other than nutritional supplements) are not likely to have much of an effect on the overall rating of this product.
With four notable exceptions…
First, we note the use of beet pulp. Beet pulp is a controversial ingredient… a high fiber by-product of sugar beet processing.
Some denounce beet pulp as an inexpensive filler while others cite its outstanding intestinal health and blood sugar benefits.
We only call your attention here to the controversy and believe the inclusion of beet pulp in reasonable amounts in most dog foods is entirely acceptable.
Next, the product includes soybean oil… red flagged here only due to its suspected (yet unlikely) link to canine food allergies.
Thirdly, we find no evidence of probiotics… friendly bacteria applied to the surface of the kibble after processing.
Finally, the minerals here do not appear to be chelated. And that can make them more difficult to absorb. Non-chelated minerals are usually associated with lower quality dog foods.
Hill’s Prescription Diet I/D Dry Dog Food
The Bottom Line
Even though this is a prescription product, we continue to limit our judgment to the estimated meat content of the recipe as well as the apparent quality of its ingredients. And nothing else.
Our ratings have nothing to do with the accuracy of claims made by the manufacturer as to this product’s ability to effectively treat or cure a specific health condition.
So, to find out whether or not this dog food is appropriate for your particular pet, you must consult your veterinarian.
With that understanding…
Judging by its ingredients alone, Hill’s Prescription Diet I/D appears to be a below-average dry dog food.
But ingredient quality by itself cannot tell the whole story. We still need to estimate the product’s meat content before determining a final rating.
The dashboard displays a dry matter protein reading of 26%, a fat level of 14% and an estimated carbohydrate content of 52%.
Below-average protein. Below-average fat. And above-average carbohydrates… when compared to a typical dry dog food.
Yet when you take into consideration the protein-boosting effect of the corn gluten meal, this looks like the profile of a dry dog food containing only a modest amount of meat.
Bottom line?
Hill’s Prescription Diet I/D is primarily a grain-based dry dog food using a modest amount of dried egg product as its main source of animal protein… thus earning the brand 2.5 stars.
Not recommended.
A Final Word
This review is designed to help you make a more informed decision when buying dog food. However, our rating system is not intended to suggest feeding a particular product will result in specific health benefits for your pet.
For a better understanding of how we analyzed this product, please be sure to read our article, “The Problem with Dog Food Reviews”
Remember, no dog food can possibly be appropriate for every life stage, lifestyle or health condition. So, choose wisely. And when in doubt consult a veterinarian for help.
Have an opinion about this dog food… or maybe the review itself? Please know… we welcome your comments.
Notes and Updates
01/04/2010 Original review
08/10/2010 Review updated
The Dog Food Advisor publishes independent reviews to help pet owners make better choices when shopping for dog food.