Home / News / Two Different Perspectives

Two Different Perspectives

Apr 23, 2023Apr 23, 2023

Tufts University, opposite opinions on nutrition.



USA Today recently posted a story titled "What is a balanced diet?" The story was regarding human nutrition (not pet nutrition), but the experts explaining what a balanced diet is in human nutrition turns out to be dramatically different from what a balanced diet is in pet nutrition.

Alice Lichtenstein, DSc, director of the Cardiovascular Nutrition Team at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University stated (bold added):

"a balanced diet should not require supplements. That is, of course, unless one has nutrient deficiencies and supplementation has been advised by a physician. Additional vitamin and mineral supplementation might also be desired for other benefits, but usually shouldn't replace the natural source of the nutrient."

To the contrary, the veterinary school at Tufts University has an opposite perspective for pet food (bold added):

"While a ‘whole foods’ approach where every nutrient comes from food, not supplements is appealing, it is nearly impossible to meet all of a pet's nutrient needs without adding concentrated supplements."

The answer could be the ultra-processed nature of many commercial pet foods and their support of veterinary institutions including the Tufts Veterinary School.


The human nutritionists at Tufts also stated "The easiest way to work towards achieving a balanced diet is to limit intake of ultra-processed food…" Per the NOVA system (a food classification system) "with its identification and definition of ultra-processed foods that has been most applied in scientific literature" – ultra processed foods are:

"It starts with the fractioning of whole foods into substances including sugars, oils and fats, proteins, starches and fibre. These substances are often obtained from a few high-yield plant foods (such as corn, wheat, soya, cane or beet) and from puréeing or grinding animal carcasses, usually from intensive livestock farming."

"Some of these substances are then submitted to hydrolysis, or hydrogenation, or other chemical modifications. Subsequent processes involve the assembly of unmodified and modified food substances with little if any whole food using industrial techniques such as extrusion, moulding and pre-frying. Colours, flavours, emulsifiers and other additives are frequently added to make the final product palatable or hyper-palatable."

Most kibble pet foods and many canned pet foods include rendered ingredients (ground animal carcasses usually from intensive livestock farming) which are markers of ultra-processed food. As well, most kibble pet foods are extruded and include dyes and flavor additives, more markers of ultra-processed food.

Financial Support from the manufacturers of ultra-processed foods.

Tufts Veterinary School provides the following disclosures (pet food related only):

"Dr. Freeman has received research or residency funding from, given sponsored lectures for, or provided professional services for Hill's Pet Nutrition, Nestle Purina PetCare, P&G Petcare (now Mars), and Royal Canin.""Dr. Heinze has provided professional services, has done consulting for WellPet, given sponsored talks for Nestle Purina Petcare and the Pet Food Institute.""Dr. Linder has received speaker fees or research funding from Hill's Pet Nutrition, Nestle Purina Petcare, Royal Canin."

Unfortunately, it is not just Tufts University pet food nutritionists that are financially involved with ultra-processed pet food manufacturers. Most (if not all) veterinary institutions accept funding from Hill's, Purina, and Mars.

Balanced through natural sources of nutrients.

It is significantly important to provide your pet with a complete and balanced diet. Nutritional deficiencies or excesses will cause health consequences in your pet. Just a few from

"Vitamin A: Deficiencies can cause decreased eating or anorexia, stunted growth, dull hair coat, and weakness. Toxicities can cause stunted growth, anorexia, and bone fractures."

"Vitamin D: Deficiencies can cause rickets, enlarged joints, osteoporosis, and other bone issues. Toxicities can include hypercalcemia, decreased eating or anorexia, and lameness."

However, your pet does NOT require a long list of supplements to achieve a complete and balanced diet. In the same way Tufts University human food nutritionists recommend, there are many pet food options available that balance the diet through ‘natural sources’ (food ingredients, minimally processed) or balance the diet through very minimal supplements.

Read the ingredient list on your pet's food and just like what the Tufts University human food nutritionists told us – limit the intake of ultra-processed foods your pet consumes.

Wishing you and your pet(s) the best,

Susan ThixtonPet Food Safety AdvocateAuthor Buyer Beware, Co-Author Dinner PAWsibleTruthaboutPetFood.comAssociation for Truth in Pet Food

Become a member of our pet food consumer Association. Association for Truth in Pet Food is a a stakeholder organization representing the voice of pet food consumers at AAFCO and with FDA. Your membership helps representatives attend meetings and voice consumer concerns with regulatory authorities. Click Here to learn more.

What's in Your Pet's Food?Is your dog or cat eating risk ingredients? Chinese imports? Petsumer Report tells the ‘rest of the story’ on over 5,000 cat foods, dog foods, and pet treats. 30 Day Satisfaction Guarantee. Click Here to preview Petsumer Report.

Find Healthy Pet Foods in Your Area Click Here

The 2023 ListSusan's List of trusted pet foods. Click Here to learn more.


May 31, 2023 at 1:39 pm

USA Today has to use the typical disclaimer (as quoted above) regarding vitamin/mineral supplementation or they run the risk of getting sued by consumers or the American Medical Association; the USA Today articles regarding anything health related have to be run by their in-house attorneys before publication to scrub clean of any verbal "contamination." The main problem with both human and animal diets in America? Both humans and animals are just used as the overprocessed chemical laden garbage disposals for unethical food processors to wreak their VERY profitable chaos upon. And Americans and their pets’ health and medical bills and shortened lifespans are the PROOF.

Terry T. Durbin

May 31, 2023 at 3:13 pm

Neither Freeman, Heinze, or Linder should be referred to as "doctor".

Diane Richardson

June 1, 2023 at 9:04 am

Freeman is a board certified veterinarian so as much as I dislike her, she is a Dr

Sue Hillerby

May 31, 2023 at 4:14 pm

"…Unfortunately, it is not just Tufts University pet food nutritionists that are financially involved with ultra-processed pet food manufacturers. Most (if not all) veterinary institutions accept funding from Hill's, Purina, and Mars…"

Not only that, Susan, but WSAVA (World Small Animal Veterinary Association) also has all of those manufacturers as partners on their Global Nutrition Committee…

Cat Lane

May 31, 2023 at 7:19 pm

I’ll respectfully disagree – there ARE reasons why a freshfood diet for a dog may and usually does need supplementation. One reason – dogs have higher requirements for many essentials than we do; I personally require 1200 mgs of calcium daily, my large breed dog needs 2200. In the absence of bones in the diet, calcium will need to be supplemented. Other reasons include – the need of many underexercised dogs (or simply dogs with slow metabolisms) to stick to lower calorie diets; difficulty for owners to obtain/afford specific nutrient dense foods (beef kidney, turkey or salmon for selenium, as an example). Dogs may also have intolerances to some nutrient dense foods. There are several reasons why a home prepared diet for a given dog would need vitamin D, calcium, zinc and potentially several others supplemented.

With some dogs, especially rawfed, you can meet the RA with food.With many others we do best to add small amounts of high quality vitamins and minerals. It's not perfection, but it's still much better than kibble. And you know what they say about letting the perfect become the enemy of the good….:)

With therapeutic diets, the need to provide the essentials in the form of supplements is very common, too.

I’ll add that I’m a nutritionist, and struggle to meet everything I need every day too. I take VitaminD, zinc, iron and copper all the time, due to some dietary restrictions and my own choices not to consume some meats.

Susan Thixton

May 31, 2023 at 8:24 pm

You might want to consider egg shell powder for a calcium source. It is simple to make – best from pasture raised hen eggs. 1/2 teaspoon provides 400 – 500 mg calcium. I’ve taken it as a supplement, and I use it for a calcium source when I make pet food.

Cat Lane

May 31, 2023 at 8:44 pm

I do, if the client prefers it, but we often use a commercial product too. There are always pros and cons, some dogs do better with one form or another….and just FYI – 1/2 tsp is more like 900 mgs. if correctly powdered. With my therapeutic cases I have to be very precise. 🙂

Susan Thixton

June 1, 2023 at 7:55 am

My only point was egg shell calcium is food. Which is a natural source of the nutrient. And to my understanding, the calcium content could vary depending on what the hen ate/how it was raised. I’m in total agreement there are different needs for different animals.

Cat Lane

June 1, 2023 at 10:01 am

We cannot always know to the mg, how much nutrient is *really* in a food – it's a judgement call for me, as a nutritionist, when to go above the RA (calcium is often safe to go a bit higher) and when to be cautious(iron with cancer, phosphorus with kidney issues). I appreciate you allowing my reply, and my point is simply that if we need a supplement – which often happens – it's not a catastrophe to use one. Better a good quality indivdual supplement than the consequences of chronic low intake.

There's just so much negativity and hyperbole about supplements, I am hoping to reassure people that if they are needed, better to use them than let the dog go without.

Thank you for allowing this discussion, too. I think it is an important one for the holistic dog community to have. 🙂


June 1, 2023 at 7:46 am

And what do you use for vitamin E , vitamin D, and copper? B vitamins for cats, especially B1? And manganese? Not everybody has access to green-lipped mussels. I don't have access to human-grade organ meat, they’re impossible to source in my area, unfortunately.

Susan Thixton

June 1, 2023 at 7:57 am

You can search what foods provide these nutrients.

Diane Richardson

May 31, 2023 at 8:15 pm

There's also a more sinister reason for the disparity and it has nothing to do with animals. USA gvt is hugely anti human supplements and nutritional herbs. To the point that each year they attempt to tighten accessibility to these by the population. End game goal is massive limitation and restrictions on public access to supplements because big pharma desires this.So at every opportunity they preach that they aren't needed

Has zero to do with animals at all but the side effects is access limitation spillover

Other than the above I absolutely agree with Cat Lanes reply


June 3, 2023 at 1:33 pm – while plenty of supplement companies properly test their stuff to make sure their claims have evidence to back them, human supplements aren't super regulated, and there are also many bad ones out there that use exaggerated claims to get people to buy them while having very little or no testing at all. I mean like…regulation is needed, I think the bigger problem is WHOM the gvt goes after with those regulations. In which that can obviously be influenced with lobbying.

David Boothman

June 2, 2023 at 1:48 pm

It's really quite simple. Food is deficient in essential nutrients. It would appear that scientists are unable to read, or at least unable to read the Smart fertilizer handbook. Even in its introduction it notes that zinc is the most deficient essential mineral in soils, worldwide, and leads to billions of dollars of losses worldwide and to death and sickness for millions of people. Add to this food content deficiencies in many others such as magnesium and and we should be recognizing a crisis. Again scientists have been unable to put two and two together and realize human zinc deficiency underlies to a significant extent the deaths and serious illnesses in the recent epidemic. Zinc inhibits a virus from entering a cell and converting it to a virus factory. Want an example? I’m eighty years old but I’m not dumb so we supplement with zinc. We caught covid and had the symptoms of the start of a really bad cold, for one day, followed by one day of weakness and rest. On the third day I was back in the boatyard working on commissioning the boat for 12 hours. Now I am a trained scientist but not in life sciences however I can read and understand so I dont take for granted that malnutrition is something left behind in a pervious era. Malnutrition today is worse than it was 50 years ago due to diet, lifestyle and farming methods. For example the over-fertilization with nitrogen fertilizers inhibits the plant production of compounds such as quercetin which facilitates the entry of zinc into cells, and so it is also deficient. These things are basic life-science common knowledge and the fact that trained scientists either don't know them or ignored them means they are idiots. This sounds petty grumpy and condemning but this is how scientists treat people pretending to be scientists and getting it consistently wrong.

Your email address will not be published. Required fields are marked *

Comment *

Name *

Email *



Human Grade & Feed GradeDo you know what the differences are between Feed Grade and Human Grade pet food? Click Here .

The RegulationsPet Food is regulated by federal and state authorities. Unfortunately, authorities ignore many safety laws. Click Here to learn more about the failures of the U.S. pet food regulatory system.

The Many Styles of Pet FoodAn overview of the categories, styles, legal requirements and recall data of commercial pet food in the U.S. Click Here.

The IngredientsDid you know that all pet food ingredients have a separate definition than the same ingredient in human food? Click Here.

Click Here for definitions of animal protein ingredients.

Click Here to calculate carbohydrate percentage in your pet's food.

If your pet has become sick or has died you believe is linked to a pet food, it is important to report the issue to FDA and your State Department of Agriculture.

Save all pet food – do not return it for a refund.

If your pet required veterinary care, ask your veterinarian to report to FDA.

Click Here for FDA and State contacts.

Subscribe to our NewsletterClick Here

Pet Food Recall History (2007 to present)Click Here

Find Healthy Pet Foods StoresClick Here

About TruthaboutPetFood.comClick Here

Friends of TruthaboutPetFood.comClick Here

a balanced diet should not require supplements Additional vitamin and mineral supplementation might also be desired for other benefits, but usually shouldn't replace the natural source of the nutrient. it is nearly impossible to meet all of a pet's nutrient needs without adding concentrated supplements Ultra-processed. fractioning of whole foods grinding animal carcasses hydrolysis extrusion pre-frying Colours, flavours Financial Support from the manufacturers of ultra-processed foods. Balanced through natural sources of nutrients. your pet does NOT require a long list of supplements to achieve a complete and balanced diet Become a member of our pet food consumer Association. What's in Your Pet's Food? Find Healthy Pet Foods in Your Area Click Here The 2023 List Human Grade & Feed Grade Click Here . The Regulations Click Here The Many Styles of Pet Food Click Here The Ingredients Click Here. Click Here Click Here Click Here Click Here Click Here Click Here Click Here Click Here