Myth? Nutritional Balance Over Time
July 26th, 2011
The theory goes like this. It doesn’t matter if each individual meal we feed ourselves or our pets is balanced … because overtime, with enough variety, it’ll all balance out. I know I’ve said this to myself, especially if ice cream is on the menu for dinner.
I’ve heard the idea used to explain / justify things like:
- Supplementing a commercial pet food with “people food” (which I do)
- Rotating through a variety of commercial pet foods (which our pet food shopping habits survey shows 45% of our readers do)
- Making a variety of homemade pet foods (and not worrying too much about day-to-day nutritional balance)
Ongoing micronutrient imbalance can erode a pet's health over time.
Thanks to a press pass at the recent American College of Veterinary Internal Medicine Forum, I got to attend some pet nutrition seminars given by board-certified veterinary nutritionists. I wrote a bit about one session on homemade pet diets earlier (on my own blog), but I wanted to give more time and space to one concept in particular:
This idea of nutritional balance over time.
Jennifer Larsen, DVM, a board-certified veterinary nutritionist at University of California-Davis, poked a few wholes in the idea during her seminar. After reading through my notes from the event, I sent her some follow-up questions via email to find out more.
When Larsen chooses or creates a pet diet for a veterinary teaching hospital client, she explains, “First, my perspective is that the primary goal of the nutritional management of any case is to provide adequate amounts of energy as well as all the required nutrients. Secondly, specific nutritional modifications are considered if needed (like fat restriction, limitations in potassium or phosphorus, etc). Then, I consider ingredients that work within these parameters (as well as withing criteria from the patient and client) and go from there. This is the same process whether I ultimately meet my goals using a commercial diet (over the counter or prescription), a parenteral formulation [via IV], a liquid elemental enteral product [via feeding tube], or a home-cooked diet.”
Other considerations include:
- The pet’s nutrient requirements compared to a “normal” pet population
- How a pet’s energy intake affects micronutrient requirements
- The bioavailability of those micronutrients in specific diets or ingredients
- What digestibility values determine nutrient content of the diet
Calling nutrition both a quantitative and a qualitative science, Larsen sums up her concerns about “nutritional balance over time,” like this: “I have heard the ‘balance over time’ concept as a means to promote dietary variety and achieve nutrient balance, and specifics on how this is achieved are never provided.”
Questions to Ask, Answers You Need: Nutritional Balance Over Time
Which version of nutrient requirements will you use? There are several … National Research Council, Association of American Feed Control Officials … etc.
How exactly will you balance out the various deficiencies? For example, if the diet is deficient for your pet’s needs (in something like zinc) and you feed the diet for two weeks, then do you on day 14 give a supplement that has 14 x the daily requirement? Or, do you give various levels of supplements over many days with the idea that the total amount will average out to the daily requirement?
Nutritional Balance Over Time: Concerns [emphasis mine]
“My fear,” says Larsen, “is that it is a convenient way to justify the approach of feeding casually and not worrying about such things as micronutrient requirements. It seems to me that this practice could set us up for multiple chronic marginal deficiency syndromes, such that over clinical signs of such would show up after a long period of time, if ever (given the short life spans of our pets). Also, this brings up the concern of suboptimal performance that may only be manifested in certain parameters of health and well-being that we don’t typically measure. I do see overt deficiency and toxicity cases. But, what about the many potential others that have more vague signs? The deficiency signs for multiple nutrients include lethargy and inappetence.”
Ingredient variables include things like cooking method (which can alter nutrient levels). Then, there is the common mistake of substituting volume measurements for weight ones. And, even a seemingly well-balanced homemade pet food that looks good for protein, carbs, and fats … can still be deficient in micronutrients (there are 40 of them). So, even if you use a decent recipe and merely swap out protein or carb sources once in a while, a fundamentally deficient recipe is still fundamentally deficient.
Plus, there is a tendency for “recipe drift,” where:
- Measurements get less precise over time
- Ingredients get substituted
- Feeding amounts shift (up or down)
Nutritional Balance Over Time: The Human Comparison
Larsen calls the human analogy (that we don’t feed ourselves particularly well and we’re mostly OK) a poor one … because there are many forms of rampant malnutrition in industrialized countries, including:
- Obesity
- Vitamin D deficiency
- Vitamin B12 deficiency
- Iron deficiency
- Calcium deficiency
In other words, we don’t do a terrific job on this for ourselves. Even if we work hard at a dietary variety, most people return to the same foods again and again.
Do you believe it’ll all work out? Or are you regularly calculating and re-calculating your pet’s nutritional intake, especially when it comes to micronutrients? If so, I’d love to know more about your methods and strategies.
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Tags: American College of Veterinary Internal Medicine, American College of Veterinary Nutrition, cat food, cat nutrition, dog food, dog nutrition, homemade cat food, homemade dog food, pet food rotation, veterinary nutritionist
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2 Responses to “Myth? Nutritional Balance Over Time”
A professional writer based in Colorado, Roxanne Hawn doesn't just love dogs. She deep-down requires them in life. Something inside her genes, perhaps? That's why it's such a joy to write about all things canine. Roxanne began writing about pets in 1995, when she worked for the American Animal Hospital Association and later for the American Humane Association. During this period in her career, Roxanne served on the board of directors for the National Council on Pet Population Study and Policy (a coalition of animal welfare groups). Roxanne also volunteered for many years at an animal shelter, where she witnessed firsthand what happens when the human-animal bond breaks or never forms.
ok, first of all “clinical signs of such would show up after a long period of time, if ever (given the short life spans of our pets).”
Um, so HOW is this an issue? I mean so what if Fido was technically deficient in micronutrient #28/40 if there would be no clinical signs until YEAR 30 & Fido dies at 16 years, which is a good old age for his breed??
I’m a balance over time person for both people and animals. I think our success on this planet is due to a wide adaptability to various foods. I have no desire to have ‘scientifically prepared’ NASA meals for me or for my pets.
For one thing – scientists do make mistakes too. Up to the 80′s, infant formula was missing taurine b/e nobody knew infants lack the enzyme to convert it. Ooops. Then we started adding nucleotides. Now essential fatty acids are being added – and keep in mind that in THIS case, we actually HAVE the perfect model that we’re trying to copy: breastmilk. And we still keep tinkering with the substitute as science develops.
The biggest problem with nutritionists from my perspective is their ties to corporations. Even gov’t nutrition advice is heavily influenced by agricultural and food production lobbies. I admire science – I’m an IBCLC myself & value evidence based practice – but I’m always following the $ in these discussions.
Corporations have convinced us that dogs, cats, infants & children are too complicated to eat ‘normal’ food and instead need scientifically prepared diets. I don’t believe that at all.
I am listening to people’s reasoning of balance over-time, because I am always willing to listen to any opinion.
Personally though, I think that balance with each meal is ideal.