Importance of Micronutrients in Fresh Food Diets
Updated: Oct 7, 2021
I appreciate that many people love to hear that it’s easy to feed our dogs fresh food, and it shouldn’t be complicated. I know that feeding myself for optimal health isn’t easy, so I expect that some effort has to go into planning my dog’s diet. Changes in soil quality and its impact on our food supply, nutrient differences in meat from commercially raised animals vs naturally raised and all the stressors and toxins in our environment make obtaining optimal health quite challenging!
Dogs have quite high nutrient requirements per body weight, puppies even higher, so it requires some planning to ensure their needs are met -whether it’s daily or over a week or two. As an example, the zinc RDA for a human adult is 15mg and the recommended allowance for a 50lb dog is 21mg (the same as a 10lb puppy)!
People are familiar with macronutrients- protein, fat and carbohydrate- what doesn’t get as much emphasis are the micronutrients. Microminerals and vitamins are required in smaller amounts but are vital to the proper functioning of all body systems. Essential micronutrients include Iron, Zinc, Manganese, Copper, Iodine and Selenium as well as a Vitamins A, D, E, K and the B Complex vitamins.
Chronic micronutrient insufficiency is seen in over 90% of the human population so it’s not surprising that our dogs also have similar inadequacies.
We can categorize nutrient intake into four levels:
Level 1 -Nonexistent to Below the minimum requirement- clearly deficient
Level 2- Below the recommended intake requirements
Level 3 -Meeting individual optimal micronutrient amounts
Level 4- Excessive – Overnutrition and even toxic levels
In addition to insufficient intake, mineral interactions take place so excess intake of one can create a deficiency in another.
Level 1 is where we expect to see more overt clinical symptoms such as skeletal abnormalities and impaired growth. Level 2 is where the symptoms of deficiency may be insidious; marginal nutrient insufficiencies may not be severe enough to produce the classic deficiency symptoms. Adult dogs have reserves to draw on, but puppies who have much higher requirements, have not had a chance to build these reserves.
The body has amazing adaptive abilities to prioritize micronutrients needed for survival and short-term health by borrowing from less critical stores in the body. Despite over or under ingestion, there are mechanisms that attempt to maintain homeostasis including control of intestinal absorption or excretion. Duration and degree of shortfalls (or excessive intake), age, and health status are all factors in changes of physiological function that arise.
Chronic micronutrient insufficiency increases our dog’s susceptibility to illness, chronic disease, immune dysfunction, cognitive dysfunction and cancer. Early signs of marginal nutrient deficiency may include: changes in skin and coat, fatigue, lethargy, hyperactivity, poor wound healing, cracked pads and trouble focusing during training.
Manganese is an example of a trace mineral that is often low in fresh food canine diets as there are limited animal based sources that provide significant quantities. Manganese has important roles in mitochondrial function and is critical in bone formation and cartilage synthesis. Some veterinarians believe that in addition to genetics, manganese deficient diets may play a role in the rise of cruciate ligament tears.
If you accept that epigenetic factors such as diet, toxin exposure and stress influence the way genes interact – then although your dog may have a genetic susceptibility, their genes are dynamic and modifiable. A personalized diet focused on ideal nutrient intake and balance can play an important role in this expression.
Popular infographics depicting good food sources of nutrients can make it easy to think you’ve got your bases covered as long as you feed a variety of these foods. What these well-meaning tables don’t show are the dog’s nutrient requirements and how much of the nutrient the food actually provides.
We still have more to learn about optimal nutrient intake - breed differences, digestibility, absorption and gut microbiome health, and physiological changes in various disease states all need to be considered. I use the National Research Council numbers as guidelines because it’s out of my comfort level to rely on guessing when potential serious issues can be easily prevented.