I’m always looking for pre-packaged raw foods my dog sitter can use while I’m away.
Recently, I bought a new brand of pre-made raw food. It contained proteins from small regional farms. So … the ingredients and sourcing were impressive. But the black plastic bowl labeled “please microwave me” … well, not so much.
How could any reputable raw food company ever advocate microwaving dog food to heat it up?
Most of us have a microwave in our kitchens. But should we really be using them? Let’s look at a bit of microwave history.
In October 1945, self-taught electrical engineer Percy Spencer filed the first microwave patent. He worked for Raytheon, famous for their work on combat radar during World War II. Percy learned microwaves could heat food when a candy bar melted in his pocket during an unrelated experiment.
In 1967, the first countertop microwave was available for about $495. Fast forward to 2020. Microwave ovens are a 25 billion market and more than 90% of all US households own a one. And now we have “smart” microwaves that connect to the internet. They can monitor food for moisture, download cooking instrucions and more.
What Happens When You Heat Your Dog’s Food
Microwaves use high-frequency waves called non-ionizing radiation. This energy vibrates the water molecules in food at the rate of 2.5 million times per second. So they’ll heat your dog’s food fast. Conventional cooking on a stovetop works much more slowly. It works by heating the outer material, which transfers heat to the food inside.
Any time you “cook” food you’re changing its molecular structure. Overcooking food by any method can rob food of vitality, enzymes, and nutrients. The question is, how fast do these processes occur inside a microwave oven? And what other effects do microwaves have on food?
The Microwave Effect
The “microwave effect” comes from the field of science called microwave chemistry. This field recognizes two things.
- Organic reactions occur faster with microwave heating than with conventional heating.
- Several reactions that occur with microwaves don’t happen at all with conventional heating.
The mainstream consensus is that microwaves are safe. The WHO says they’re “safe and convenient for heating and cooking a variety of foods.” They’re viewed as equal to other forms of cooking, with a negligible effect on foods.
But long-term studies on microwave safety and their effects on health don’t exist. And that’s a good reason to be cautious about using it.
3 Reasons To Rethink Your Microwave
Here are some of the main reasons you should reconsider using your microwave to heat your dog’s food.
1. Plastics and Chemical Leaching
When our doctor diagnosed my partner with cancer, they gave us a handout. It advised us to dispose of plastic food and drink containers, and plastic wrap. It also warned of the risks of using plastic to heat and store anything hot, especially in a microwave.
Plastics contain a myriad of hazardous chemicals like …
- Polyethylene terpthalate (PET)
- Bisphenol A (BPA)
When heated, plastics can off-gas chemicals into the air … or transfer chemicals into porous substances like food. In 2004, researchers at Johns Hopkins University warned against phthalates and heating plastics.
“Phthalates are environmental contaminants that can exhibit hormone-like behavior by acting as endocrine disruptors in humans and animals. If you heat up plastics, you could increase the leaching of phthalates from the containers into water and food. In general, whenever you heat something you increase the likelihood of pulling chemicals out.”
“But what about microwave safe plastic dishes like the one I found in the raw dog food bag?”
So-called microwave-safe dishes should have a label that says “leaching chemicals into your food at a slower rate.” Frederick Von Saal is a biologist at the University of Missouri’s Endocrine Disruptors Group and an expert on BPA. He says there’s “no such thing as microwave safe plastic. As you heat it, you degrade the chemical bond. You can’t see this happening. You can’t taste it, you can’t smell it.”
So, if you choose to use a microwave to heat your dog food, please don’t ever use any type of plastic. Use microwave-safe glass or ceramic containers instead.
2. Nutrients At Risk
Whether you’re thawing, warming or cooking food … microwaving your dog’s food depletes nutrients faster than conventional cooking. Enzymes, trace minerals, amino acids and antioxidants are all affected.
Rapid or prolonged heat destroys enzymes in most foods making them difficult to digest. This puts added strain on the pancreas and leads to slower digestion times. For example, the enzymes diastase and invertase rapidly break down when heated less than a minute in a microwave. (Institute of Agriculture and Fisheries Research Center, 2015.)
In 2003, a Spanish study found that broccoli lost 97% of its antioxidants when cooked in a microwave. By comparison, steamed broccoli lost 11 percent or fewer of its antioxidants. And a Scandinavian study found that microwaving asparagus spears caused a reduction in vitamins.
Another study found that the anti-cancer constituents of garlic were blocked by 45 minutes of heating in a regular oven … but only 60 seconds in a microwave!
Other studies show microwaving causes 5 to 40% reduction in some minerals in fresh produce as well as in protein sources. Even microwaving breast milk can remove some important nutrients. And it can promote growth of pathenogenic bacteria.
So, think twice before you microwave foods for your dog to heat them up. You may be causing some important nutrient loss.
While cooking makes vegetables more digestible for dogs, it’s best to steam (or puree) the veggies instead.
RELATED: What vegetables can dogs eat …
3. Oxidation And Protein Damage
Microwaves speed up cooking and they’ll heat your dog’s food unevenly. This is true even using the defrost setting. When meat gets heated too rapidly the carcinogen acrylamide can form. I’ve found studies that say microwaves don’t form acrylamide when cooking meats. But others disagree. So why risk it? Don’t thaw your dog’s meat in the microwave!
Oxidation of fats can be an issue when microwaving foods containing fats and oils … including meat. When oils oxidize they become unstable, rancid and toxic.
Italy’s University of Bari did a study on olive oil. It showed that when microwaved it had a higher and faster rate of oxidization than conventionally heated oil.
Meat is an important protein source for dogs. And it’s best fed raw. Using the microwave to heat raw dog food for any reason completely negates nutritional benefits of feeding raw. It can also make bones splinter. So if you forget to thaw your dog’s meal, give him a nice big recreational bone and call it a fast day instead!
And don’t microwave kibble either … even if you think your dog would like a warm meal for a change! Microwaving further depletes kibble’s already poor nutritional value.
The Take Away
There’s not enough research either validating or discrediting the negative effects of microwaving on food … or the effects of eating microwaved food on the body. The fact is, we don’t really know much about any harmful long term effects of microwaving. In my opinion. the lack of research creates a valid need for caution … and preferably, avoiding the microwave altogether!
George DF, Bilek MM, McKenzie DR. Non-thermal effects in the microwave induced unfolding of proteins observed by chaperone binding. Bioelectromagnetics. 2008 May;29(4):324-30.
Eke BC et al. Effects of the Ingestion of Microwaved Food Items on Some Haematological Parameters in Albino Wistar Rats. Current Journal of Applied Science and Technology. 2014;5(1):99-103.
Porcelli M et al. Non-thermal effects of microwaves on proteins: thermophilic enzymes as model system. FEBS Letters. 1997;402(2–3):102-106.
Lorenz K, Decareau RV. Microwave heating of foods ‐ changes in nutrient and chemical composition. C R C Critical Reviews in Food Science and Nutrition. 1976;7(4):339-370.
Song K, Milner JA. The influence of heating on the anticancer properties of garlic. J Nutr. 2001 Mar;131(3s):1054S-7S.
F Vallejo et al. Phenolic compound contents in edible parts of broccoli inflorescences after domestic cooking. Journal of Science of Food & Agriculture. 2003;83(14).