Microwaving Food: A Follow Up

If you haven’t heard of Dr. Joeseph Mercola, don’t lose sleep over it. He’s an alternative health guru prone to making poorly substantiated claims about what is going to cause your death this week. He has good ideas, but plenty of bad ones too. Why do I bring him up? I recently found out he has an article on his website detailing his reasons for not liking microwaves. I recently wrote a blog post where I declared microwaves a perfectly acceptable method of cooking based on the science, so I was curious about his reasoning. This article by Mercola contained a few studies that caught my attention and were presented as anti-microwave evidence, so I decided I would evaluate them and see if I came to a different conclusion than I did before.

Study #1: “The influence of heating on the anticancer properties of garlic”

This study looked at the effects of heating on the health properties of garlic, specifically the cancer preventative effects of garlic in rats. They found that garlic looses its anti-carcinogenic effects when cooked. This was seen after baking and microwaving, not microwaving alone.

Study #2: “Effects of Microwave Heating on the Loss of Vitamin B(12) in Foods”

I actually covered this study in my last post and it showed that the loss of vitamin B12 after microwaving is about 30-40%.  I cited this study showing that conventional cooking causes a similar loss of vitamin B12. Cooking causes B12 loss of food, regardless of how that cooking is performed.

Study #3: “Non-thermal effects in the microwave induced unfolding of proteins observed by chaperone binding”

This study reported that microwaves may increase protein unfolding more than a similar method of heating. This may sound bad to a person who doesn’t know what that means, but protein unfolding is not necessarily bad. It is if it’s happening to the proteins in your body, but it’s probably not if it happens to the proteins you eat. This process is called denaturing and it happens during all methods of cooking. Microwaves may increase this process, but it does not follow that this is bad. Certain secondary and tertiary protein structures may have benefits when consumed and microwaves would reduce such benefits, but this study hardly gives us that room to speculate.

Study #4: “Effects of microwave radiation on anti-infective factors in human milk”

There are a number of things in milk that can prevent the growth of bacteria, like lysozyme, immunoglobulins, and lactoferrin. This study confirms that microwave heating reduces these compounds, allowing E. coli to grow more readily. Again, this is not unique to microwaving. Heat in general reduces the anti-bacterial compounds in milk, though perhaps microwaving is a bit worse. For further reading on this, check out Chris Masterjohn’s post on raw milk. In my opinion, heating of milk should typically be avoiding for maximum health benefits.

Study #5: “Inactivation of
Lactobacillus bacteriophage PL-1 by microwave irradiation”

Bacteriophages are essentially anti-bacterial viruses, I’ve written about them a bit before. This study found that microwaving inactivated bacteriophage PL-1 and although heating in general has been shown to inactivate PL-1, this study suggests microwaving may be kill PL-1 more effectively than other methods of heating. Still, two important points about this: 1) Bacteriophages aren’t nutrients and haven’t really been researched enough for us to know how important the bacteriophage content of our food is. 2) Bacteriophages infect bacteria, which might be good when it’s a nasty bug like Listeria monocytogenes or E. coli, but in this case it’s a phage of Lactobacillus (often casei), a harmless probiotic found commonly in yogurt. So in this case, this study really says nothing bad of microwaving.

Well, there you go. None of these studies have caused me to reevaluate my opinion. The Mercola article presents these studies as proof of the danger of microwave cooking. Yet these studies show either the negative effects of cooking in general (microwaving or otherwise), or the greater effect of microwaves on things which evidence does not or has not shown to be important.

So I once again will say: don’t fear the microwave, just because some strange doctor on the internet says that you should.

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