The Microwave Controversy
We’re almost 3 weeks into the new year, and many have started with a list of new years resolutions, and perhaps even thrown a few of those resolutions out the window. For many these included eating healthier (particularly more vegetables & fruit) and an exercise program. They're all very formidable goals, made even more difficult when the aspiring healthy consumer is tasked with separating reality from nonsense in their pursuit of what works, what doesn’t, and what is rooted in solid reality-based principles.
I don’t want to carry on too long with this intro, so let’s skip right to the crux of the matter; Microwaving vegetables, should you do it? And does it denature the nutrients? There’s a popular belief which has been around for quite some time that microwaving vegetables (and meat, carbohydrates, or any other nutritional victim bound for the microwave) decreases the nutritional value of the food by altering the molecular structure of the macro or micronutrients.
Nonsense. In fact, the very opposite is the case for a number of important nutrients.
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| Dispelling nonsense makes Mr Broccoli very happy. |
Of course microwaving your food affects the molecular structure, this is what we call “cooking”. There have been plenty of studies investigating the effects of microwaving vs stove cooking vegetables and other food, for example here, here1, and here2. These studies show that microwaving vegetables or other foods is superior when considering nutrient preservation (at least, for those nutrients being studied) when compared to traditional stove-top cooking.
There’s some history behind the ‘Microwave Militia’ as they have been dubbed by the more sceptical community, however I won’t expound upon them here. In addition, I recommend listening to (or reading the transcript) of Brian Dunning’s “Skeptoid” podcast episode which was entirely devoted to this issue, though his focuss isn’t specifically on nutrient preservation but rather unsupported claims of negative health effects when microwaving food and beverages.
Getting enough vegetables and good nutrition is hard enough without being fed misinformation from those who stubbornly oppose evidence based research, particularly those who ought to know better. So throw those veggies into your microwave and be happy in the knowledge that you’re not only saving time and effort, but also increasing your nutrient intake and increasing the likelihood of sticking to a healthier diet.
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References
1. Effect of microwave cooking or broiling on selected nutrient contents, fatty acid patterns and true retention values in separable lean from lamb rib-loins, with emphasis on conjugated linoleic acid
Abstract
Proximate composition and fatty acid profiles, conjugated linoleic acid (CLA) isomers included, were determined in separable lean of raw and cooked lamb rib-loins with their subcutaneous and intermuscular fat, prepared as roasts or steaks. Two combinations “cooking method × type of cut” were selected: one is a traditional method for this meat (broiling of steaks), while the other (microwaving followed by final grilling of roasts) is far less widely used. The two methods, similar as regards the short preparation time involved, were also evaluated for cooking yields and true nutrient retention values. The cooking yield in microwaving was markedly higher than in broiling. Significant differences between the two methods were also found in the true retention values of moisture, protein and several fatty acids, again to the advantage of microwaving. On the basis of the retention values obtained, with microwaving there was a minimum migration of lipids into the separable lean, consisting almost exclusively of saturated and monounsaturated fatty acids, while there were small losses of lipids in broiling, almost equally divided between saturated, monounsaturated and ω6 polyunsaturated fatty acids. On the whole, the response to cooking of the class of CLA isomers (including the nutritionally most important isomer cis-9,trans-11) was more similar to that of the monounsaturated than the polyunsaturated fatty acids.
2. Sensory attributes and nutrient retentionin selected vegetables prepared by conventional and microwave methods
Abstract
Sensory characteristics and retention of vitamin C, vitamin B6, calcium, and magnesium were determined in vegetables cooked by conventional and microwave methods. Fresh broccoli, cauliflower, and potatoes and frozen corn and peas were cooked by boiling, steaming, microwave boiling and microwave steaming to equivalent tenderness as measured by a shear press. The sensory analysis of the vegetables cooked by the four methods indicated that some differences existed in color, flavor, texture, and moistness of the vegetables. No one method resulted in vegetables with optimum sensory characteristics. The nutrient retention was highest in foods cooked by microwave steaming, followed by microwave boiling, followed by steaming, and then by boiling. Generally vegetables cooked by microwave techniques retained higher percentages of the U. S. Recommended Daily Allowances for the nutrients than those cooked by conventional methods.
