In a review of research, we have found that microwave heating, for the most part. impacts food nutrients in much the same way as other forms of heating. The microwaving of food creates greater nutrient loss when higher heats are created, when heating is extended over a long period of time, or when food is heated while being submerged in water. Each of these principles applies to stovetop cooking as well. Surrounding a food with water and placing it in the microwave on high temperature for several minutes will result in significant nutrient loss in a way that is parallel to boiling a food on the stovetop for several minutes.

There haven't been any wide-scale, peer-reviewed journal studies on the impact of microwave cooking on food structures. We realize that other websites have recommended avoidance of microwave cooking due to changes in food proteins. We have not seen evidence to support this recommendation. We've seen purified, chemical extracts from food taken into a laboratory setting and then exposed to microwave radiation from laboratory equipment. But we've not seen intact, edible foods placed in a microwave oven and then analyzed for structural changes in nutrients such as protein.

There was one small clinical study on the effect of microwave cooking that is widely discussed on the Internet. While it was not published in a peer-reviewed journal and is not indexed on Medline, we will still report its findings. This study showed that the consumption of microwaved foods was followed by a short-term decrease in the number of white blood cells in the study participants consuming the microwaved food.

Food safety may be an issue when it comes to cooking in microwaves. One published study found the inability of microwaving to assure elimination of E. coli 0157:H7 from food. Another study found that owing to non-uniform heating of microwaves, some samples of microwaved chicken still contained the Listeria bacteria while another one found that the time needed cook mincemeat to achieve doneness, as observed by agreeable taste and texture, was insufficient to kill Salmonella and Streptococcus bacteria.

We've found two basic health concerns to be well documented in relationship to microwave cooking. First and foremost is the choice of food containers to be placed inside of a microwave oven. Most plastics, including film food wrap (LDPE, or low density polyethylene, displaying a Number 4 recycling symbol) and styrofoam containers (PS, or polystyrene, displaying a Number 6 recycling symbol) have been shown to migrate from plastic packaging into microwaved foods. This contamination of the food with plastic particles is beyond question in the science research—but researchers disagree on the health implications. Researchers who look at "invisible" changes occurring inside human cells (including metabolic patterns and nutrient ratios) find reason for broad-based concern about the use of plastic packaging in microwave ovens. From our perspective, there is simply no good reason to take the risk. If you do decide to use a microwave oven, we recommend using non-plastic food containers only. These containers would include glass, Pyrex, and all microwave-safe ceramics.

All this being said, we choose not to use microwaves in our homes. The quick cooking methods that we like to use to cook foods like vegetables really do not take that much more time than if we cooked with a microwave. Until more research is done on the subject, we feel more comfortable using the stovetop and oven for cooking.