Tokyo Food Safety Information Center » Tokyo Metropolitan Government food safety FAQ » I’ve heard that when you warm foods in the microwave, the electromagnetic waves destroy nutrients such as vitamins; is this true?

I’ve heard that when you warm foods in the microwave, the electromagnetic waves destroy nutrients such as vitamins; is this true?

I’ve heard that when you warm foods in the microwave, the electromagnetic waves destroy nutrients such as vitamins; is this true?

  • Are there any ways to prepare food which don’t destroy vitamins?
  • Do the changes caused in food by the electromagnetic waves of a microwave have any negative influences on health?

 

Electromagnetic waves do not destroy vitamins.




More information

The amount of vitamins in a given food will change when the food is heated and cooked, regardless of whether you use a microwave or not.
Vitamin C, for example, is a nutrient which is easily destroyed by heat. Reducing heating times (the time during which the food is at a high temperature) will increase the amount of vitamin C which remains. Accordingly, when cooking vegetables, using a microwave reduces the amount of time required to cook the food over boiling the vegetables, thus increasing the amount of vitamin C left over after cooking. Vitamin C is also water soluble and will dissolve into water when foods are boiled. Using a microwave to cook food, which does not require excess water, thus actually prevents vitamin C from leaching away.
Conversely, spinach, for example, contains large amounts of oxalic acid in addition to vitamin C. When spinach is cooked in a microwave, large amounts of vitamin C remain, but unfortunately so do large amounts of oxalic acid. Boiling spinach gets rid of this oxalic acid and is thus the better choice. Accordingly, the best cooking method depends on the ingredients being used.
Note that food does not undergo any changes caused by the electromagnetic waves of a microwave which will have a harmful effect on human health.

Bureau of Public Health, Tokyo Metropolitan Government
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