Here is a cut and paste of some info. The link to the full article is below.
Decrease In Food Value — Microwave exposure caused significant decreases in the nutritive value of all foods researched. There was a decrease in bioavailability of B-complex vitamins, vitamin C, vitamin E, essential minerals and lipotropics in all foods, a loss of 60 to 90% of the vital energy field of all tested foods, and a marked acceleration of structural disintegration in all foods.
http://www.jrussellshealth.com/microwaves.html