Numerous research studies show that cooking food in a microwave significantly reduces antioxidants, vitamin and minerals, and also effects protein availability. Studies also show possible cancer risks, particularly related to the release of toxins from plastics used in common foods heated up including chips, pizza and popcorn.
When considering the nutritional quality of foods alone, a 2009 of the composition of food historically have found a 5 to 40% reduction in some minerals in fresh produce, and another study found a similar decline in our protein sources.
A 1999 Scandinavian study of the cooking of asparagus spears found that microwaving caused a reduction in vitamins. Another study found that as little as 60 seconds of microwave heating inactivated allinase, garlic’s primary ingredient that fights cancer.
A 2003 study found that microwaved broccoli lost up to 97% of its helpful antioxidants while steamed broccoli only lost 11% of its antioxidants.
A 1992 study found that breast milk that has been microwaved loses lysozyme activity and antibodies that your child needs.
Davis D R., Declining fruit and vegetable nutrient composition: What is the evidence? American Society of Horticultural Science, February 1, 2009
Kidmose U, and associates, Acta Agriculturae Scandinavica B 1999:49(2):110-117
Journal of Science of Food and Agriculture, Nov. 2003