24 Good Reasons Why You May Need Vitamin Supplements
7. Overcooking
Hard-cooked meat and vegetable or reheating will oxidize and degrade vitamins such as B, C, and E. The water-soluble vitamins B and C, as well as several minerals, are drained from boiling vegetables. Steaming with light is preferred. Certain vitamins, such as vitamin B6, can be damaged by microwave irradiation.