Expert Q&A

Microwave cooking: Does it destroy vitamins?

Does microwave cooking destroy the vitamins in food?

Vitamins are often destroyed during the cooking process, regardless of the chosen cooking method. The factors that most significantly affect the extent of that destruction are temperature, cooking time, and liquid use. Let’s take a look at each of these factors to see how the microwave measures up. 

  • Temperature.  Microwave ovens use less heat than most other cooking methods.  Therefore, heat-sensitive vitamins such as vitamin B and vitamin C are less susceptible to destruction in the microwave. In fact, a study at Cornell University found that spinach retained nearly all of its folate (a B vitamin) when cooked in the microwave, but lost 77% when cooked on the stove. 

  • Cooking time.  Microwaving is faster than other conventional methods of cooking. Food heated quickly in a microwave retains more nutrients than foods kept hot for a long time, such as those simmered on a stove. The longer the food cooks, the more nutrients are destroyed. 

  • Liquid use.  Regardless of the cooking method, foods cooked in water lose more nutrients than those cooked without water. This is because vitamins leave the food, enter the water, and are then discarded. Less water is generally used in microwave cooking, and therefore it is similar to steaming, which minimizes the loss. 

The bottom line: The microwave is one of the best cooking methods for retaining nutrients in foods, as long as you limit the amount of water you use when cooking.

Erica Lesperance, RD, LD
Contributing Expert

Have a question for our Experts? Send it in!