Does microwave food destroy its nutritional content?

Cooking in general reduces the nutritional value of food, but by how much is a microwave much worse?

Cooking, in general, destroys some vitamins. Vitamin C and Thiamine (B1) Pantothenic acid (B5) and folic acid (B9) will be denatured to varying degrees, but folate requires a temperature of over 100°C to destroy it, and a deficiency of pantothenic acid is unheard of.

All the other major nutrients in food — carbohydrates, fats, proteins, fiber and minerals — are either affected or become more digestible due to heat. Cooking explodes with open vegetable cells. Your body will absorb plenty of the antioxidants beta-carotene and phenolic acid from carrots, and lycopene in tomatoes, when they're cooked. There is nothing about a microwave that destroys food more than other cooking methods. In fact, a microwave can preserve nutrients.

Boiling vegetables tends to strip away the soluble vitamins in the cooking water, and ovens expose food to longer cooking times and higher temperatures. Since microwaves penetrate food, they heat it much more efficiently and quickly, so there is not enough time to break down the vitamins and you do not get a crust on the outside that is heated more than in the middle. Microwave food has the same nutrient levels as steamed food.