Boiling steaming, frying and a direct exposure to heat for a longer period of time can damage the nutrients while cooking.
Boiling and steaming reduce vitamin C in the vegetable from 22-34%. Lettuce, spinach and broccoli lose vitamin C up to 50% on boiling because vitamin C is heat sensitive and easily soluble in water.
1. Microwaving is one of the best moist cooking methods. It is quick and less exposure to heat helps preserve the nutrients.
2. Boiling increases nutrition loss because most of the vitamin c leaches out of vegetables.