While cooked meat is usually accepted as healthier than raw meat -- due to the foodborne illnesses possible from raw meat -- the nutritional value of raw versus cooked produce has been debated. However, in some cases, cooking vegetables can bring out their antioxidants, raising their nutritional value.
Cooking and Nutrients
In some cases, cooked vegetables are more nutritious than raw vegetables. The heat of cooking breaks down the thick cell walls of the plants, and enables your body to absorb their nutrients better. However, this primarily applies to steaming or boiling vegetables. Frying vegetables reduces their nutritional value because the antioxidant properties of plants are eliminated by the oxidation caused by the deep frying process. The various vegetable groups also can react differently to cooking.
Dark Green Vegetables
Boiling and steaming broccoli, spinach and the other leafy greens can provide you with more antioxidants, but some of the mineral content may be slightly reduced. For example, a 100 gram serving of raw broccoli has 316 milligrams of potassium, while a similar serving of boiled broccoli has 293 milligrams. The cooked broccoli has 77 micrograms of the antioxidant vitamin A and 929 micrograms of beta carotene, while the raw broccoli only has 31 micrograms of vitamin A and 361 micrograms of beta carotene.
Red and Orange
The red and orange produce group, which contains vegetables like carrots, peppers and tomatoes, is particularly rich in the antioxidant group carotenoids, which are brought out by cooking. For example, 100 grams of raw carrots has 8,285 micrograms of beta carotene, 3,477 micrograms of alpha carotene and 256 micrograms of the compounds lutein and zeaxanthin. On the other hand, cooked carrots have 8,332 micrograms of beta carotene, 3,776 micrograms of alpha carotene and 687 micrograms of lutein and zeaxanthin. Unfortunately, cooking causes their vitamin C levels to drop by around 50 percent.
Among the group of other vegetables, the best ones to cook include zucchini and asparagus. Zucchini contains five times as much vitamin A, and even a little more folate and niacin, after cooking. Cooked asparagus contains more vitamin A, beta carotene and lutein, as well as significantly higher amounts of the antioxidant lycopene.