Water-soluble nutrients like vitamin C and vitamin B are most vulnerable to degradation in processing and cooking.
Fat-soluble compounds like vitamins A, D, E and K do better during cooking and processing.
· EATING RAW: Boiling was better for carrots, zucchini and broccoli than steaming, frying or serving them raw. Boiling carrots, significantly increases measurable carotenoid levels compared with raw carrots.
· COOKING: Cooking removes about two-thirds of the vitamin C in fresh spinach. Steaming and boiling caused a 22 percent to 34 percent loss of vitamin C.
· MICROWAVING: Vegetables cooked in a microwave may have a higher concentration of certain vitamins. Microwaved and pressure-cooked vegetables retained 90 percent of their vitamin C.
· FRYING: Frying vegetables is by far the worst method for preserving nutrients.
· Canned is also bad. Canned peas and carrots lose 85 to 95 percent of their natural Vitamin C. frozen cherries lost as much as 50 percent of anthocyanins.
The bottom line
No single cooking or preparation method is best and that includes eating vegetables raw.
Just eat more vegetables.