A Dietitian Says Raw Isn’t Always Best for Vegetables

A dietitian’s review finds that vegetable nutrition depends on both the food and the nutrient in question. Heat can reduce vitamin C and folate, especially when vegetables spend a long time in high temperatures or water. But cooking can also soften plant cell walls, helping the body take in compounds such as tomato lycopene and carrot beta-carotene. That makes “raw” an incomplete answer.

Steaming generally preserves more nutrients than boiling, particularly in broccoli and red cabbage. Microwaving can also limit losses when little water is used. Roasting keeps minerals and fat-soluble vitamins such as A, K, and E, although hotter, longer cooking can lower vitamin C. Stir-frying works quickly and uses a small amount of oil, which may help preserve some antioxidants and improve absorption of fat-soluble compounds.

Boiling can move vitamin C and folate into the cooking water, including from broccoli, spinach, and peas. Raw vegetables retain heat-sensitive nutrients, and bell peppers may provide more vitamin C this way, but cooked vegetables can be easier for some people to digest. The differences among methods are modest overall; eating more vegetables matters more than preparing every serving perfectly. A mix of raw and cooked vegetables can provide different benefits, while the method that makes vegetables appealing may help people eat them more often.