Increased Availability. Eating a raw diet to avoid losing nutrients to cooking is not the answer. A study published back in 2008 in the British Journal of Nutrition found that following a strict long-term raw food diet was associated with relatively high blood levels of beta-carotene and normal levels of vitamin A, but low levels of prostate-cancer fighting lycopene. “Heat breaks down the cell matrix and allows some nutrients to be released from the cell walls,” says Rasmussen. This explains why studies find cooked tomato products like tomato sauce and ketchup have higher levels of available lycopene than raw tomatoes. Other studies have found vegetables like carrots, spinach, broccoli, mushrooms, zucchini, asparagus, cabbage, and peppers supply more carotenoids to the body when cooked than when eaten raw.
Method Matters. How vegetables are cooked and eaten does make a difference in nutrient availability and absorption. In general, steaming preserves nutrients best, since this method avoids the leaching of water-soluble compounds and limits exposure to heat that can degrade some vitamins. Regardless of cooking method, some nutrients will be better absorbed if veggies are prepared or eaten with some healthy fat. “Fat soluble vitamins (A, D, E, and K) and phytonutrients (especially beta-carotene, lycopene, and other carotenoids) are better absorbed when cooked with vegetable oil,” says Blumberg. “Chopping also helps release these health-promoting compounds.” When eating vegetables raw, such as in a salad, add some dressing, avocado, or nuts to help with absorption of fat-soluble nutrients.
“The best choice is to eat vegetables however they most appeal to you,” says Rasmussen. Blumberg agrees. “Taste and texture matter. If you don’t like them, you won’t eat them at all,” says Blumberg. “More important than raw versus cooked is to eat your veggies. Getting 50 percent of a nutrient is still better than getting nothing.”
-Eat a variety of vegetables and enjoy them raw or cooked to vary the nutrients your body receives.
-Cook with less water and heat exposure when possible to preserve water-soluble and heat-sensitive nutrients. (Try steaming, microwaving, or blanching.)
-Pair veggies high in fat-soluble nutrients (such as asparagus, carrots, Swiss chard, and squash) with healthy fats (like vegetable oil, seeds, nuts, and avocado) to increase absorption.
-Store non-root veggies in the refrigerator to preserve nutrients longer (although keeping some out where they can be seen may increase intake).
-Wash raw vegetables well to remove any bacteria. Rinse with clean cold water; use a vegetable brush for produce with thick skin; soak produce with nooks and crannies (such as broccoli and cauliflower) for one to two minutes in clean cold water.