Technically a fruit but widely considered a vegetable, tomatoes are the fourth most popular market veggie in the United States (after potatoes, lettuce and onions) and the top homegrown garden crop. Native to Central America, tomatoes appear in almost every national cuisine and are served any time of the year, whether fresh or processed.

Although the plump, shiny-red, baseball-size orbs known as slicing tomatoes are usually the most common in U.S. grocery stores, there are actually as many as 7,500 varieties of tomatoes, including heirlooms, which are found in stores and at farmers’ markets throughout the summer.

Lycopene, an antioxidant that gives tomatoes their rich, red color, has been linked to the prevention of certain cancers, macular degeneration, cardiovascular disease and stroke. Cooked or processed tomatoes contain higher amounts of lycopene compared with raw tomatoes, so feel free to use the canned versions in recipes. And because lycopene is a fat-soluble carotenoid, add a little high-quality olive oil when making tomato sauces or bases for better absorption of the nutrient. Tomatoes are also a good source of vitamin C.

At the store, look for tomatoes with tight, shiny and smooth skin with a sweet or spicy aroma. Tomatoes that lack an aroma were probably picked too early, before they were allowed to ripen naturally, and they’ll have a bland flavor. Stems usually indicate that the tomatoes were allowed to ripen on the vine, so they’ll have a better taste but a shorter shelf life.

We recommend choosing organic tomatoes when possible to avoid any unnecessary pesticide exposure; when you buy conventional, wash them thoroughly before eating. At home, avoid refrigerating tomatoes—the cold destroys their flavor and makes their flesh mealy and unappetizing.