In most studies, eating more vegetables and fruits has been linked with a lower risk of lung, oral (mouth), esophagus (swallowing tube from mouth to stomach), stomach, and colon cancer. But few studies have been done on whether a diet that includes many vegetables and fruits can reduce the risk of cancer coming back (recurrence) or improve survival. Some recent studies suggest that a higher intake of vegetables may have a helpful effect on recurrence or survival for breast, prostate, and ovarian cancers, but this is not definite.
Still, cancer survivors should get at least 5 servings of a variety of vegetables and fruits each day because of their other health benefits. It is not known which of the compounds in vegetables and fruits are most protective. Because of this, the best advice is to eat 5 or more servings of different kinds of colorful vegetables and fruits each day.
Fresh foods are usually thought to have the most nutritional value. But some frozen foods can have more nutrients than fresh foods. This is because they are often picked ripe and quickly frozen, whereas nutrients can be lost in the time between harvest and eating fresh foods. Canning is more likely to reduce the heat-sensitive and water-soluble nutrients because of the high temperatures needed in the canning process. Be aware that some fruits are packed in heavy syrup, and some canned vegetables are high in sodium.
Choose different forms of vegetables and fruits.
Boiling vegetables, especially for long periods, can leach out their water-soluble vitamins. Microwaving and steaming are the best ways to preserve the nutrients in vegetables.
Juicing can add variety to the diet and can be a good way to get vegetables and fruits, especially for those who have trouble chewing or swallowing. Juicing also helps the body absorb some of the nutrients in vegetables and fruits. But juices may be less filling than whole vegetables and fruits and contain less fiber. And drinking a lot of fruit juice can add extra calories to a person’s diet. Buy juice products that are 100% vegetable or fruit juices and pasteurized to remove harmful germs. These are better for everyone, but are of special concern for people who may have weak immune systems, such as people getting chemotherapy.