You may be surprised to hear that close to half our daily nutritional vitamins and minerals can be found in a single sandwich. Take, for example, a few ingredients found in popular sandwiches or wraps these days; whole meal bread, avocados, lettuce, onions, tomatoes, sprouts, grilled chicken, marinated beef or fresh tuna.
Whole wheat has a wide variety of health benefits. It helps with gastrointestinal problems and lowers the risk of diabetes, breast cancer, asthma and heart disease. It is significantly better for you than white wheat flour which when processed from natural wheat, loses almost 70% of its natural vitamins and minerals. 
Avocados are a good source of vitamin K, dietary fiber, vitamins B6 and C, folate and copper. They are also a good source of potassium – one avocado contains more potassium than a medium-sized banana.
Onions, you either love them or you hate them, but like garlic, they are rich in powerful sulfur-containing compounds. These are responsible for their pungent odor and many of their health-promoting effects. They also contain large amounts of chromium, a mineral that helps cell reformation. Plus, they’re rich in vitamin C.

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