Vegetables are important for human health because of their vitamins, minerals, phytochemical compounds, and dietary fiber content. Especially antioxidant vitamins (vitamins A, vitamins C, and vitamins E) and dietary fiber content have important roles in human health. Adequate vegetable consumption can be protective of some chronic diseases such as diabetes, cancer, obesity, metabolic syndrome, cardiovascular diseases, as well as improve risk factors related to these diseases. Fruits and vegetables are universally promoted as healthy. Fruits and vegetables include a diverse group of plant foods that vary greatly in the content of energy and nutrients. Fruits and vegetables also supply vitamins and minerals to the diet and are sources of phytochemicals that function as antioxidants, phytoestrogens, and antiinflammatory agents and through other protective mechanisms. Multivitamins may slightly reduce the risk of cancer but don’t prevent heart disease. There is a wealth of data available within the health care system. Advanced data mining techniques can help medial situations. The Harvard-Led Physicians Health Study II (PHS II) recently found that taking a multivitamin slightly lowers the risk of being diagnosed with cancer. Fruits and vegetables contain many biologically active ingredients that may help to prevent cancer in ways that vitamins and minerals alone do not. The PHS II was the first study to test a standard multivitamin for the prevention of chronic disease. The cardiovascular disease portion of the study focused on whether taking a multivitamin reduced the risk of heart attacks, strokes, and death from cardiovascular disease. It’s important not to overplay the benefit that PHS II found for preventing cancer. What you eat and don’t eat can have a powerful effect on your health, including your risk for cancer. We conducted a systematic review and meta-analysis to clarify these associations.