Phytochemicals are non-nutritive plant chemicals that have protective or disease preventive properties

• Thousands of phytochemicals exist which can be classified in different families; • The major action of phytochemicals in plants is protection against reactive oxidative species and insects; • A couple of experimental and epidemiological studies show data that some phytochemicals may exert beneficial effects in humans against cancer, coronary heart disease and neurodegenerative diseases; • The data of the studies do not justify a recommendation for the use of single phytochemicals. A general recommendation can be made to increase fruit and vegetable intake as these are the major sources and will help to increase supply; • Patients having a low intake of fruits and vegetables are at risk of oxidative stress. Specifically polyphenols, involved in the regulation of inflammatory response, are of great importance.