Fruits and vegetables are vital components of a healthy diet, and their sufficient daily consumption could help prevent major diseases, such as cardiovascular diseases and certain cancers. Approximately 1.7 million (2.8%) of deaths worldwide are attributable to low fruit and vegetable consumption. Insufficient intake of fruit and vegetables is estimated to cause around 14% of gastrointestinal cancer deaths, about 11% of ischemic heart disease deaths and about 9% of stroke deaths globally (WHO data).
There are several mechanisms by which the protective effects of consuming fruits and vegetables may be mediated, involving antioxidants and other micronutrients, such as flavonoids, carotenoids, vitamin C and folic acid, as well as dietary fibre. These and other substances block or suppress the action of carcinogens and, as antioxidants, prevent oxidative DNA damage.
The World Health Organization (WHO) states that while eating fruit and vegetables can help prevent cardiovascular diseases and some cancers, low intake of them as part of a diet is responsible for almost 3 million deaths a year from those diseases. At the same time, changes in living and working patterns have led to less physical activity and less physical labour. This causes some cancers, diabetes and heart disease.
A WHO/FAO report recommends a minimum of 400g of fruit and vegetables per day (excluding potatoes and other starchy tubers) for the prevention of chronic diseases such as heart disease, cancer, diabetes and obesity, as well as for the prevention and alleviation of several micronutrient deficiencies, especially in less developed countries. More information at http://www.who.int/dietphysicalactivity/fruit/en/