Fruit and vegetable consumption is a focus of research and nutrition education, but there is no universal agreement on the meaning of 'fruits and vegetables'. Foods that require specific instruction include rice, dried beans, potatoes, tomatoes and fruits and vegetables in mixtures and condiments.
Fruit and vegetables are important components of a healthy diet, and their sufficient daily consumption could help prevent major diseases. A recently published 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.
Fruits and vegetables are universally promoted as healthy. The Dietary Guidelines for Americans 2010 recommend you make one-half of your plate fruits and vegetables.
Fruits and vegetables include a diverse group of plant foods that vary greatly in content of energy and nutrients. Fruits and vegetables supply dietary fiber, vitamins and minerals to the diet and are sources of phytochemicals (phytonutrients) that function as antioxidants, phytoestrogens, and antiinflammatory agents and through other protective mechanisms.
Fructose and glucose are simple sugars, monosaccharides, with the general formula C6H12O6.
Fructose, or fruit sugar, occurs naturally in fruits, some root vegetables, cane sugar and honey and is the sweetest of the sugars.
Glucose, dextrose or grape sugar, occurs naturally in fruits and plant juices and is the primary product of photosynthesis. Most ingested carbohydrates are converted into glucose during digestion and it is the form of sugar that is transported around the bodies of animals in the bloodstream.
Sucrose is a compound sugar, disaccharide, with the general formula C12H22O11. Sucrose is found in the stems of sugarcane and roots of sugar beet. It also occurs naturally alongside fructose and glucose in other plants, in particular fruits and some roots (carrots). A molecule of sucrose is formed by the combination of a molecule of glucose with a molecule of fructose, and it is split into these parts during digestion.
The different proportions of sugars found in plant foods determines their sweetness.