Phytochemicals are sometimes referred to as phytonutrients and these terms are often used interchangeably. Most broadly defined, they could be said to be any chemical or nutrient derived from a plant source. However, in common usage they have a more limited definition. They are usually used to refer to compounds found in plants which are not required for normal functioning of the body but which nonetheless have a beneficial effect on health or an active role in the amelioration of disease. Thus, they differ from what are traditionally termed nutrients in that they are not a necessity for normal metabolism and their absence will not result in a deficiency disease -- at least not on the timescale normally attributed to such phenomena. A minority claim that many of the diseases afflicting the people of industrialized nations are the result of those people's lack of phytonutrients in their diet. What is beyond dispute is that phytonutrients have many and various salubrious functions in the body. For example, they may promote the function of the immune system, act directly against bacteria or viruses, reduce inflammation, or be associated with the treatment and/or prevention of cancer, cardiovascular disease or any other malady affecting the health or well-being of an individual.
Phytochemicals naturally occur in vegetables and fruit and highest levels are therefore consumed by vegetarians and vegans..
Families of phytochemicals
The following are groups or families of related phytochemicals and common sources of phytochemicals arranged by family.
Click here for a more extensive list of phytochemicals and here for a list of phytonutrient rich foods.
Food processing and phytochemicals
Many phytochemicals are thought to be destroyed or removed by modern food processing techniques, possibly including cooking. For this reason, it is believed that industrially processed foods are less beneficial (contain fewer phytochemicals) than unprocessed foods. The absence or deficiency of phytochemicals is believed to have contributed to the increased prevalence of the above-cited preventable or treatable causes of death in contemporary society. Interestingly though, lycopene, which is a phytonutrient that can be found in tomatoes, is concentrated in processed foods such as spaghetti sauce and ketchup, making those foods much better sources of that compound than the tomatoes themselves.