Phytochemicals – A Nutraceutical Source of Vegetables

Vegetables play an important role in human diets, as they support the normal functioning of the different body systems. They provide our cells with vitamins, minerals, fibber, essential oils and phytonutrients. Vegetables contain low amounts of fat and calories. Phytochemicals are the primary source of antioxidants in the human diet and play an important role in combating the damaging effects of oxidative stress and other adverse cell responses that can lead to a wide variety of chronic and degenerative illnesses [11]. These phytochemicals typically consist of a wide array of phenolic compounds, ascorbic acid, alpha tocopherol and carotenoids, and have been shown to promote health and provide protection against a growing list of diseases including various cancers and cardiovascular and neurodegenerative diseases. Phytochemicals are part of a plant‟s natural systems of defense and repair. Our bodies utilize a small fraction of these components by incorporating them into various cellular and metabolic processes that enhance cellular growth, regeneration and repair. Some phytochemicals act as antioxidants, some protect and regenerate essential nutrients, and still others work to deactivate cancer-causing substances. Phytochemicals impart health benefits to humans in addition to those provided by vitamins and minerals alone. Phytochemicals differ from vitamins and minerals in that they are not considered “essential” nutrients, i.e., those which are critical for normal metabolism and growth. With the exception of carotenoids, they are similar to vitamins and minerals in that they are not stored in the body for later use and must be consumed consistently over time [3]. Perhaps, the most well-known phytochemicals are the antioxidant group, which protect cells from damage caused by the by-products (free radicals) of metabolism, as well as toxic substances in the environment and foods. At high levels, reactive species, such as reactive oxygen and nitrogen species, can be damaging to cells and may contribute to cellular dysfunction and disease. Antioxidants significantly decrease the adverse effects of reactive species by eliminating free radicals as they circulate throughout the body. Beta-carotene and the other carotenoids are not antioxidants, but influence the biochemical reactions involved in the oxidative process. Other phytochemicals include: sulfides (allium), indoles, phytosterols, protease inhibitors, phenols, tannins and terpenes. The phytochemicals can play chemo preventive roles in regards to human cancer by modulation of the cancer cell cycle, proliferation inhibition, and induction of apoptosis [6]. A phytochemical is often found in the coloring agent of fruits and vegetables, so eating brighter colored varieties may have benefits. However, there are also several beneficial phytochemicals in colorless or less colorful fruits and vegetables for example, onions and corn are rich in phytochemicals. Based on their chemical structure phytochemical are classified into the ten categories; basically they are subdivided into three main categories i.e. phenolic acids, flavonoids and stilbenes or ligans; these flavonoids are further subdivided into anthocyanins, flavones, flavanones, isoflavones as well as flavonols and flavanols. The Abstract Phytochemical literally means „Plant chemicals‟. Vegetables have immense beneficial properties for human health, because of the presence of phytochemicals which include flavones, flavonols, isoflavones, phenolic acids and glucosinolates. These phytochemicals seem to play a role against the development of different types of cancer and cardiovascular diseases, because these compounds could provide antioxidant capacity, anti-inflammation properties, lipid profile modification and antitumor effects. In addition to these beneficial properties of phytochemicals in human health, they are responsible for the color, flavor and smell of fruits and vegetables. During recent decades, many studies have examined the relationship between vegetables and health benefits. This article explores the role of phytochemicals in the diet and stresses the importance of vegetable consumption habit right from the start for the welfare of humanitarian.