Health benefits of phytonutrients – watercress
The cruciferous vegetable with powerful cancer fighting properties watercress is the most ancient vegetable known to man and is also the most nutritious and medicinally powerful vegetable. It is a cruciferous plant in the same family as broccoli, cabbage, cauliflower and mustard. Watercress is loaded with vitamins, minerals and phytonutrients that it contains. To refresh your memory, watercress contains the following minerals: calcium, potassium, sodium, magnesium, manganese, iron, copper, phosphorus and selenium. The vitamins found in watercress are: Vitamins A, C, E and K. Others are Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Panthotenic acid and choline.
The phytochemicals present in watercress are in three major groups. The first is the glucosinolate derivatives such as phenylethyl isothiocyanate PEITC and methylsulphinylakyl isothiocyanates MEITCs. The second group is the flavonoids represented by querceitin and hydroxycinnamic acid. The third are the carotenoids like beta-carotene and lutein. These all have different mechanisms of action and this explains why watercress is a powerful cancer fighter.
The glucosinolates are organic compounds that contain sulfur and nitrogen, which are derived from glucose and amino acid. They are water-soluble anions and secondary metabolites of plants in the family Brassicaceae to which watercress belongs. These plants also contain an enzyme called myrosinase, whose action is to hydrolyze glucosinolates to form isothiocyanate, a nitrite and a thiocyanate. These products act to protect the plants against herbivores, insects and as interspecies defences. They also play a role in wound healing in the plants. The glucosinolates and enzyme myrosinase are usually stored in different compartments inside the cells of the plant. They are only released and get to mix together when the plant is injured, cut or crushed when chewed by man or juiced in either a fruit juicer or a liquidizer. At high doses, the isothiocyanates can be toxic to the tissues of the human body but at subtoxic doses, the hydrolytic and metabolic products of glucosinolates act as chemoprotective agents against chemically induced carcinogens. They do this by blocking the initiation of tumours in a variety of rodent tissues like the liver, colon, mammary, pancreas etc. Watercress is nature’s richest source of PEITC especially if the vegetable is eaten raw. Cooking destroys the enzyme myrosinase but the bacterial flora in the colon hydrolyzes a bit of the glucosinolates but not as efficient as the enzyme would do. For this reason it is advised that watercress should be eaten raw, either as part of the salad vegetables or as a juice.
Another way by which watercress carries out its anticancer function is by the activities of the antioxidants. The antioxidants in watercress are the flavonoids, carotenoids, vitamins and selenium. In every metabolic process in the body waste products are released. These waste products known as free radicals are highly reactive, unstable and destructive oxygen molecules, lacking an electron. As they move about in the blood circulation or tissues, they can attach themselves to any other molecule, cell structure or substrates in other to become balanced. In so doing they can course damage to the cells and tissues of the body, giving rise to conditions like cancer and other chronic degenerative diseases. The antioxidants like the ones we have already mentioned donate an electron to the free radicals so that they become balanced and no longer destructive. By this mechanism of action, the antioxidants are considered to be cancer fighters themselves and a preventive against cancer.
A third way by which water cress may be considered as an anti-cancer agent is by the immune enhancing ability of the vitamins and minerals found in it. Vitamins A, C and the B group of Vitamins help to boost the immune system. Not only that, watercress being about 93 per cent water, increases the circulation and also helps to improve the immune system. More oxygen and nutrients get to the cells and toxic wastes get eliminated as fast as they are produced.