Phytonutrient vegetables – cruciferous vegetables, a case study
The cruciferous vegetables belong to the family of plants known as Brassicaceae. Their name, cruciferous is derived from the arrangement of the four petals of their flower, like the cross.
The phytochemicals in the cruciferous vegetables are known as sulphoraphanes. They belong to the organosulphur group of compounds called isothiocyanates. Sulphoraphanes are bonded to glucose molecules and become known as sulphoraphane glucosinolates. They make up a family of about 120 compounds securely stored in the cells of the plants. In this way, they are kept away from the enzyme, myrosinase which catalyses the hydrolytic reaction that breaks glucosinolates down to several bioactive products.
Myrosinase is only released when the plant is cut, cooked or chewed and the products that are produced as it acts on glucosinolates include isothiocyanates, oxazolidine-2-thione, nitriles, thiocyanate ions and indole products. These glucosinolates are sulfur-containing compounds, which have a pungent aroma and a spicey taste. This pungent aroma comes from mustard oils released from glucosinolates when myrosinase acts upon them.
In other words, when the plant is intact, you may not perceive the pungent aroma, until it is cut or chewed. They are predominantly found in cruciferous vegetables of the family, Brassicaceae. They include Brussels sprouts, broccoli, cabbage, cauliflower and Chinese cabbage. Others are horseradish, mustard seed, rapeweed and watercress.
Apart from these phytochemicals, all these vegetables are rich in vitamins like Vitamins C, K, B2, B6 and folic acid. Also found in them are minerals such as potassium, magnesium and the potent antioxidant selenium. They are also a rich source of soluble fiber and plant based Omega 3.
Common phytochemicals, isothiocyanates, in the cruciferous plants which make them potent anticancer agents, are the 3,3’ diindolylmethane, sulphoraphane, and selenium. With these vitamins, minerals and phytonutrients, the cruciferous vegetables help to lower the risk of diseases such as cancer and cardiovascular disease; they are both preventive and curative.
These vegetables do these in the following ways:
1. They stop the growth of cancer cells in tumours of the breast, endometrium (the inner lining of the womb), lung, colon, liver and cervix.
2. The phytochemical, sulphoraphane stimulates enzymes in the body that detoxify carcinogens before they cause damage to the cells.
3. They reduce oxidative stress (overload of free radicals which destroy cells and their contents – DNA, causing cancer).
4. In combination with fish oils, the cruciferous vegetables help to protect against cardiovascular diseases.
5. 3,3’ diindolylmethane is a strong androgen receptor antagonist which makes these vegetables a good preventive against cancers like prostate cancer in men. They generally act against those cancers that are hormone dependent in both males and females.
6. Indoles in the vegetables eliminate oestrogen from the body and prevent it from triggering the growth of breast cancer.
7. Studies have shown that a high fiber diet can reduce breast cancer risk by as much as 54 per cent.
A cruciferous vegetable, loaded with a high concentration of soluble fiber does actually reduce the risk of breast cancer in those who regularly consume them. Soluble fiber, which gets absorbed into the system binds to chemicals, heavy metals and other pollutants for easy elimination from the body.
Generally speaking, cruciferous vegetables are associated with improved health and reduced risk of various chronic diseases, including cancer and cardiovascular diseases.
How should cruciferous vegetables be eaten? It is best to eat them raw but if this is not possible because of their sharp taste and pungent smell, they can be steamed lightly before eating. Boiling cruciferous vegetables or any other type of vegetable destroys the nutrients in them.
How often should they be eaten? Eating half a cup or a full cup of these vegetables daily will not cause any harm. Where this is not possible, four to five servings a week will be adequate.
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