Vegetables and Human Nutrition

Deepali Tewari Pandey, GBPUAT, Pantnagar

Nutritive value of vegetables:        

Vegetables are rich source of nutrients, important for human health.  They are particularly important sources of micronutrient, pro-vitamin-A, B₆, C and E as well as folic acid, iron and magnesium.Table given below explains different groups of vegetables according to the primary type of nutrients they provide:

• Vegetables, as protective food: The nutritional value of vegetables as a vital source of essential minerals and vitamins is given in Table above.
• In addition to these constituents vegetables also supply fair amounts of dietary fibers. Due to their high water content and fiber (which constitute of high percentage of complex carbohydrates), leafy vegetables and roots help in digestion and utilization of the more concentrated food in the human diet. Vegetables containing high amount of fiber are spinach (6.3%), peas 95.20, broad bean (4.2%) and okra (3.1).
• Vegetables neutralize the acid substances produced in the course of digestion of meat, cheese and other high-energy foods.
• Dietary fibre in known to be associated with reduced incidence of coronary heart diseases. The mechanism of its action is attributed to its binding to bile salts and preventing its re absorption and in reducing cholesterol level in circulation.
• These fibres particularly the gums, pectins when ingested with a diet are reported to reduce post parandial levels of glucose in blood. These types of dietary fibers are often recommended for the management of certain types of diabetes. For example, Garlic extracts lowers the blood glucose level by increasing the release of insulin from pancreas B cells. Thioglycaocides found in cabbage have a hypoglycemic effect.
• Dietary fiber increases the transit time and reduces the time of release of ingested food in colon. Low fibre diet is associated with colon cancer and dietary fibre may play a role in reducing the risk of colon cancer. It is suggested that an intake of 40 g dietary fibre a day is sufficient.
• Folic acid commonly referred to as folate, found in abundance in spinach (123 mg/100g), other green leafy vegetables (40-80 mg/100g) and beans (144 mg/100g) is required for the multiplication and maturation of red cells. Its deficiency results in megaloblastic Anaemia that is often seen in children and pregnant women.
• Recent researches have also associated it with reduced risk of cardio vascular disease. Earlier studies linked diets high in folic acid with a reduced risk of colon cancer.
• Folic acid lowers homocysteine that has an adverse effect on the lining of arteries. Scientists opine that if homocysteine is lowered, it will decrease the incidences of heart attacks and strokes.
• Secondary metabolites of vegetables act as anti carcinogenic compounds. Recently, Interest has grown steadily in to develop diet-based chemo protection, utilizing fruits and vegetables. Vegetables are rich source of such compounds. Table below gives brief information about anti carcinogenic secondary metabolites and their source vegetables:

• Green leafy vegetables are rich source of antioxidants, which are now a days, being widely promoted as agents that act as protectants against various disorders of human health.
• Vegetables also have traditionally accepted curative properties:

Vegetables as general medicines:

Besides their role to specific diseases, many of the vegetables have curative properties. The brief list of such important vegetables along with their properties is given below:

• Vegetables help in checking obesity as these are low in fat and have high proteins, minerals, vitamins and water.
• Greeks recommended the juice of cabbage as an antidote for eating poisonous mushrooms.
• Juice of bitter luffa is known to be an effective medicine against jaundice.
• Carrot has therapeutic action in intestinal disorders of infants because of the presence of compounds of terpene series in essential oil found in this crop.
• It is believed that extracts of carrots seeds prevent pregnancy by inhibiting the implantation of the fertilized egg in the uterus.
• Onion, garlic and other sulfur containing vegetables possess antiseptic properties. There is a triterpene compound, inotoldiol in garlic, which is reported to inhibit the fungal growth under in-vitro conditions.
• Sweet potato contains bitter substance known as ipomeamarone. Natives of New Zealand use this vegetable as antipyretic.
• Pungent extract (capsaicin) of red pepper has been used in curing neurogenic bladder (Nitti 1994).
• Multi-variant therapeutic role of ginger and turmeric is well documented

In present scenario, we talk about 'Nutritional security". Vegetables can be very reasonable source of all kind of nutrients and minerals. Now days the whole world is converting into vegetarian. It's unfortunate that despite of being a vegetarian country, per capita availability of our country is very poor. Its need of hour to supplement our food bowls with vegetable and move towards attaining a healthy nation.