Patricia Thompson - NUTRITION TALKLEAVES ARE to the plant what the liver is to the human body. The leaf is the seat of energy production and nutrient conversions as well as the site for deposition of toxic substances. These two functions make the leaves the most important organ to the plant and also a very important addition to the diet.
Chlorophyll, the green pigment of leaves traps sunlight, used for photosynthesis to produce food substances and energy. Leaves therefore have carbohydrate as starch, protein and many minerals and vitamins. Waste products of metabolism are also transferred to the leaves and when these levels become too high, the leaves are shed from the plant. Substances such as alkaloids and oils can be used for their medicinal or cosmetic properties. Leaves are used in salads, cooked as vegetables and infused to produce teas.
DARK-GREEN LEAFY
VEGETABLES (DGLV)
The darker the green colour of the leaf the more nutritious it usually is. The local Amaranth or spinach known popularly as callaloo is a rich source of the minerals calcium, iron as well as vitamin A in the form of carotene and the B vitamins, riboflavin and folic acid. Callaloo is so rich in calcium that weight for weight, it provides more of this mineral than milk.
Spinach however has the inhibitor oxalic acid that binds the calcium thereby making it unavailable for absorption but the local varieties of spinach have much less oxalic acid than the American spinach. Other edible DGLVs are from dasheen (callaloo in Trinidad), yam, sweet potato, papaya and pumpkin but these are rarely used in Jamaica. Many species of amaranth grow wild and this is the most economic buy among the vegetables.
LEAVES AS HERBS
Leaves used as herbs include sage, thyme, mint and rosemary. Herbs are used in cookery to bring out their particular flavour as well as enhance and release the aroma and flavour of foods. Persons who have reduced their use of salt will appreciate the variety of herbs to lift the taste of food. Thyme for example, has a distinct odour and spicy taste and is good for soups, meats, poultry and fish. Mint can be found in about five species, well known as flavouring for beverages, meats, fruit and vegetables.
Parsley leaves are widely used as a garnish and for flavouring meat dishes, soups, sauces and stuffing. It is also nutritious being rich in iron, vitamin C, vitamin A and folic acid. When used along with garlic and onion, chewing the fresh leaves helps get rid of the lingering taste of these stronger vegetables.
TEAS AND MEDICINAL EFFECTS
Locally, tea can mean any brew made from a variety of leaves or other parts of the plant. Bush teas of all kinds are being used more frequently partly because they are caffeine-free but because of the range of medicinal effects they provide. The medicinal effects result from the many alkaloids, glycosides, acids, tannins and essential oils present. Green tea contains the alkaloids caffeine, theobromine and theophylline which act as stimulants.
The tannins of tea are noted in controlling diarrhoea, dysentery and haemorrhages and in reducing the swelling in sore throats and other parts of the body. They can however bind iron making it unavailable to the body. Green tea also contains phytochemicals such as flavonoids, flavanols and phenolic acids noted for their antioxidant effects to decrease the risk of death from heart disease.
Among your New Year's resolutions, include the increased use of leaves in your diet.
Patricia Thompson M.Sc., Registered Nutritionist, The Nutrition Centre, Eden Gardens.
