by Kerin de Maria
Eat plenty of dark green leafy vegetables and you
can practically forget everything else you know about nutrition.
So says Keith Akers, author of A Vegetarian Sourcebook (Vegetarian Press,
1993). He goes on to explain that, calorie for calorie, green leafy
vegetables provide more calcium than milk, more iron than beef, about
as much vitamin A as carrots, more vitamin C than oranges, generous
quantities of the B group vitamins, zinc, magnesium and various other
minor nutrients too numerous to mention.
Add to this the fact that leafy greens are an excellent source of vitamins
E and K, are rich in phytochemicals that fight cancer and regulate hormones
and are brimming with chlorophyll, the green plant pigment that has
a very similar composition to human blood. Chlorophyll acts as an excellent
tonic and cleanser for the whole body. Leafy greens stimulate digestion
and absorption and have long been used as tonics for the liver and gall
bladder. An old French proverb tells us “spinach is the broom of the
Ayurveda (the traditional Indian system of health care) recommends the
frequent consumption of dark, leafy greens as a specific healer for
the liver and immune system, as well as the skin, eyes and mucous membranes.
In recent years a number of studies have been conducted on Mediterranean
and Asian populations in an attempt to discover why these people have
a much lower incidence of common western ailments such as heart disease,
cancer, diabetes and osteoporosis. Foods such as soybeans, nuts and
olive oil have been given much credit, no doubt with good cause. But
these people are also big consumers of dark, leafy greens both wild
and cultivated, and it seems likely that this, too, plays a significant
role in their health and well being.
Leafy greens have in fact been an important part of the diet of most
cultures for many thousands of years. Here in Australia, it’s wonderful
to see a renewed interest in these health-giving and delicious plants.
Demand by our ethnic population, together with the growing awareness
of the need to eat such life-giving foods, has led to the increased
availability of a large range of greens in the marketplace.
These days you can eat a different green every day of the week, and
the ways to serve them are endless. Try them in salads, sandwiches,
juiced, stir- fried, steamed; in stuffings, pancakes, omelettes, casseroles,
curries; in pastas and pasta sauces, in dips, sauces and spreads, soups,
pies and tarts. Use vine leaves, cabbage, chard or lettuce leaves to
wrap around other ingredients. Imagination is the only limit. Try to
use greens that are as fresh as possible, but they will store for 4-5
days in the refrigerator if wrapped in some paper towelling and placed
in a plastic bag or container.
Lettuce, broccoli, cabbage, chard (silverbeet) and spinach spring instantly
to mind when one mentions greens. We are also becoming increasingly
familiar with Asian greens including bok and pak choy, choy sum, shungiku,
mizuna and tatsoi. Most Asian greens belong to the brassica family,
as do broccoli and cabbage. Other brassicas include kale and collards
(excellent sources of calcium), watercress and rocket. Turnips and kohlrabi
are brassicas grown for their roots, but the leaves can also be eaten.
So too can the leaves of beetroot.
Chicory and endive are closely related greens, whose names cause much
confusion. Endive is an annual and includes curly leaf varieties as
well as broad-leaved ones, sometimes known as escarole. Chicory is a
perennial and includes a number of cultivars, including the confusingly
named ‘Belgian endive’. Radicchio also belongs to the chicory family.
Both chicory and endive are bitter leaved and can liven up a salad bowl.
They can also be cooked like spinach.
Dandelion leaves, which are an excellent tonic for the liver, can be
used in the same way. Four leaves a day are said to provide most of
an adults essential minerals and vitamins. Another ‘weed’ of value is
purslane, said to contain good amounts of omega-3 fatty acids, the sort
found in flaxseed and fish oils. Purslane’s crunchy, mild taste can
be enjoyed raw or cooked. Orache or summer spinach is a two metre tall
annual also known as ‘fat hen’. Sorrel, much beloved by the French,
adds a refreshing bite reminiscent of tart apple with hints of orange
and lemon. Lambs lettuce ( aka ‘corn salad’ or mache) provides a mild,
The only preparation most greens need is a good wash in a couple of
changes of water to get rid of any grit. Keep the leaves whole, tear
into bite size pieces, or shred according to the recipe. Very woody
or stringy stems and ribs can be removed, but the more tender ones can
be included in the dish to provide a nice contrast in texture. If they
are a little coarse you can add them to the pot a few minutes before
the leaves to give them longer to cook. Most greens only take about
3-5 minutes to cook, although some of the coarser members of the brassica
family may take twice as long.
Many greens can be eaten raw in salads and sandwiches. Young, tender
leaves are best for this. Even bitter greens such as dandelion and chicory
are quite palatable when picked young. Older leaves may be more appetizing
if blanched first. To do this simply plunge the leaves into boiling
water for about 30 seconds, drain and refresh under cold running water
to stop the cooking process.
Growing Your Own
For ultimate flavour, nutrition and satisfaction the best way to enjoy
greens is picked straight from your own garden. Even a few pots on a
balcony can make a valuable contribution to the green part of your diet.
Greens are among the easiest vegetables to grow, and very economical.
Most nurseries stock a variety of seedlings, but for an even wider choice,
try growing from seed. Organic, non-hybridised, open-pollinated seeds
are the best and there are several mail-order companies in Australia
that can provide you with these. (See useful addresses, below). The
Seed Savers Network is another avenue worth exploring here you can access
many different varieties of plants not commercially available. Local
organic and permaculture groups are another source of good quality seeds,
as well as information on the best varieties and time of year to plant
for your particular area.
But what about oxalic acid and other anti-nutrients in leafy greens?
Many plants contain both nutritional and anti-nutritional substances,
the anti-nutrients having evolved as a protective mechanism against
insects and other predators. In general, they do not pose a hazard when
consumed in normal quantities. One must remember that even water can
be toxic when consumed in excess!
Oxalic acid is an anti-nutrient compound found in spinach, chard, beet
greens and sorrel. It binds with calcium, preventing absorption of this
important mineral. Oxalate deposits also play a part in the formation
of kidney stones. (But stones can still form on an oxalic-acid free
diet, so it would seem a dietary source is not the main culprit.)
It has been suggested that heat, as in cooking, denatures oxalic acid,
reducing its effect on the body. Ayurvedic physicians recommend the
use of spices such as garlic, turmeric, coriander and nutmeg with oxalic
acid containing foods, to help eliminate the harmful aspect. But unless
you are consuming huge quantities of oxalic-rich foods you are unlikely
to have a problem. Two or three servings per week of spinach is not
going to affect calcium balance in a healthy person, and in fact will
do a lot more good than harm.
Glucosinolates are a group of compounds that give the mustardy flavour
to cruciferous vegetables such as turnips, mustard greens, cabbage and
kale. Some glucosinolates may interfere with the uptake of iodine by
the thyroid gland, resulting in goitre. Again, this is only likely to
occur where consumption is excessive. Most goitres are caused by a lack
of iodine in the diet. On the positive side, certain glucosinolates
are thought to be protective against cancer, helping to detoxify cancer-causing
nitrosamine chemicals in the liver.
Saponins are found in a wide range of foods, particularly legumes, but
also some greens such as New Zealand spinach. They have been branded
as anti-nutrients because of a belief that they cause bloating in animals
and haemolise red blood cells. However these assumptions were based
on in vitro (test tube) experiments, and animal studies now suggest
that saponins may in fact help with digestion. There is no evidence
that the oral ingestion of saponins is toxic to red blood cells. Moreover,
experiments on primates show that saponins have a cholesterol lowering
effect, and at least one study showed inhibition of colon cancer.
Consume a wide range of different greens and you are unlikely to be
affected by any particular anti-nutrient. The only people who need to
be cautious about their intake of greens are those on anti-coagulant
medication such as warfarin. Vitamin K, which is so plentiful in leafy
greens, can interfere with the function of such drugs.
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