Photo source: http://www.mangalorean.com/recipes/images/articles/20060111carving1.jpg
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Food is often seen the gracious gift of God. Unequivocally,
the meetei traditional cuisine engirds of multifarious
delicious-vegetables dishes; most notable examples are sinju-bora, kangshoi, eromba, chagem-pomba and so forth. Since
time immemorial, to cinch our daily aliments, there are various indigenous
vegetables which have always been dish out our tummy without foxiness—from
hilly tribes to city kin alike. Ironically, when it comes to devouring, we do
not realize what we eat as long as it is ambrosial. Things can get crappy, when
the food we eat becomes the reason for our bodily dysfunction. But the realm of
fact is vegetables often also contain many toxic substances and antinutritive
factors, which are noxious for human health.
At first, it sounds like gibberish, but here are some of the vegetables which
contain potentially harmful levels of the toxic compound. These toxic
substances include oxalate acid (amaranthus-chengkrup), calcium oxalate
crystal (acridity incolocasia-paan), tetracyclic triterpenoid
cucubitacins (bitterness in cucurbits-cucumber, bottle gourd-khongdrum,
pumpkin and melon. They are considered one of the healthiest vegetables but
they can turn lethal, if bitter; drinking one or two glasses of fresh bottle
gourd juice in the morning on an empty stomach is one such practice
particularly in India. However,
the advisory council to the Department of Indian Alternative Medicines has
suggested that a small piece of bottle gourd should be tasted before extracting
its juice and if it tastes bitter it should not be used as juice to drink),
saponin (spinach, soy bean, tomato), While tomatoes (the fruit) are non-toxic,
atropine is present in the stems and leaves, solanin (do discard any potatoes
that have green eyes, sprouts, or greenish skins, rather than prepare and serve
them, especially to children), linamarin (lima beans-hawai apakpi/thampak),
linustatin & neolinustain (in seeds of lotus), cyanogenic glucosides
(cassava-umaangra), phytohaemagglutinin (kidney Beans-rajma),
chaconine (potato naturally produced toxicant in green potatoes & gives the
potato a bitter taste), trypsin and chymotrypsin inhibitor, amylase inhibitors,
phytohemag-glutinins, cyanogenic glycosides, and perhaps saponins (winged bean-tenoumanbi),
nelumbins (lotus-petioles, pedicels and embryo contains the alkaloid which acts
as a cardiac poison), sinigrin (mustard-unpleasant smell in seeds pod and
inflorescence-flowers), canavins (sword bean-debhi), cyanogenic
compounds-linamarin and lotaustralis (lotus-thambal, from leaves, stem,
flowers, root), piperine (black pepper), capsaicin (pungency in hot pepper). The neurotoxic effect of capsaicin in rats was investigated in a study by
Sugimoto et al. in 1998. Numerous
fragments of DNA were seen in the neonatal rats, 18 to 24 hrs after capsaicin
injection. For now the neural toxic effects found in neonatal rat suggests that
capsaicin containing foods should not be given to children because of the
potential damage to the developing neuroanatomy. A population-based,
case-controlled study was conducted in Mexico City from 1989 to 1990 to
evaluate the relationship between chili pepper consumption and risk for gastric
cancer (Lopez-Carillo et al. 1994). Chili pepper consumption may be a risk
factor for gastric cancer, but further studies are needed to test this
hypothesis. Although the debate
continues over whether the affects of capsaicin are good or bad, many people
currently use capsaicin as an herbal remedy, allyl isothiocynate (oil of
mustard), tripsin inhibitors and lectin (taro-palukabi), vicine (
broadbean-hawai mubi, consumption of uncooked broad bean causes
"favism", which is characterised by haemolytic anaemia,
haemoglobinasia and jaundice), hamagglutinin, goitrogen (substances that cause
goiters), tannins, phyto estrogens, flatus producing oligosaccharides
(carbohydrates of small molecular weight that cause flatulence-gas), phytates
(soy bean), saponins & tannins (tree bean-yongchak, though these
constituents are known to inhibit digestion and absorption in the ruminants,
they could be removed through processing), bamboo shoots (soibum, soidon)
of some species are known to contain phytate, saponin, tannin and cyanogenic
glycosides (HCN), called taxiphyllin and are therefore very bitter. Different
indigenous methods of reducing acidity/bitterness from fresh bamboo shoots has
been reported, boiling in water/salt water and draining or keeping shoots in
hot water for 10-15 minutes for a week at ambient temperature. The optimum
cooking conditions that resulted in 97% reduction of HCN were 98-1020C
for 148-180 minutes.
Depending on the concentration, such compounds may reduce the edibility,
nutritional value, and health benefits of dietary vegetables. Properly cooking
and / or other processing may be necessary to eliminate or reduce them. Even
so, cooking has a relatively small impact on the oxalate content of foods.
Repeated food chemistry studies have shown no statistically significant
lowering of oxalate content following the blanching or boiling of green leafy vegetables.
A lowering of oxalate content by about 5-15 % is the most we should expect when
cooking a high-oxalate food. It does not make sense to overcook
oxalate-containing foods in order to reduce their oxalate content. Because many
vitamins and minerals are lost from overcooking more quickly than are oxalates,
the overcooking of foods (particularly vegetables) will simply result in a far
less nutritious diet that is minimally lower in oxalates. Despite of trifling
results, a conscious effort should be taken to cut down foods that cause damage
to our body.
Above all, the dietary intake of oxalate is of interest for several reasons.
So, let us check over together tangibly about the vegetables which content high
oxalate that we should conscious about them in our daily diets. Have you ever
checked the oxalate content of your food? If you haven't, it's time to wake up.
Eating high oxalate food exposes us to certain irregularities in some of the
functions of our body. Since, consumption of foods high in oxalate results in a
disorder of the urinary tract, commonly known as "kidney stones".
The kidneys are one of the most vital parts of our body. Malfunction of the
kidneys due the blockage of urine by stones causes severe pain. If you have any
kidney stones, your doctor or dietician may talk with you about an eating plan
to prevent new stones. The most common types of kidney stones are calcium and
oxalate. Each type may require a different eating plan. There are certain foods
you can have, and other foods you should avoid, to reduce the chance that you
will get kidney stone again.
Oxalate is an organic acid, primarily found in plants, animals and humans. The
occurrence and distribution of oxalate vary enormously among the organisms. For
instance, in plants the highest oxalate concentrations commonly occur in the
leaves and the lowest in roots. It is not an essential molecule and is excreted
from our body in an unchanged form. Our body either produces oxalate on its own
or it converts other molecules like vitamin C — high in agathi
(chuchurangmei-169mg/100g); Capsicum (shimla morok-137mg/100g), coriander leaves (phadigom-135mg/100g),
king chilli (umorok-115.67mg/100g), broccoli (113mg/100g), cabbage
(124mg/100g), chilli (111mg/100g) and tomato (31mg/100g of edible portion), Parkia roxburghii (yongchak-26mg/100) — to
oxalate. Vitamin C is one of the substances that our cells routinely convert
into oxalates. External sources like the foods we eat also contribute to the
accumulation of oxalate in our body. The oxalate present in the body is
excreted in our urine as a waste. Too much of oxalate in our urine, results in
a medical condition called as hyperoxaluria, commonly referred to as kidney
stones.
Vegetables can be divided fairly readily into those containing high concentration
of oxalate acid and those containing small or negligible amounts. No close
correlation was found between the oxalic acid content and the content of
calcium, magnesium or phosphorous, although the concentration of calcium and
magnesium tend to be high in those plants or parts of plants that contain large
amounts of oxalate. Indeed, totally avoiding foods high in oxalate would be
something next to impossible. Howbeit, care has to be taken to keep a check on
the consumption of high oxalate foods. The oxalate amount should be restricted
to 40 to 50 mg per day.
The following some list given and quantum in the parenthesis will help you to
avoid certain oxalate containing foods. Food with an oxalate content exceeding
10 mg/100 g of the edible portion are spinach-palangshak (412mg), amaranths-chengkrup (280.62mg),
amaranthus tricolor-chengkrup marangbi (131.4mg), sweet potato leaves-maangra (48.6mg), bitter gourd (26.631mg),
wild lotus (20.88mg), okra-belendri (20.547mg),
French beans-rajma (22.8-30.2mg),
beetroot (121.0mg). Foods with oxalate content of 1-10 mg/100g; leek
flower-tilhau (9.63mg), celery (9.504mg), luffa-shebot (7.866mg), chayote
leaves-dashkush (6.03mg), lotus root-thambau (5.6691mg), chives-nakupi (4.05 mg), eggplant-khamen (3.51mg), wax gourd-torbot (2.7mg), chinese yam (2.691mg), carrot
(7.4mg), tomato (5.3mg) etc. Spinach is a well known high oxalate vegetable; it
belongs to the family chenopodiaceae. Another well known high oxalate food in
this family is sugar beet. Many vegetables from the family Amaranthaceae are
high in oxalate content.
The leaves and seeds of Amaranthus species are edible. Both Amaranthus and A. tricolor are high in oxalate content, and they are
similar in appearance; the difference between them is that tricolor has
purplish leaves. Maximum oxalate concentration is noticed in amaranth (742 mg).
Bitter gourd (Karot akhabi) shows a high oxalate content. In taro
(palukabi) tubers and leaves acridity is due to the presence of calcium
oxalate crystal. Most of the cultivated varieties are free from acridity.
However, it is best not to taste any variety raw. The acridity is destroyed by
cooking. Vegetables with high oxalate content also include cucumber-thabi,
green peppers-morok, parsley (salad crop) and greens of all kind.
Withal, we should limit the use of condiments like black pepper, cinnamon (dalchini)
and ginger.
Renal stones (kidney) have beset humans for centuries. Researchers have found
evidence of kidney stone in 7,000 year old Egyptian mummy. Each year, worldly
people make almost 3 million visits to health care providers and more than half
a million patients go to emergency room with urolithiasis. Factors leading to
initiation of calcium oxalate concentrations are still not known. In our state
Manipur, a case study conducted in the Department of Biochemistry in
collaboration with the Department of Urology, RIMS, Imphal was shown that
urolithiasis was found to be most predominant in the age of group of 31-41
years comprising of 30.6%. It was observed that the higher incidence of urinary
stones case in male (68%) than female (32%). Meanwhile, P.P. Singh et al., in
their 196 stones analysis in Manipur showed calcium and oxalate were present in
all the stones.
Comparatively little is known about the daily intake of oxalate, the proportion
normally absorbed or the proportion of the urinary oxalate that is of dietary
origin. Several extensive studies of the oxalate content of foods have been
made within recent years, but the accuracy of the analytical procedure is
sometimes open to question. Meanwhile, oxalate that a human body absorbs from
food was thought to be an insignificant contributor to urinary oxalate
excretion. However, many researchers indicated that dietary oxalate can provide
up to 80% of the oxalate excreted. Some risk factors for stone disease are
associated with a low calcium intake and dietary oxalate is believed to be an
important contributing factor. An interesting fact to note is that, most leafy
vegetables contain high levels of minerals such as calcium and iron, however,
these minerals may not be readily available biologically due to the presence of
oxalates which forms insoluble salts with the minerals and prevent their
absorption in the digestive tract (small intestine). In addition, some of the
oxalate in urine is made by the body. But eating certain foods with high levels
of oxalate can increase the amount of oxalate in the urine, where it combines
with calcium to form calcium oxalate stones.
For all of the above reasons, when healthcare providers recommend restriction
of dietary oxalates to prevent calcium oxalate stone formation in individuals
who have previously formed stones, they often suggest "limiting" or
"reducing" oxalate intake rather than setting a specific milligram
amount that should not be exceeded. Besides oxalate stone formation, high
oxalate intake has other effects on human being. Small dose of oxalate in the
body may cause headache, pain and twitching in muscle and cramps. Larger doses
can cause a week an irregular heartbeat, a drop in blood pressure and sigh of
heart failure. Large doses of oxalate can rapidly put a person in a shock life
state, causing convulsion, coma, and possibly death. The mean lethal dose for
an adult is about 15-30 g, but the lowest reported lethal dose is only g (70
mg/kg).
Of course, our region, being blessed with a variety of natural surrounding and
varying climates, has a number of indigenous underutilized-vegetables, which
are available seasonally, and practically no relevant information is available
on the nutrient content and anti-nutritional factors, especially the oxalate
content of such vegetables. So, if you have been bringing on foods that are
listed as "high oxalate foods", it's time for some reality check.
In Shakespeare's one of the best-known plays, The
Merchant of Venice, there is a famous adage: "All that
glisters/glitters is not gold", from a secondary plot of the play, the
puzzle of Portia's boxes. It's still doubtlessly conceded in every realm of
life, therewith, when it comes to sporadically saying: "All that
vegetables contain is not always edible or nutritious". Needless to
say, think twice - or about a dozen times-before using the delicious-looking
vegetables in any styles of partaking. For the food we eat today, will determines
how salutiferous our society will be later on in life.
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Note: See also same article by Angomcha Jinus Senjam,
http://e-pao.net/epSubPageExtractor.asp?src=education.Science_and_Technology.Latent-poison-in-the-food-we-devour
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