1. Dr. Mohammad Tufail Banday
Associate Professor, Skuast (K)
2. Dr. Sheikh Adil Hamid
M.v.sc. Scholarh
Human
beings require a well balanced diet containing proper amount of
proximate principles which include proteins, lipids,
carbohydrates, vitamins, minerals and water to enable them to
live and thrive. Nutritionists know that all foods contain at
least one of these six nutrient groups. Eggs have been regarded
as one of nature’s perfect foods.
The table egg is the most nutritious, yet relatively cheaper
natural food having one of the highest digestibility
coefficients.
Eggs contain all six of these nutrient groups.
Eggs are one of the best protected foods available to man in a
form originally packed by nature. They cannot be adulterated
because of their outer covering or the shell.
Their judicious
use in the diets can effectively combat nutritional imbalances
against the vulnerable groups particularly nursing mothers,
infants, children and convalescent persons.
Both eggs and milk are considered to be the two best protective
foods because they are concentrated sources of nutrients viz
proteins, energy, vitamins and minerals. When the dietary value
of egg is compared with that of milk, we find egg is richer in
proteins, fats, vitamin A, B12 , riboflavin and folic acid than
milk on per unit basis. Similarly eggs are rich sources of iron
which is deficient in milk and other foods except leafy
vegetables .Again egg is rich source of vitamin D as compared to
milk which is important for bone development for children. Eggs
are given in persons suffering from conditions such as
Kwashiorkor, anemia, typhoid, tuberculosis; post operative
stages, pregnancy etc.
Eggs contain all the dietary essential amino acids needed by the
human being which are needed for the maintenance, growth, repair
and production of antibodies that protect us from the diseases
.The protein of egg is of such a high quality that the
nutritionists use it as a standard for measuring the quality of
other food proteins. Thus egg protein is the best available in
nature for human consumption with well balanced amino acid
profile, having the highest biological value, protein efficiency
ratio, net protein utilization, net protein value and chemical
score (Table.1)
Table.1 Protein quality of egg protein in comparison
with other foodstuffs.
Food stuff |
Biological value |
Protein efficiency
ratio |
Net Protein
utilization |
Chemical score |
Egg |
96 |
4.5 |
91 |
100 |
Cow’s milk |
84 |
3.0 |
75 |
65 |
Meat |
80 |
2.8 |
76 |
70 |
Fish |
85 |
3.0 |
72 |
60 |
Liver |
77 |
2.9 |
65 |
66 |
Pulses |
56 |
1.6 |
45 |
44 |
|
About 60% of the fat in an egg is in
the form of unsaturated fatty acids. These unsaturated fatty
acids are often considered better for our health than the
saturated fatty acids. Eggs contain very little carbohydrates
and no fiber.
One egg contains approximately 85 calories, which is only 3-4%
of the total calorie needs of an adult human being. The fat
soluble vitamins A, D, E and K are found in eggs along with the
B-complex vitamins. Egg contains no vitamin C. Eggs are also an
excellent source of iron, phosphorus, selenium and other
minerals. Its nutritional value, chemical composition and %
contribution towards daily nutrient requirements are presented
in Table 2
Table2. Nutrient composition of 100g of egg content
and the percentage of daily recommended nutrients
contributed by two eggs.
Nutrient |
Content in 100g of egg
contents |
Requirements/day/man |
%contribution by two
eggs |
Protein (g) |
13.3 |
67 |
22.2 |
Lipids(g) |
11.4 |
50 |
76.0 |
Ash(g) |
0.8 |
0.2 |
1.6 |
Linoleic acid (g) |
1.8 |
12.5 |
14.4 |
Cholesterol(mg) |
400 |
1500-2000 |
852 |
Energy(Kcal) |
162 |
2700 |
5400 |
Total saturated fatty
acids(g) |
3.34 |
14.97 |
6.68 |
Total un- saturated
fatty acids(g) |
6.4 |
20.45 |
13.04 |
Calcium(g) |
50 |
0.8 |
1.6 |
Phosphorus(g) |
178 |
0.9 |
1.8 |
Iron(mg) |
1.44 |
12 |
24 |
Vitamin A (I.U) |
634 |
5000 |
1268 |
Vitamin D (I.U) |
49 |
400 |
98 |
Vitamin B1(mg) |
0.062 |
1.5 |
0.124 |
Vitamin B2(mg) |
0.508 |
2.0 |
1.016 |
Vitamin C(mg) |
---- |
75 |
------ |
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Despite having nutritional
supremacy, abundant availability and within the reach of common
man, the per capita consumption of eggs in many countries,
including India, is far below the minimum recommended level is
half an egg per head per day.
However, the egg has been under intense attack by
anti-cholesterol advocates. The egg has been blamed and defamed
as one of the major culprits in causing heart problems.
MYTHS AND MISCONCEPTIONS ABOUT EGGS
Scientific and logical explanations are given based on the
advances made in nutrition, food science and medicine to
disprove the above misconceptions.
I.Egg is a non-vegetarian food and consumption is a sin.
No doubt the table egg is of animal origin just like milk. But
milk is considered as an acceptable food for vegetarians (Lacto-
vegetarian), than logically the infertile table eggs also shall
be an acceptable food for vegetarians (lacto-ovo-vegetarian).
Milk is the secretion of udder primarily meant for feeding
growing calves, whereas egg is the secretion of ovary and
oviduct to feed the growing embryo (only in case of fertile
eggs, incubated for hatching) and not a potion of meat. A table
egg is infertile and there is no living cell in a table egg.
Hence there is no sin or cruelty in eating table eggs which are
infertile and lifeless. If eating lifeless egg is considered as
sin, then eating the vegetable and fruits which are obtained
from live plans is a great sin.
Scientific and logical explanations are given based on the
advances made in nutrition, food science and medicine to
disprove the above misconceptions. Scientific and logical
explanations are given below based on the recent advances made
in nutrition, food science and medicine to disapprove the above
misconcepts
.
II.Egg is not suitable food during summer, since it produces
excess heat:
Some people are under the belief that consuming eggs will
generate excess heat in the body, hence are not suitable during
summer. Probably such persons might have misunderstood its high
nutritive value as high calorific value. In fact egg is
relatively one of the low energy foods supplying only 81 Kcal of
energy per egg or about 162 Kcal/100g of edible portion of the
egg, when compared to more than 320Kcal/100g of grains or
pulses. Hence egg is ideal food for all seasons and even for
those who want a low calorie and /or high protein food. Egg is
contaminated with harmful bacteria like Salmonella and E. coli
and consumption of such eggs would lead to food poisoning and
other diseases.
III.Egg is contaminated with harmful bacteria and consumption
of such eggs would lead to food poisoning and other diseases:
The table eggs, like any other perishable food material, like
milk, meat, vegetables, fruit etc contains high levels of
moisture and may also contain few micro organisms especially on
its shell surface. Even raw milk is not recommended practice and
has to be consumed only after pasteurization or boiling.
Similarly eggs have to be boiled or subjected to any heat
treatment before eating. Generally salmonella and E.coli are
common harmful bacteria that are noticed on egg shell surface.
However, due the cage rearing of layers, increased automation
and improved farm sanitation, the surface contamination of eggs
has been reduced considerably. Moreover, there are more than
2000 serotypes in these in these bacteria and only very few of
them are harmful to human beings. Due to many defense mechanisms
the chances of food poisoning due egg consumption is only 1 in
1,600,000 (0.0000625%).Moreover, eggs are consumed only after
cooking which will destroy the harmful microorganisms .With many
natural defense mechanisms, egg is the only perishable food
which can maintain its quality fairly well even for a period of
two weeks at room temperature.
IV.Desi eggs are more nutritious than farm eggs:
Except for the shell colour and size, none of the egg quality
traits and chemical components is influenced by breed of
chicken. As far as the desi eggs are concerned, their
nutritional composition is comparable with the farm eggs. The
desi egg weighs only 2/3rd or 3/4th of the farm egg. Hence one
desi egg supplies only 2/3rd 3/4th of the nutrients supplied by
a farm egg. Desi eggs have darker yolks due the higher
xanthophyll pigment content than the farm eggs but their vitamin
A contents are comparable. Moreover, many traders are exploiting
the ignorance of the public, by dipping eggs in tea decoction to
change the shell colour to brown so as to sell them at a premium
price.
V.Raw eggs are more nutritious than cooked eggs:
In order to tap the maximum nutritional value from eggs with
least risk, the table should consumed as hard boiled and a raw
should never be consumed due the presence of antinutrional
factors like Avidin, Ovoinhibitor etc which interfere with the
bioavailability of biotin and reduction in the protiolytic
enzymes. On the other hand poaching, frying and scrambling of
eggs may lead to partial loss of certain heat labial nutrients
like B- complex group of vitamins and bioavailability of certain
proteins.
VI.Brown shelled eggs are more nutritious than white shelled
eggs:
The shell colour is due the pigments ooporphyrin and oocyan. The
shell colour is a breed character and has nothing to do with the
quality or nutritional value of the eggs. Moreover, the shell
forms the inedible portion of the egg. Traders have exploited
the ignorance of the consumers and are selling brown shelled
eggs at a premium price.
VII.Eggs contain high levels of cholesterol, hence
consumption of eggs will increase the risk of coronary heart
diseases (CHD):
Cholesterol is essential component of every body cell.
Consequently the body does not rely on the dietary intake, while
as the liver manufacturers 70-80% of the body’s cholesterol. The
remaining comes from dietary sources. Cholesterol functions as a
structural component of every animal cell membrane. The brain
and the spinal cord have high concentration of cholesterol
because of the important role in the nervous system. It is
needed to make many hormones, such as the male and the female
sex hormones. The adrenal gland use cholesterol to make hormones
that help to control sodium and potassium excretion as well as
protein and glucose metabolism. Without cholesterol, vitamin D
could not be synthesized and subsequently calcium and phosphorus
could not be utilized. Cholesterol is needed by the liver to
make bile salts that help in the proper digestion and absorption
of lipids and fat soluble vitamins. The skin contains large
amount of cholesterol which along with other fatty materials
makes the skin highly resistant to the absorption of water and
water soluble substance.
What is relationship between dietary cholesterol and blood
cholesterol levels?
Since there a sufficient biosynthesis, dietary cholesterol plays
no significant role on serum cholesterol levels. Extensive
research and survey work carried out by the scientists of FAO,
WHO.ICMR, MRFIT and DHSS of UK. COMA, ADA, AHA, USDA, and NAS
also confirmed these findings. A joint study was conducted in
USA screening 2,000 individuals having different levels of egg
consumption per week. The study revealed no significant
variations in the total serum cholesterol levels based on the
number of eggs eaten by them.
Among the dietary causes, excess energy consumption is the main
factor responsible for elevated serum cholesterol levels. This
was followed by excess saturated fat intake and least by dietary
cholesterol. Out of the various factors responsible for
hypercholestremia , all dietary causes put together will account
for 20-25% only. Moreover, cholesterol is poorly absorbed(<40%)
from intestines. The remaining is due to non-dietary causes. The
non-dietary factors account for nearly 75-80% of increase in the
serum cholesterol levels. Several factors are responsible for
the hypercholestremia. Among them heredity plays a major role.
Persons with the family history of hypercholestremia and
coronary heart disease are prone for elevated serum cholesterol
levels. This is followed by the age of an individual. Similarly
smoking, severe emotional stress, diabetes mellitus,
hypertension, hypothyroidism and other hormonal imbalances,
excess testosterone levels in men, menopause in women, sedentary
habits and occupations, lack of exercise, drugs like caffeine,
obstructive jaundice, nephritis, left ventricular hypertrophy,
obesity are some of the major factors responsible for
hypercholestremia rather than dietary cholesterol levels.
Therefore, any attempt to control serum cholesterol levels
without attempting to reduce the total energy intake, obesity,
smoking, alcoholism etc will be futile.
Why this cholesterol phobia?
Egg has been regarded as one of nature’s most perfect foods. It
is perhaps the only food on the planet to get a 100 point rating
from the World Health Organization.
Many consumers still have great deal of anxiety about eating
eggs. This anxiety originated many years ago when media
sensationalized the fact that eggs contain cholesterol.
Following this initial uncontested research, some simplistic
logic developed. If any food containing cholesterol is eaten, a
rise in blood cholesterol will lead to atherosclerosis and heart
attacks. The public was immediately bombarded with unwarranted
sensationalism about cholesterol in eggs. Today we know that the
unwarranted anxiety about eggs is unjustified .The egg industry
has never tried to hide the fact that eggs are a rich sources of
cholesterol, yet because eggs do indeed contain cholesterol ,
they have been singled out as a food which everyone should omit
from the diet. The public should realize that such blanket
recommendations do not apply to everyone.
Today consumers are more educated and health conscious than they
were 20 years ago. Informed consumers can make reasonable
decisions about their own health. Consumers should be realistic
enough to know that some manufacturers continuously try to sell
their products by sensationalism. Some companies are still using
the “cholesterol phobia” in their tactics. Most people who
understand the vital functions of cholesterol are not swayed or
scared by such advertisements.
In normal people, a short-term increase in the blood cholesterol
may occur following a meal that contains high levels of
cholesterol. Normally this cholesterol is properly metabolized
and utilized by the body. Therefore, the increase in the blood
cholesterol is short lived and these levels will eventually go
down. The body has also has a regulatory mechanism to control
the blood cholesterol levels.
The continuous highly published association of cholesterol to
CHD has scared the public and made it very difficult for
consumers to accept the conclusion of the up-dated research. To
keep from being confused on the issue, the consumer has to
understand that a low cholesterol diet is a misnomer. Eating
less cholesterol diet does not necessarily mean that the blood
cholesterol levels will be lowered. Every person is different to
cholesterol absorption. Some people may absorb as much as 85%
from the diet, whereas others may have only 20% of dietary
cholesterol absorption. Also the body size is not necessarily a
good indicator of blood cholesterol.
Who need to worry about high blood cholesterol?
Certain people with continuously high cholesterol levels are
classified as high risk individuals and should not be concerned
about their total dietary cholesterol intake as well as total
fat intake. Such individuals have to be put on cholesterol
lowering drug therapy. However, normal individuals have a
mechanism for regulating blood cholesterol.
Intelligent eating habits in order to stay healthy require more
than completely eliminating nutritious foods such as eggs, meat
and milk from one’s diet. Such foods should never be thought of
as poison. Some very high quality foods are being eliminated due
simply to unnecessary fear. Because of what is now known about
diet and CHD, there is no reason for the normal person to single
eggs or other foods and eliminate them from the diet. All people
should be encouraged to have their blood cholesterol level
screened especially if they have parents with high blood
cholesterol or other risk factors. These individuals with high
levels should consider further diagnostic tests to determine
their HDL: LDL ratios. The rest of us should not be as concerned
about eating eggs and other animal products. However, everybody
should maintain normal body weight, eat a balanced diet made of
wholesome food and continue to make healthy food choices.
PAKISSAN
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