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Nutritional
Values of the Egg
Eggs are
an important source of protein, essential vitamins and minerals and
can make a significant contribution to a healthy diet. To illustrate
the contribution that eggs make to the diet and nutritional requirements,
please refer to the table below. The data on the nutritional content
of a single egg is based on a medium egg and all percentage composition
figures relate to the contents, excluding the shell.
Source:
Royal Society of Chemistry/ MAFF 1991 The Composition of Foods (5th
edition)
| Nutritional
analysis of egg without its shell |
For
a medium egg (Av 58g) |
| Constituent
of Egg |
Amount
per egg |
|
Weight*
|
|
51.6
|
|
Water
|
g
|
38.8
|
|
Energy
|
kj/
kcals
|
316/76
|
|
Protein
|
g
|
6.5
|
|
Carbohydrate
|
g
|
trace
|
| Fat |
g
|
5.6
|
|
Inc
saturated f.a.
|
g
|
1.6
|
|
Monounsaturated
f.a
|
g
|
2.4
|
|
Polyunsaturated
f.a.
|
g
|
0.6
|
|
Dietary
fibre
|
g
|
none
|
|
MINERALS
AND TRACE ELEMENTS
|
| Sodium |
mg
|
72
|
|
Potassium
|
mg
|
67
|
|
Calcium
|
mg
|
29
|
|
Phosphorus
|
mg
|
103
|
|
Magnesium
|
mg
|
6.2
|
|
Iron
|
mg
|
1.0
|
|
Zinc
|
mg
|
0.7
|
|
Copper
|
mg
|
0.04
|
|
Iodine
|
mg
|
27
|
|
Chlorine
|
mg
|
83
|
|
Sulphur
|
mg
|
93
|
|
Selenium
|
mg
|
6
|
|
VITAMINS
|
| Vitamin
A |
mg |
98
|
|
Vitamin
D
|
mg |
0.9
|
|
Vitamin
E
|
mg |
0.57
|
|
Vitamin
C
|
mg |
none
|
|
Thiamin
(B1)
|
mg |
0.05
|
|
Riboflavin
(B2)
|
mg |
0.24
|
|
Niacin
|
mg |
1.94
|
|
Vitamin
B6
|
mg |
0.06
|
| Folate |
mg |
26
|
|
Vitamin
B12
|
mg |
1.3
|
| Biotin |
mg |
10
|
|
Pantothenic
acid
|
mg |
0.91
|
* Assumes
edible portion = 89%
Energy
value of eggs
A medium egg has an energy value of 76 kilocalories
(318 kilojoules) and the consumption of one egg daily would contribute
only around 3% of the average energy requirement of an adult man; 4%
for an adult woman.
With their significant protein, vitamin and mineral content and relatively
low saturated fat content, eggs are a valuable component in a healthy
diet.
Protein
Eggs are an excellent source of protein. Egg
protein is of high biological value as it contains all the essential
amino acids needed by the human body. Eggs therefore complement other
food proteins of lower biological value by providing the amino acids
that are in short supply in those foods. 12.5% of the weight of the
egg is protein and it is found in both the yolk and the albumen. Although
protein is more concentrated around the yolk, there is in fact more
protein in the albumen.
On the evaluation scale most commonly used for assessing protein, egg
is at the highest point, 100, and is used as the reference standard
against which all other foods are assessed.
Vitamins
Eggs contain most of the recognised vitamins
with the exception of vitamin C. The egg is a good source of all the B
vitamins, plus the fat-soluble vitamin A. It also provides useful amounts
of vitamin D, as well as some vitamin E.
Minerals
Eggs contain most of the minerals that the human
body requires for health. In particular eggs are an excellent source
of iodine, required to make the thyroid hormone, and phosphorus, required
for bone health. The egg provides significant amounts of zinc, important
for wound healing, growth and fighting infection; selenium, an important
antioxidant; and calcium, needed for bone and growth structure and nervous
function. Eggs also contain significant amounts of iron, the vital ingredient
of red blood cells, but the availability of this iron to the body is
uncertain.
Carbohydrate
and dietary fibre
Eggs contain only traces of carbohydrate and
no dietary fibre.
Fat
10.8% of the egg content is fat. The fat of
an egg is found almost entirely in the yolk; there is less than 0.05%
in the albumen.
Approximately 11% of an egg’s fatty acids are polyunsaturated, 44%
monounsaturated and only 29% saturated.
Cholesterol
Cholesterol and Lecithin are fat-like substances and
are essential to the structure and function of all cells in the body.
Cholesterol helps to maintain the flexibility and permeability of cell
membranes and is also a raw material for the fatty lubricants that help
to keep the skin supple. Cholesterol is essential for the production
of sex hormones, cortisol, vitamin D and bile salts.
Lecithin is involved in general lipid transportation in the blood and
in the metabolism of cholesterol.
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