NUTRIENTS
Nutrition refers to the intake, digestion, and
absorption of the nutrients needed to maintain the
body in good health and, in children and
adolescents, to allow for growth. The major classes
of nutrients are proteins, carbohydrates, lipids, the
major minerals, the trace minerals, and vitamins.
Proteins, carbohydrates, lipids, and the major miner-
als are referred to as macronutrients because of the
relatively large quantities of these nutrients ingested
daily in a typical Western diet. The trace minerals
and vitamins are called micronutrients. The trace
minerals, vitamins, the major minerals, and some
fatty acids and amino acids (Table 8.1) are essential
nutrients in that they cannot be synthesized at all or
they cannot be produced in an adequate amount
under normal conditions so they must be derived
from the diet (Linder 1991). Calciferols, the dietary
forms of the prohormone cholecalciferol, are a
conditional essential nutrient. In tropical and south-
ern temperate latitudes, adequate amounts of chole-
calciferol can be synthesized from 7-dihydro-
cholesterol by ultraviolet photolysis in skin cells.
However, at northern latitudes, the exposure to
sunlight is less and the synthesis of cholecalciferol
cannot meet the needs of growing children. Hence,
for children living in northern lands, the endogenous
production of cholecalciferol must be supplemented
by the intake of dietary calciferols.
The diets of peoples living in affluent countries,
such as the United States, almost invariably
completely satisfy the dietary needs for the macronu-
trients and the widespread practice of fortifying
foods with micronutrients assures that even individu-
als consuming unbalanced diets will still obtain a
Nutritional Status
8-1
Chapter 8
NUTRITIONAL STATUS
© 2001 Dennis A. Noe
Table 8.1
Essential Nutrients
amino acids
trace minerals
isoleucine
chromium
leucine
cobalt
lysine
copper
methionine
iodine
phenylalanine
iron
threonine
manganese
tryptophan
molybdenum
valine
selenium
zinc
fatty acids
linoleic acid (n-6 fatty acids)
fat-soluble vitamins
linolenic acid (n-3 fatty acids)
calciferols (vitamin D)
menaquinones and
water and major minerals
phylloquinones (vitamin K)
water
retinoids (vitamin A)
potassium
tocopherols (vitamin E)
sodium
calcium
water-soluble vitamins
magnesium
ascorbic acid (vitamin C)
chloride
biotin
phosphate
cobalamin (vitamin B
12
)
folate
niacin (vitamin B
3
)
pantothenic acid (vitamin B
5
)
pyridoxine (vitamin B
6
)
riboflavin (vitamin B
2
)
thiamin (vitamin B
1
)
