Food Pyramid
123RF
(#1656863)
Macronutrients [1, 2]
Fats
Fat is
important for many of our body's processes. We need fat in our diets. It
protects our organs, helps to maintain body temperature and it assists nutrient
absorption and distribution. It also helps hormone production. However, where
our health is concerned, it is important not to have too much fat. And even
then, some fats are better than others.
Dietary fats
are classified by their structure. Saturated fats contribute to the risk of
heart disease by raising blood cholesterol levels and are more likely to
contribute to weight gain, while mono- and polyunsaturated fats both tend to
lower blood cholesterol. Among polyunsaturated fats, omega-3 fats are
particularly important.
Benefits of omega-3 fats
Omega-3 fatty acids are beneficial for:
-
Brain and nerves (development and
maintenance)
-
Heart, blood & circulation
(anti-clotting)
-
Eyes (development and maintenance)
-
Immune system and inflammation
(maintenance)
Proteins
Proteins are the body's building blocks and every part of our body is
made up of protein. It is estimated that about half of the body's dry weight is
made up of protein. Many of the foods we eat contain protein, particularly meat
and fish, as well as legumes like beans and lentils. These proteins are
digested to release amino acids for the construction of other proteins, or to
be used as an energy source.
Carbohydrates
Food and
drinks provide fuel for our body in the form of fat, protein, carbohydrates and
alcohol. Carbohydrates are the body's preferred fuel source. The digestive
system breaks down complex carbohydrate-containing foods into simple sugars,
mainly glucose which is used as an energy source.
Foods that contain complex carbohydrates include bread, breakfast cereals,
rice, pasta, legumes, corn, and potato, while fruit, milk, yoghurt, sugar,
biscuits, cakes and lollies consist of simple sugars.
Micronutrients [2]
A lot of
research has been performed investigating our requirement for vitamins and
minerals. Below is a summary of the more important micronutrients and how they
play an important role in our health and wellbeing.
Vitamin A
Vitamin A is a
fat-soluble vitamin that:
-
helps cells reproduce (differentiation)
-
is required for vision and eye health
-
influences genes for normal growth and development
-
is required for normal reproductive function (development and
function of sperm, ovaries and placenta.
Good sources
of vitamin A include liver, dairy products and fish oil.
Vitamin B1
Vitamin B1 is needed to process
carbohydrates, fat, and protein. Every cell (particularly nerve cells) requires
vitamin B1 for the formation of adenosine triphosphate (ATP) to fuel cells.
Found in wheat
germ, whole wheat, peas, beans, fish, peanuts and meat.
Vitamin B2
Vitamin B2 is needed to process amino acids
and fats, to activate vitamin B6 and folic acid, and assist the conversion of carbohydrates
into energy. Vitamin B2 can also act as an antioxidant.
Found in dairy products, eggs, meat, leafy
green vegetables and whole grains.
Vitamin B3
The body uses vitamin B3 in the process of
releasing energy from carbohydrates. It also:
-
converts
carbohydrates into storage fat
-
is
involved in alcohol processing
-
regulates
cholesterol (as niacin).
Found in peanuts, brewer's yeast, fish and meat.
Vitamin
B5
Pantothenic acid (vitamin B5) is involved
in:
-
energy
production
-
making
the neurotransmitter acetylcholine.
-
producing,
transporting, and releasing energy from fats
-
cholesterol
synthesis for vitamin D and steroid hormone manufacture
-
adrenaline
production and release
-
lowering
blood cholesterol and triglycerides.
Found particularly in liver, yeast and salmon.
Vitamin B6
Vitamin B6 is required for protein,
neurotransmitter and hormone synthesis.
Found in potatoes, bananas, raisin bran cereal,
lentils, liver, turkey and tuna.
Vitamin
B9 (folate or folic acid)
Folic acid is a B vitamin needed for cell
replication and growth. Folic acid assists DNA, RNA and protein synthesis in
cells. Rapidly growing tissues, such as those of a foetus, and rapidly
regenerating cells, like red blood cells and immune cells, have a greater need
for folic acid. Folic acid deficiency results in a form of anaemia.
Found in beans, leafy green vegetables, citrus
fruits, beets, wheat germ and meat.
Vitamin B12
Vitamin B12 is required for nerve cell
activity, DNA replication and lowering homocysteine levels (reducing the risk
of heart disease, stroke, and potentially osteoporosis and Alzheimer's disease).
Found in all foods of animal origin,
including dairy, eggs, meat, poultry and fish.
Biotin
Biotin, is a B vitamin required for protein,
fat, and carbohydrate metabolism and DNA relication and gene expression. Biotin
is essential for skin, intestinal and nervous system function.
Found in organ meats, oatmeal, egg yolk, soy,
mushrooms, bananas, peanuts and brewer's yeast.
Vitamin
C
Vitamin C or ascorbic acid is necessary for
numerous biological functions, including several key metabolic reactions, the formation
of collagen in bones, cartilage, muscle, and blood vessels, and the absorption
of iron.
Found primarily in fruit and vegetables, including
broccoli, red peppers, currants, Brussels sprouts, parsley, potatoes, citrus
fruit and strawberries.
Vitamin D
Vitamin D's most important role is
maintaining calcium levels and sparing the calcium that is stored in bones. Recently
it has been suggested that vitamin D may benefit other body systems including
the heart.
The predominant source of vitamin D is
through the skin's exposure to sunlight. Vitamin D is also found in cod liver
oil, egg yolks and butter.
Vitamin
E
Vitamin E is an antioxidant that protects
cell membranes and other parts of the body from damage. Vitamin E has been suggested
to be particularly beneficial for the skin, heart and men's health.
Found in wheat germ oil, nuts and seeds, whole
grains, egg yolks and leafy green vegetables.
Vitamin
K
Vitamin K is needed for proper bone formation
and blood clotting.
Found in leafy green vegetables including spinach,
kale, collards and broccoli, as well as soybean oil, olive oil, cottonseed oil
and canola oil.
Calcium
Calcium is the most abundant, essential
mineral in the human body. 99% of calcium is located in the bones and teeth,
where it is required for strength, growth and formation. Calcium is also required
for blood clotting, transmission of signals in nerve cells and muscle
contraction.
Found in dairy products, sardines, salmon,
green leafy vegetables and tofu.
Copper
Copper is an essential trace element required
for iron absorption, energy utilisation and metabolism
Found in oysters, nuts, dried legumes, cereals,
potatoes, vegetables and meat.
Iodine
Iodine is a trace mineral required for
thyroid hormone synthesis, which is necessary for maintaining cell metabolism.
Found in seafood, iodised salt, sea
vegetables (eg. kelp), dairy products and vegetables grown in iodine-rich soils.
Iron
Iron is an essential mineral required for:
-
the
blood's ability to carry oxygen throughout the body
-
helping
muscle cells store oxygen
-
Energy
synthesis and utilisation.
Iron is found in higher amounts in oysters,
meat, poultry, and fish.
Magnesium
Magnesium is required for bone, protein,
and fatty acid formation, making new cells, activating B vitamins, relaxing
muscles, clotting blood and energy synthesis.
Found in nuts, grains, beans, dark green vegetables,
fish and meat.
Zinc
Zinc is utilised by more than 300 enzymes involved
in several key biological functions including wound repair, fertility and
growth maintenance, protein synthesis, cell reproduction, vision preservation, immunity
and protection against free radicals.
Found in oysters, meat, eggs, seafood, black-eyed
peas, tofu and wheat germ.
1. Trumbo P, Schlicker S, Yates AA, Poos M:
Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids,
cholesterol, protein and amino acids. J
Am Diet Assoc 2002, 102(11):1621-1630.
2. Diet, nutrition
and the prevention of chronic diseases. World
Health Organ Tech Rep Ser 2003, 916:i-viii, 1-149, backcover.
