Water
Water
may be taken for granted yet, next to oxygen, water is the nutrient
most needed for life. You could live for weeks without food but only a
few days without water. Water acts as a solvent, coolant, lubricant and
transportation agent. Besides keeping body temperature stable, water
carries nutrients, eliminates toxins and waste products, maintains
blood volume and provides the medium in which cell chemical reactions
occur. Even if you're inactive, your body loses up to 10 glasses of
water a day. To replace this loss, it is recommended that you consume
at least 8 full glasses of water a day. Intense exercise in hot humid
weather can cause excess water loss through sweat. That water must be
replenished immediately to prevent serious dehydration, even death. If
too much fluid is lost through sweating, blood pressure falls and
decreases oxygen delivery to the brain. However, the quality of the
water we drink is very important with bottled water being, unarguably,
far safer than the tap variety, although any bottled water with a
sodium content of over 2mg per liter should be avoided.
Carbohydrates
Carbohydrates
are the body's primary source of fuel (glucose) and include sugars and
starches. Though both types end up as glucose, foods that are high in
starches, such as grains and vegetables, usually supply a bonus of
vitamins, minerals and fiber. Sugars from candy, cakes, table sugar,
syrups, and sweetened cereals contribute "empty calories" that provide
energy but no nutrients. In addition, there are carbohydrates with a
high or low glycemic index.
High-GI foods have carbohydrates that can be rapidly digested and
absorbed and send blood sugar soaring to high levels, which is
dangerous for those suffering from diabetes. Low-GI foods include
unprocessed carbohydrate foods, which are absorbed more slowly so that
the blood sugar does not rise at such a fast rate as in high-GI food.
Fats
The
body needs some fat to build healthy cells, cushion internal organs,
keep skin and hair healthy and provide a layer of insulation beneath
the skin. The body can make most of the fat it needs, but dietary fat
also supplies us with the fat-soluble vitamins A, D, E, and K, as well
as essential fatty acids, which can't be synthesized by the body.
Saturated fats are the most dangerous type and are linked to a higher
risk of heart disease. These fats are found primarily in animal foods
and dairy products, but also in processed foods, snacks and other foods
that use coconut, palm and other cooking oils. Most saturated fats
raise blood cholesterol but polyunsaturated fats, found in vegetable
and fish oils and monounsaturated fats, found in olive, canola and
peanut oils, lower blood LDL cholesterol. Fats only become a problem
when they make up more than 15 to 20 percent of your diet and,
therefore, should be eaten in moderation with the emphasis on lowering
saturated fat consumption and replacing it with more polyunsaturated
and monounsaturated fats. Watch out for "hydrogenation" on labels;
hydrogen is added to an unsaturated fat to give a product more texture;
that hydrogenation turns a vegetable oil into transfat, which can raise
cholesterol as much as animal fats. Your fat intake should not exceed
30% of your calorie intake.
Proteins
Proteins
form the body's main structural elements and are found in every cell
and tissue. Your body uses proteins for growth and to build and repair
bone, muscles, connective tissue, skin, internal organs and blood.
Hormones, antibodies and the enzymes that regulate the body's chemical
reactions are all made of protein. Without the right proteins, blood
won't clot properly and cuts won't heal. Also, if carbohydrates and fat
can't meet your energy needs, proteins can be broken down and used as a
source of emergency energy. Each protein is a large complex molecule
made up of a string of building blocks called amino acids. The 20 amino
acids the body needs can be linked in thousands of different ways to
form thousands of different proteins, each with a unique function in
the body. The average person needs 50-65 grams of protein each day (15%
of your calorie intake).
Fibers
Fiber is
indigestible carbohydrate found in the cell walls of plant foods.
Although fiber is not a source of calories, vitamins or minerals it
contributes to health in several ways, keeping your digestive system
running smoothly, helping you lose weight and it may lower your risk of
heart disease and certain cancers. The two types of dietary fiber,
soluble and insoluble, both contribute in different ways. A diet high
in soluble fiber helps lower cholesterol levels and helps to regulate
both constipation and diarrhea and slow the absorption of simple
sugars, which helps control the rise in blood sugar after eating. You
should get 11.5 gms of dietry fiber from every 1,000 calories you
consume.
Vitamins
Vitamins
are substances the body needs in small amounts to support body
functions and prevent disease. Although they have no calorific value
they are essential for the transformation of nutrition into energy.
Vitamins play a role in growth and work with each other and with other
nutrients to keep our hearts pumping, our bones and immune system
strong, our digestive system moving and our skin and hair healthy. It
is important to get the right amount of vitamins because either too
much or too little can be problematic. The best way to get all the
vitamins you need is to eat a varied diet containing plenty of fresh
fruits and vegetables, whole grains, nuts and seeds, some animal
produce and to spend some time in the sun.The 13 vitamins are divided
into two groups:
Water-soluble vitamins
include vitamin B complex (thiamin, riboflavin, niacin, vitamin B6,
folic acid, vitamin B12, pantothenic acid, biotin) and vitamin C. Since
they cannot stored in the body in appreciable amounts, they must be
replenished regularly through the food we eat.
Fat-soluble vitamins
include A, D, E and K. Your daily diet should supply these vitamins but
since fat-soluble vitamins are stored in the body, it's possible to
achieve toxic levels, especially of vitamins A and D, if you take
excessive amounts of supplements.
Minerals
The
minerals we need in our body are those found in rocks, metals, soil and
water. While each mineral plays a unique role, collectively they
support the body's enzyme systems and keep blood and other fluids in
the body balanced and healthy. Minerals, the major components of bones,
also help regulate blood pressure and heart muscle contraction, heal
wounds and conduct nerve impulses. The minerals needed in relatively
large amounts are calcium, phosphorus, magnesium, sodium, potassium,
chloride and sulfur.
Other minerals needed in smaller amounts,
called "trace elements," consist of iron, copper, fluorine, iodine,
selenium, zinc, chromium, cobalt and manganese. Overdosing on minerals
can be toxic or interfere with the function of other minerals.
Phytochemicals
Found
in plants, phytochemicals have been proven to strengthen our defenses
against disease, cancer and other serious illnesses. They are found
exclusively in fruits and vegetables and help fight environmental
toxins including pollution, smoking, pesticides and food additives.
