Carbohydrates: Glucose is the most
readily available source of energy for
the body. Carbohydrates are digested
to monosaccharides that can be
converted to glucose. Glucose is
stored in the liver in the form of
glycogen. Between periods of eating,
the blood glucose level is maintained
at about 50-80mg/100ml of blood by
the breakdown of glycogen or the
conversion of fat or amino acids to
glucose
Proteins: Foods rich in protein include red
meat, fish, poultry, dairy products,
legumes, and nuts. After proteins
are digested, amino acids enter the
bloodstream and are transported to
the tissues. Most often, the amino
acids are not used for energy, but
rather, they are used in protein
synthesis to make the structural
proteins found in muscles, skin, hair
and nails; or other proteins such as
hemoglobin, plasma proteins,
enzymes, antibodies,
neurotransmitters, and hormones.
Protein synthesis requires 20
different types of amino acids. Of
these, eight are required in the d
Lipids: Fats, oils, and cholesterol are
examples of lipids. Saturated fats,
which are usually from animal origin,
are solid at room temperature. Oils are
unsaturated fats because they contain
unsaturated fatty acids, which do not
promote cardiovascular disease, are
more filling and have a low glycemic
index. Corn oil and safflower oils are
high in polyunsaturated fatty acids.
Polyunsaturated oils are nutritionally
essential because they are the only
type of fat that contains linoleic acid
and linolenic acid, two fatty acids the
body cannot make. The body needs
these two polyunsaturated fatty acids
to produce various hormones and the
cell membrane of cells.
Cause: Cardiovascular diseasbecause the
blockage of arteries by plaque, a
substance that contains saturated fats
and cholesterol.
Vitamins: Vitamins are organic
nutrients required in small amounts to
maintain growth and healthy
metabolism. Unlike carbohydrates,
lipids, and proteins, they do not provide
energy or serve as building blocks for
the body, but acts as coenzymes. Most
vitamins cannot be synthesized by the
body and must be ingested in food.
Other vitamins, such as vitamin K are
produced by bacteria in the GI tract and
then absorbed. The body can make
some vitamins when provitamins, the
precursors, are provided. Vitamins are
divided into fat-soluble and
water-soluble vitamins. Fat-soluble
vitamins include vitamins A, D, E, and K,
and are absorbed along with other
dietary lipids in the small intestine and
packaged into chylomicrons. They
cannot be absorbed in sufficient
amounts unless they are ingested with
other lipids. Fat-soluble vitamins may
be stored in cells, especially the liver
cells. The water-soluble vitamins include
the B vitamins and vitamin C, and they
readily dissolve in water. Excess quant
Minerals: Minerals are inorganic elements
that occur naturally in the Earth’s crust.
Minerals have different functions in the body.
Minerals can be divided into two types:
macro minerals and trace minerals. Macro
minerals are those that the body needs in
large amounts and examples are calcium,
phosphorus, sodium, and potassium. Trace
minerals are needed in very small amounts
and include iron and zinc. Minerals with
known functions in the body include calcium,
phosphorus, potassium, sulfur, sodium,
chloride, magnesium, iron, iodide,
manganese, copper, cobalt, zinc, fluoride,
selenium, and chromium. Attention must be
paid to eating food that provide enough
calcium, phosphorus, iron, and iodide. Excess
amounts of most minerals are excreted in the
urine and feces.
Water: Water is the most
important and abundant
inorganic compound in all
living systems. It is a nutrient
needed in the largest amount,
about 2-3 liters per day. As the
most abundant compound in
the body, water provides the
medium in which most
metabolic reactions occur,
and it also participates in
some reactions, such as
hydrolysis reactions
Metabolism: chemical reactions in the body’s cells that
convert the fuels form food into the energy needed to
everything from moving to thinking to growing. It is a
vital process for all life that begins at conception and
ends when we die. When people eat, they take in sugars
and other cell building chemicals. The sugars are broken
down to release energy that can be used as fuel for the
body’s cells.
Catabolism:Catabolism refers to those
chemical reactions that break down
complex organic molecules into simpler
ones. These reactions break down body
tissues and energy stores to generate
more fuel for body functions.
Anabolism: Anabolism refers to chemical
reactions that combine simple molecules
and monomers to form complex structural
and functional components in the body.
These reactions build up body tissues and
energy stores. The molecule that usually
participates in energy exchanges in living
cells is ATP (adenosine triphosphate)
Obesity: Obesity is a complex disorder involving
an excess amount of body fat that increases your
risk of diseases such as cardiovascular illness,
diabetes mellitus and hypertension. Being
extremely obese means you are more likely to
have health problems related to your weight
Symptoms: Obesity is likely when a person’s body
mass index (BMI) is equal to or greater than 30. BMI
can be calculated by dividing your weight into
kilograms (kg) by your height in meters (m) squared.
Eating disorders
Anorexia Nerovosa: makes people lose more
weight than is considered healthy for their age and
height. Individuals with this disorder have a
morbid fear of gaining weight, even when they are
underweight. This fear causes them to be on very
restrictive diets, exercise in excess, and use
methods such as vomiting or using laxatives to
bring about further weight loss.
Symptoms: low blood pressure, irregular
heartbeat, constipation, constant chilliness;
bone density decreases, leading to
osteoporosis and stress fractures;
menstruation ceases in females; the internal
organs, including the brain start shutting
down; the skin becomes dehydrated; the
person becomes malnourished; and death
may be imminent
Bulimia nervosa is an eating disorder
characterized by consuming large amounts of
food in a short amount of time (binge eating),
followed by an attempt to rid oneself of the
food (purging) by vomiting, taking a laxative,
diuretic or stimulant, and doing excessive
amounts of exercise because of an exaggerated
concern for body weight.
Consecuences: Vomiting can cause inflammation of the
pharynx and esophagus. The stomach and esophagus may
even rupture due to strong contractions during repeated
vomiting.