An Overview of Nutrition

An Overview
of Nutrition
Assist. Prof Dr. Lujain A. Alkhazrajy
Nutrition: the process by which a living organism
assimilates food and uses it for growth and
maintenance of tissues
Nutrients- components of food:
 Provide energy
 Provide structural materials
 Provide regulatory agents that support cell
growth, maintenance, and repair of tissues
 May reduce the risk of certain diseases
Nutrition :
the science of food, the nutrients
and the substances there in, their
action, interaction, and balance in
relation to health and disease, and the
process by which the organism ingests,
absorbs, transport, utilizes, and
excretes food substances”---- The
Council on Food and Nutrition of the American
Medical Association
Actions in the body include:
Nutritional Goals
Quality intake: that allows you to
function at your best and promotes
health. Intake that provides adequate
levels of each nutrient
Quantity of intake that promotes a
healthy body weight.
Diet and Health
Diet - the foods one consumes
 The quality of your daily diet affects the
risk of chronic diseases
Meaning…..The food choices you make
daily have a cumulative impact on your
Nutrition and Health
Nutrition plays a central role in all life functions
Animals often spend a large amount of time and energy
obtaining food and feeding, but we humans do not
Nowadays we can choose between nutritious/nonnutritious foods
Food choice makes a big difference to our health and the
risk of: deficiency – under nutrition ,excess – over
Our food choices are determined by:
- habits usually established in childhood
- personal likes and dislikes
- cost of food
- convenience of shopping and preparing
- education about what is nutritious and healthy
Nutrition and Health
Chronic health issues associated with diet
 Cardiovascular disease
 Hypertension
 Obesity
 Type II Diabetes
 Osteoporosis
What’s Considered Food?
Foods contain nutrients and are derived
from plant or animal sources
Nutrients are used by the body to
provide energy and to support growth,
maintenance and repair of body tissues
~ 40 nutrients identified at this time
Classifying Nutrients
There are 6 Classes of Nutrients
1. Carbohydrates
2. Lipids (fats)
3. Proteins
4. Vitamins
5. Minerals
6. Water
Body Composition
Describing the Nutrients
There are several ways to classify the classes
of nutrients:
 Essential or nonessential
 Organic or inorganic
 Macronutrient or micronutrient
 Energy yielding or not
Classifying Nutrients
Essential nutrients – nutrients the body either
cannot make or cannot make enough of to
meet its needs.
These nutrients must be obtained from foods
(ingested in some manner)
Calcium, iron, and other minerals
Some of the amino acids
The Six Criteria for Nutrient Essentiality
The nutrient….
is essential for one or more of the (8) functions of life
is not synthesized or synthesized adequately in the
has a function that is either biochemical or structural
if deficient, a recognizable loss of function or structure
if deficient the loss of function or structure is
proportional to degree and duration of depletion
if deficient the loss of function is, in the short term,
reversible by the specific nutrient
Essential Nutrients and Life Functions
Life Functions
Key Essential Nutrients
Calcium and vitamin D – bones,
Protein and potassium - muscles
Vitamin B – metabolism, iron – oxygen transport,
Iodine – thyroid hormone and metabolic rate
B vitamins - central and peripheral nerves
Iron and iodine - intellectual development
Zinc and iron - appetite
Water, sodium and potassium - urine excretion
Iron and B vitamins – fertility and pregnancy outcome
Energy, protein, iron, zinc, vitamin A – infant growth
Protein, vitamin A and zinc - immune function
Classifying Nutrients
Nonessential nutrients – body can make from
other nutrients ingested
 Examples:
Some amino acids
Classifying Nutrients by Composition
Organic nutrients - contain carbon
Inorganic nutrients - do not contain carbon
The Nutrients
Copyright 2005 Wadsworth Group, a division of Thomson Learning
Quantity Needed
Macronutrients: need in relatively large
Carbohydrates, lipids, proteins
Micronutrients: need in relatively small
All other nutrients
Classifying Nutrients
Energy-yielding nutrients (3):
Fats (lipids)
Where does the energy come from?
Food guide pyramid
In 1992, the USDA (United States Department of
Agriculture) adopted the nutritional guide that was created at
Tufts University. It is in the shape of a pyramid, to help
people remember what food to eat. The pyramid looks like
This pyramid shows different food groups, and the
servings you should have of each. For example, you
should have 6 to 11 servings a day of foods in the
Bread, Cereal, Rice & Pasta Group
Notice that the bottom of the pyramid, the biggest
part, is the Bread, Cereal, Rice & Pasta Group. This
pyramid shows that that is where you should get the
most servings per day. The top part, the Fats, Oils &
Sweets Group is the smallest. That shows that you
shouldn't have too much fat or oil in your diet.
Serving size:
1. The portion of food used as a reference on the
nutrition label of that food.
2. The recommended portion of food to be eaten.
In April 2005, the USDA replaced the original pyramid with another
pyramid by turning it on its side and making the sections vertical instead of
horizontal. Looking at this pyramid, there are different colored parts of the
pyramid, but each one gets smaller as it goes toward the top. The part
toward the top is for the less healthy foods in the category, and the part at
the bottom is for the healthier foods..
For example, you might put whole milk at the top of
the Milk group, and non-fat milk at the bottom; or
you could put whole grains at the bottom of the
Grains group and refined grains at the top.
The parts of the pyramid also show how important
they are by the width of the band. The small yellow
one that has no name on the bottom contains fats
and oils. The unsaturated oils, like peanut, canola,
or olive, would be at the bottom. Butter would be at
the top. The person climbing the steps on the left
side of the pyramid symbolizes the importance of
Faculty members at the Harvard School of Public Health made an
alternate pyramid, which they called the Healthy Eating Pyramid.
Notice this pyramid has a section on the bottom called Daily Exercise
and Weight Control. It is built this way to show that daily exercise and
weight control are the foundation for good health.
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