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Judith E. Brown
www.cengage.com/nutrition/brown
Key Nutrition Concepts and Terms
Unit 1
Prof. Albia Dugger • Miami-Dade College
The Meaning of Nutrition
• What do each of these photos illustrate?
Nutrition Defined
• Nutrition
• The study of foods, their nutrients and other
chemical constituents, and the effects that food
constituents have on health
A “Melting Pot” Science
• Nutrition is an
interdisciplinary science
• Behavioral and social
sciences
• Biological, chemical,
physical, and food
sciences
• Quantitative sciences
(mathematics, statistics)
Nutrition Knowledge is Applicable
• The science of nutrition can be applied to
your own diet, health, and eating behaviors
• Knowledge about nutrition and health
• Skills to use this information in your life
Foundation for Nutrition
• To think like a nutritionist, you need a working
knowledge of nutrition terms and basic
nutrition concepts
Common sense requires a common
knowledge
– Thomas Paine
10 Basic Nutrition Concepts
#1: Food is a Basic Need of Humans
• Humans need:
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Enough food to live
The right assortment of foods for health
A sufficient supply of safe, nutritious foods
The ability to acquire food in a socially acceptable
way
Food Insecurity
• Food insecurity exists in 12.6% of US and 7%
of Canadian households
Key Terms
• Food security
• Access at all times to a sufficient supply of safe,
nutritious food
• Food insecurity
• Limited or uncertain availability of safe, nutritious
food – or the ability to acquire them in socially
acceptable ways
Food Terrorism
• Food security includes safety from foods used
for bioterrorism
• Toxins such as ricin or botulism toxin
• Contamination with radioactive particles
• Contamination with microorganisms
On the Side
• Ricin is a deadly nerve toxin which comes
from the seeds of the castor bean plant
#2: Substances Needed for Health
• Food provides energy, nutrients, and other
substances needed for growth and health
Key Terms
• Calorie (kilocalorie or large Calorie)
• Unit of measure of the amount of energy supplied
by food
• Nutrients
• Chemical substances in food used by the body
for growth and health
• Six categories: carbohydrates, proteins, fats,
vitamins, minerals, and water
Six Categories of Nutrients
CARBOHYDRATES are substances in food that
consist of a single sugar molecule, or of multiple sugar
molecules in various forms. They provide the body with
energy.
Simple sugars are the most basic type of carbohydrates.
Examples include glucose (blood sugar), sucrose (table
sugar), and lactose (milk sugar). Starches are complex
carbohydrates consisting primarily of long, interlocking
chains of glucose units. Dietary fiber consists of complex
carbohydrates found principally in plant cell walls. Dietary
fiber cannot be broken down by human digestive
enzymes.
Six Categories of Nutrients
PROTEINS are substances in food that are
composed of amino acids. Amino acids are
specific chemical substances from which
proteins are made. Of the 20 amino acids, 9
are “essential,” or a required part of our diet.
Six Categories of Nutrients
• Carbohydrates and proteins
Six Categories of Nutrients
FATS are substances in food that are soluble in fat, not water.
Saturated fats are found primarily in animal products, such as
meat, butter, and cheese, and in palm and coconut oils. Diets
high in saturated fat may elevate blood cholesterol levels.
Unsaturated fats are found primarily in plant products, such as
vegetable oil, nuts, and seeds, and in fish. Unsaturated fats
tend to lower blood cholesterol levels. Essential fatty acids are
two specific types of unsaturated fats that are required in the
diet. Trans fats are a type of unsaturated fat present in
hydrogenated oil, margarine, shortening, pastries, and some
cooking oils that increase the risk of heart disease. Cholesterol
is a fat-soluble, colorless liquid primarily found in animals. It can
be manufactured by the liver.
Six Categories of Nutrients
• Unsaturated fats are
found in plant products
such as vegetable oils
Six Categories of Nutrients
VITAMINS are chemical substances found in food that
perform specific functions in the body. Humans require
13 different vitamins in their diet.
MINERALS are chemical substances that make up
the “ash” that remains when food is completely
burned. Humans require 15 different minerals in their
diet.
Six Categories of Nutrients
• Fruits and vegetables contain vitamins and
other important substances
Six Categories of Nutrients
WATER is essential for
life. Most adults need
about 11–15 cups of
water each day from food
and fluids.
Other Substances in Food
• Food also contains phytochemicals which are
biologically active in the body
• Diets rich in phytochemicals reduce risk of
some cancers, heart disease, infections, and
other disorders
Key Terms
• Phytochemicals (phytonutrients)
• Chemical substances in plants that perform
important functions in the human body
• Give plants color and flavor
• Enable plants to grow and protect themselves
against insects and disease
• Some are antioxidants
Key Terms
• Antioxidants
• Chemical substances that prevent or repair cell
damage caused by oxidizing agents such as
environmental pollutants, smoke, ozone and
oxygen
• Includes pigments such as lycopene,
anthocyanins, and beta-carotene
Good Sources of Phytochemicals
Some Nutrients Must
Be Provided by the Diet
• The body can manufacture some nutrients
from raw materials supplied by food
• Other nutrients must be obtained from a
dietary source
Key Terms
• Nonessential nutrients
• Substances required for normal growth and
health that the body can manufacture in sufficient
amounts from other sources in the diet
• Do not require a dietary source
• Essential nutrients
• Substances required by the body that the body
cannot produce (or produce in sufficient amounts)
and must be obtained in the diet
Our Requirements
for Essential Nutrients
• Dietary deficiency of an essential nutrient
causes a specific deficiency disease
• Example: Scurvy (vitamin C deficiency)
• The amounts of essential nutrients needed
vary among the nutrients
Essential Nutrients for Humans
Units of Measure
Essential Nutrient Requirements (cont.)
• Different people need different amounts of
nutrients depending on:
• Age, sex, growth status, body size, genetic traits,
and disease states
• Special conditions such as pregnancy,
breastfeeding, illness, drug/medication use, and
exposure to environmental contaminants
Nutrient Intake Standards
• Recommended Dietary
Allowances (RDAs)
• Recommended levels of
nutrient intakes needed
to prevent deficiency
disease
• Based on age, gender,
and condition
Dietary Reference Intakes (DRIs)
• Recommend intake
levels and safe upper
intake levels that:
• Meet the needs of 97%
of healthy people
• Promote health and
reduce risk of chronic
disease
AIs and EARs
• Adequate Intakes (AIs)
• Recommended intakes for nutrients for which
there is not enough evidence to determine RDAs
• Examples: Calcium, vitamin D, fluoride
• Estimated Average Requirements (EARs)
• Intake levels estimated to meet requirements of
50% of individuals in a comparable group
Tolerable Upper Intake Levels
• Tolerable Upper Intake Levels (ULs)
• Estimates of safe upper limits of nutrient intakes
• Amounts that should not be exceeded due to
potential for toxicity reactions
Terms Used in DRIs
Revising the DRIs
• All nutrients in the DRI tables are examined
about every 10 years
• Special committees periodically review and
update intake standards for specific nutrients
• Recently reviewed: Vitamin D, calcium
#3: Health Problems Originate in Cells
• Body processes
required for health and
growth occur in cells
• Cell functions are
maintained by the
nutrients they receive
Key Terms
• Metabolism
• Chemical changes within and outside cells
• Maintains normal cell health and function
• Example:
• Formation of energy molecules from
carbohydrates
Nutrient Functions at the Cellular Level
• Too few or too many nutrients can disrupt cell
functions
• Examples:
• Too little folate: Cells produce abnormal proteins
• Too much iron: Damages cell components
#4: Poor Nutrition Results From
Inadequate Or Excessive Intakes
• Each nutrient has a range of optimal intake
• Inadequate intake results in deficiency disease
• Marginally deficient nutrition produces changes in
behavior or physical condition
• Excessive intake may cause mild to severe
changes
Optimal Nutrient Intake
Vitamin A Deficiency
Nutrient Deficiencies Are Often Multiple
• Poor diets affect intake of many nutrients
• Example: Protein deficiency accompanied by
deficiencies of B vitamins, iron, and zinc
• “Ripple effect”
• Dietary changes in intake of one nutrient may
affect the intake of other nutrients
#5: Adaptive Mechanisms Manage
Fluctuations in Nutrient Intake
• Humans have adaptive mechanisms that
conserve nutrients when supply is low, and
eliminate excess nutrients
• Energy expenditure declines when calorie intake
is low; excess calories are stored as fat
• Iron absorption increases when supplies are low
and decreases when enough iron is stored
• Excess vitamin C is excreted in urine
#6: Malnutrition
• Malnutrition (poor nutrition)
• Results from poor diets (excess or lack of calories
or nutrients): e.g. vitamin A toxicity, obesity,
scurvy, underweight
• Results from disease states: e.g. diarrhea,
alcoholism, cancer, ulcers, HIV/AIDS
• Results from genetic factors: e.g. high
cholesterol, diabetes, heart disease, cancer
#7: Some Groups at Higher Risk
• Some groups have higher risk of malnutrition
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Women who are pregnant or breastfeeding
Infants and growing children
People recovering from illness
People living with food shortages due to natural
disasters or war
• People living in poverty
#8: Development of Chronic Disease
• Poor diets may lead to development of
chronic diseases
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Diets high in animal fat: Heart disease
Diets low in fruits and vegetables: Cancer
Diets low in calcium, vitamin D: Osteoporosis
Diets high in sugar: Tooth decay
Key Terms
• Chronic diseases
• Slow-developing, long-lasting diseases that are
not contagious
• Can be treated, but not always cured
• Examples:
• Heart disease, diabetes, cancer
#9: Keys to a Healthy Diet
• Adequacy, variety, and balance
• Adequate amounts of essential nutrients and a
calorie intake that maintains normal weight
• Variety of foods from each basic food group to
obtain assorted nutrients and phytochemicals
• Balanced selection of food types and amounts
from the MyPyramid basic food groups
MyPyramid
Energy and Nutrient Density
• Most Americans consume excess calories
and consume inadequate diets
• Americans need to consume:
• More vegetables, fruits, whole grains, dried
beans, low-fat meats and dairy products
• Less sugar, animal fat, and saturated fat
Key Terms
• Energy-dense foods
• Provide relatively high levels of calories per unit
weight of food
• Examples:
• Fried foods, cheeseburgers, potato chips, biscuitegg-sausage sandwich
Key Terms
• Empty-calorie foods
• Provide an excess of energy or calories in
relation to nutrients
• Examples:
• Soft drinks, candy, sugar, alcohol, animal fats
Key Terms
• Nutrient-dense foods
• Contain relatively high amounts of nutrients
compared to their calorie value
• Examples:
• Broccoli, collards, bread, cantaloupe, lean meats
#10: No “Good” or “Bad” Foods
• All foods can fit into a healthful diet, as long
as nutrient needs are being met at caloric
levels that maintain a healthful body weight
• Energy-dense foods – too many calories
• Empty-calories foods – low in nutrients
• Nutrient-dense foods – the healthy solution
Empty Calories vs Nutrient-Dense