Lecture 1: What is Nutrition? Flashcards
What drives our food choices
Socio-environmental factors
Psychologic Factors
Biologic factors
Nutrition knowledge
Habits
Emotions
Convenience
Advertising
Cost
Culture
Taste
Nutrients
What is Nutrition?
The science that studies how nutrients and compounds in foods nourish the body and affect body functions and overall health
Exploration of how food is:
Digested
Absorbed
Transported
Metabolized
Used or stored in the body
What are nutrients?
Compounds in foods that serve as building blocks for body components and sustain body processes
Nutrients found in foods are also found in the body
What are the 6 categories of nutrients
Carbohydrates
Fats (lipids)
Protein
Vitamins
Minerals
Water
What are non-nutrient compounds?
Non-digestible fiber
Chemicals that are added by food manufacturers to:
Enhance color
Enhance flavor
Add texture
Extend shelf life
What is the most abundant nutrient in the body and in food?
Water
What makes up the rest of the nutrients in the body besides water?
Carbohydrates, fats, proteins, vitamins, and minerals
Food also contain non-nutritive compounds such as phytochemicals and fiber
What makes nutrients organic?
Containing carbon in their chemical structure
What are the organic nutrients?
Carbohydrates
Proteins
Lipids
Vitamins
What are the inorganic nutrients?
Minerals
Water
What are Essential Nutrients?
Nutrients that must be consumed in diet
Can not be made in the body in sufficient quantities to meet its needs and to support health.
What are nonessential nutrients?
Can be made in sufficient quantities in the body to meet the body’s requirement to support health
What are conditionally essential nutrients?
Nutrients that can become essential under some circumstances
What is energy?
Energy is the capacity to do work
The body derives energy from the nutrients in the foods that store energy in the chemical bonds called ATP which is released when bonds are broken
What are energy-yielding nutrients?
Carbohydrates
Lipids (fats)
Proteins
what is the non-nutrient source of energy?
Alcohol
Kilocalorie (kcal) or Calorie
The amount of energy required to raise the temperature of 1 kg of water by 1 degree Celsius
Used to express the measurement of energy in foods
1 Kilocalorie is equal to 1,000 calories
Calorie (uppercase C) is used on nutrition labels to express the energy content of food
Calculating energy in foods
Carbs= 4kcal/gram
Protein= 4kcal/gram
Fat (lipid)= 9kcal/gram
Alcohol= 7kcal/gram
Energy in Body
Energy is trapped within bonds that keeps molecules together so breaking them releases energy
Role of energy
Used in multiple bodily functions:
Needs of energy varies according to age, gender, and activity level
Unused energy is stored predominantly as fat
Using more energy than is consumed results in fat breakdown
Primary roles of Individual Nutrients
Individual nutrients serve unique roles in the body:
Supply energy
Regulate metabolism
Provide structure
Macronutrients
Nutrients the body needs in large amounts
Ex: carbs, fats, proteins, and water
Micronutrients
Essential nutrients the body needs in smaller amounts
Ex: vitamins and minerals
Primary Source of Energy (Carbohydrates)
Made up of carbons, hydrogen, and oxygen
Function:
Supply glucose (energy source of many body cells including red blood cells and brain cells.
Food sources:
Plants: Breads, cereals, legumes, nuts, fruits, and vegetables
Animal: Dairy products are the only animal products that provide significant carbohydrates
Additional Energy (Lipids)
Made up of carbon, hydrogen, and oxygen
Three categories:
Triglycerides
Sterols
Phospholipids
Function:
Provide energy to cells, structural component to cell membranes
Food sources:
Margarine, butter, oils, and animal products
Proteins
Provide the building blocks for Tissue Synthesis
Made up of carbon, hydrogen, oxygen, and nitrogen
Food Sources:
Animal: Meat, poultry, fish, and dairy
Plant: legumes, soy, nuts, and seeds
Minimal protein amounts: whole grains, vegetables, and some fruits
Protein Functions
Contribute the basic building blocks that are used to synthesize, grow, and maintain tissues
Primary source of tissues in muscles, bones, and skin
Participate as neurotransmitters
play a role in the immune system
Act as enzymes
Energy source, but not a primary one
Vitamins and Minerals
They play a vital role in the metabolism
Composition:
Vitamins: carbon, hydrogen, and oxygen
Minerals: just the mineral
Function:
Do not provide energy
Metabolism regulation
Water
Makes up the majority of all body fluids
Part of every cell in the body
Cannot be stored; must replenish daily
Recommendations for health
Eat a well-balanced diet
that contains a variety of whole foods.
– Whole grains
– Fruits and vegetables
– Lean meats
– Low-fat dairy
Consuming a balanced diet provides…
Other dietary compounds beneficial to health
– Phytochemicals, zoochemicals, and fiber
Functional Foods
Foods that may provide additional
health benefits beyond the basic nutrient value
Phytochemicals
Nonnutritive plant chemicals found in
foods that reduce risk for developing chronic diseases
Zoochemicals
Nonnutritive animal compounds that play
a role in fighting chronic diseases
Chronic Disease
Noncommunicable disease
characterized by a slow onset, long duration, and
gradual progression
▪ Examples are heart disease, cancer, stroke, and
diabetes.
A healthy diet helps to achieve and maintain a healthy
weight which can decrease the risk of chronic disease.
Leading cases of death in the US
- Heart Disease*
- Cancer*
- Respiratory
Diseases - Unintentional
injuries - Stroke*
- Alzheimer’s Disease
- Diabetes*
- Influenza/Pneumonia
- Intentional Self-Harm
- Kidney Disease
*nutrition related
Nutritional Statuses
A person’s state of nutrition is defined as:
– Healthy
– Malnourished
– Undernourished
– Overnourished
ABCD of Nutrition: A
Anthropometric
Height
Weight
Body mass index
Waist-to-hip ratio
Waist circumference
Determines: Growth, obesity, changes in
weight, and risk of developing
chronic diseases such as
diabetes and heart disease
ABCD of Nutrition: B
Biochemical
Blood
Urine
Feces
Determines: Protein, mineral, and vitamin
status and disease
ABCD of Nutrition: C
Clinical
Observe hair, fingernails,
skin, lips, mouth, muscles,
joints, overall appearance
Determines: Signs of deficiencies and
excesses of nutrients
ABCD of Nutrition: D
Dietary Intake
Diet history
Diet record
Food frequency questionnaire
24-hour dietary recall
Determines: Usual nutrient intake and
deficiencies or excesses of
various nutrients
Two tools to collect dietary intake data
~ Food frequency questionnaires (FFQs)
▪ Identifies patterns of intake over time
~ Dietary interviews
▪ Food record
– Diary of the foods and beverages eaten, how much,
and when they are eaten over a period of time
▪ 24-hour recall
– Quick assessment by a trained interviewer
– Asks client to recall all food and drinks eaten in the
previous day
Anthropometric Data
Anthropometric data measures body size or body
composition.
Common anthropometric measures
– Height
– Weight
– BMI
– Waist-to-hip ratio
– Waist circumference
– Growth chart (for children and adolescents)
– Body composition
Conducting a Physical Examination
Several parts of the body can be inspected during the
physical examination for evidence of poor nutrition.
Areas of the body that show signs of malnutrition
– Hair
– Skin
– Eyes
– Fingernails
– Tongue
– Lips
Collecting Biochemical Data
Laboratory tests assess nutritional status by measuring
the nutrient levels in body fluids, including blood and
urine.
Might measure:
– How fast a nutrient is excreted through urine
– Metabolic by-products of various nutrients in urine
Uses of Surveys
National surveys have been developed by federal
agencies to assess the health and nutritional status of
Americans.
Survey data may be used for:
– Nutrition monitoring and surveillance
– Relating diet to health
– Informing nutrition policies and programs
The National Health and Nutrition Examination Survey
(NHANES)
Series of surveys that evaluate the nutritional status
of Americans of all ages
– NHANES I began in 1970
– What We Eat in America (WWEIA) is the dietary
intake interview component
The Framingham Heart Study
– Established in 1948 to establish recommendations for
cardiovascular disease
– Collection of data on three generations and over
10,000 people
Excess intake in American diet
*Added sugar
– 13% of daily kcal intake
* Sodium
* Saturated fat
Too little intake in American Diet
Fiber
* Some vitamins (vitamin D)
* Some minerals (potassium and
calcium)
– Most men meet the
recommendations for vitamins
and minerals.
– Women tend to be low in iron
Cause of poor American Diet
Can be a result of where American eat:
- Most Americans eat in the car, buy prepared meals, or eat in front of the TV or computer.
Healthy Eating Index
can be used to see how well the diets of Americans align
with the Dietary Guidelines for Americans (more in Chapter 2)
– Ideal score = 100
– Average HEI-2015 score is 58!
Overweight/Obesity in ADULTS
~70% have overweight and of those, approximately 40%
have obesity
Overweight/Obesity in CHILDREN aged 2-19
19.3% have obesity
– Obesity rates higher in Hispanic and Black children than
in White and Asian children
What does overweight/obesity lead to?
– Type 2 diabetes
– Heart disease
– Cancer
– Stroke
Credible Nutrition Research
- Diet trends and popular wisdom change frequently.
- Basic scientific knowledge about nutrition is more
consistent.
– Sound advice is based on a consensus of multiple
research findings.
– Be wary of results from only one report
What is the scientific method
The scientific method is
a process used by
scientists to gather and
test information for the
sake of generating
sound research findings
Hierarchy of Evidence Pyramid
Study Slide 54 Lecture 1
Look at Screenshot
Types of nutritional research
Mechanistic Studies: aim to uncover a mechanism
Observational Research
Experimental research – Randomized control trials (RCT) involve at least two groups of subjects.
Mechanistic Studies
– In vitro – cells and cell cultures
– In vivo – animal models
– Cell and animal research often focused on single
nutrients at high doses
Observational Research
– Epidemiological studies
– Examines health and disease in populations of people
– Shows correlation, not causation
– Participants are required to recall what they eat
Experimental Research
– Experimental group
▪ Given treatment
– Control group
▪ Used as a standard for comparison
▪ Placebo: An inactive substance administered to a
control group during an experiment
– Double-blind placebo-controlled study is the gold standard.
▪ Researcher and the subjects are unaware of who gets the
treatment or the placebo.
Challenges of Randomized Control Trials in Nutrition Research
- Sample size must be adequate to support results.
- Compliance with intervention.
- May not be able to blind participants to the intervention.
- Controls/placebos are often difficult to design.
- Cannot always keep the control group from the exposure.
- Difficult to examine disease prevention.
– Easier to examine surrogate outcomes (e.g. blood
lipids, blood glucose) - “Gold standard” trials are difficult to conduct
- Overreliance on observational and mechanistic studies
Challenges of Communicating Nutrition Research
- Small but critical caveats are not conveyed
– Study design may be suboptimal but interpreted as if optimal
– Placebos or comparisons may be ignored
– Conclusions may be over-emphasized
– Results may not be put into context of all the literature
Small but critical caveats are not conveyed
– Study design may be suboptimal but interpreted as if optimal
– Placebos or comparisons may be ignored
– Conclusions may be over-emphasized
– Results may not be put into context of all the literature - Consumer interest is high
– Goal is to get clicks and keep the audience engaged
– Lay public is interested and invested in their health
– Framing may be irresistible – “What if everything we know about nutrient X or
food Y is wrong” - Conflicts of interest may exist
Trusted sources of Nutrition information
Health professionals with nutrition expertise:
– Registered dietitian nutritionist (RDN)
– Nutrition scientists
– Medical profession with nutrition expertise
▪ Who aren’t trying to sell a product or service
– Public health nutritionist - has a degree in nutrition but is not an RDN
- Reliable media sources – scientific journalist from established media sources
- Peer reviewed sources
