NS 332: Exam 1 Flashcards
What are the two major types of nutritional science studies?
Epidemiological(Observational) and Interventional(Experimental)
What is the difference between epidemiological (observational) and interventional (experimental) studies?
Epidemiological studies are used to generate the hypothesis.
Interventional studies are used to test the hypothesis generated previously.
What do researchers do during epidemiological studies?
Explore correlations between exposures and outcomes (example: cigarettes and lung cancer)
What do researchers do during interventional studies?
Manipulate one or more factors (independent variables) and measure outcomes (dependent variables) in subjects
What can an interventional study determine?
Causal relationships (if well designed)
What can an epidemiological study determine?
Can establish complex associations/correlations
What is the difference between retrospective and prospective studies?
Retrospective looks back at a subject’s history, while prospective looks at the future.
What are the three types of epidemiological studies?
- Cross-sectional studies
- Retrospective studies
- Prospective cohort studies
What is a cross-sectional study?
Measure various exposures and outcomes simultaneously
Example: a one-time survey
What is a retrospective study?
Assess outcomes before potential causes; compare individuals with and without the condition
What is a prospective cohort study?
Follow the same group of people over a period of time
Example: Framingham Heart Study; followed a small town of people to determine cardiovascular risk
What is the strongest epidemiological study type?
Prospective cohort study
What does it mean when a cause is necessary?
If the cause is not there, the outcome will not occur.
Example: Essential nutrients are necessary for health.
What does it mean when a cause is sufficient?
If the cause is there, the outcome will too.
Example: Being human to being a mammal.
What does it mean when a cause is contributory?
The cause is necessary and/or sufficient (and
thus has effects) only under certain circumstances.
Example: Niacin necessary for preventing Pellagra only when protein (amino acid) consumption is insufficient.
What are some key challenges in human nutrition research?
- Assessment of exposures due to lack of reliable measurements or potential confounding factors or biases
- Assessment of health outcomes of interest because indexes/biomarkers of diseases are used and nutritional assessments are often not specific
What are the deficiencies in assessing habitual dietary intake with 24-hour recall, food frequency questionnaire, and a food record/diary?
*24-hour Recall: Recall bias, may not represent usual intake
*Food frequency questionnaire: food intake patterns limited in accuracy and completeness
*Food record/diary: (most accurate) may not be representative, observer effect (will eat healthier and exercise more)
How is a person’s nutritional status determined?
The health of the person related to how well their diet meets individual needs requirements. Adequate intake leads to optimal function.
What are the four (ABCD) ways of assessing nutritional assessment outcomes?
- Anthropometric Measurements (Waist Size)
- Biochemical Testing (Lab Tests)
- Clinical assessments (Physical examination)
- Dietary assessments (using one of three methods)
What is the difference between primary and secondary deficiencies?
Primary deficiency is caused by inadequate diet or secondary deficiency is caused by a problem in the body
Which assessment method(s) can reveal primary or secondary nutritional deficiency?
Diet history and/or health history
Which assessment method can reveal declining nutrient stores (subclinical) and abnormal functions inside the body (covert)?
Laboratory tests (biochemical testing)
Which assessment method can reveal physical signs and symptoms in the body (overt)?
Physical examination (clinical assessment) and anthropometric measurements
What are some characteristics of a randomized human clinical trial?
“Ideal design” to address human nutritional needs
-Large Scale
-Double Blind
-Placebo Controlled
What are two advantages of randomized human clinical trials?
- Well-designed interventions can prove causality
- Can be directly applied to humans
What are five advantages of randomized human clinical trials?
- Costly and time consuming
- Difficult to control for all confounding factors
- Ethics
- Subjects may not be representative: “Generalizability”?
- Reproducibility?
What is nutrition?
The process by which a living organism obtains, assimilates, and uses nutrient or other food components for growth, maintenance of tissues, and reproduction.
What is human nutrition?
Science of how dietary intakes affect development, health, and risk of developing diseases later in life.
What are nutrients?
Chemical components in diet (food and drinks) that organisms need to sustain life
What are the three functions of nutrients, at the organismal level?
- Promote Growth
- Maintain Tissues
- Regulate Physiological Processes
What are the three functions nutrients serve, at the cellular level?
- Energy Substrate
- Structural Material
- Regulatory Agent
What are phytochemicals?
chemical compounds found in plants; don’t provide fuel (these do not meet the definition of a nutrient)
example: Broccoli contains the cancer-fighting phytochemical called sulforaphane)
What are the six groups of nutrients?
water, carbs, protein, lipids, minerals, vitamins
What are the macronutrients?
water, carbs (mostly from plants), protein (found everywhere), lipids
What are the micronutrients?
minerals and vitamins (only exist in minute amounts, don’t need many)
What are the pros and cons of processed foods?
Pros: Increases shelf life and preserves them
Cons: Rids food of water and some essential nutrients
Out of the six groups of nutrients, which four groups are organic (contain C-C bonds)?
Carbohydrates, proteins, lipids, and vitamins
Out of the six groups of nutrients, which two groups are inorganic (do not contain C-C bonds)?
Water and minerals
What is the exception to this statement?
“Organic groups of nutrients are energy-yielding.”
Vitamins are organic, but too complex in structure to be energy yielding.
Where do the majority of carbohydrates come from?
Plants
What else can be classified as an energy-yielding, other than the four nutrients?
Alcohol (yields energy, but not a nutrient)
What defines a nutrient requirement?
The lowest intake level of a nutrient that maintains
basic physiological functions and supports
optimal health (Nutrient requirements differ among individuals)
How many kcals/g in carbs?
4 kcal
How many kcal/g in protein?
4 kcal
How many kcal/g in lipids?
9 kcal
How many kcal/g in alcohol?
7 kcal
What is an essential nutrient?
Required for physiological function, but can’t be produced by our body in sufficient amounts
What is the operational definition of an essential nutrient?
When removed from a diet, health declines; when added to a diet, health improves
What is choline?
The most recently discovered essential nutrient; necessary for making acetyl-choline.
Why are young women more able to tolerate insufficiency in choline?
The enzyme that makes choline is moderated by estrogen
What is the Recommended Dietary Allowance’s primary concern?
To prevent nutrient deficiencies
What is the “intake goal” range associated with?
The intakes goal range are associated with the lowest risk of inadequacy and excess.
What is nutrient density?
The amount of micronutrients and protein of a food item relative to its energy content
What are nutrient-dense foods?
high in nutrients but relatively
low in calories. Nutrient-dense foods contain vitamins, minerals, complex carbohydrates, lean protein, and healthy fats
What is energy density?
The energy content (kcal) of a food item relative to its
weight (g)
What is the chance of a person’s intake being adequate, if following the RDA (Recommended Dietary Allowance?
> 98% because RDA covers the needs of most people
What is the chance of a person’s intake being adequate, if falling somewhere between EAR and RDA?
50-98%; more difficult to assess, but chances are greater that it will be inadequate, compared to RDA
What is the chance of a person’s intake being adequate, if falling below the EAR (Estimated Average Requirement)?
<50% chance intake is inadequate
What are carbohydrates?
Saccharides, sugars; range of digestibility; range in structure
Rank the three digestible sugar types from simple to complex.
Monosaccherides, Disaccharides, Polysaccharides
What are the three monosaccharides (Hexoses)?
Glucose, fructose, and galactose
What are the three digestible disaccharides?
Maltose, sucrose, lactose
What are the three digestible polysaccharides?
Amylose, amylopectin, glycogen
Which type of sugar can we absorb?
Simple sugars
What is the difference between aldose and ketose?
Aldose and ketose are both simple sugars (monosaccharides). They differ in composition: aldose contains an aldehyde (CHO) group (consisting of carbon, hydrogen, and oxygen), while ketose contains a ketone (CO) group (consisting of carbon and oxygen)
