NUTR400 part4

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  1. Whay are animal diets important in research? (2)
    • Diet can influence most physiological measures
    • One of the most neglected aspects of rodent (main animal model) studies.

    • It is therefore essential that rodent (and other experimental animal diets be carefully considered and described in all studies
    • Assurance of adequacy & safety (Fed Regulations around the content of research animal diets)
  2. What are feeding protocols to consider? (5)
    • 1. Ad libium
    • 2. Meal feeding
    • 3. Pair feeding
    • 4. Dark and light cycle
    • 5. Fasting a rodent
  3. What types of animal diets are there (5)
    • Natural product diets –Open or closed label diets
    • Chow is not a control diet
    • –20-24% energy is protein
    • –8-10% of the energy is fat
    • –70% of the energy is carbohydrate (mainly complex)
    • Semi-purified diets
    • Chemically defined diets
    • Vitamin & mineral mixes
  4. How are animal diets determined
    • Nutritional needs of rodents are defined by the National Research Council (rodent requirements posted with lecture)
    • Usually expressed on a per kg basis
    • the nutrient needs are defined as the minimum requirement: they do not include a safety factor (i.e.. +2SD) and they change with energy density of the diet.
    • –They have been determined mainly on assuring general health and growth
  5. How are animal diets expressed?
    What semi synthetic ingredients are listed in these diets?
    • - w/w or g/kg
    • - Corn oil, deextrose, corn startch, glutamine, inulin, celluolose
  6. Calculate the caloric content of 100g of diet
    Calculate the % energy from fat, protein & carbohydrate in the animal diet.
    –How does the carbohydrate & fat proportions relate to human recommendations?
    Calculate how much calcium is in the diet as a percent of energy?
    –How does this relate to human requirements?
  7. What are human research diets used for? (2) Why?
    • 1)Controlled Feeding Studies
    • 2) Behavioral Counseling Studies
    • Both useful in determining the effects of diet on biological processes and/or risk factors for chronic diseases- both are used in controlled research trials.
  8. What two important factors must be considered in dietary interventions? (2)
    • Control over the composition of the diet
    • Degree of compliance/adherence required
  9. Degrees of Dietary control spectrum
    Low ==> High
    defn: free living and metabolic ward
    • Low-
    • 1) free living/ seletcion of food
    • 2)food provided, take out, free living
    • 3) free living, food provided, eat in
    • 4) live in, food provided, eat in
    • 5) live in, formulat diet or defined whole food special products ( pudding, cookies, bars), eat in
    • High-
  10. What are the problems of diet interventions?
    Behavior modification: Counseling of subjects to adhere to a specific dietary modification

    • Issues:
    • –Designing the diet recommendations
    • –Documenting the intervention (?standardized)
    • –Training others to counsel subjects
    • –?control treatment
    • –Adherence; ensuring & assessing
  11. How are contrilled feeding trials done?
    Subjects consume foods that have been precisely prepared & given to them

    • Usually used in randomized controlled (?blinded) clinical trials
    • Usually of shorter duration
    • Controlled diet, strict/measured dietary compliance
    • Can also be done in free living individuals.
  12. Key Features of a Controlled Feeding study (2)
    • Precise knowledge of diet composition
    • –Chemical or detailed analysis of the diet and/or ingredient of interest
    • Meet the energy needs of the subjects precisely
    • –How can you determine that?
    • –How can you monitor that?
  13. Controlled feeding trial (features): 12
    • Expensive
    • Precision of the diet: mathematically calculated then validated with chemical analysis
    • Individually calculated based on study purpose & to ensure nutrient needs are met.
    • Allowable variation in average daily nutrient content is very small
    • Precisely prepared in a research kitchen: weighed
    • If possible blinded to subjects
    • Adherence is essential; unconsumed food carefully recorded
    • Subject‟s routines are changed: restriction on consumption of other foods & beverages, travel, ?exercise, timing meals are consumed
    • Usually used in randomized controlled (blinded) clinical trials
    • Usually of shorter duration
    • Controlled diet, strict/measured dietary adherence
    • Diet is prepared & provided to the research volunteers
  14. What factors influence compicance and adherence of the study (2)? How would you control these?
    Recruitment & selection of subjects: (Screen your subjects carefully, Monitor compliance, Monitor subject moral- social support, Removal of subject who don‟t comply?)

    Design of the study (study length, Menu cycle, Diet composition, Rigidity….Allowing self-selection? –?Alcohol –?Some free days –?Eating all food provided )
  15. How might you measure compliance?
    In a controlled feeding study?
    In a behavioral modification study?
  16. What factors influence adherence?
    –In a behaviour modification study? ( think of 10 factors)
    –In a controlled feeding study? (think of 10 factors)
    How do to measure it?
Card Set:
NUTR400 part4
2011-11-08 06:34:56

Animal/human diets
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