exam Flashcards
what are the non- nutrients. are they beneficial, neutral or harmful?
Additives, pigments, alcohol, polyphenolics (beneficial, neutral or harmful, depending on how they’re consumed)
Steps to obtain primary data about contents of a food
- OBTAIN sample
- PREPARE sample (remove inedible parts/ prepare how it will be eaten)
- Create COMPOSITE SAMPLE
- ANALYSE the sample
24hr recall
- structures interview process
- quantitative
-time consuming for large groups
3- Pass Method
1st= quick list of consumed foods
2nd= collection of very detailed info.
3rd= Recall review- additional foods are added that have been previously forgotten
Adv: short time period, quantitative so more accurate.
Disadv: may misrepresent eating patterns, people alter diet from fear of judgement, incorrectly measured foods
History recall Technique
- 24hr recall
- note deviations from normal intake
- checklist of foods/ food groups
Adv: more info than 24hr recall, can focus on seasonal variation, see change in diet
Disadv: subjective, less valid as requires memory of longer time period
Food Frequency Questionairre
People indicate how much they eat certain types of foods and frequency
- Widely used in Australia
- questions focus on a 12- month period
Adv: good for groups, can be completed online, low burden if survey is short.
Disadv: different populations require different questions for accuracy, not good at capturing variation, language barriers may pose issue
weigh food record
Record everything consumed with scales
- most common method
Adv: high precision, low bias, can vary time period per participant
Disadv: people don’t carry scales around, laborious, people are likely to eat more measurable foods
Photographic Food record
Take photos of consumed food, often put beside a standardised object to compare size
Adv: Low burden, most people have cameras on their phones.
Disadv: combination foods are difficult to break down, difficult to estimate portion size
Direct observation
Watching people eat and recording what’s consumed
- uncommon
Duplicate Meals
Prepare two identical meals and recording the food eaten by comparing the difference in what’s left on the plate
- uncommon
Calorimetry definition and process
Method to measure the heat exchanged with surroundings
1. Homogenize food and dehydrate over 3 days
2. Dried samples -> pallets to be put in the calorimeter
3. Produced heat is measured and used to determine calories
Indirect calorimetry
- Basal metabolic rate (50-60% daily energy expenditure)
- Thermic effect of food (10%)
- Movement (10-35%)
Storage of macronutrients
Carbs- Glucose- glycogen
Fat- FAs- Adipose tissue
Proteins- AA- Prioritised as fuel (ATP)
Conditionally essential AAs
GAST- PC
Glutamine, Arginine, Serine, Tyrosine, Proline, Cysteine
Types of proteins
SETHS AC
Structural
Enzyme
Transport
Hormones
Storage
Antibodies
Contractile
Dietary Protein Quality
- determined by presence/ absence of all essential aa (out of 9)
- most foods that contain all= >90% absorbability
- foods that don’t meet criteria can be paired together as ‘complimentary proteins’
Biochemistry nutritional assessment
Laboratory analytical measured that can be made from biospecimens
- Iron studies
- Lipid profile
- Fluid/ electrolyte balance
- Blood+ glucose control
Oligosaccharides
3-10 sugar units bonded together
Polysaccharides
10< sugar units bonded together
Limiting Amino Acid
AA supplied in less than the amount required for protein synthesis
Glycemic response
Effect that food has on blood glucose concentration.
- Measure of this is known as GI
Glycemic Index
- Low GI food= <55, more slowly digested, absorbed, and released into the bloodstream. - Medium GI foods, 55-70
- High GI foods= >70, rapidly released into the bloodstream.
Minerals
- Inorganic, individual elements that can be ingested from food either as individual charged ions, mineral salts or mineral acids.
- On dissolving in water, the mineral salts and acids will ionise
- regulates water distibution
- Major, trace, non- essential
Bioavailability
Rat ate which, and the extent to which, a nutrient is absorbed and used.
- the rate of digestion and absorption of a nutrient
Influences:
- GI tract transit time (speed of bolus/ chyme)
- GI tract integrity ( if tract is damaged)
- presence/ absence of other nutrients
- food prep and storage
