Human Nutrition And Body Composition

Question 0

Why is nutrition important?

Answer 0

Provides chemical energy
Organic materials required for growth
Essential nutrients

Relationship with disease

Question 1

What is nutrition?

Answer 1

Action/process of supplying, or of receiving, nourishment or food

Question 2

What are carbohydrates?

Answer 2

Organic compounds
Sugars and starches
Energy source
Simple- mono/di saccharides
Complex- starches eg potato

Question 3

What are lipids?

Answer 3

Essential for cell structure and energy reserve
Main dietary source and triglycerides
Saturated increases LDL (Dairy)
Unsaturated decreases LDL (Fish oil)
Trans- unsaturated but changes conformation in refining process

Question 4

What is protein?

Answer 4

2nd most abundant compound in body- 16-20% body mass
Chain of amino acids
Approximately half can be synthesised
Excess protein eliminated (mainly via kidney)
Protein deficiency- impaired physical and mental development

Question 5

body composition figures

Answer 5

Total body weight= fat mass + fat-free mass

Composition dependent on organ

Question 6

What is fat mass?

Answer 6

Body fat is useful for energy and insulation
90% stored under skin- abdominal cavity and muscles
Gender difference in at storage
Females- gynoid
Male- android

Question 7

Difference of fat between genders?

Answer 7

Females have more fat mass that an be utilised more effectively
Female may use all fat stored, males probably can’t

Question 8

Abdominal ft and cv disease

Answer 8

Abdominal fat more sensitive to stimuli
Increased breakdown of fatty acids
Increased likelihood of hyperlipdaemia, hyperinsulinaemia and hypertension

Question 9

Abdominal fat and diabetes

Answer 9

Releases resistin

Leads to insulin resistance and reduced insulin sensitivity

Question 10

Best measurement for weight loss?

Answer 10

Bmi= body mass/height2
Assumes all variations in body mass due to fat
Not sufficient for research purposes

Question 11

Skin fold thickness?

Answer 11

Measurement f subcutaneous fat in mm
Taken over 4 sites- biceps, triceps, sub scapular, supra-iliac
Can also involve measurement of other sites
Uses skin calipers
Sum of ski folds related to body fat
Differed depending on age

Question 12

Total body weight measurement?

Answer 12

Tbw= fat mass + fat-free mass
Assumes fat free mass has constant density, water and potassium
More complicated measurements measure water , bone and density
More accurate

Question 13

Underwater weighing?

Answer 13

Archemides principle
Loss of weight on water= weight of water displaced
Body density =weight in air- weight in water
Body fat = (495/bd)- 450
Air on lungs and gi tract
Expensive
Not appropriate for some populations

Question 14

Measurement of total body water

Answer 14

Assume fat free mass is 73% water
Ffm= Tbw/0.73
Fm= bw-ffm
Measure tbw using stable isotopes
Detroit oxide
Ingest and equlibrate in body water for several hours
Observe dilution
Expensive

Question 15

Dual energy x-Ray absorptiometry

Answer 15

Measures bone, fat and lean tissue
Works in a similar way to x- rays but with different energy levels
Different tissues will defect the path of either f the beams in different ways
Allows determination of composition of tissues
Expensive

Question 16

Bio electrical impedance analysis

Answer 16

Fat-free mass conducts electricity
Fat doesn't 
If you pass small electrical current through body, the resistance of the current will be greater where there is more fat than less fat
Relatively cheap
Not vey accurate