Session 4 - Nutrition, Diet and Body Weight

Question 1

How many joules in a calorie?

Answer 1

1 cal = 4.2J

1kCal = 4.2 kJ

Question 2

Define a catabolic process

Answer 2

The breakdown of a molecule to release energy in the form of reducing power (so are oxidative)
The breaking down of larger molecules into smaller ones

Question 3

Define an anabolic process

Answer 3

Use energy and raw materials to make larger molecules for growth and maintenance (so are reductive)
The use of smaller molecules to build larger ones

Question 4

Define an exergonic reaction and by contrast an endergonic reaction.

Answer 4

Exergonic
When the energy releases is greater than the energy input
Endergonic
When the energy input is greater than the energy released

Question 5

What is the standard daily expenditure of a 70kg male and a 58kg female assuming moderate physical activity?

Answer 5

Male = 12,000 kJ/2868kcal
Female = 9,500kJ/2270kcal

Question 6

BMR is mainly controlled by what?

Answer 6

The thyroid hormones

Question 7

Why is the BMR lower in women than men of the same weight?

Answer 7

Women have more adipose tissue. And fat is less metabolically active than muscle tissue

Question 8

What are three components of daily energy expenditure?

Answer 8

1) basal metabolic rate
2) energy for voluntary physical activities
3) diet-induced thermogenesis (energy required to process the food we eat)

Question 9

What is diet induced thermogenesis?

Answer 9

Daily energy expenditure due to the processing (digestion, absorption, distribution and storage) of the food we eat.

Question 10

What role does fibre play in our diet?

Answer 10

Fibre is required for normal GI function. It also lowers plasma cholesterol. Fibre binds to bile salts (which are essentially cholesterol) and they are then passed out of the body. They are normally recycled but as they are excreted it means cholesterol is removed from the blood to manufacture bile salts and as such it lowers blood cholesterol

Question 11

What is meant by DRVs, RNI, LRNI, EAR?

Answer 11

DRVs - a series of estimates of the amount of energy and nutrients needed by different groups of healthy UK population
RNI - reference nutrient intake - used for protein, vitamins and minerals
LRNI - lower reference nutrient intake - intakes below which are insufficient for most people
EAR - used for energy

Question 12

Why can a fat free diet lead to deficiencies of certain vitamins? And which ones are they?

Answer 12

Fat is necessary for the absorption of the fat-soluble vitamins (A, D, E and K)

Question 13

What type of fatty acids are essential, name some and explain why they are essential.

Answer 13

Certain Poly unsaturated fatty acids are essential fatty acids (linoleic and linolenic acids). The are structural components of cell membranes and important precursors however they are not synthesised by the body so much be consumed in the diet.

Question 14

How is nitrogen from degraded amino acids excrete from the body?

Answer 14

In the urine and urea

Question 15

How do you calculate BMI and what is the desirable range?

Answer 15

Mass/height^2 (kg/m^2)

18.5-24.9
<18.5 = underweight
24.9 + 5 = overweight +5 obese +5 severely obese

Question 16

What factors may influence the tendency to put on weight?

Answer 16

Genetic, drug therapy, endocrine disorders

Question 17

What fuel courses can erythrocytes use and what can the CNS utilise?

Answer 17

• Erythrocytes can on utilise Glucose (and only via anaerobic respiration as they have no mitochondria)
• CNS can use glucose and ketones (takes a little while for it to change to ketones though)

Question 18

What is MUST?

Answer 18

the Malnutrition Universal Screening Tool

Question 19

What is marasmus?

Answer 19

A type of protein-energy malnutrition. Commonly seen in children under 5. Child looks emaciated with obvious signs of muscle wasting and fat. Thin, dry hair.

Question 20

What is kwashiorkor?

Answer 20

A result of a low protein diet typically when a young child is displaced from breastfeeding by a new baby. There is generalised oedema and typically a pitting oedema. As a result of low protein uptake the liver has insufficient amino acids to produce normal levels of blood proteins. As such the plasma oncotic pressure reduces increasing the net flow of fluid to the interstitium.

Question 21

How many amino acids are there and list the essential amino acids that can’t be synthesised.

Answer 21

20 amino acids used in the body
9 are essential

Private (PVT.) Tim Hall - remember “a” isn’t on the list it is a semi-essential

Isoleucine
Lysine
Threonine
Histidine
Leucine
Methionine
Phenylalanine
Tryptophan
Valine

Question 22

What conditions are related to vitamin deficiencies of A,B12,C,D,K

Answer 22

A - xerophthalmia (night blindness)
B12 - Anaemia
C - Scurvy
D - Rickets in children and osteomalacia in adults
K - Defective  Blood Clotting