Protein in Health and Disease

Question 1

How many amino acids emerged from biosynthetic pathways?

Answer 1

10

Question 2

Explain protein turnover

Answer 2

It is the process by which cells produce proteins that are needed and dissemble proteins that are not used.

Question 3

How many grams of protein a day and adult makes and degrades?

Answer 3

About 250 g

Question 4

Essential amino acids must:

Answer 4

Be consumed in a diet

Question 5

Non-essential amino acids may:

Answer 5

Be synthesised in the body.

Question 6

Conditionally essential amino acids:

Answer 6

If diet provides inadequate amounts of precursors, can become essential

Question 7

What amino acids are essential for children?

Answer 7

Arginine, histidine and cysteine

Question 8

Complete protein:

Answer 8

Contains all essential aa

Question 9

Incomplete protein:

Answer 9

Lacks at least one essential aa

Question 10

List the non-essential amino acids

Answer 10

Alanine
Asparagine
Aspartate
Glutamate
Serine

Question 11

List the conditionally essential amino acids

Answer 11

Arginine
Cysteine
Glutamine
Glycine
Proline
Tyrosine

Question 12

List the essential amino acids

Answer 12

Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine

Question 13

What is the recommended intake of protein for sedentary adults?

Answer 13

0.75g/kg/day

Question 14

What are the key factors to assess dietary protein quality?

Answer 14

Digestibility and ability to provide the essential amino acids

Question 15

Examples of a combination of foods for protein complementary

Answer 15

Milk and grains
Milk and legumes
Grains and legumes

Question 16

What is Protein Efficiency Ratio (PER)?

Answer 16

Determines protein quality by measuring animal growth.
Computed value compared to a standard value of 2.5, the value corresponding to casein protein’s effect on growth.
Any value >2.5 indicates an excellent protein source.
PER = gain in body mass (g) protein intake (g)

Question 17

Explain Biological Value to asses protein quality

Answer 17

Biological Value.
Measures the nitrogen retained in the human body from the test food, which is theoretically taken up by tissues and used. It cannot be measured directly. Measures the amount of excreted nitrogen from the test diet.

Question 18

List 7 protein sources and their biological value

Answer 18

Eggs 100
Fish meal 92
Beef 78
Milk 78
Wheat 60
Corn 54
Wheat Gluten 40

Question 19

Explain Protein Digestibility Corrected Amino Acid Score (PDCAAS)

Answer 19

Adopted by WHO 1989. A measure of a protein’s digestibility and its ability to provide adequate levels of essential amino acids for human needs. The test protein is compared to a standard amino acid profile. Scores from 0-1, with a score of 1.0 indicating maximum amino acid digestibility.
Based on the essential requirements of a pre-school-age child.

Question 20

Explain the different scores of DIAAS

Answer 20

> 100 = Excellent quality
75-99 = Good quality
<74 = Poor quality

Question 21

Facts about High Fibre

Answer 21

High fibre may help reduce serum cholesterol and prevent heart disease. It also aids digestion and prevents disorders of the GI tract. Fibre interferes with the absorption of bile in the intestines, so it is excreted instead - therefore, the liver has to make more bile salts and requires LDL cholesterol, so it is removed from the blood to make more bile salts.

Question 22

Nutritional advantages of protein foods of animals over those of vegetable origin

Answer 22

Vitamin B12, Iron and Retinol

Question 23

Protein requirements in infancy and childhood

Answer 23

0-6m = 2g/kg/day
6m-7y = 1.6g/kg/day
7-14y= 1g/kg/day
>14y = 0.75g/kg/day

Question 24

Estimated loss of lean body mass between 35 - 70 years

Answer 24

20-25%

Question 25

Ideal protein requirements for the elderly

Answer 25

1.0 to 1.3 g/kg/day dietary protein combined with twice-weekly progressive resistance exercise

Question 26

Which amino acid appears to play an important role in the prevention of sarcopenia?

Answer 26

Leucine

Question 27

Which patients need higher protein intake?

Answer 27

burn patients; their protein oxidation rates are 50% higher
1.5 to 2.0 g/kg

Question 28

Which diet results in less proteolysis and more improvement in lean body mass?

Answer 28

High carbohydrate, high protein, low-fat diet

Question 29

Recommendation for red meat intake

Answer 29

no more than 70g/day

Question 30

How does meat increase cancer risk?

Answer 30

Haem forms N-nitroso compounds in the gut, damaging the gut lining.
Processed meat contains chemicals that generate N-nitroso compounds, e.g. nitrite preserves. Celery juice/salt is high in nitrates.
Cooking meat at high temp creates chemicals in meat that can increase cancer risk.
Eating red meat causes 13% of bowel cancer and 1.5% of UK cancers.

Question 31

Explain how excess protein may affect kidney function

Answer 31

Increased protein increases urinary nitrogen.
It may increase the glomerular filtration rate (GFR), which is the rate at which plasma is filtered from capillaries into Bowman’s capsule. High GFR may increase pressure in kidneys - structural damage

Question 32

Statements about conditionally essential amino acids

Answer 32

They may be essential in some populations and non-essential in other populations.
Whether or not amino acid is considered conditionally essential can depend on the life stage.