15/16 - Nutrition and aging

Question 1

What are some of the hallmarks of aging? (4/9)

Answer 1

>genomic instability 
>telomere attrition 
>mitochondrial dysfunction 
>cellular senescence 
>epigenetic alterations 
>loss of proteostasis 
>deregulated nutrient sensing 
>stem cell exhaustion 
>altered intercellular >communication

Question 2

What are the 2 consequences of reductions in salivary flow (due to ageing)

Answer 2

Xerostomia = dryness of oral mucosa
Dysphagia = impairment of oral function

Question 3

What is Periodontal disease and what does it cause?

Answer 3

Lesions on the peridontal tissues (tooth supporting structures)
Cause tooth loss

Question 4

What is Atrophic gastritis and what does absorption problems does it cause?

Answer 4

Reduction in the production of acid, intrinsic factor and pepsin
- limits calcium, iron, folate, vitamin B12 absorption

Question 5

Give some impacts of the ageing process on GI tract function (6)

Answer 5

• Loss of teeth
• Xerostomia -> Dysphagia
• Atrophic gastritis
• Bacterial overgrowth of small intestine
• Lactose intolerance
• Loss of colon motility

Question 6

What is the impact of the ageing process on physiological systems? (7)

Answer 6

- Organs lose function 
• Decline of Immune function 
• High levels of chronic illnesses 
• Connective tissues and blood vessels become stiff
- Decreased brain neurones
- Psychological + cognitive changes
- Sensory impairments

Question 7

What is the impact of ageing on body composition (4)

Answer 7

-Increased body fat, sarcopenic obesity
• Decreased muscle and lean tissue
• Decreased production of hormones
• Bone mineral density declines

Question 8

What is the Hayflick limit?

Answer 8

a set number of divisions, at which point the cell enters the senescent stage and is permanently arrested in the G1 phase of the cycle

Question 9

What is senescence?

Answer 9

capacity of the stem cells to regenerate tissues and

restore tissue function becomes outstripped

Question 10

Cell Senescence is associated with permanent arrest of cells at the ___ stage of the mammalian cell cycle.

Answer 10

Cell Senescence is associated with permanent arrest of cells at the G1/S stage of the mammalian cell cycle.

Question 11

What are the 3 mechanisms of cellular senescence?

Answer 11

• Oxidative senscence
• Telomere shortening
• INK4a/ARF(p14) axis

Question 12

What two drivers of cellular ageing act on the P53 enzyme?

Answer 12

DNA damage (oxidative senescence)
Telomere shortening

Question 13

What happens in ageing which increase oxidative damage to cells, activating P53?

Answer 13

• Increased ROS
• Decreased antioxidant capacity
• Decreased cell capacity to repair damage to DNA

Question 14

What is P53 and what is its role in the cell cycle?

Answer 14

• A transcription factor
• Activated as a result of cell cycle abnormalities or DNA damage
• Causes senescence or apoptosis

Question 15

What does P53 activate in order to inhibit the cell cycle?

Answer 15

P21 (cyclin-dependent kinase inhibitor 1)

Question 16

What is the sequence of events that allows P53 to cause apoptosis?

Answer 16

P53 -> Bax
-Cytochrome C release from mitochondria
\+ APAF1 (apoptotic peptidase activating factor 1)
-> Activation of caspase 9
-> Activation of caspase 3-7
Apoptosis

Question 17

What is the repeating sequence of bases on the telomere?
What happens every time the cell divides?
What does this cause senescence or apoptosis?

Answer 17

> TTAGGG
Telomeres shortern with each divide as DNA polymerase is unable to copy the ends.
Telomerase can replace some.. but not all
Critical levels = p53 activation

Question 18

Other than telomere shortening, what other 3 events can activate p53?

Answer 18

> DNA damage
Hypoxia
Hyperproliferative signals

Question 19

What are the 2 locus at chromosome 9p21 which encode two distinct
proteins known to have a pro-ageing influence?

Answer 19

INK4a and ARF

Question 20

What is the role of INK4A and how does it contribute to the physical signs of ageing?

Answer 20

Inhibitor of cell cycle - arrest in the G1 phase

Promotes accumulation of senescent cells within tissues
and apposes regen of tissues by stem cells

Question 21

What is the role of ARF

Answer 21

induces G1 and G2 arrest in the cell cycle as it stabilizes p53

Question 22

How does caloric restriction increase lifespan?

Answer 22

> Reduce ROS production
Reduce body mass
Insulin, thyroid and sex hormone are reduced
Reduces inflammatory processes, and therefore oxidative processes
Upregulates repair system
Decreases DNA damage

Question 23

What can cause protein deficiency in the elderly?

Answer 23

> Finances
> Poor appetite
> Avoidance of fat intake
> Trauma
> Difficulty chewing
> High needs

Question 24

What are some results of protein deficiency in the elderly

Answer 24

> Suppressed immunity
Slow wound healing
Loss of muscle mass
e.c.t

Question 25

With increased age, what nutrients need to be increased and why?

Answer 25

> Protein (increased need)
Vitamin D (decreased bone density and less ability to synthesise)
Calcium (Decreased absorbtion and decreased bone density
B vitamins (low stomach acid levels, decreased absorption, increased need for immune function)

Question 26

With increased age, what nutrients can be decreased and why?

Answer 26

> Fibre due to decreased energy intake and need for high energy food
Iron due to cessation of menstruation and lean tissue

Question 27

What is hypernatremia?

Answer 27

high levels of sodium per ml of blood indicating dehydration

Often from impaired thirst mechanism

Question 28

What is the difference between osteoarthritis and rheumatoid arthritis?

Answer 28

Osteo: wear and tear
RA: Younger adults, not to do with obesity or overuse

Question 29

Give some common food:drug interactions of:
Antacids:
Anticoagulants:
Aspirin:
Diuretics:
Laxatives:

Answer 29

Antacids: decrease abs of iron, calcium, folate, B
Anticoagulants: Oppose clotting activity of K
Aspirin: Decrease blood folate levels and increase iron loss
Diuretics: Decrease or retention of electrolytes
Laxatives: Increase excretion of fat and fat soluble vitamins

Question 30

What are the 3 types of anemia prevalent among elderly people?

Answer 30

> Iron deficiency
Anaemia of chronic disease
Megaloblastic anaemia

Question 31

What accounts for a significant proportion of iron deficiency anaemia in the elderly?

Answer 31

Blood loss due to ulcers or tumours within the GI and atrophy of
the tract

Question 32

What is megaloblastic anaemia?

What is it caused by?

Answer 32

> Characterized by the enlargement of red cells, - related to production of dysfunctional erythrocyte
Caused by deficiency in B12 or folic acid

Question 33

If malabsorption of vitamin B12 is due to atrophy of gastric
parietal cells, the condition is termed ________

Answer 33

pernicious anaemia