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3) Metabolism and Human Nutrition > Undernutrition: Adaptations of Protein and Energy Metabolism > Flashcards

Undernutrition: Adaptations of Protein and Energy Metabolism Flashcards

1
Q

What is starvation?

A

The physiological condition as a consequence of chronic insufficient food intake

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2
Q

What are clinical features of protein-energy malnutrition?

A
  • Reduced body weight
  • Muscle wasting and decreased strength
  • Reduced respiratory and cardiac muscular capacity
  • Skin thinning
  • Decreased metabolic rate
  • Hypothermia
  • Apathy
  • Edema
  • Immunodeficiency
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3
Q

How may hypothermia be induced in protein-energy malnutrition?

A

As a result of decreased amount of subcutaneous fat and a slower metabolism

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4
Q

What are adaptive mechanisms to inadequate protein and/or energy intake in terms of protein stores?

A
  • Decreased skeletal muscle mass
  • Decreased heart muscle mass
  • Decreased respiratory muscle mass
  • Decreased protein reserve
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5
Q

What are adaptive mechanisms to inadequate protein and/or energy intake in terms of metabolic rate?

A
  • Hypotension
  • Bradycardia
  • Hypothermia
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6
Q

What indicates a successful adaptation to inadequate protein and/or energy intake?

A
  • Zero protein and energy balance

- Normal serum albumin

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7
Q

What may induce a failed adaptation to inadequate protein and/or energy intake?

A
  • Metabolic stress
  • Micronutrient deficiency
  • Starvation too severe
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8
Q

What indicates a failed adaptation to inadequate protein and/or energy intake?

A
  • Continuing protein and fat loss
  • Hypoalbuminemia
  • Immune deficiency
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9
Q

What did the results of the Dutch famine cohort study demonstrate?

A
  • Intrauterine growth restricted (IUGR) infants were followed for decades, and were shown to be more vulnerable to certain chronic diseases
  • The children of these infants also tended to be IUGR
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10
Q

What were individuals fed in Keys’ starvation study?

A
  • 1500 kilocalories and 50 grams of protein per day

- For 6 months

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11
Q

What occurred to the subjects in terms of weight change in the Keys’ study after 6 months of starvation?

A
  • Total weight change: -23%
  • Change in lean tissue mass: -24%
  • Change in fat mass: -71%
  • Change in extracellular fluid mass: +4%
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12
Q

What occurred to the subjects in terms of the rate of weight change in the Keys’ study after 6 months of starvation?

A
  • Rate of weight change: 0
  • Rate of fat loss: 0
  • Rate of lean tissue lost: 0
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13
Q

How did participants in the Keys’ study adapt to starvation?

A
  • The rate of energy expenditure decreased to roughly around 1500 kcals per day
  • Decreased BMR and voluntary movements
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14
Q

What does stable body composition imply?

A
  • Cessation of fat loss

- Cessation of lean tissue loss

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15
Q

In starvation, what is reduced in terms of resting energy expenditure? How fast are these mechanisms activated?

A
  • Reduced mass of metabolically active tissue (slow, weeks)

- Reduced energy expenditure per unit of active tissue (fast, days)

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16
Q

In starvation, what is reduced in terms of non-resting energy expenditure?

A
  • Reduced work of moving

- Reduction of voluntary movements

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17
Q

In starvation, what is reduced in terms of energy expenditure per kilogram of active tissue?

A
  • Reduced heart rate, blood pressure, and hematocrit

- Reduced muscle tone

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18
Q

In starvation, how did protein requirement differ?

A
  • Protein requirement lowers

- They are more efficient in their retention of dietary protein, which slows protein turnover

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19
Q

What are the costs of successful adaptations to protein and energy malnutrition?

A
  • Lean tissue loss
  • Fatigue and inactivity
  • Immunodeficiency
  • Reduced tolerance to stress
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20
Q

Why should there only be a mild energy restriction in weight loss diets?

A
  • Because decreasing lean mass decreases all aspects of metabolism (lowers BMR and causes muscle atrophy), which is counter-productive to losing weight
  • Exercise may avoid the loss of lean tissue and muscle
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21
Q

What percentage of malnutrition and undernutrition occurs in hospitalized patients?

A

45%

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22
Q

What are causes of in-hospital starvation disease?

A
  • Secondary to the diseased state
  • Anorexia
  • Pain
  • Nausea
  • Depression-anxiety-delirium-dementia
  • Cachexia
  • Thrush
  • Dysgeusia
  • Economic poverty
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23
Q

What is thrush?

A

Infection in the oral cavity

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24
Q

What is dysgeusia?

A

Altered taste, which may be caused by chemotherapy drugs

25
Q

Why may in-hospital starvation disease be secondary to the diseased state?

A

Because the acute phase response produces cytokines that promote anorexia, fever, inflammation, immune responses, which increase protein and energy demand

26
Q

What are consequences of in-hospital starvation disease?

A
  • Muscle atrophy
  • Weakness
  • Loss of function
  • Mood disturbance
  • Immune deficiency
  • Surgical complications
  • Skin breakdown
  • Infections
  • Death
27
Q

How does hospital food provision contribute to in-hospital starvation disease?

A
  • Unappealing institutional food
  • Meals are often cut short
  • Little staff capacity for assisted or hand-feeding
  • Extreme budget constraints
28
Q

What are the six causes of muscle atrophy?

A

1) Cachexia
2) Hormone excess or deficiency
3) Old age - Sarcopenia
4) Protein-Energy Malnutrition - Starvation Disease
5) Inactivity - Disease Atrophy
6) Neuromuscular Disease

29
Q

What is cachexia?

A

Metabolic scenario of systemic inflammation and wasting, characterized by a resistance to anabolism

30
Q

Provide an example of hormone excess provoking muscle atrophy.

A
  • Cortisol concentrations increase up to 10-fold during surgery, which promotes protein breakdown,
  • Glucagon to insulin ratio is high, increasing the catabolic response
31
Q

What is sarcopenia?

A
  • After the age of 40, a certain quantity of muscle mass is lost every year
  • Muscle structure becomes more infiltrated with fat
32
Q

What is the way to counteract sarcopenia?

A

Increasing movement during hospitalization

33
Q

How would you plan how many calories to feed a patient in hospital?

A
  • Indirect calorimetry

- Individualized nutrition support

34
Q

How do injuries affect metabolism?

A

They drastically increase metabolic rate (hypermetabolic)

35
Q

How does starvation affect metabolism?

A

Hypometabolic; slows energy and protein metabolism

36
Q

How do injuries affect protein metabolism and nitrogen excretion? How does it change after 10 days?

A
  • Significant increase in nitrogen excretion, as amino acid catabolism increases drastically
  • After 10 days, nitrogen excretion decreases, illustrating the protein-sparing effect of ketones as we adapt to the starvation scenario
37
Q

What is the major cause of death in children?

A
  • Half of deaths are during the neonatal period (first month)
  • Many deaths result from infections that are exacerbated by malnutrition
38
Q

Provide an example of how an infection may be exacerbated by malnutrition.

A
  • Vitamin A is required for cell differentiation and gene expression, maintaining the epithelial cell barrier intact
  • A deficiency in vitamin A results in an increased vulnerability to pneumonia and diarrhea
39
Q

Which is the successful adaptation to PEM in children? Which is the unsuccessful adaptation?

A
  • Successful: marasmus

- Unsuccessful: kwashiorkor

40
Q

Which age group develops marasmus? Which age group develops kwashiorkor? Do they develop rapidly or slowly?

A
  • Marasmus: infancy (6 to 18 months), develops slowly

- Kwashiorkor: older infants and young children (18 months to 2 years old), develops rapidly

41
Q

What is marasmus? What are the consequences?

A
  • Marasmus is the severe deprivation or impaired absorption of protein, energy, vitamins, and minerals
  • Results in severe weight loss and muscle wasting, including the heart
  • May have a good appetite
  • <60% weight-for-age
42
Q

During what period is kwashiorkor particularly vulnerable? What may increase the risk of its development?

A
  • During the weaning period when the mother stops breastfeeding following the birth of a second child
  • The presence of over diluted formula or unclean water may increase the risk
43
Q

What is kwashiorkor? What are the consequences?

A
  • Inadequate protein and energy intake leads to fluid accumulation in the abdomen
  • Unable to regulate fluid and electrolyte balance
  • Results in the accumulation of fat in the liver
44
Q

How does kwashiorkor usually occur?

A

From an infection, or a factor that prevents the successful adaptive response

45
Q

How is kwashiorkor treated, in order?

A

1) Stabilization of electrolytes
2) Resolving edema and infection
3) Re-feeding

46
Q

What is edema?

A
  • Plasma leaves leaky blood vessels and moves into tissues

- Proteins, such as albumin, attract water, causing swelling

47
Q

What are the rules of ethics in nutrition research?

A
  • “Do no harm”
  • Must treat rather than observe
  • Offer best standard of care possible
48
Q

What kind of trials are used in nutrition research? May they always be used?

A
  • Double-blind randomized placebo-controlled clinical trials

- May not always be used for ethical reasons

49
Q

What does the loss of body protein in response to surgery result in?

A
  • Immunosuppression (delayed wound healing)

- Muscle wasting (delayed convalescence)

50
Q

Colorectal surgery may result in a period of around four days without feeding, which is the opposite of what should occur during surgery. What philosophy has been set in place to narrow the window of perioperative fasting?

A
  • A philosophy called ERAS (enhanced-recovery after surgery)
  • Promotes early enteral feeding and mobility after surgery, which incredibly enhances recovery
  • Starting intravenous feeding before surgery to avoid the metaboilc fasting phase
51
Q

What causes the loss of body protein during surgery?

A

Inflammatory response and neuroendocrine response lead to insulin resistance and hyperglycemia

52
Q

How does hyperglycemia occur following surgery? What are the consequences?

A
  • Insulin resistance in peripheral tissues decreases glucose uptake, resulting in hyperglycemia
  • Hyperglycemia promotes complications and infections
53
Q

What does insulin resistance following surgery promote?

A
  • Muscle protein breakdown and gluconeogenesis, producing an increased quantity of glucose
  • This is exactly the opposite of what ideally happens during insulin resistance and hyperglycemia
54
Q

What is an epidural?

A

Local anesthetic that stops pain signals from getting to the brain

55
Q

How does epidural analgesia promote anabolism?

A
  • A local analgesic decreases the neuro-endocrine response by decreasing cortisol, blood pressure, and heart rate
  • Also, provides the best pain control if maintained after surgery
56
Q

How does an epidural allow the body to make better use of nutrition support?

A
  • By decreasing stress, catabolic response, and insulin resistance
  • Allows amino acids in nutrition support to be able to build protein
57
Q

What is the standard of care for protein intake?

A
  • Enteral nutrition
  • Protein intake of 1.0 g/kg/d
  • Prescribed a gram, but only found to intake around 0.6 grams
58
Q

What quantity of protein intake is more appropriate for extremely sick patients in a catabolic state?

A

2.5 g/kg/d

59
Q

What is parenteral nutrition?

A

Amino acids are given and bypass the usual process of eating and digestion

3) Metabolism and Human Nutrition (17 decks)

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