Undernutrition: Adaptations of Protein and Energy Metabolism Flashcards
What is starvation?
The physiological condition as a consequence of chronic insufficient food intake
What are clinical features of protein-energy malnutrition?
- Reduced body weight
- Muscle wasting and decreased strength
- Reduced respiratory and cardiac muscular capacity
- Skin thinning
- Decreased metabolic rate
- Hypothermia
- Apathy
- Edema
- Immunodeficiency
How may hypothermia be induced in protein-energy malnutrition?
As a result of decreased amount of subcutaneous fat and a slower metabolism
What are adaptive mechanisms to inadequate protein and/or energy intake in terms of protein stores?
- Decreased skeletal muscle mass
- Decreased heart muscle mass
- Decreased respiratory muscle mass
- Decreased protein reserve
What are adaptive mechanisms to inadequate protein and/or energy intake in terms of metabolic rate?
- Hypotension
- Bradycardia
- Hypothermia
What indicates a successful adaptation to inadequate protein and/or energy intake?
- Zero protein and energy balance
- Normal serum albumin
What may induce a failed adaptation to inadequate protein and/or energy intake?
- Metabolic stress
- Micronutrient deficiency
- Starvation too severe
What indicates a failed adaptation to inadequate protein and/or energy intake?
- Continuing protein and fat loss
- Hypoalbuminemia
- Immune deficiency
What did the results of the Dutch famine cohort study demonstrate?
- 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
What were individuals fed in Keys’ starvation study?
- 1500 kilocalories and 50 grams of protein per day
- For 6 months
What occurred to the subjects in terms of weight change in the Keys’ study after 6 months of starvation?
- Total weight change: -23%
- Change in lean tissue mass: -24%
- Change in fat mass: -71%
- Change in extracellular fluid mass: +4%
What occurred to the subjects in terms of the rate of weight change in the Keys’ study after 6 months of starvation?
- Rate of weight change: 0
- Rate of fat loss: 0
- Rate of lean tissue lost: 0
How did participants in the Keys’ study adapt to starvation?
- The rate of energy expenditure decreased to roughly around 1500 kcals per day
- Decreased BMR and voluntary movements
What does stable body composition imply?
- Cessation of fat loss
- Cessation of lean tissue loss
In starvation, what is reduced in terms of resting energy expenditure? How fast are these mechanisms activated?
- Reduced mass of metabolically active tissue (slow, weeks)
- Reduced energy expenditure per unit of active tissue (fast, days)
In starvation, what is reduced in terms of non-resting energy expenditure?
- Reduced work of moving
- Reduction of voluntary movements
In starvation, what is reduced in terms of energy expenditure per kilogram of active tissue?
- Reduced heart rate, blood pressure, and hematocrit
- Reduced muscle tone
In starvation, how did protein requirement differ?
- Protein requirement lowers
- They are more efficient in their retention of dietary protein, which slows protein turnover
What are the costs of successful adaptations to protein and energy malnutrition?
- Lean tissue loss
- Fatigue and inactivity
- Immunodeficiency
- Reduced tolerance to stress
Why should there only be a mild energy restriction in weight loss diets?
- 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
What percentage of malnutrition and undernutrition occurs in hospitalized patients?
45%
What are causes of in-hospital starvation disease?
- Secondary to the diseased state
- Anorexia
- Pain
- Nausea
- Depression-anxiety-delirium-dementia
- Cachexia
- Thrush
- Dysgeusia
- Economic poverty
What is thrush?
Infection in the oral cavity