Nutritional Concepts: Refeeding Syndrome & Aging

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Questions and Answers

What is a potential outcome of long-term starvation in the absence of adequate nutrition?

Enhanced renal function

Decreased dependence on ketone bodies

Severe alterations in electrolyte balance (correct)

Increased muscle mass

Which of the following processes is primarily utilized by the body during short-term starvation to maintain energy levels?

Lipolysis

Proteolysis

Ketogenesis

Glycogenolysis (correct)

What contributes to anorexia of aging and potentially increases the risk of morbidity and mortality in older adults?

Increased hunger sensations

Diminished sensory functions (correct)

Improved gastric emptying

Enhanced social interaction

What happens to the body's energy sources as starvation progresses from short-term to long-term?

Increased lipolysis in adipose tissue Signup and view all the answers

What can be a direct consequence of malnutrition from eating disorders?

Life-threatening conditions Signup and view all the answers

What condition can occur when oral or enteral nutritional therapy is started in severely malnourished individuals?

Refeeding syndrome Signup and view all the answers

Which ions are primarily affected during refeeding syndrome due to increased insulin levels?

Potassium, magnesium, and phosphate Signup and view all the answers

What is a consequence of rapid carbohydrate refeeding in malnourished individuals?

Fluid overload Signup and view all the answers

What role does white adipose tissue (WAT) play in the body?

It stores triglycerides and secretes hormones. Signup and view all the answers

Which type of adipose tissue is responsible for thermogenesis due to its high mitochondrial content?

Brown adipose tissue Signup and view all the answers

What is one effect of hypophosphatemia in refeeding syndrome?

Altered shape of red blood cells Signup and view all the answers

In which locations can white adipose tissue (WAT) be found?

In visceral, subcutaneous, muscle, and bone marrow Signup and view all the answers

What is a common supportive strategy for managing the anorexia of aging?

Improved food appearance Signup and view all the answers

What is the primary role of brown adipose tissue (BAT) and beige adipose tissue (bAT) in the body?

To protect against obesity and metabolic syndrome Signup and view all the answers

Which hormones are secreted by skeletal muscle that activate BAT and bAT for thermogenesis?

Irisin and fibroblast growth factor-21 Signup and view all the answers

Which definition best describes obesity?

A condition defined as a BMI greater than 30 kg/m² in adults Signup and view all the answers

What role do orexigenic neurons in the arcuate nucleus of the hypothalamus play in energy regulation?

They stimulate eating and decrease metabolism Signup and view all the answers

What is a consequence of increased leptin levels in obesity?

Leptin resistance leading to overeating Signup and view all the answers

Which factor contributes to the overriding of hypothalamic control of food intake?

Brain centers related to reward and pleasurable memories Signup and view all the answers

What effect does RBP4 have in the context of visceral adiposity?

It promotes insulin resistance and hepatic steatosis Signup and view all the answers

How does bone marrow adipose tissue interact with osteoclasts?

It releases adipokines to maintain bone structure Signup and view all the answers

What effect does adiponectin have on the body in the context of obesity?

It increases inflammation and insulin resistance. Signup and view all the answers

Which of the following best describes the impact of ghrelin in obesity?

It increases food intake but has unclear effects on obesity. Signup and view all the answers

How does visceral obesity differ from peripheral obesity in terms of health risks?

Visceral obesity has greater risks for complications due to chronic inflammation. Signup and view all the answers

Which substance is notably increased in obesity and promotes food intake?

Ghrelin Signup and view all the answers

What is a key characteristic of the chronic inflammation associated with obesity?

It arises from the expansion of adipocyte macrophages and other immune cells. Signup and view all the answers

What role does glucagon-like peptide 1 play in the regulation of appetite?

It suppresses appetite and promotes energy expenditure. Signup and view all the answers

How can obesity treatment be best described?

It includes tailored lifestyle interventions and possible bariatric surgery. Signup and view all the answers

What is a common feature of eating disorders such as anorexia nervosa and bulimia nervosa?

They are psychogenic disorders that can lead to malnutrition. Signup and view all the answers

Study Notes

Refeeding Syndrome

Occurs in severely malnourished individuals when nutritional therapy is started.
During starvation, minerals like phosphate, magnesium, and potassium move out of cells into the bloodstream.
Refeeding initiates insulin release, causing these minerals to return to cells.
Rapid shifts can result in dangerously low levels of minerals (hypophosphatemia, hypomagnesemia, etc.)
Also causes fluid overload.
Hypophosphatemia affects red blood cell shape and function.
Prevention involves slow reinstitution of feeding (e.g., 21400 kcal/day for first few days) and monitoring mineral levels.

Anorexia of Aging

Risk factors include functional impairments (vision, teeth), medical/psychiatric conditions (malabsorption, depression), loneliness, medications, social isolation, and neglect.
Consequences include malnutrition, weight loss, frailty, mitochondrial dysfunction, and reduced regenerative capacity.
Supportive strategies (improved appearance, dental and eye care, social stimulation) are used.
Death rates higher in those with anorexia of aging compared to other types.

Adipose Tissue

Functions as insulation and tissue support; major energy reserve (triglycerides, glycerol).
Endocrine organ, secreting hormones (adipokines) for metabolism and immune response.
Contains macrophages, mast cells, neutrophils and fibroblasts, endothelial cells, nerves.
Two major types: visceral and subcutaneous.
White Adipocytes : single lipid droplet. Storage increases through hypertrophy (visceral) and adipogenesis (subcutaneous).
Brown Adipocytes: multiple lipid droplets, high mitochondria count with iron. Generates heat (nonshivering thermogenesis) through UCP1 and fatty acid oxidation; triggered by cold, sympathetic stimulation, and T3.
Beiging of WAT: emergence of BAT within WAT through cold exposure, exercise, or PPARγ ligands.

Obesity

Global epidemic, fifth leading cause of death in the United States.
Three leading causes of death associated with obesity: cardiovascular disease, type 2 diabetes, and certain cancers.
Defined by BMI > 30 kg/m² in adults and age/sex-specific 95th percentile in children.
Results from energy intake exceeding expenditure.
Genetic (rare, single gene) and polygenetic disorders and metabolic issues are linked to obesity
Hypothalamus regulates appetite and energy metabolism via orexigenic and anorexigenic neurons.
Reward/pleasure centers influence food intake (highly palatable foods).
Adipokines and gastrointestinal hormones are altered, contributing to complications.
Obesity linked with increased leptin levels (leptin resistance), insulin resistance, and hyperlipidemia.
RBP4 levels increase with visceral adiposity (promoting insulin resistance and hepatic steatosis).

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Description

Explore the intricacies of refeeding syndrome and the anorexia of aging in this quiz. Understand the risks, prevention strategies, and consequences associated with these nutritional challenges. This quiz will deepen your knowledge of the physiological impacts of malnutrition in different age groups.