Ch. 39 Alterations in Nutritional Status-1-1

What is a nutrient source?

Derived from the digestive tract, used for energy or as building blocks for tissue growth and repair.

Note: Nutrients come from food and help you have energy and grow your body.

How does the body adapt to nutrient unavailability?

The body adapts by conserving and using its nutrient stores.

Note: When food is low, the body saves what it already has.

How is energy measured?

Measured in heat units called calories—the amount of heat or energy required to raise the temperature of $1$ gram of water by $1^\circ C$.

Note: Calories tell us how much energy food gives, like fuel for a car.

What is the definition of metabolism?

The process through which nutrients (carbohydrates, fats, and proteins) are broken down, transformed, or converted into cellular energy.

Note: Metabolism is how your body changes food into energy.

What are the phases of metabolism?

Anabolism (storage and synthesis of cell constituents, requires energy) and Catabolism (breakdown of complex molecules into substances used for energy production).

Note: Building stuff = anabolism, breaking stuff down = catabolism.

What are metabolites?

Chemical intermediates for anabolism and catabolism.

Note: Metabolites are like little pieces in the building and breaking process.

What is the cellular energy currency?

Adenosine triphosphate (ATP), which almost all body cells store and use as their energy source.

Note: ATP is tiny energy money cells spend to do work.

What is basal metabolic rate (BMR)?

The minimum amount of energy expended that is compatible with life.

Note: BMR is the energy your body needs just to stay alive at rest.

How much of the body’s energy needs are met by BMR?

Provides $50\%$ to $70\%$ of body energy needs.

Note: More than half your daily energy is used just to keep your body running.

What factors affect BMR?

Age, sex, physical state, and pregnancy.

Note: Your age, gender, health, and if you’re pregnant change how much energy your body burns at rest.

How does BMR change with age?

Progressive decline occurs with aging, related to loss of muscle mass and replacement with adipose tissue.

Note: Older people burn less energy because they have less muscle and more fat.

What is the main source of stored fuel?

Lipids stored in adipocytes (fat cells).

Note: Fat cells are the body’s fuel tank.

Where are adipocytes located?

Found in loose connective tissue.

Note: Fat cells live under your skin and around your organs.

What percentage of body energy is stored in adipose tissue?

Adipose tissue stores more than $90\%$ of body energy.

Note: Most of the body’s energy is saved as fat.

What is the function of adipose tissue?

Serves as a storage site for body fuels, provides insulation, fills body crevices, and protects body organs.

Note: Fat stores energy, keeps you warm, and cushions your body.

What are the types of adipose tissue?

White fat and brown fat.

Note: There’s white fat (energy storage) and brown fat (makes heat).

What are the characteristics of white fat?

Prevalent form in postnatal life; lipid content exists as oil at body temperature; consists of triglycerides (major fat storage form); has the highest caloric content of all nutrients and is an efficient energy storage form.

Note: White fat is oily, stores lots of energy, and is the main fat in your body.

How is glucose transported into fat cells?

Insulin is required for the transport of glucose into fat cells.

Note: Insulin is like a key that lets sugar go into fat cells.

What is the function of brown fat?

Differs from white fat in its ability to produce heat; contains a higher concentration of specialized mitochondria; decreases with age.

Note: Brown fat is like a heater — it burns energy to make heat.

What is the function of leptin?

A peptide released from adipocytes that acts on the hypothalamus to decrease food intake and increase energy expenditure.

Note: Leptin is a signal from fat cells that tells the brain “I’m full, burn more energy.”

How do leptin levels change?

Levels rise after food intake and fall during fasting.

Note: Leptin goes up when you eat and down when you’re hungry.

What happens if there is leptin resistance?

A failure to respond to high levels of leptin may result in obesity.

Note: The brain ignores leptin → you don’t feel full → gain weight.

How can medications influence fat cells?

Some medications can cause the loss of fat cells, leading to lipodystrophy.

Note: Certain drugs can make fat disappear in weird ways.

What is obesity?

Excess body fat accumulation with multiple organ-specific pathologic consequences.

Note: Too much fat in the body can make you sick.

What is the leading cause of overweight/obesity?

An energy imbalance of consuming too many calories and not getting enough physical activity.

Note: Eating more than you burn = gaining weight.

What is the major global contributor to obesity?

Environmental influence, specifically the high availability of calorie-rich foods and decreased physical activity.

Note: Easy access to tasty food + little exercise = more obesity worldwide.

What is the most contributing environmental factor to obesity?

Increased availability of inexpensive, tasty, highly promoted, obesogenic types of food.

Note: Cheap, yummy junk food everywhere makes people gain weight.

What is BMI and what is it used for?

Body Mass Index; helps define obesity and overweight, based on height and weight measurements, and is correlated with body fat.

Note: BMI is a number from your weight and height that shows if you’re overweight.

How does WHO define overweight in adults?

BMI $\ge 25$.

Note: BMI 25+ = overweight.

How does WHO define obese in adults?

BMI $\ge 30$.

Note: BMI 30+ = obese.

What are the two types of obesity by fat distribution?

Upper body ("apple" or central/visceral/android) and Lower body ("pear" or peripheral/gynoid).

Note: Fat can sit on your belly (apple) or hips/legs (pear).

What are the characteristics of upper body obesity?

Central, abdominal, visceral; more common in men; associated with a higher proportion of intra-abdominal fat to subcutaneous fat with age.

Note: Belly fat is mostly inside, common in men, and increases with age.

How does fat distribution change in postmenopausal women?

Women acquire more central fat distribution after menopause.

Note: After menopause, women gain more belly fat.

How does BMI > $40$ affect life expectancy?

Adults with a BMI > $40$ have a shorter life expectancy by $6$–$13$ years.

Note: Very high BMI can shorten your life by 6–13 years.

Which cancers are associated with obesity?

Endometrial, colon, GB, prostate, kidney, and postmenopausal breast cancer.

Note: Extra fat increases the risk of some cancers.

How does obesity impact women's health?

Contributes to infertility, higher risk pregnancy, gestational diabetes, maternal hypertension, and delivery difficulty; infants are more likely to be high birth weight.

Note: Being very overweight makes pregnancy harder and babies bigger.

What is the most effective treatment for severe obesity?

Weight Loss (Bariatric) Surgery.

Note: Surgery is the best way to lose a lot of weight safely.

What are the criteria for bariatric surgery?

Severe obesity (BMI > $40$) or BMI > $35$ with comorbid conditions who have failed medical attempts to control weight.

Note: Surgery is for very high BMI or serious health problems after other methods fail.

What is the major benefit of bariatric surgery?

Resolution or remission of comorbid disease states.

Note: Surgery often makes other health problems better.

What are the types of bariatric surgery?

Restrictive (e.g., adjustable gastric band, sleeve gastrectomy) and Malabsorptive (e.g., biliopancreatic diversion with duodenal switch) or combined.

Note: Some surgeries shrink the stomach, some reduce nutrient absorption, some do both.

What is malnutrition/starvation?

Conditions where a person does not receive or is unable to use an adequate amount of nutrients for body function.

Note: Not getting enough food or nutrients to keep your body working.

What are the causes of malnutrition?

Poverty and ignorance, acute and chronic illness, and self-imposed dietary restriction.

Note: Not enough money, sickness, or choosing not to eat can cause malnutrition.

What are lean tissues?

Fat-free, metabolically active tissues of the body (skeletal muscles, viscera, and cells of the blood and immune system).

Note: The body parts that do all the work and aren’t fat.

What causes marasmus?

Progressive loss of muscle mass and fat stores due to inadequate food intake deficient in calories and protein.

Note: Not enough food or protein → body wastes away.

What are the manifestations of marasmus?

Wasted appearance, loss of muscle mass, stunted growth, loss of subcutaneous fat, protuberant abdomen, and depressed heart rate/blood pressure/body temperature.

Note: Body looks very thin, weak, small, with big belly and low energy.

What causes kwashiorkor?

Deficiency in protein.

Note: Not enough protein, even if calories might be okay.

What is the key pathophysiology in kwashiorkor?

Severe protein deficiency causes extensive loss of the visceral protein compartment, leading to hypoalbuminemia and resultant generalized or dependent edema.

Note: Low protein → swelling everywhere because water leaks out of blood vessels.

What is the appearance of kwashiorkor?

Growth failure and muscle wasting, but subcutaneous fat is normal because calorie intake is adequate.

Note: Skinny muscles, but fat looks okay since they eat enough calories.

What is the "flag sign" in kwashiorkor?

Hair becomes a sandy or reddish color, with linear depigmentation.

Note: Hair changes color in stripes like a flag.

What is marasmus–kwashiorkor?

Advanced protein–energy deficit coupled with increased protein requirement or loss, resulting in rapid decrease in measurements, wasting, and obvious edema.

Note: Worst case — body is starved of calories and protein → very thin + swollen.

What are the characteristics of anorexia nervosa (AN)?

Determined dieting and compulsive exercise resulting in sustained low body weight, intense fear of gaining weight, and disturbed body image.

Note: Eating almost nothing + exercising a lot because scared of getting fat.

What are endocrine complications of AN?

Amenorrhea and loss of secondary sex characteristics with decreased estrogen levels, leading to osteoporosis.

Note: Low hormones → no periods, weak bones, and loss of body development.

What causes sudden death in AN?

Caused by myocardial degeneration and heart failure.

Note: Starving damages the heart → can stop working.

What are the characteristics of bulimia nervosa (BN)?

Recurrent binge eating followed by inappropriate compensatory behaviors (vomiting, fasting, excessive exercise, laxative/diuretic use).

Note: Eat a lot, then try to undo it by vomiting or over-exercising.

What is the weight status in BN?

Most people with BN are of normal weight.

Note: Even though they binge and purge, weight can look normal.

What are complications of self-induced vomiting in BN?

Dental disorders, parotitis, fluid/electrolyte disorders, esophagitis, dysphagia, esophageal strictures, and metabolic alkalosis with hypokalemia.

Note: Throwing up too much ruins teeth, throat, and body salts.