Human Nutrition, Energy Balance, and Metabolic Regulation

Flashcards covering energy expenditure, leptin signaling, nutritional status, food labeling, basal metabolic rate, malnutrition forms, hormonal regulation of appetite, insulin resistance, and overnutrition-induced inflammation.

What is the average total daily energy expenditure of adults for women and for men?

The average total daily energy expenditure is between $7.5\,\text{MJ}$ and $10\,\text{MJ}$ for women, and between $8\,\text{MJ}$ and $12\,\text{MJ}$ for men.

How do low versus high circulating leptin levels regulate appetite and neuroendocrine signaling?

Low leptin levels increase hunger and can stop ovulation and menstruation by lowering $\text{GnRH}$ hormone. High leptin levels signal sufficient body fat reserves, decreasing neuropeptide $\text{Y}$ (to reduce hunger) and increasing $\text{POMC}$ (to promote fullness).

What is nutritional status, and how is it assessed given that it cannot be measured directly?

Nutritional status is the overall outcome of food intake, absorption, and utilization, influenced by disease status and physical demands. Because it is multifactorial and cannot be measured directly, it is assessed using anthropometric measurements such as weight, height, and arm circumference.

What $5$ types of information are required by the FDA on every food label, and which foods are exempt?

The $5$ required types of information are: 1. Statement of identity; 2. Net contents of the package; 3. Name and address of manufacturer; 4. Ingredients list; 5. Nutrition information. Fresh produce and seafood are exempt.

What is Basal Metabolic Rate (BMR), and under what standardized environmental temperature is it measured?

BMR is the energy expenditure in the post-absorptive state measured while awake but completely at rest, under standardized conditions of thermal neutrality at an environmental temperature of $26\,^\circ\text{C}-30\,^\circ\text{C}$.

What is the Double Burden of Malnutrition?

The Double Burden of Malnutrition refers to facing both undernutrition and problems like overweight, obesity, and diet-related diseases at the same time.

How do the severe protein-energy undernutrition conditions of marasmus and kwashiorkor differ regarding edema and body tissue depletion?

Marasmus is characterized by severe wasting with markedly depleted body fat and muscle, with edema being absent. Kwashiorkor features bilateral pitting edema (which can mask tissue reduction), hair and skin changes, and potential fatty liver.

What hormonal and appetite alterations were identified by Sumithran et al. (2011) following a $10$-week very-low-energy diet?

Following a mean weight loss of $13.5 \pm 0.5\,\text{kg}$, participants showed decreased leptin, increased ghrelin, decreased $\text{PYY}$ and $\text{CCK}$, and increased hunger, which remained significantly different from baseline at the $1$-year follow-up.

What is insulin resistance, and what are the three major metabolic target tissues involved?

Insulin resistance is a reduced sensitivity or responsiveness of target tissues to the metabolic actions of insulin. The three major metabolic tissues involved are skeletal muscle, adipose tissue, and the liver.

In macronutrient overnutrition, how do enlarged fat cells trigger chronic inflammation?

Enlarged fat cells trigger chronic inflammation by releasing harmful pro-inflammatory substances (such as $\text{TNF}$ and $\text{IL-6}$) and lowering protective substances (such as adiponectin), resulting in a pro-inflammatory state and oxidative stress.