Hubi 3003 (MUN) - Chapter 3 Definitions and Questions (Part 1)

Nitrogen Balance

The amount of nitrogen consumed compared with the amount excreted in a given time period.

What are the three states of nitrogen balance?

- Equilibrium Nitrogen Balance

- Positive Nitrogen Balance

- Negative Nitrogen Balance

Equilibrium Nitrogen Balance

A state of nitrogen balance where protein synthesis is equal to protein degradation, and nitrogen balance is reached.

Positive Nitrogen Balance

A state of nitrogen balance where protein synthesis is greater than protein degradation.

Negative Nitrogen Balance

A state of nitrogen balance where protein degradation overpowers protein synthesis.

What are some situations where positive nitrogen balance occurs?

- Pregnancy

- Child Growth and Development

- Athletic Training

- Recovery from Illness

What are some situations where negative nitrogen balance occurs?

- Inadequate Intake of Protein

- Illness

- Bed Rest

- Essential Amino Acid Deficiency

What kinds of nitrogen loss does nitrogen balance measure?

- Fecal

- Urinary

- Insensible (skin, hair, nails)

What are some criticisms of nitrogen balance?

- It might not measure all losses, so retention could be overestimated or underestimated

- Nitrogen balance does not equal amino acid balance

If one amino acid is limiting, protein synthesis will be ______, and the other amino acids in excess will be _______.

Limited; Catabolized

What is the RDA for protein intake?

0.8 g/kg of body weight.

True or False:

A resistance athlete (e.g., a competitive weightlifter) needs to eat more protein than the average sedentary Canadian normally consumes.

False

What are some examples of protein deficiencies?

- Kwashiorkor

- Marasmus

- Sarcopenia

- Other Clinical Conditions

Kwashiorkor

A form of protein deficiency with adequate energy.

Marasmus

A disease of protein and energy deficiency characterized by chronic insufficient macronutrient intake.

Sarcopenia

The loss of muscle mass, strength, and function that comes with aging.

What other clinical conditions can cause protein deficiencies?

- Surgery

- Cachexia

- Malnutrition