Review of Nutrients Lecture 2B

Question 1

Name some basic functions nutrients are involved with in the body?

Answer 1

Act as structural components
Enhance (or involved in) chemical reactions of metabolism
Transport substances into, throughout or out of the body
Maintain body temperature
Supply energy

Question 2

What is an essential nutrient?

Answer 2

Essential:

Nutrient can not be synthesized by the animal, must be obtained in the food

Question 3

What is a non essential nutrient?

Answer 3

Non-essential:

Nutrient can be synthesized in adequate quantities by animals and are not specifically required in the food

Question 4

What is a conditionally essential nutrient?

Answer 4

Conditionally essential:
A non-essential nutrient that becomes an essential nutrient when certain physiologic conditions result in relative deficiency

Question 5

What is the definition of “digestibility”?

Answer 5

Digestibility:
Percentage of food’s gross nutrient content released following mechanical and chemical digestive processes
Is influenced by both food characteristics and the digestive efficiency of the host

Question 6

What is “bioavailability”?

Answer 6

Bioavailability:
The degree to which a nutrient becomes available to support metabolism after digestion and absorption
Bioavailability – means that not all nutrients digested are in form of sustained growth form. – nutrient digested but not available

Question 7

What might examples of nutrients that sometimes are digestible but not available?

Answer 7

Lysine - during maillard reaction when binds with sugar on nitrogenous group

Question 8

What is apparent digestibility?

Answer 8

Apparent digestibility:
Nutrient intake minus nutrient excretion in feces
Apparent – have diet / fecal sample – deduction – measured beyond digestibility is APPARENT – reason is because nutrients collected – some of them aren’t from the diet – are in digesta because secreted by animal into GIT – can make correction for this

Question 9

What is true digestibility?

Answer 9

True digestibility:

Nutrient intake minus nutrient excretion in feces corrected for intestinal endogenous losses

Question 10

What are intestinal endogenous losses?

Answer 10

Intestinal endogenous losses:

Excretion of nutrient into gut due to cell turn over, intestinal secretions, sloughing of intestinal cells etc.

Question 11

What is a simple carb? Give examples

Answer 11

Simple Carbohydrates (one sugar) C-H
Monosaccharides
Glucose, fructose, galactose
Disaccharides [degree of polymerization (DP) = 2]
Maltose, sucrose, lactose

Question 12

What is a complex carb, give examples?

Answer 12

Complex Carbohydrates
Oligosaccharides [DP = 3-10] (larger list)
Fructo-, galacto-oligosaccharides
Polysaccharides [DP = > 10]
Starch (indigestible), cellulose (fiber molecule also), glycogen (animal made stored in liver / muscle)