Nutrition Introdution

Question 1

Define nutrition

Answer 1

Nutrition is utilization of foods by living organisms for growth, reproduction and maintenane of health.

Question 2

Define nutrients.

Answer 2

Nutrients are substances and qualities of food that are required for life, and for growth, maintenance, and repair of body tissues.

Question 3

Nutrients are divided into two broad groups known as

Answer 3

Organic compounds and inorganic compounds

Question 4

Some nutrients are classes of substances, give examples of five:

Answer 4

Fiber, energy, omega-3 fatty acids, vitamin E, vitamin A

Question 5

Define fiber as a nutrient

Answer 5

Many subtanes that are variably water soluble and fermentable.

Question 6

Define energy as a nutrient

Answer 6

Chemical bond energy in organic susbtances

Question 7

omega-3 fatty acids include:

Answer 7

Eicosapentaenoic acid (EPA), docosahexaneoic acid DHA

Question 8

nutrients classified under Vitamin E include:

Answer 8

tocopherols and tocotrienols

Question 9

Describe nutrients classified under vitamin A:

Answer 9

substances with retinol-like activity in animals (ex. carotene)

Question 10

What are the two general functions of nutrients?

Answer 10

1. Supply energy for metabolic processes

2. Substrate for body structural and functional substances

Question 11

Define an essential nutrient.

Answer 11

An essential nutrient is a substance that is required and cannot be synthesized or synthesized in amounts sufficient to meet animal needs.

Question 12

Define a conditionally-essential nutrient.

Answer 12

A substance that is essential under certain conitions, such as a physioligcal stage (choline for growth) or a disease stage (vitamin C during liver insufficiency)

Question 13

List the essential nutrients for most animals.

Answer 13

1. Water - greatest mass of daily intake
2. Energy - derived from protein, fat, and carbs
3. Amino acids - 20 in diet, about half are essential
4. Minerals - macrominerls and trace- or micro-minerals
5. Vitamins - fat soluble and water soluble
6. Fatty acids - omeg-6 and omega-3 series

Question 14

Vitamins

Answer 14

Organic compounds of low concentration that are variably provided in foods

Question 15

Nutrients must be provided in ________ and _______ relative to one another.

Answer 15

Nutrients must be provided in proper amounts and proper proportions relative to one another.

Question 16

Nutrient disproportion is known as a _______.

Answer 16

Malnutrition

Question 17

Amount and proportions of nutrients needed vary with physiological state and disease. List 4 physiological states.

Answer 17

1. Growth
2. Maintenance
3. Gestation
4. Lactation

Question 18

Define optimal nutrition.

Answer 18

A concept of animal response to nutrient exposure. Nutrients are provided in amounts and proportions that optimize a physiological or economically important response.

Question 19

Define deficiency in regards to a nutrient-animal response relationship graph.

Answer 19

When response variable increases with increasing nutrient concentration.This condition indicates diet has too little nutrient, and that diet is not meeting the animal’s requirement for the nutrient.

Question 20

Define suboptimal in regards to a nutrient-animal response relationship graph.

Answer 20

The response variable increases with increasing nutrient amount but diminishing returns occurs with further increases in nutrient amount.

Question 21

Define optimal in regards to a nutrient-animal response relationship graph.

Answer 21

The animal response does not change with increasing nutrient amount. This condition is usually desired.

Question 22

Define “excess” in regards to a nutrient-animal response relationship graph.

Answer 22

The response decreases with increasing nutrient amount. More nutrient is not always better, a nutrient may become toxic. Excess of a nutrient may cause deficiency of another nutrient. Amount excess that toxicity varies among species.

Question 23

Determining “optimal” nutrient concentration.

Answer 23

1. For each nutrient there is more than one response variable that may be used to determine the optimal nutrient amount.
2. Body reserves of nutrient will affect the response to dietary concentration (i.e. a deficiency may not be observed for a long time because of body reserves. An apparently optimal concentration found in a short-term trial may actually be inadequate over long-term.

Question 24

Define nutrient requirement.

Answer 24

Nutrient requirement is the minimum dietary amount of a highly bioavailable nutrient that optimizes a response important to a physiological feature.

Question 25

Define bioavailable.

Answer 25

Readily obtained from diet for use in tissues. (efficiently digested and absorbed, also needs to be available to tissues)

Question 26

A nutrient requirement varies with the _____.

Answer 26

A nutrient requirement varies with the physiological state.

Question 27

Define nutrient allowance.

Answer 27

Nutrient allowance is the minimum dietary amount of a nutrient that should be present in a practical formulation (ex. a commercial diet) that will maintain health.

Question 28

How does a nutrient allowance differ from a nutrient requirement?

Answer 28

1. A nutrient allowance is for ‘health’ not a single response variable.
2. A nutrient allowance is typically greater than its corresponding nutrient requirement.

Question 29

What is a ‘safety factor’ in regards to a nutrient allowance?

Answer 29

A nutrient allowance typically is a nutrient requirement plus an agreed upon added amount, known as a safety factor.

Question 30

Why are safety factors used?

Answer 30

1. Bioavailability of a nutrient is typically less than 100%
2. Nutrient content in dietary ingredients may unpredictably vary
3. Nutrient requirements are often extrapolated from other species

Question 31

What are the shortfalls of nutrient allowances?

Answer 31

1. Safety factors are sometimes arbitrarily agreed to.
2. Safety factors may be based on incorrect assumptions about nutrient bioavailability, and/or nutrient contents in dietary ingredients.
3. Safety factors do not account for unrecognized interactions of dietary factors that may substantially affect bioavailability.

Question 32

Is there a ‘best diet’ for an animal species?

Answer 32

No, there is no one best diet or food for any animal species!

Question 33

Is it easy to know determine dietary nutrient composition?

Answer 33

No, knowing nutrient composition of any diet with complete certainty is difficult because individual nutrient assays are not readily available and are expensive. Also, standard tables of nutrient composition of dietary ingredients are useful but limited.

Question 34

List three useful estimates of dietary nutrient composition.

Answer 34

1. Proximate analysis
2. Guaranteed analysis
3. “average nutrient content” determined from diet samplings

Question 35

Proximate analysis is also known as?

Answer 35

Wende analysis

Question 36

Define a proximate analysis.

Answer 36

A very crude estimation of dietary nutritional value. It is an analysis of 6 physical-chemical characteristics:

1. Moisture - good estimate of water content of a diet
2. Crude fat
3. Crude fiber
4. Ash - weight of diet after drying and burning off all organic mater. “Crude” estimate of dietary mineral content.
5. Crude protein
6. Nitrogen free extract - crude estimate of the digestible carbohydrate content of a diet

Question 37

Define guaranteed analysis.

Answer 37

A listing of proximate analysis results and other assay results “guaranteed” by the manufacture to be packaged in feed or food.

Question 38

Why is the guaranteed analysis of limited value?

Answer 38

Because results of the “analysis” are:

1. either minimums or maximums
2. Often an incomplete listing of proximate analysis of contents

Question 39

Facts about average nutrient content.

Answer 39

Rarely are results for all nutrients given. Better than proximate and guaranteed analysis for assessing nutritional adequacy. Value is limited because bioavailability of nutrients is unknown.