(Also called nourishment or aliment) is the provision, to cells and organisms, of the materials necessary (in
the form of food) to support life. Many common health problems can be prevented or alleviated with a
healthy diet.
The diet of an organism is what it eats, which is largely determined by the perceived palatability of
foods. Dietitians are health professionals who specialize in human nutrition, meal planning, economics,
and preparation.
They are trained to provide safe, evidence-based dietary advice and management to individuals
(in health and disease), as well as to institutions.
Clinical nutritionists are health professionals who focus more specifically on the role of nutrition in
chronic disease, including possible prevention or remediation by addressing nutritional deficiencies
before resorting to drugs.
While government regulation of the use of this professional title is less universal than for "dietician", the
field is supported by many high-level academic programs.
There are six basic classes of nutrients that must be considered in formulating diets; water, protein,
carbohydrates, fats, vitamins and minerals.
In Frank B. Morrison's Feeds & Feeding, a nutrient is defined as "Any feed constituent or group of feed
constituents of the same general chemical composition that aids in support of human life."
Six Classes of Nutrients
1. Water
 The Most Critical Nutrient!
 Functions in transport, chemical reactions, temperature maintenance, lubrication, etc.
 Water deprivation ---> dehydration ---> electrolyte imbalance ---> death
 Requirements vary from one species to another.
 Management problems leading to lack of water
 bad taste (high sulfur content)
 don’t know how to use or cannot find water
 2. Carbohydrates (CHO)
 Functions
 energy source
 building block for other nutrients
 dietary excess stored as fat
 Two main components of carbohydrates
 Crude fiber (cellulose mainly)
 Nitrogen-free extract (soluble sugars, starches)
 Management Problems
 poor quality feedstuffs
 improper ration balancing
 3. Fats (lipids)
 Functions
 Energy (stored at higher conc./g than CHO)
 Source of heat, insulation, body protection (cushioning)
 Essential fatty acids (immune function, anticancer link?)
 4. Proteins
 Most expensive ingredient in ration, need decreases as animal matures
 Source of Essential Amino Acids (number, type and level of amino acids required
varies with animal species)
 Functions -- basic structural unit, needed in metabolism, hormone, antibody and
DNA production
When fed in excess, converted to energy, fat
5. Minerals
Two classes
 Major minerals -- Ca, P, Na, Cl, Mg, K, S
 Minor (Trace minerals) -- Co, Cu, F, I, Fe, Mn, Mo, Se, Zn
 The need for supplementation of minor minerals such as Se and F varies
with the region
Functions -- skeleton, protein synthesis, oxygen transport, fluid and acid-base balance
in body, enzyme reactions
Mineral/mineral and vitamin/mineral interactions
 Ca - Vitamin D
 P - Vitamin D
 Co - Vitamin B12
 Se - Vitamin E
Both deficiencies and excesses can lead to disease
6. Vitamins
Two classes
Water soluble -- B & C
Fat soluble -- A, D, E, K
Functions -- most vitamins have multiple functions in body involving metabolism,
enzyme reactions, etc.
 Requirements increase with age
 Both deficiencies and excesses lead to disease
Factors influencing the food intake:
Nutritional problems may stem from physical conditions, drugs, diet, or life style factors.
physical conditions:
1. Chronic illness (diabetes or neurological, cardiac, or thyroid problems)
2. Family history of diabetes or heart diseases 3. draining wounds or fistulas
4. Obesity or a weight gain of 10% above normal weight.
5. Unplanned weight loss of 10% below normal weight.
6. History of or recent GI disturbance
7. Anorexia or bulimia
8. Depression or anxiety
9. Severe trauma
10. Recent chemotherapy or radiation therapy
11. Physical limitation (paresis or paralysis)
12. Recent major surgery
13. Pregnancy, especially teen or multiple births
Drugs and diet
1. Steroid, diuretic, or antacid
2. Mouth, tooth, or denture problems
3. Excessive alcohol intakes
4. Strict vegetarian diet
5. Liquid diet or nothing by mouth for more than 2 days
6. Polypharmacy
1. Lack of support from family and friends
2. Financial problems
3. Isolation or homebound status
The role of diet in healthy status:
Nutrients play a role in maintaining health and wellness. They have several important functions
1. Providing energy which can be stored in the body or transformed for vital activities
2. Building and maintaining body tissue
3. Controlling metabolic process such as growth, cell activity, enzyme production, temperature