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Definition of Nutrition

Processes involved in eating and using food to provide energy for the functions of our organs, for the movement of our body, also helps in maintenance of body temperature, provides raw material for the functions of enzymes for growth, for cell replacement, for the repair of cells and tissues

What nutrition is:

What we eat and how our body uses the food

Nutrition important:

- In prevention of disease
- In healing process

5 basic processes involved in body's use of nutrients:

- Ingestion
- Digestion
- Absorption
- Metabolism
- Excretion

INGESTION

Food taken into digestive tract
Orally
Feeding tubes
- NG
- GT

DIGESTION

Breakdown of foods into simpler forms for absorption

Mastication (chewing), churning, mixing

Food w/ enzymes and saliva
- Chemical breakdown of food taking place

Hormones

Control flow of digestive juices

Enzymes

Protein like substances act as catalysts to speed up biochemical reactions
- Essential for digestion to take place

Deglutition - esophagus - peristalsis - stomach

-Digestion begins in mouth, once food chewed/swallowed (Deglutition) then enters esophagus, moved along by peristaltic waves, enters stomach where remain for varying amounts of time (around 3 hours)
-Length of time in stomach depends on:
Type of food eaten, gastric motility, psychological influences

Chemical digestion

Carbs, proteins, fats
Make nutrients available for absorption

Chyme

Food leaves stomach as acid, liquified mass

Chyme flows into

- duodenum and continues to move along by peristalsis in small intestine mixing w/ secretions
- Major portion of digestion takes place in small intestine

ABSORPTION

- End products of digestion
- Pass through small intestines membranes where absorbed by blood and lymph system

Intestinal contents move by peristalsis into large intestine

- Water absorbed through membrane
- Rest of intestinal contents excreted as waste products

METABOLISM

- Process of converting nutrients into energy by the body
- Sum total of all chemical reactions that occur in living cells

2 Processes of Metabolism

Anabolism
Catabolism

Anabolism

build-up
- Production of more complex chemical substances
- Occurs by combining nutrients
- Results in formation of new tissue
- Requires energy
- Occurring continuously in body

Catabolism

break-down
- Breaking down of chemical substances into simpler substances
- Produce some energy but requires energy to do process

In healthy adult

Rate of catabolism = rate of anabolism

Metabolic rate

- Rate of energy utilized by the body
- Usually expressed in calories

Calorie

Amount of heat required to raise temperature of one gram of water by one degree Celsius

Kilocalorie

- Represents energy values of food
- Each kilocalorie = 1000 calories

Basal Metabolism

Amount of energy required to maintain physiological functions for involuntary activities of the body when body at rest
- Respirations, circulation, muscle tone

Basal Metabolism influenced by body composition

- Lean tissue require more calories to maintain than someone w/ more fat tissue
- Loss of lean tissue as age (esp women) one reason why energy requirements decrease as ppl get older - bc losing lean tissue
- Decrease in thyroid hormones - also cause lower rates of metabolism
- Increase in thyroid hormones - increase rate of metabolism

EXCRETION

Removal of waste material from the body

Physical indicators of sound nutrition:

- Alert, responsive
- Weight normal
For height, age, and body build
- Good posture
No malformations in posture
- Well developed muscles
Firm, good tone
- Good attention span, normal reflexes, psychological stability
- Good appetite, digestion, regular elimination
- Normal heart rate, rhythm, BP
For age
- Sleep well, energetic
- Shiny, lustrous hair, healthy scalp
- Smooth, moist skin - good color
- Pink oral membranes
No swelling
No lesions
- Eyes bright, clear
- Nails firm, pink

Physical indicators of inadequate nutrition:

- Listless, apathetic
- Overweight, underweight
- Poor posture
Hunched, slouching
- Flaccid, poor muscle tone
- Inattentive, irritable, confused
- Anorexia, indigestion, constipation, diarrhea
- Rapid heart rate, abnormal rhythm, elevated BP
- Fatigued, no energy
Fall asleep easy
Feel tired
- Stringy, dry, brittle thin hair
- Rough, dry, pale skin
- Oral membranes swollen
Gums inflamed
- Eyes dull, pale, dry
- Nails brittle

Nutritional History Components

- Food allergies
- Physical activity
Amount, level
- Cultural, socioeconomic, religious restrictions
- Personal preferences
What foods like/dislike
- Psychological factors
- Perception of food
- Alcohol and drug use
- Food fads or concerned w/ diets

METHODS TO OBTAIN NUTRITIONAL HISTORY

- 24 - hour recall
- Food-frequency questionnaire
- Food record
- Diet history

FACTORS INFLUENCING NUTRITION

- Culture
- Religion
- Socioeconomic
- Fads
- Superstitions
- Preferences

Nutrients

- Chemical substances supplied by food
- Body needs for growth, maintenance and repair

6 classes of nutrients:

- Carbohydrates
- Fats
- Proteins
- Vitamins
- Minerals
- Water

Simple Carbohydrates "sugars"

Monosaccharide
Disaccharide

monosaccharide

"one glucose molecule"
- glucose
- fructose
- galactose
Absorbed without undergoing digestion, used immediately as energy or stored as glycogen

glucose

(dextrose)
- fruit, vegetables, honey, corn syrup

fructose

(fruit sugar)
- fruit, honey

galactose

- Not found in appreciable amount in food
- Combined w/ glucose to make Lactose

Disaccharide

"two sugar molecules"
- sucrose
- maltose
- lactose
In order to be absorbed, must be separated into monosaccharide components through digestion first

sucrose

(table sugar)
- We refer to as sugar
- Formed from glucose and fructose

maltose

- two glucose molecules
- not normally found in food

lactose

(milk sugar)
- Glucose and galactose combined
- Found naturally in milk
- Enhances absorption of calcium
- Promotes friendly growth of bacteria in intestines to produce vitamin K

1 tsp of sugar

4 grams

Complex Carbohydrates "starches"

Polysaccharides "many sugars"

polysaccharides

- starch
- glycogen
- fiber

starch

- storage form of glucose in plants
- most abundant in grains, legumes, starchy vegetables - corn, potatoes

glycogen

- carbohydrate made in liver, stored in liver and muscles
- used between meals to maintain blood glucose levels and to provide fuel for tissues
- glycogenisis
- glycogenolysis
- glucose metabolism depends on insulin

glycogenisis

process of converting glucose to glycogen

glycogenolysis

process of changing glycogen back to glucose

insulin

pancreatic hormone used by cells to produce energy and for the liver to produce and store glycogen

fiber

- roughage, residue
- body unable to break down fiber
eliminated as waste material
- insoluble fiber
- soluble fiber
- dietary fiber has no nutritional benefit because body cannot digest but does aid in elimination - adds volume to stool, helps lower blood cholesterol

insoluble fiber

does not dissolve in water
- includes cellulose - holds water, aids in prevention or release of constipation
- sources: whole grains, wheat bran, legumes, vegetables, skins of fruit, shell of corn kernels

soluble fiber

- includes gum, pectins, etc.
- slows gastric emptying and movement of chyme through intestines
- delays absorption of glucose from small intestines
- helps lower blood cholesterol
- sources: fruits, oats, barley, legumes, broccoli

complex carbs digested more slowly than simple carbs

also supply body w/ energy for a longer period of time

digestion of carbs

- Mix w/ salivary enzyme ptyalin
- Little digestion occurs until reaches small intestine
- >Pancreatic and intestinal enzymes break down carbs
- >Breaks down complex carbohydrates then used completely by body

absorption of carbs

- Glucose, fructose, galactose - absorbed through intestinal mucosa cells
- Travel to liver - converted into glucose

metabolism of carbs

- Glucose released into bloodstream - move into cells (to meet energy needs)- stored in liver (as glycogen) - remaining glucose converted to fatty acids and stored as fat

Daily requirements of carbohydrates

- 50-60% total calories per day
- Each gram = 4 calories

deficiency of carbs

- Mild - result in fatigue, weight loss
- Significant - causes ketosis = abnormal accumulation of ketones (chemical compound)
- Ketosis often seen in diabetics, ppl who suffer from starvation
Can lead to coma, or death
Serious abnormality

excess carbs

- obesity - stored as adipose tissue

PROTEINS

- Composed of amino acids (building blocks)

- Organic compounds made up of hydrogen, carbon, oxygen, nitrogen

- Contained in every living cell

2 types of amino acids:

- essential amino acids (9)
- non-essential amino acids (11)

essential amino acids

- 9
- cannot be made by the body
- must be consumed through food

non-essential amino acids

- 11
- can be produced in liver if nitrogen and other precursors are available

in order for the body (cells) to produce proteins it needs/must have

20 amino acids

all tissues and fluid contain protein except for

urine and bile

FUNCTIONS OF PROTEINS

1) Needed in order for body to grow, repair itself, maintain structures
2) Facilitate specific chemical reactions in body
- Enzymes are proteins
3) Regulate specific body processes
- Hormones: insulin; neurotransmitters: serotonin; antibodies
4) Regulate fluid balance
- Attract water
- Albumin - not enough = edema
5) Acid-base balance
- Amino acids both acid and base so can regulate the pH
6) Transport other substances through blood
- Hemoglobin - transports oxygen
7) Provide energy (gluconeogenesis - convert amino acids to glucose) especially if carbs and fats are inadequate

digestion of proteins

- Chemical digestion of proteins begins in stomach when hydrochloric acid converts to pepsinogen and then enzyme pepsin
Pepsin in turn breaks down protein
- Most of digestion in small intestine
Pancreatic and intestinal enzymes reduce proteins to amino acid

absorption of proteins

- Proteins reduced to amino acids - amino acids absorbed through mucosa lining of small intestine
- Released into blood stream - transported to liver

metabolism of proteins

- Liver uses amino acids it needs, releases amino acids needed elsewhere in body, store the rest as glucose, glycogen, or fat
- Body not able to store amino acids

PROTEIN SYNTHESIS

- Complicated efficient process in which amino acids are assembled in order to create proteins needed by body

- Ability to replicate specific proteins in the body is determined through genetic codes contained in DNA

- Proteins either break down (Catabolism) or will be built up (Anabolism)

NITROGEN BALANCE

Cells continuously make proteins to replace those proteins broken down/lost through catabolism

Say that body is in neutral nitrogen balance:

- When amount of protein made during anabolism = amount of protein lost in catabolism
- Healthy adults should be in neutral nitrogen balance

positive nitrogen balance

- When production of protein greater (anabolism) than amount of protein broken down (catabolism)
- Examp: during pregnancy

negative nitrogen balance

- When protein breakdown exceeds protein production
- examp: starvation
- undesirable state

DAILY REQUIREMENTS OF PROTEINS

Determined by the body according to amount of protein needed to maintain neutral nitrogen balance

Factors determine amount of protein needed by body:

- age
- gender
- growth
- body weight
- muscle mass
- pregnancy
- stress
- infection
- healing process
- factors increase need for more protein by body

who requires a protein restriction

people with liver disease and renal failure because they cannot excrete nitrogenous waste material

daily requirements of protein

15-20% total calories per day

1 gram of protein

4 calories

sources of proteins

- complete proteins
- incomplete proteins
- complimentary proteins

complete proteins

- Those that provide all 9 essential amino acids so body can maintain tissues and growth
- All animal sources except gelatin
- Soy protein (plant protein)

incomplete protein

- Proteins in which one or more of essential amino acids is missing
- All plant proteins except soy protein

complimentary protein

- Combination of two incomplete proteins or small amount of complete protein combined with and incomplete protein so that there are sufficient quantities and proportions of all 9 amino acids

Fats (lipids) composed of:

carbon, hydrogen, oxygen

fats are a group of water-insoluble organic compounds including

- triglycerides (fats, oils)
- phospholipids
- sterols (cholesterol)

all fats contain a mixture of

saturated, monounsaturated, and polyunsaturated fatty acids

types of fats

saturated
unsaturated

saturated fat characteristics

- solid at room temp
- high melting point
- more stable than unsaturated fats - less likely to become rancid
- animal in origin except for tropical oils (cocoanut, palm)

unsaturated fats

characteristics:
- soft or liquid at room temp
- low melting point
- susceptible to rancidity when exposed to light, oxygen, or prolonged period of time
- predominately found in plant fats and oils, except tropical oils

unsaturated fats can be further divided

monounsaturated
polyunsaturated

visible fat

fat that surrounds piece of steak, butter

not visible fat

fat found in cheese, cookies, baked goods, etc.

sources of fat

animal fat
- lard, egg yolks, milk
- account for 57% total fat intake
vegetable fat
- plant oils (corn, safflower), nuts
- account for 43% total fat intake

transfatty acids

- Commercially baked goods, fried foods, hard margarin/shortening, crackers, biscuits, some cake mixes, candy, animal crackers/cookies, frozen waffles/pancakes, popcorn
- Look at labels

Functions of fat

- provide us with energy (carbs main source)
- support and protect internal organs
- assist w/ temperature regulation - insulation
- necessary for absorption of fat-soluble vitamins

digestion of fat

- Little occurs in stomach - most occurs in small intestine
- Bile released by gal bladder - helps prepare fat for digestion
- Pancreatic enzymes assist w/ digestion of fat
- End products of fat are fatty acids and glycerol

absorption of fat

- Most absorbed into small intestine (95%)
Some escape digestion - excreted in feces
- Cholesterol absorbed as is
Does not undergo digestion

storage of fat

- not immediately needed by body stored as adipose tissue

lipoproteins

- VLDLs: 50% triglycerides (true fat)
- LDLs: 50% cholesterol (bad cholesterol)
- HDLs: 50% protein (good cholesterol)

daily requirements of fat

- no more than 20-25% caloric intake per day

1 gram of fat

9 calories

VITAMINS

- Organic compounds made of: Hydrogen, carbon, oxygen, and sometimes nitrogen or other elements

- Promote biochemical reactions within cells to assist in regulating body processes such as growth and metabolism

- Essential to life/Need vitamins

vitamins may be susceptible to destruction and loss of function

- Susceptible to light, heat, alkalize, etc.
- Come in bottle where light cannot get to them

types of vitamins

- fat-soluble
- water-soluble

fat-soluble vitamins

- Vitamins A, D, E, K
- Absorbed with fat into lymph system
- Attach to protein characters so they can be transported through the blood
- Stored in liver and in adipose tissue when in excess - not excreted
- Toxic when large doses consumed - toxicity
Vitamin A, D
- Do not have to be eaten daily
Can be taken from storage
- Found in fat and oil portion of food

Function of Vitamin A

Night vision; growth; development bones and teeth; maintain skin and membranes; immune function

Function of Vitamin D

- Maintains serum calcium concentrations; needed for absorption of calcium and phosphorus
- Important for women - calcium & vitamin D to prevent osteoporosis

Function of Vitamin E

Antioxidant; protects cell membranes; protects RBCs from breaking down

Function of Vitamin K

Production of blood-clotting protein - prothrombin

ABSORPTION AND STORAGE OF FAT SOLUBLE VITAMINS

Absorbed into lymphatic system

Vitamin A:

- Body can store large amounts
- Vitamin A deficiency: major cause of blindness
- Toxicity: occurs from megadoses
- Food sources: green leafy vegetables, deep yellow and orange fruits and vegetables rich in beta-carotene (carrots)

Vitamin D:

- Produced from cholesterol and ultraviolet light
- Needed for calcium to be absorbed
- Deficiency: blood calcium levels fall - bones lose minerals
Calcium needed for heart to work properly
- Increase: blood calcium levels increase - kidney damage
- Toxicity: occurs when taking supplements
More likely to produce toxic symptoms than others
- Food sources: liver, fatty fish, egg yolks, fortified in milk, cereal, margarine

Vitamin E

- Deficiencies: rare, except in chronic fat malabsorption syndromes
- Can interfere with action of vitamin K in blood clotting by decreasing platelet aggregation
- Large doses potentiate effects blood-thinning drugs
- Food sources: vegetable oils, margarine, salad dressings

Vitamin K

- Quickly depleted when requirements not obtained
- Deficiency: results in hemorrhaging
- Food sources: green leafy vegetables (broccoli), liver, milk, produced by bacteria

WATER-SOLUBLE VITAMINS

- Vitamin C, B-complex
- Absorbed directly into bloodstream
- Move freely through watery environment of blood, within cells
- Excreted in urine when in excess
Consume daily - have to (unlike fat-soluble)
- Release into water when foods cooked, lost if water discarded

Function of Vitamin C

Promotes formation of collagen (protein) which results in building and maintaining strong tissues; promotes iron absorption, promotes wound healing, assists in resisting infection

Function of Thiamine (B2)

Promotes energy metabolism, nervous system functioning

Function of Riboflavin (B2)

Promotes energy metabolism, promotes production of DNA, assists production of proteins

Function of Thiamine (B3)

Promotes energy metabolism, aids tissue protein building, aids oxidation, promotes normal nervous system functioning

Function of Vitamin B6

Amino acid and fatty acid metabolism, promotes blood formation, maintains nervous tissue

Function of Folate (Folic Acid)

Vital for new cell production and transmission of inherited characteristics, prevention neural tube defects, promotes amino acid metabolism, promotes formation of RBC & WBC

Function of Vitamin B12

Activates folate, production of DNA, promotes blood formation, promotes normal functions of cells especially nervous system

Function of Pantothenic Acid

Promotes energy metabolism

Function of Biotin

Involved in energy metabolism, necessary for glycogen formation

ABSORPTION AND STORAGE OF WATER-SOLUBLE VITAMINS

Absorbed directly into the blood stream and excreted in urine

Thiamine

- Deficiency: beriberi - disease of peripheral nerves
Causes fatigue, diarrhea, weight loss, anorexia, paralysis, etc.
- Deficiency seen in alcoholics
- Food sources: whole grained and enriched breads and cereals, liver, dried peas and beans, nuts

Riboflavin

- Deficiency: rare
- Food sources: milk, dairy products, whole grain and enriched breads and cereals, eggs, green leafy vegetables

Niacin

- Deficiency: pellagra - metabolic defect
- Toxicity: liver damage and gout
- Food sources: all protein foods, whole grain and enriched breads and cereals

Vitamin B6

- Deficiency: uncommon
- Toxicity: infrequent
- Food sources: means, fish, poultry, dried peas and beans, fruits, green leafy vegetables, whole grains, nuts

Vitamin B12

- Only water-soluble vitamin not found naturally in plants
- Deficiency: years to develop symptoms - pernicious anemia - injections of Vitamin -B12 = cobalamy given IM z-track
- Food sources: all animal foods, some cereals

Folate

- Deficiency: alcoholics at risk, due to effect of alcohol on GI system
- Infants, adolescents, pregnant women difficulty consuming adequate amounts
Due to growth of new tissue
- Food sources: green leafy vegetables, dried peas and beans, seeds, liver, orange juice, enriched bread and grain products

Pantothenic Acid

- Deficiency: none
- Food sources: meat, fish, poultry, whole grain cereals, dried peas and beans

Biotin

- Deficiency: long term TPN usage - Total Parenteral Nutrition
- Given through IV
- Food sources: eggs, liver, yeast breads, cereals

Vitamin C

- Most famous vitamin - thought to lessen cold symptoms
- Deficiency: scurvy
- Toxicity: diarrhea and GI disturbances, excessive iron absorption
- Food sources: citrus fruits and juices, peppers, broccoli, kiwis, strawberries, tomatoes

MINERALS

- Inorganic elements, originate from earth's crust

- Accounts for 4% of total body weight

- Found in body fluids and tissues

Types of Minerals

- Major Minerals
- Trace Minerals
- both types necessary for life

Major Minerals

- Present in amounts of greater than 5 g
- Needed in relatively large amounts
- Calcium, phosphorus, magnesium

Trace Minerals

- Present in body in amounts less than 5 g
- Only needs small amounts
- Iron, iodine, zinc, selenium, copper, manganese, fluoride, chromium, molybdenum

minerals present in body - potentially harmful

mercury, gold, lead

minerals are not destroyed by

light, air, heat or acids during food preparation
- lost only when food soaked in water

Calcium

- Needed for bone and teeth formation, muscle contraction and relaxation, blood clotting, nerve transmission, promotes normal cardiac rhythm, needs Vitamin D for absorption
- Deficiency: osteoporosis, impaired growth - rickets, tetany diseases
- Toxic effect: kidney stones
- Food sources: milk, dairy products, green leafy vegetables, whole grains

Phosphorus

- Needed for bone and teeth formation, regulates acid base balance, metabolizes energy, provides structure to cell membranes
- Deficiency: rare
- Food sources: animal proteins, soft drinks, additives

Sodium

- Regulates fluid balance, regulates cell permeability, regulates nerve transmission
- Deficiency: results from prolonged vomiting or diarrhea or renal disorders
- Toxic effect: hypertension, cardiovascular disturbance, edema
- Food sources: table salt, milk, processed foods

Potassium

- Maintain fluid balance, acid base balance, transmit nerve impulses, regulate muscle activity, aid in production of proteins, carbohydrate metabolism
- Deficiency: muscle cramps, fluid and electrolyte imbalance, cardiac weakness
- Toxic effect: muscle weakness, mental confusion, cardiac disturbances, cardiac arrest
- Food sources: bananas, orange juice, vegetables, coffee, red meat, milk

Iron

- Aids in formation of hemoglobin - transport oxygen, aids in antibody formation
- Deficiency: anemia
- Toxic effect: hemochromatosis - too much iron in blood
- Food sources: animal sources and plant sources

Iodine

-Component of thyroid hormones
- Deficiency: cretinism, goiter
- Toxic effects: hyperthyroidism, death
- Food sources: table salt (iodized), milk

Zinc

- Needed for tissue growth and wound healing, sexual reproduction and maturation, ensures normal taste and smell, component of DNA and RNA
- Deficiency: poor wound healing, growth retardation
- Toxic effect: renal failure
- Food sources: meat, oysters, eggs, milk, whole grains

Fluoride

- Formation and maintenance of tooth enamel, resistance to dental decay, contributes to bone formation
- Deficiency: dental decay, osteoporosis
- Toxic effect: mottling of teeth - white/yellow patches - too much in water
- Food sources: fluoridated water, seafood, tea

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