Nursing - Nutrition

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)