56. Physiological basis of nutrition, essential nutrients Flashcards
What is rational nutrition
The supply of foods adequate to the energetic and synthetic needs of the body
That secure a good health, welfare and physical performance of the individual and future generations
what does an optimal diet include
intake of calories, proteins, lipids, carbohydrates, water, minerals, microelements, vitamins
What is the energy liberated from the complete oxidative breakdown of 1g carb to carbon dioxide and water
4.1 kcal (17.15 kJ)
What is the energy liberated from the complete oxidative breakdown of 1g of fats
9.3 kcal ( 38.91 kJ)
What is the energy liberated from the complete oxidative breakdown of proteins to carbon dioxide, urea and water
4.35 kcal 1(8.20 kJ)
Since the absorbtion of the substances vary in gastointestinal tract, what is the avergae physiologically available energy per gram
Carb:fats:proteins
4:9:4
What are the major principles of rational nutrition
- Energy intake with food should correspond to the energy requirements of the body
- It is based on the principle of proper nutrient balance
3.The daily menu should provide the required amounts of vitamins, water, minerals, microelements, fibres
- Rational nutrition presumes a proper daily plan of food intake distribution - number of meals, mealtimes etc
Principles of rational nutrition: 1
It should be enough to maintain basal metabolism and physical activity
Including increased energy needs for growth, prgenancy, lactation, bod building
Its different for diff genders, age and level of physical activity
Principles of rational nutrition: 2
Food should contain basic nutrients= P:F:CHO
Ratio of P:F:CHO= 1:1:4
CHO increased to 5/6 in intensive physical activity
How much protien should be from animal origin
40-60%
How much fats should be from plant oriign
33%
Principles of rational nutrition: 3
ceratin vitamisn and microelements have upper limits - hypervitaminosis id exceeded
Vit A= 5000 IU
Vit D=400 IU
thiamine=1.5 mg
riboflavin=1.8 mg
niacin=20 mg
Ascorbic acid = 45 mg
Vit k 70 mg
Principles of rational nutrition: 4
Need variety of foods from all 7 basic food groups
Take into account amount of food (satietyand fiber), quality of food ( health) cooking (depends on family)
Where are protiens broken down and what into
broken down in the lumen of the digestive tract
Into amino acids
What do cells use proteins for
synthesis of enzymes,transport protiens, hormones, cell membranes, antigens, antobodies
What is the average half life of body proteins in the body
Half life= rate of synthesis and degradtion of proteins
average = 80 days
The essential amino acids are those that need to be taken up via diet. What are they
histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine
What are first class proteins and second class proteins
first= proteins of animal origin and contain all essential amino acids
second= proteins of plant origin, dont contain all essential amino acids
What is the required protein intake of adults
protein of animal origin: 0.75g/kg
protein of mixed origin; 0.9g/kg
if protien intake is low in essential amino acids,the amount of protein eaten is larger
Does protein demands decrease with age?
no
]although energy requirements decrease, protein requirement does not
Who may have a greater demand for protein in food
adolescents
during disease and injury
heavy physical workers and athletes
In additioon to enery, what other properties does carbs have
structure forming-glycosaminoglycans are part of intracellular matrix
cell membrane composition- glycoproteins
What is the main energy source for our body
Carbohydrates
What are the classes of carbs in food
simple= glucose, fructose, gaalctose, lactose maltose
complex= starch, cellulose, glycogen, pectin
What is the main difference btw simple and complex carbohydrates
simple sugars are assimilated more rapidly and cause an abrupt rise in concentration of glucose therefore increased insulin in blood
the digestible carbohydrates are broken down in the lumen of the digestive tract into monosaccharides
which carbohydrates are not
cellulose and hemicellulose
What % should carbohydrates be part of the body daily energy requirement
55-63%
Why should a minimum amount of carbohydrate be present in diet
brain cells use only glucose as enery source
Why are carbs known as protein sparing compounds
Excess carbs stored as fat reserves
Foods richest in carbohydrates
grains, fruits, veg
Carb content LOWER in animal orgin= milk, glyogen from meat
What are fibers
indigestible plant polysacchrides and other types of iopolymers
they pass along the small intestine and absorb water, toxic/carcinogenic substances, heavy metals,
What are the main dietary fibers
cellulose, hemicellulose, pectins, gus,lignins
What is the beneficial effects of fibers
their ability to increase the volume and rate of intestinal contents passage
reduces the stay of fecal masses in colon
Amount of fiber needed by an adult
16-24g/day
main sources are cereal seeds, root veg,cauliflower, broccoli legumes
What does dietary fats consist of
triglycerols, cholesteral, holesterol esters, phospholipuids, liid soluble votamisn
As well as energy what else is lipids used for
cell membranes, synthesis of hormones, bile salts, vit D
How are fats classified
unsaturated= double bonds (veg fats)
Saturated= no double bonds (animal fats)
What are essential fatty acids
Important for normal growth of children and animals
They are polyunsaturated fats- omega-3 fatty acids and omega-6 fatty acids
Not synthesied by body cells
What is the main omega-3 fatty acid
a-linolenic acid
Eicosapentaenoic acid and docosahexaenoic acid are synthesied from this
The latter imp for development of brain-phospholipds in brain, synatic transmission
Also precursors of eicosanoids-functional regulators
Fats daily energy intake
25-30%
saturated= less than 10%
polyunsaturted=3-7%- potential source of free radicals
cholesterol=less than 300mg
Where is cholesterol found
ONLY in animal products=egg yolk, butter, meat
What fats are high in essential fatty acids
fish oil and veg fat
