N- Nutrition! + Dental relevance Flashcards
What is nutrition?
sum of processes for living organism to receive and use materials from environment to promote its own vital activities.
What are nutrients?
- substances digested, absorbed, promote body function
* carbohydrate, fat, protein, vitamins, minerals, water
What are essential nutrients?
substance necessary for life, cannot be synthesised by body, must be in diet.
Basic role of carbohydrates
Heat and energy
Basic role of proteins
tissue formation and repair
broken down to produce energy
Basic role of fats
Heat and energy
incorporated into body tissue
Vitamins and Minerals function
for regulation of body processes incorporated into tissue (minerals)
Water basic role?
> fluid medium essential for metabolism
temperature regulation
waste product excretion
What does COMA stand for?
Committee on Medical Aspects of Food Policy - give reference values for food energy/nutrients
> estimated average requirement (EAR)
reference nutrient intake (RNI)
What does SACN stand for?
Scientific Advisory Committee on Nutrition
Advises PHE etc., on nutrition and related health issues
Name 3 forms of carbohydrates
Foods of plant origin e.g. grain, fruit, vegetables
Monosaccharides (simplest form) e.g.
glucose, fructose, galactose
Disaccharides (pairs) e.g.
sucrose, lactose, maltose
Polysaccharides, complex form e.g.
starch (amylose [straight chain] and amylopectin [branched])
What are Non-starch polysaccharides (NSPs) ?
From- plant cell walls
Found in: cereal, veg, fruit
Dietary fibre! Not digested…
Advantages of NSPs?
- Bulky
- Full feeling; Stays in stomach for longer
- Prevents constipation
- Prevent colonic cancer?
Disadvantages of NSPs?
- Binds to minerals (Ca, Fe) -> deficiencies
-Wind from metabolism of NSP in caecum and colon:
methane, CO2, H2
-Depending on type of NSP and bacterial flora
- insufficient energy intake: bulky, takes longer to eat
Liver digestion of carbohydrates- 3 fates:
1- Metabolism for energy
2- converted to glycogen: stored in muscles and liver
3- converted into fat: when glycogen stores are full
What is the Glycaemic index ?
(GI 1-100): ranks carbohydrates
- Rate at which the CHO reaches bloodstream as glucose…
What is the optimal blood sugar level ?
3.5-10mmol/l
Low GI foods…
Slow and steady release of glucose
What % of energy intake should be carbohydrates?
40-80%
Advantages to carbohydrates
Foods cheap, plentiful, palatable, easy to prepare, low fat content
What is the free sugars recommendation?
‘Free’ term replaces Non-Milk Extrinsic Sugars (NMES) and
‘added’ terms
< 10% strong recommendation
(12 tsps/dy) total energy intake
< 5% conditional recommendation
Reduction throughout life course
Examples of Saturated fats
- Butter
- Cheese
- Full-fat milk
- Pizza
- Takeaways
- Pies
Examples of monounsaturated fats
- Olives
- Nuts
- Avocado
Examples of polyunsaturated fats
Omega 3- oily fish, soya bean
Omega 6- sunflower seeds, wheat germ, corn
Trans fatty acids (hydrogenated)
in frying and baking fats, baked goods, long shelf life;
Essential fatty acids- role? (2)
for structure and function of cell membranes
to regulate cholesterol metabolism
Sources of fat
- Meat
- Dairy
- Eggs
- Vegetable (olive, coconut oil)
What is cholesterol?
- from diet and synthesised in the body
- associated with animal tissues
Functions of fat
- energy for tissue activity and body temperature maintenance
- incorporated into body structure
e. g. brain + nervous tissue - hold position and protection of vital organs
- insulation (subcutaneous heat loss)
- satiety – presence in duodenum delays stomach emptying
- provide fat-soluble vitamins and assist absorption
How much % of energy intake is from fats
RNI in g/dy??
35%
70-95g/dy;
20-30g/dy sat fat.
Protein found in which foods?
- Meat (myosin)
- Fish
- Eggs (albumin)
- Cheese
- Milk
- Nuts
- Pulses: lentils, beans
- Cereals: wheat (gluten)
RNI for protein?
45-55g/dy
Protein function?
> replacement during metabolism and wear and tear
e.g. hair, nails, skin, digestive secretions,
bone, dentine, epithelium, antibodies
> new tissue production
e.g. growth, recovery from injury, pregnancy, lactation
> forming enzymes, hormones
> energy source
3 fates of protein
1- Structural proteins
2- Converted into other AAs
3- Oxidised for energy
What are minerals used for?
3% body wt
Essential constituents of soft tissues, fluids, skeleton, teeth
Incorporated into enzymes, proteins and soluble salts.
What % body wt is water
65-70% of body weight
Water function
fluid medium for almost all body processes.
body secretions, excretions
sufficient urine flow, prevention of constipation
joint lubrication
temperature control (lung and skin evaporation)
death after a few days
How is water lost
urine, faeces, sweat (lose salt), exhaling, vomiting, diarrhoea, haemorrhage, exudate from burns
How much water ?
2.5-3 l/day
Problems with too much water?
kidneys can’t keep up excretion
blood diluted, lower salt concentrations
water moves from blood to cells and organs
brain swells and prevents vital functions
How much energy from 1g of…
- Carbo
- Fat
- Protein
- Alcohol
1g carbo = 16kJ (4kCal), most efficient source
1g fat = 37kJ (9kCal)
1g protein = 17kJ (4kCal), takes time to turn into energy, needs
energy
1g alcohol =29kJ (7kCal)
What is Basal metabolism ?
amount of energy required for basic life processes e.g. heartbeat, respiration, cellular activity
what is a Healthy Balanced Diet?
Lots of fruit and vegetables (40%)
Starchy staple foods (wholemeal bread, wholegrain cereals; 40%,
incl B vits and fibre)
Protein rich foods (lean meat, fish, eggs, lentils)
Some dairy foods (pref. lower fat variety)
