1 healthy balanced diet

Question 1

what are the components of a healthy balanced diet?

Answer 1

Macros: cho, protein, fats micros: vitamins and minerals fibre water

Question 2

what are the classifications of CHO?

Answer 2

• mono and disaccharides (sugars) - oligosaccharides: inulin, 3-9 degree of polymerisation - polysaccharides : starch and non starches (NSP)

Question 3

what are the functions of CHO?

Answer 3

1. energy source (TCA and glycolysis) 2. fuel for CNS (120g/day brain) 3. control of blood glucose and insulin metabolism 4. satiety and gastric emptying 5. cholesterol and triglyceride metabolism 6. fermentation and control of colonic epithelial cell function 7. bowel laxation/ motor activity

Question 4

what is the concept of glycemic index?

Answer 4

allows quantitative comparison of blood glucose response to ingestion of equivalent amounts of CHO from different foods relative to pure glucose (GI= 100)

Question 5

examples of low GI foods and GI

Answer 5

GI <55 muesli, legumes, oats, fructose, apples

Question 6

examples and high GI foods and GI

Answer 6

GI > 75 white bread, instant mashed potatoes correlation with diabetes

Question 7

what is the glycemic load

Answer 7

determines whether a diet is high or low GI depends on CHO content as well Total carbohydrate content is not detrimental to diseases- more to do with type of carbohydrate

Question 8

state the dietary recommendations of CHO

Answer 8

up to 50% of daily intake of total energy no more than 5% of calorie intake from free sugars - no more than 30g a day of added sugar >11 years daily intake fibre 30g

Question 9

what are the types of dietary fibre

Answer 9

Soluble: pectin, beta glucans. forms gel, slow digestion insoluble: cellulose, adds water and bulks so good for constipation (plants and wholegrains)

Question 10

functions of fibre

Answer 10

1. bulking effect- speeds up colonic transit time- constipation and cancer (carcinogenic compounds) 2. decreases cholesterol- dietary fibre changes secretions of bile acid, modifies glyceamia and insulinea 3. fermentation- produces SCFA (butyrate, acetate and propionate) - fuel for colonocytes - acetate and propionate absorbed by hepatic portal vein, used as energy in liver - maintains healthy bowels

Question 11

define vitamins

Answer 11

organic substances required in small amounts for normal metabolism but cannot be synthesised by body in sufficient quantities

Question 12

water soluble vitamins

Answer 12

1. intermediary metabolism (coenzymes): thiamin, nicotinic acid, riboflavin, panthothenic acid 2. anaemia preventing: B12 and folate 3. antioxidants: vit C and E

Question 13

why is B12 and folate important?

Answer 13

needed for thymidylate synthesis, DNA synthesis

Question 14

B12 deficiency

Answer 14

megaloblastic anaemia, neuropathy (myelin sheath) intrinsic factor to allow B12 to be absorbed- same protein that secreted from cells that secret Hcl gastric acid so anything that limits this would affect, binds to B12 to be absorbed; atrophic gastritis- functional deficiency- common in older people

Question 15

folate deficiency

Answer 15

anaemia, neural tube defect, green veg

Question 16

Methionine synthetase

Answer 16

B12 dependent enzyme which catalyses a reaction that yields free folate in tissues via methylation of homocysteine to methionine provides link between physiological functions of B12 and folate • Danger that consume enough folate but if less B12 than there is neuropathy Deficiency of B12 would effect folic acid deficiency (functional if the enzyme has an issue

Question 17

actions of vitamin D

Answer 17

1. intestinal absorption of calcium and phosphorous 2. renal absorption of calcium and phosphate 3. neuromuscular and immune functions, apoptosis and inflammation (VDRs (receptors) form dimers with RXR (retinoid X receptor- related to vit A)& regulate gene expression)

Question 18

low levels of plasma Ca

Answer 18

PTH stimulated and vitamin D synthesis activated vitamin D increases intestinal Ca absorption and regulates Ca excretion from kidneys and bone

Question 19

high levels of plasma Ca

Answer 19

calcitonin secreted from thyroid gland, promotes Ca excretion and prevents bone releasing Ca

Question 20

Answer 20

Through heat isomerisation

Hydroxylation in liver -> storage in adipose tissue and main transport

Hydroxylation in kidney -> active form of vit D

calcidiol form measured in blood

Question 21

vitamin d deficiency

Answer 21

rickets (child) and osteomalacia (adults- de mineralisation of bone)

Question 22

vitamin d toxicity

Answer 22

nausea, loss of appetitie, headache, abdo pain

hypercalcemia

Question 23

what is iron needed for?

Answer 23

1. electron transport chain
2. Hb in RBC
3. cytochrome P450

Question 24

dietary sources of vitamin D

Answer 24

supplements, oily fish,

Question 25

define minerals

Answer 25

inorganic elements needed for physiological functions in body. must be supplied by diet

calcium and iron

Question 26

dietary sources of iron

Answer 26

10% haem- meat

90% non-haem- veg

Different absorption mechanisms into mucosal cells

Absorption approx. 10% intake, can be up and down regulated (15-35 haem, 1-90 non-haem)

Absorption: only in ferrous form so enhanced by reducing agents (eg. Ascorbic acid)

Question 27

enhances and inhibitors of iron absorption

Answer 27

Enhances:

D: Vit C, fructose, alcohol, meat

P: Fe deficiency and anaemia. Pregnancy

Inhibitors:

D: Tannins (tea and coffee), polyphenols, phosphates, phytates, bran, lignin, other minerals (Ca etc)

P: Fe overload, Cu deficiency