Minerals: calcium / iron / fluride

Question 1

Calcium Functions

Answer 1

Bone structure
Nerve function
Blood clotting
Muscle contraction
Cellular metabolism

Question 2

Calcium Dietary recommendations

Answer 2

RNI 700 mg day

LRNI 400 mg day

Question 3

Calcium Food sources

Answer 3

1 portion Canned Sardines 390 mg >
1 cup Milk 225 mg > 40 g Cheese 290 mg >
20 g Almonds 50 mg > 1 portion Broccoli 72 mg

Question 4

Dietary sources of calcium

Answer 4

Dairy products (Ca levels not reduced when milk is skimmed)
Bread	 94-156mg Ca/100g flour
Green leafy vegetables
Canned fish
Hard water- 220mg Ca/day

Question 5

UK- daily intake for Ca

Answer 5

940mg men & 730mg women

Ca intake teenage girls low

Question 6

Ca absorption %

Answer 6

10-35% dietary Ca absorbed
absorption high from dairy products due to caesin and phosphopeptides

25-40% supplemental Ca absorbed
- CaCO3 and CaCM high absorption rates

Question 7

Ca absorption by which transport system

Answer 7

Passive transport system

- nonsaturable paracellular
- occurs when dietary Ca high
- predominant means in infants on milk

Active transport system-
Ca uptake by ECaC [epithelial Ca channels]
–> bind to CaBP9K [calcium binding protein calbindin D 9K] with aid of Vit D… (VitD increases calbindin synthesis)
–> transport Ca to PMCA [ plasma membrane calcium ATPase] with ATP used or NCX [Na/Ca- exchanger]
(both into plasme)

Question 8

Ca absorption efficiency highest in which part of gut

Answer 8

Duodenum & proximal jejunum-Ca

Question 9

Factors increased Ca absorption

Answer 9

Vit D & parathyroid hormone
[PTH does not influence Ca absorption directly but upregulates vit D synthesis in the kidney. PTH is released in response to low plasma Ca]

Ingestion with a meal
lactose
increased need (e.g. pregnancy)

Question 10

Factors decreased Ca absorption

Answer 10

oxalate- most potent inhibitor
phytate
fibers
rapid GI movement
very high fat diet/ fat malabsorption
excess P or Mg
age
menopause
decreased gastric acid 	(without a meal)
diseases such as coeliac disease, Crohn’s Disease

Question 11

which diets would increase Ca excretion

Answer 11

Very high protein diets , such as the Atkins Diet

Question 12

Regulation of Blood Calcium

Answer 12

Hormones

• Vitamin D
• Parathyroid hormone
• Calcitonin

Target tissues

• Small intestine
• Kidneys
• Bone

Question 13

if Ca lv too high

Answer 13

thyroid release calcitonin

• -> increase Ca deposition in bones
• -> decrease Ca uptake in intestine
• -> Decrease Ca reabsorption from urine
• -> Ca lv falls –> homeostasis

Question 14

if Ca lv too low

Answer 14

Para_thyroid release Parathyroid hormone [PTH ]

• -> increase ca release from bone
• -> increase Ca absorption from gut
• -> increase Ca reabsorption from urine
• -> increase Ca lv

Question 15

Bone Growth

Answer 15

Infant : 1% BW is Ca

Infrancy (1y) : Double bone weight = 400mg Ca/d

Childhood: growth slows 100mg Ca/ d

Pre-adolescene & puberty: growth spurt; 45% adult skeleton formed
10% increase bone Ca/ y

adolescence: 40% of adult skeleton formed

adult (18- 30y): bone growth slows, further 10% increase

adult (over 40y) : loss of bone

Question 16

Peak bone mass

Answer 16

~30- 35y
loss of bone after age 40 when bone minerals reabsorbed

major factor for osteoporosis risk in later life

Question 17

Peak bone mass factor

Answer 17

race/ gender/ genetics,
Ca, Vit D, protein, hormones (GH, PTH, calcitonin, sex hormones)
physical activity
anorexia nervosa

Question 18

Calcium deficiency

Answer 18

5 % UK women consume less than LRNI

Gambia:
Lactating women ~200 mg day
No increased risk of bone fracture

Question 19

Potassium recommendation

Answer 19

UK RNI 3500 mg day

Intake as a % of RNI: 
Men 96    (6 % below LRNI)
Women 76     (19 % below LRNI)

Question 20

roles of K in body

Answer 20

Major cellular cation:

• membrane potentials
• Osmotic gradients
• Water balance
• Active transport systems

Question 21

K Deficiency

Answer 21

Hypokaleamia

Question 22

Sodium Functions

Answer 22

Fluid balance

Nerve impulse transmission

Question 23

Na & Cl RNI

Answer 23

Salt RNI 4.1 g, LRNI 1.5g
Sodium RNI 1.6 g, LRNI 575 mg/day
Chloride RNI 2.5 g, LRNI 888 mg/day

Question 24

UK Na intake

Answer 24

Men 11g day

Women 8.3 g day

Question 25

Salt and associated disease

Answer 25

Gastric cancer:
Japanese, highest rates of gastric cancers

Hypertension:
Coronary heart disease
Haemorrhagic stroke

Question 26

Sodium and hypertension

Answer 26

Low Na lv –> low blood pressure

as population aged, % of hypertension increase exponentially

Question 27

reduction in sodium

Answer 27

• decreases insulin sensitivity
• disrupts aldosterone agiotensin and renin pathways
• very low intakes increase mortality in heart disease patients

Question 28

Factor affect Na sensitivity

Answer 28

After aerobic training, decrease Na sensitivity and increase Na resistant

Question 29

Sodium induced damage of which heart disease was found to be independent of blood pressure

Answer 29

hypertrophic cadiomyopathy

Question 30

reduction of salt can reduce how many % of stroke & CVD

Answer 30

a 23% reduction in the rate of stroke

a 17% overall reduction in the rate of CVD

Question 31

salt reduction has more potential benefits in which population ?

Answer 31

black women [ middle age > elderly] > black men [same] > non- black men (slight more) non- black women

Question 32

Sources of Dietary Sodium

Answer 32

75% in processed food
15% in cooking and on table
10% naturally in food

Question 33

Fluoride recommendation

Answer 33

No RNI

0.05 mg/ kg BW safe intake for babies

Question 34

Dietary sources of F

Answer 34

Tea / seafood

Question 35

F Toxicity

Answer 35

Skeletal abnormalities

Question 36

Dental action of fluoride

Answer 36

Plasma Fluoride combines with calcium phosphate hydroxyapetite –> Strengthens tooth enamel

Salivary fluoride inhibits bacterial enzymes in the mouth

Salivary fluoride increases remineralisation of damaged tooth enamel

Question 37

Benefits of fluoridated toothpaste

Answer 37

Reduced missing tooth , decayed tooth or filled tooth index