Lecture 2

Question 1

Bioavailability

Answer 1

Not all consumed is absorped

Question 2

Absorption of Calcium

Answer 2

10-60% of intake

Question 3

What effects uptake

Answer 3

Uptake control via PTH is dependant on demand for example pregnancy

Bioavailability differs between foods e.g. phytate, oxalate and dietary fibre decrease availability

Question 4

Bioavailability of Ca from Milk

Answer 4

30-35%

Question 5

Bioavailability of Ca from Spinach

Answer 5

5%

Question 6

Reason for Vitamin C

Answer 6

Necessary for collagen synthesis

Question 7

Electrolyte Balancing

Answer 7

We need a 1:1 balance between calcium and phosphorus

Question 8

Result of consuming excess phosphorus

Answer 8

Causes leaching of Ca from bone mineral

Question 9

Food examples of ratios

Answer 9

Milk: 1.25:1
Cola: 0.2:1

Question 10

Nutrients required for the metabolic processes related to bone formation

Answer 10

Calcium, protein, magnesium, phosphate, Vitamin D, potassium, fluoride.

Question 11

Nutrients required for the metabolic processes related to bone formation

Answer 11

Manganese, copper, boron, iron, zinc, Vitamins A, K, C and the B vitamins

Question 12

Effect of caffeine on bone

Answer 12

Certain epidemiological studies have shown a correlation between consumption of high- caffeine beverages and low BMD, Too much caffeine is detrimental

Question 13

How has caffeine shown to affect bone metabolism

Answer 13

Calciuresis, Altered Calcium Absorption, Altered Sex steroid Levels

Question 14

The significance of calciuresis to calcium balance is questionable

Answer 14

Calciuretic effect of caffeine is biphasic

Question 15

Other problems with caffeinated beverages

Answer 15

May contain other compounds that affect bone health, e.g. Phosphoric Acid.

Question 16

Caffeine Conclusions

Answer 16

Any effect of caffeine upon BMD is likely to be mild for the majority of the population

Effect will be dependent on dose and factors related to : 
Diet
Gender
Genetic Predispostion
Current physical states

Question 17

What is Tea

Answer 17

Processed leaf of Camellia sinensis

Contributes up to 80% of the Uk dietary intake of Flavonols and Flavones.

Question 18

Polyphenol

Answer 18

Flavonols and Flavones.

Question 19

Black Tea

Answer 19

.

Bright orange colour, low astringency, sweet flavour

Question 20

PPO

Answer 20

Polyphenol Oxidase

Question 21

Oolong Tea

Answer 21

Fermentation stage half the time as for black tea,

Light, subtle flavour, bright yellow colour

Question 22

Green Tea

Answer 22

No defined fermentation stage, PPO deactivated, very little oxidaisation of catechins, subtle, bitter flavour and pale in colour

Question 23

Role of tea and bone health

Answer 23

Consumption of tea has been associated with high BMD/ low incidence of fracture in several populations e.g. MEDOS

Greater benefits for those with longer drinking habits Wu et al, 2002

Question 24

Tea and Flavonoids

Answer 24

Increase numbers and activity of osteoblasts (Bone Making)
Decrease numbers and activity of osteoclasts (Bone reabsorbing)
Reduce damage to osteoblasts caused by oxidative stress.

Question 25

Tea and Fluorine

Answer 25

Occurs as salts in vivo, Fluorine ion becomes incorporated into bone, increasing overall stability
This is fluorapatite

Question 26

Fluorosis

Answer 26

Associated with doses of >8 mg/day

Question 27

Problems with Brick Tea

Answer 27

Brick tea in small populations such as Tobet consume vast quantities of Brick Tea, Theses are made from much older leaves, which results in a greater storage of fluoride.

Question 28

Protein and the acid base theory

Answer 28

Skeleton acts as a buffer, maintaining in vivo pH

Base- forming components neutralise acid- forming components thus limiting resorption of skeletal calcium

Question 29

Effect of Onions

Answer 29

Rats fed diets rich in animal protein (casein) or vegetable protein, similar total protein, Ca and phosphate content
Casein diet gave lower urine pH
Addition of onion slightly raised urinary pH and decreased acid content and decreased bone resorption
Muhlbauer et al, 2002

Question 30

Effects of flavonoid

Answer 30

Found in orange peels, has many benefits, including protecting the heart and brain, reducing diabetes symptoms and preventing cancer.

Question 31

Chiba et al 2003

Answer 31

Previously shown hesperdin treatment has prevented bone loss in OVX mice (removed ovaries).
Reduced numbers of osteoclasts, increased Ca content of bones.

Question 32

Effect of Soy

Answer 32

Isoflavones: May benefit post- menopausal women, in terms of general as well as bone- specific health.

Question 33

Genetic Predisposition

Answer 33

Effects on peak bone mass as well as activity of osteoclast cells.

Question 34

Race and Ethnicity

Answer 34

Osteoporosis risk is reported to be higher in white race compared to back race.
for example: African populations have higher bone mass compared to chinese populations

Question 35

Body Weight

Answer 35

Low body weight increases risk of osteoporotic fractures

Question 36

Physical Activity

Answer 36

Bones lose structural strength due to inactivity

Question 37

Smoking

Answer 37

Decreased Ca absorption in gut

Question 38

Alcohol

Answer 38

Influences on PTH, Vit D metabolism and osteoblast proliferation

Question 39

HRT use in PM women

Answer 39

Benefits to BMD possible overshadowed by other effects