Dietary Fiber & body weight

Question 1

Dietary fiber & body weight

Answer 1

Stretch effects - increase viscosity & gastrointestinal bulking

Increase nutrient density - high fiber foods often highly nutrient dense> fewer cravings

Question 2

impact of Fibrous bulk

Answer 2

More fibrous bulk triggers stretch receptor in stomach and hypothalamus send signal to suppress appetite > less nutrient in intestine

less fibrous bulk lead to over-eating >more nutrients trigger nutrient receptors> hypothalamus send signal to suppress appetite > less nutrient in intestine

less nutrient in intestine > over- eating to get nutrients

Question 3

SCFA produce in gut used for ? % of TE

Answer 3

6 - 10%

Question 4

SCFA produce in gut

Answer 4

Butyrate - colonocytes

Propionate - liver

Acetate- systemic

Question 5

SCFA produce in gut induce release of __________ for ________

Answer 5

release of satiety signals

to control appetite

Question 6

Antherosclerosis is the risk factors of ?

Answer 6

High LDL
Low HDL
High total cholesterol

Hypertension
Hyperglycemia
Inflammation
Oxidative stress

Question 7

High DF diet reduce (elevated haemoglobin sugar ?) by %

Answer 7

25%

Low DF intake has higher blood sugar than high intake

Question 8

high DF intake effects on CVD

Answer 8

Diebetes linked to CVD

26.2g DF/ d reduced 40 % CVD risk and 50 % heart attack risk

Question 9

Fiber effects on cholesterol

Answer 9

[Bile salt make micelles in gut for fat absorption]

Cholesterol is burned in liver to make bile salts which pumped through GI tract; Bile salt will eventually recollected back to liver via portal vein (together with fat & toxins)

DF has inhibit effects of bile salt
as it is bulky and soluble, it binds the bile salt and carried out of body

Liver need to synthesis its own cholesterol for bile production to recover the loss bile.

Liver increases its production of LDL receptors and pull cholesterol out of the LDL molecules in the blood –> lower blood LDL level

Question 10

Different fiber have effect to reduce total cholesterol and LDL

Answer 10

Konjac-mannan fiber has most profound effects >pectin >guar gum = oats >psyllium

Question 11

High fibre diet associated with

Answer 11

• Weight loss
• Reduce risk of hypertension, CVD, storke
• Prevent cancer, type 2 diabetes
• Decreased inflammatory status
• Lower cholesterol

Question 12

UK DF intake

Answer 12

14g/ d

declined over last century

Question 13

Recommended DF intake

Answer 13

12 - 24g/day , mean intake 18g/d

• No recommendations for children
• Greater than 32g/day not advised
• Caution for some group consuming NSP sources with phytates (eg unprocessed wheat bran)