Functional foods

Question 1

What is pharmacognosy?

Answer 1

‘the study of natural product molecules that are useful for their medicinal, ecological, gustatory or other functional properties.’

Question 2

What are Nutraceuticals?

Answer 2

‘A food (or part of a food) that provides medicinal or health benefits, including the prevention and/or treatment of a disease’

Question 3

What are functional foods?

Answer 3

‘Food fortified or enriched with nutrient content already present in them or other complementary nutrients’

Question 4

What products can make functional food?

Answer 4

Carotenoids, dietary fibre, fatty acids, minerals, prebiotics, probiotics, vitamins

Question 5

What are probiotics?

Answer 5

‘Live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. The general benefit of probiotics on gut microbiota derives from creating a more favourable environment and supporting a healthy digestive tract and a healthy immune system’

Question 6

What are the two phyla dominant in the gut?

Answer 6

Bacteriodetes - specialist in protein and complex carbohydrate degradation

Firmicutes - includes Lactobacilli

The ratio of these 2 phyla changes with age, with Bacteriodetes levels increasing in elderly

Question 7

What change in gut bacterial flora occurs in those with type 2 diabetes

Answer 7

They have more firmicutes which cause a change in balance in the gut

Question 8

What are some widespread possible distribution of mechanisms among probiotics?

Answer 8

• Colonisation resistance
  -Regulation of intestinal transit (slow down how fast food moves through the intestines)
• Acid and SCFA production
• Normalisation of perturbed microbiota
• Increased turnover of enterocytes
• Competitive exclusion of pathogens

Question 9

What are some frequent possible distribution of mechanisms among probiotics?

Answer 9

Species-level effects
- Vitamin synthesis (b and k)
- Bile salt metabolism
- Enzymatic activity (influence receptors on toxins)
- Neutralisation of carcinogens
- Direct antagonism
- Gut barrier reinforcement

Question 10

What are some rare possible distribution of mechanisms among probiotics?

Answer 10

Strain-specific effects
- Neurological effects (e.g. increase satiety)
- Immunological effects
- Endocrinological effects (e.g. increase insulin resistance)
- Production of specific bioactives

Question 11

What is the relationship between probiotics and IBS

Answer 11

• moderate evidence it helps
• bda sate the evidence is inconclusive to support use
• could help with easing of some symptoms such as bloating
• NICE recommends taking consistently for 4 months to see if there is any effect

Question 12

What is prebiotics?

Answer 12

‘A selectively fermented ingredient that results in specific changes in the composition and/or activity of the gastrointestinal microbiota this conferring benefit upon health’

All prebiotics are fibre, not all fibre is prebiotics

‘Resists gastric acidity, hydrolysis by mammalian enzymes and absorption in the upper gastrointestinal tract.
Is fermemented by the intestinal microflora.
Selectively stimulates the growth and/or activity of intestinal bacteria potentially associated with health and well-being.’

Question 13

What is resistant starch?

Answer 13

Starch that is not hydrolysed to D-glucose in the small intestine. It is fermented in the colon by anaerobic bacteria to yield short chain fatty acids - acetic, propionic and butyric acids, which can lower the lumen pH, creating an environment less prone to the formation of cancerous tumours.
RS reduces postpradinal glycaemic response with beneficial implications in the management of diabetes..
Associated with a decrease in the levels of cholesterol

Question 14

What are some examples of food containing resistant starch?

Answer 14

New potatoes, rice, barley and oats

Question 15

What are some examples of prebiotic foods?

Answer 15

Onions, bananas, leeks, garlic

Question 16

What function does cholesterol have in the body?

Answer 16

• helps make the outer coating of cells
• makes up the bile acids involved in digesting fat in the intestine
• allows the body to make more vitamin D and hormones

Question 17

How much cholesterol in the small bowel is from diet?

Answer 17

25%
The rest comes from bile acids

Question 18

How are fats digested and absorbed?

Answer 18

Fat globules are broken up by gut motility and emulsion droplets. Emulsion droplets are coated with bile salts and phospholipids in bile.
Emulsification increases the surface area where water soluble lipase can work to digest triacylglycerol (TAG)
TAG is hydrolysed to lipase to release free fatty acids and monoglycerides.
Smaller micelles are formed which carry the monoglycerides and fatty acids to the microvilli where they dissolve and diffuse across the enterocyte membrane.

Question 19

What is the bile acid cycle?

Answer 19

• Primary bile acids made from cholesterol
• Hepatocytes conjugate the acids into bile salts
• They are released into the duodenum where bacteria change them into secondary bile acids
• Secondary bile acids are reabsorbed by the ileum
• They are take back to the liver via the portal circulation for reuse

Question 20

What is bile and where is it stored?

Answer 20

Bile is produced in the liver and stored in the gall bladder. It is released into the duodenum following a meal to emulsify fats.

Question 21

What are Oat B-glucans and what do they do?

Answer 21

Oat B-glucans form a viscous layer in the small intestine inhibiting intestinal uptake of dietary cholesterol and re-absorption of bile acids.
By binding to bile and cholesterol, oat B-glucan prevents them from being reabsorbed lower down the digestive tract.
Inhibition of bile acid re-absorption increases the synthesis of bile acids from cholesterol and reduces circulating LDL cholesterol levels.
Therefore using and reducing the excess cholesterol in the body.

Question 22

What do plant stanols and sterols do?

Answer 22

• Sterols compete with cholesterol for micelle binding during absorption
• Sterols broken down by hydrolysis more easily than cholesterol so are more easily taken up by micelles
• Potential interaction of plant sterols with enterocyte ATP binding cassette transport proteins to direct cholesterol back into the intestinal lumen.

The mechanism of action of plant sterols is different from those of statins, thus their effect is additive
Adding phytosterols to statin therapy led to a 7-20% reduction in LDL cholesterol compared to statin alone.

Question 23

Who should not be advised to take plant stanols or sterols for the prevention of CVD?

Answer 23

• those being treated for primary or secondary prevention
• people with CKD
• people with type 1 or 2 diabetes
• pregnant or breastfeeding women

Question 24

How much plant sterols are recommended per day?

Answer 24

2-3g/day for a 5-15& LDL reduction