Download 1 Suggest one reason why people might eat functional foods. 2

Probiotics and prebiotics
https://www.youtube.com/watch?v=
xjZikdw0W2M
https://www.youtube.com/watch?v=
q5lGogzkzjQ
What are:
1. Probiotics
2. Prebiotics
3. Plant stanol esters
Use the information in the text to find out. Write
the definitions in your books. 5 mins
ALL: Explain the difference between a probiotic and a prebiotic (Grade C)
MOST: Analyse data to explain the effect of plant stanol esters (Grade B)
SOME: Evaluate the evidence for the benefits of functional foods (Grade A)
1. Probiotics – Foods containing live bacteria that
produce lactic acid in the gut and may improve the
health of your digestive system.
2. Prebiotics –Substances in food that cannot be
digested by enzymes. Are food for probiotic
bacteria in the intestine. Eg oligosaccharide.
3. Plant stanol esters – oily substances found in
plants that appear to lower cholesterol.
ALL: Explain the difference between a probiotic and a prebiotic (Grade C)
MOST: Analyse data to explain the effect of plant stanol esters (Grade B)
SOME: Evaluate the evidence for the benefits of functional foods (Grade A)
By the end of the lesson you should be
able to:
ALL: Explain the difference between a probiotic
and a prebiotic (Grade C)
MOST: Analyse data to explain the effect of
plant stanol esters (Grade B)
SOME: Evaluate the evidence for the benefits of
functional foods (Grade A)
Starter: The digestive tract – Alimentary Canal – Can you
label the parts you know.
Mouth
Bolus of food
Oesophagus
Liver
Stomach
Gall Bladder
Pancreas
Small intestine
Large Intestine
Anus
Grade C
Can you state which organs
are involved in digestion and
establish their function?
Grade B
Can you discuss the role of
the liver and pancreas in
digestion.
Grade A
Can you explain the role of
the gall bladder and bile in
digestion.
Match up – what does what
1. Mouth
A. Makes bile.
2. Oesophagus
B. Enzymes breakdown large food molecules into smaller food
molecules which are absorbed into the blood.
3. Stomach
C. Contains amylase enzyme in the saliva which breaks up
starch into simple sugars.
4. Small
Intestine
D. Tube that uses muscular contractions called peristalsis to
move food from the mouth to the stomach.
5. Large
Intestine
E. Emulsifies fats to increase the surface area for lipase to work
on. Also increases the pH of the food coming out of the
stomach to make it more alkaline.
6. Rectum
F. Faeces egested (passed out) from here.
7. Anus
G. Churns up food. Contains hydrochloric acid and pepsin.
8. Pancreas
H. Absorbs water to produce firm faeces.
9. Liver
I. Stores the faeces.
10. Gall
Bladder
J. Stores the bile.
11. Bile
K. Produces enzymes, releases them into the small intestine.
Chloesterol probiotic
enzyme
Catalyst protein
stomach
pepsin
Amylase
carbohydrates
glucose
Amino acids
fats
yoghurts
Protease
Pancreas
oligosaccharide
1 What is a functional food and suggest one reason why people might eat
functional foods.
2 What is a probiotic and what do probiotic foods contain? What do
the makers of these probiotic yoghurts claim?
3 What is a prebiotic and what do prebiotic foods contain and how do
they work?
4 What are plant stanol esters? How are plant stanol esters
meant to work and how is this a benefit?
5 How would you evaluate the data given in Figure D on the impact of
oligosaccharides on health? (Give a detailed discription of what you think
it shows, does it prove anything?).
6 In fig C Is it worth taking the higher dose of plant stanols? Explain your
answer.
7 A new functional food for toddlers is being advertised on TV, claiming
to increase the numbers of ‘good bacteria’ in the gut.
How would you evaluate these claims?
ALL: Explain the difference between a probiotic and a prebiotic (Grade C)
MOST: Analyse data to explain the effect of plant stanol esters (Grade B)
SOME: Evaluate the evidence for the benefits of functional foods (Grade A)
Answers
• 1. A functional food is a food that claims to
make you healthier.
• People may think they will help them digest
food better/make their digestive system or
immune system work better/to try to prevent
possible health problems in the future.
2. Probiotic foods contain live bacteria such as
Lactobacillus or bifidobacteria that produce
lactic acid. This increases the bacteria number in
your digestive system.
The makers of the yoghurts claim to make you
healthier by improving your digestive system,
reduce disease, reduce allergies,
3. Prebiotics are substances that cannot be digested
by human enzymes but which act as food for
probiotic bacteria in the intestine.
Oligosaccharides ( a form of prebiotic in tomatoes,
bananas and onions) that cannot be digested by
humans but provide nutrients for some kinds of
bacteria.
They act as food for beneficial bacteria and so
increase the number of beneficial bacteria in your
digestive system.
4. How are plant stanol esters meant to work
and how is this a benefit?
Oily substances found in plants which are
meant to stop the small intestine absorbing
cholesterol – reducing the amount of
cholesterol which is linked to heart disease.
5. The results show that people given oligosaccharide in their
diet are much less likely to suffer from diarrhoea than people
who are given a placebo (something that looks like the
oligosaccharide but doesn't contain any). This suggests that
oligosaccharide can provide protection against diarrhoea.
A: However, the study only looked at 142 patients, which is a
small sample. And we don't know if those patients were
selected for a particular reason or are a random sample of
the population. So we cannot really extrapolate the results to
the wider population without further study.
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6d Is it worth taking the higher dose of plant
stanols? Explain your answer.
© Pearson Education Ltd 2011.
Copying permitted for
purchasing institution only.
This material is not copyright
A: The study shows that, in this group of people, blood cholesterol
is lowered. As high blood cholesterol is a risk factor for heart
disease, this suggests that including stanol esters in the diet
should help prevent heart disease. However taking the higher
dose of 2.6g a day didn’t have much of a different effect to 1.8g
a day.
Further studies for a longer period of time would be needed to
show that stanol esters did improve life expectancy by
preventing heart disease, and that it did so for all groups of
people not just those at higher risk generally.
© Pearson Education Ltd 2011.
Copying permitted for
purchasing institution only.
This material is not copyright
7 A new functional food for toddlers is being
advertised on TV, claiming to increase the
numbers of ‘good bacteria’ in the gut.
How would you evaluate these claims?
© Pearson Education Ltd 2011.
Copying permitted for
purchasing institution only.
This material is not copyright
A: You would need to see data from experiments
that clearly showed an increase in numbers of
beneficial bacteria in the guts of toddlers who ate
the food compared with those who didn't, and be
certain that the only difference in the test and
control groups was the functional food. The data
would need to come from a large study, so that
random differences between toddlers didn't mask
the overall effect.
© Pearson Education Ltd 2011.
Copying permitted for
purchasing institution only.
This material is not copyright
• Label the digestive system and explain what
happens in each structure.
• Explain the functions of bile (HIGHER ONLY)
• Know what enzymes break up which nutrient
and what the nutrient is broken into.
• The adaptations of villi.
• Explaining the small intestine model and the
strengths and weakness.
• Probiotics, prebiotics and plant stanol esters.
By the end of the lesson you should be
able to:
ALL: Explain the difference between a probiotic
and a prebiotic (Grade C)
MOST: Analyse data to explain the effect of
plant stanol esters (Grade B)
SOME: Evaluate the evidence for the benefits of
functional foods (Grade A)