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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 Stomach Small intestineLarge Intestine Anus Liver Gall BladderPancreas 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. MouthA. Makes bile. 2. OesophagusB. Enzymes breakdown large food molecules into smaller food molecules which are absorbed into the blood. 3. StomachC. 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. RectumF. Faeces egested (passed out) from here. 7. AnusG. Churns up food. Contains hydrochloric acid and pepsin. 8. PancreasH. Absorbs water to produce firm faeces. 9. LiverI. Stores the faeces. 10. Gall Bladder J. Stores the bile. 11. BileK. 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. 2What 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? 4What are plant stanol esters? How are plant stanol esters meant to work and how is this a benefit? 5How 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. 7A 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.

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 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.

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 6d Is it worth taking the higher dose of plant stanols? Explain your answer.

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 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 Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 7A 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 Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 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.

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)