Probiotics and prebiotics

Probiotics and prebiotics

  • Functional foods are eaten by people in order to make themselves healthier.


  • These contain live bacteria such as Lactobacillus and Bifidobacteria which are ‘friendly’. They are similar to those found naturally in the gut and produce lactic acid.
  • They are added to foods such as yoghurt, soya milk and dietary supplements.
  • They are claimed to improve your digestive system and makes your immune system strong.
  • However not clear evidence they are helpful: out of 180 health claims made 10 were rejected completely and there was not enough evidence to support the other 170 claims.


  • “Food” for the beneficial bacteria in the gut. We cannot digest them ourselves.
  • Oligosaccharides, a common prebiotic, are found in tomatoes, leek, onions and asparagus. However, they do not contain enough of them to have a significant effect so supplements containing prebiotics are taken.
  • These prebiotics help with the growth of good bacteria which in consequence can help improve the health of the digestive system and immune system.
  • The evidence is growing that prebiotics increase beneficial bacteria in the gut so maintain good health.

Plant stanol esters

  • Chemicals that stop the small intestine absorbing cholesterol thus lowering the levels of cholesterol in the blood.
  • Stanols occur naturally in plants but in small amounts.
  • Stanols are produced commercially by using bacteria to convert sterols into stanols.
  • They are added to spread and dairy products. People may consume these if they are worried about getting heart disease (high cholesterol has been linked with a risk of heart disease)
  • Clear evidence that they have an effect.