The way most of us wage war against germs you’d think they were all out to get us. But in fact, we need germs – some of them, anyway – and without them in our lives we would be in serious trouble.


Western society has done an excellent job in fighting bacteria – and with it banished many associated illnesses – but it has in the process reduced our stocks of good bacteria, weakened our immune systems and led to unprecedented levels of allergic reactions and gut complaints.

Enter probiotics – good bacteria that can help to recolonise our bodies and provide a natural defence against the harmful bacteria we should be fighting.

What are probiotics?

Translated from Greek, probiotic means literally ‘for life’, such is their importance to our health and wellbeing.

“Probiotics are good bacteria that create a good environment in the bowel,” says accredited practising dietitian and author of The Good Enough Diet Tara Diversi.

“They occur naturally in the digestive system, but can be supplemented by taking a probiotic supplement in liquid or powder form. Many foods are now also supplemented with probiotics.”

Probiotics are not one entity but a group of living microorganisms, such as lactobacillus and bifidobacterium bacteria. Collectively, they arm the body against the growth of harmful bacteria and improve the overall balance of our intestinal microflora. They also strengthen the body against infection and boost general immunity.

What are the best food sources?

Probiotics can be found in fermented foods, particularly milk products. Chief among these is good quality yoghurt.

“The probiotics primarily used in food products are acidophilus, lactobacillus or bifidobacterium, or streptococcus thermophilus,” Diversi says. “The bacteria is needed to ferment the product, but can be destroyed by heat, so often needs to be replaced if heat treated.

“To maintain good health a good quality yoghurt with live cultures is a great option. If you have problems with your bowel or other problems that can be assisted by probiotics you may benefit from having a higher strength product such as a probiotic drink or a powder supplement.”

Nobel Prize winning bacteriologist Dr Ilya Metchnikoff (1845-1916) asserted that probiotics found in yoghurt could in fact lengthen life span. He believed premature ageing was the result of putrefying bacteria in the lower intestines poisoning the body, which yoghurt helps to balance.

Metchnikoff identified the culture lactobacillus bulgaricus as being particularly beneficial, naming it after the yoghurt-loving Bulgarians.

Yoghurt can be an excellent food source for people suffering from lactose intolerance who otherwise find it difficult to consume dairy foods. This is due to the fact that yoghurt contains lactase enzymes, making it easier for the body to assimilate.

Other foods that contain probiotics include sauerkraut, miso and probiotic-fortified breads and cereals.

Why are good bacteria important?

Good bacteria combat the effects of bad bacteria and in the process activate and strengthen a range of the body’s natural defence systems.

“Bacteria in the digestive tract help digest food, create essential vitamins, stimulate the immune system and control the number of bad bacteria,” Diversi says.

“They help balance the digestive system which means they can help with bowel problems like irritable bowel syndrome, constipation or diarrhoea. There is a lot of evidence that probiotics help with antibiotic-related diarrhoea.”

Probiotics have also shown positive results in relieving symptoms of inflammatory bowel disease, including ulcerative colitis and Crohn’s disease.

“Although there is still much research to be done, preliminary research shows that probiotics may help in many other areas like reducing high blood pressure, reducing allergies, inhibiting food poisoning and increasing mineral absorption from high fibre foods,” Diversi says.

Research findings revealing that probiotics might aid in the treatment or prevention of allergies, such as eczema, is an exciting development.

A study conducted by the Norwegian University of Science and Technology (NTNU) found that mothers who drank milk containing a probiotic supplement during pregnancy and while breastfeeding cut the incidence of eczema in their children by half at the age of two.

What is the hygiene hypothesis?

The reason why allergies are at an all time high in developed countries and probiotics are being increasingly seen as an answer to certain allergies is explained by the ‘hygiene hypothesis’. While it’s not without its critics, the hygiene hypothesis certainly puts up a persuasive argument.

First proposed by British epidemiologist Dr David Strachan in 1989, the hygiene hypothesis asserts that a lack of exposure to bacteria during early childhood increases the chances of developing allergies. This is because our immune system isn’t being sufficiently stimulated, becomes lazy and overreacts.

Children exposed to more bacteria – those with siblings, pets or children living on farming properties – are far less likely to develop an allergy compared to a non-pet owning only child living in a city apartment, who is exposed to far less bacteria. Children from developing countries also experience considerably fewer allergies than those from developed countries.

A massive study conducted by Bristol University in the UK involving 11,000 3 to 4-year-olds adds more weight to the suggestion that we may in fact be going overboard with our cleanliness obsession.

It found that children who came from the cleanest households suffered considerably more from allergic reactions, including asthma and atopic eczema.

Should you supplement?

There are a number of reasons why additional probiotics may be beneficial.

“We naturally have trillions of bacteria in the body, some good and some bad, but because of diet, stress, antibiotics and general ageing, the good bacteria may be reduced in the body,” Diversi says.

“So if you’ve been eating poorly, drinking too much alcohol or you’re noticing poor digestion it would be a good idea to start to include probiotics in your diet.”

If you’re looking to probiotics to treat a more serious medical condition, you should seek professional medical advice.

“It depends on the condition you are trying to treat or manage, remembering that you may not need the strongest option, as this may not provide any additional benefits,” Diversi says.

A product like Yakult, which is food for everyday digestive maintenance, provides about 6.5 billion bacteria per serve. A high potency therepeutic supplement like Inner Health Plus provides about 25 billion good bacteria per serve and a prescription only supplement like VSL#3, often prescribed for inflammatory bowel disease, provides about 450 billion bacteria per serve.

“If you are having no issues, just changing to a yoghurt containing live cultures may be all you need,” Diversi says.

To ensure the bacteria are kept alive, supplementary probiotics need to be refrigerated. They can survive in a normal household freezer but not in the heat.