Probiotics; a living medicine


Most of us would baulk at the idea of eating a meal that’s still alive, but that’s the very essence of probiotics. A living meal, that tastes great and is actually good for us too. Probiotics have been around for at least as long as humans have been recording their activities and we know people were making fermented food and drink in Georgia, Armenia, Turkey, Egypt and Iran almost 10,000 years ago. The huge range of fermented and cultured products that we take for granted now probably came from many different accidental contamination of fresh food with naturally occurring yeasts and bacteria. Our uniquely human ability to record and refine those initial chance outcomes has enabled us to harness yeast to produce foods like bread and wine that are consumed across the globe. The same is true for lactic acid bacterial culture products like yoghurt and salami and sauerkraut.


People have known for thousands of years that what we would call probiotics, foods like yoghurt, are particularly good for you. Especially your gut health. In the last 150 years modern science has brought together various strands of the story and we now understand that the microbiome in our gut affects our wellbeing, even our mental health, in a profound way. The vagus nerve is the main highway for information transfer between your gut and your brain; generally called the gut-brain axis. The interplay between your microbiome and your immune system continues to be the subject of intense research, because it’s clear that your health can be dramatically affected by it. The lining of your gastrointestinal tract is the front-line; where your immune system ‘sees’ your microbiome and gets to decide which microbes are good and bad. This system is a balancing act, where your microbiome affects your immune system and vice versa. The general understanding now is that a healthy microbiome goes a long way towards having a healthy immune system.


Surely 10,000 years is long enough?

So; we have used probiotics for thousands of years, and science now understands quite a lot about how they affect our microbiome and general health. Why aren’t probiotics a public health priority, with all of us consuming scientifically proven yoghurts? Well; it’s complicated. The numbers alone are staggering; your gastrointestinal tract should contain more than 100 trillion microbes; one of the most densely populated microbial habitats known. All those microbes have around 3 million genes, whereas you only have approximately 23,000 genes. The scientific race is on to understand how this system works and what probiotics we should take to maintain our health and repair the system after it’s been damaged by things like antibiotics. The development of antibiotics has saved hundreds of millions of people, but they can cause problems by damaging your microbiome and globally by contributing to the rise of antibiotic resistant bacteria. Studying the microbiome, and how to use probiotics, is difficult because of the tremendous variation in people and their lifestyles, which probably leads to even bigger variation in their microbiomes. Cutting through that ‘noise’ requires very large numbers of people and many years to observe the outcomes and be able to say with confidence that a difference between two cohorts was a result of a probiotic.


Should you take probiotics?

Trying to find the answer to this question can be overwhelming; there is so much information out there on probiotics and the effects, good and bad, of using them. If you’re searching, I recommend looking at national healthcare sites that are administered by organisations like the National Institutes of Health (NIH) in the USA, or the National Health Service (NHS) in the UK; as well as the Australian department of health.


What I can say is that regulators and healthcare systems in countries like Australia the USA and UK say that generally speaking, probiotics are safe to use and may help healthy people to stay that way. So, if you’re already using probiotics there’s no reason to stop, or you’re generally healthy and are looking at adding probiotics to your diet, it’s likely to be safe. If you’re not generally healthy, or have any concerns about probiotics, ask your doctor before you give them a go. You can find plenty of additional information at sites such as:


What about probiotics for pre-pregnancy health or during pregnancy?

Most of the health agencies I referred to above don’t make definitive statements about probiotics in relation to pregnancy health, except to say that they are generally safe. They talk about ‘emerging evidence’ and trends that require more research. This was from the NHS in 2018, "Fish oil supplements and probiotic yoghurts during pregnancy may decrease children's risk of developing allergies,". The issues are usually to do with the statistical power of these studies. They require very large numbers of women and many years to observe the outcomes and be able to say with confidence that a difference between two cohorts was a result of a probiotic.


One of the largest studies I have seen is the Norwegian Mother and Child Cohort Study (MoBa), which has looked at over 70,000 pregnancies since 1999. They have investigated whether the consumption and/or timing of probiotic milk intake before, during early or late pregnancy had any effects on preeclampsia and preterm delivery.


Probiotic milk intake in late pregnancy was significantly associated with lower preeclampsia risk. Probiotic intake during early pregnancy was significantly associated with lower risk of preterm delivery. The MoBa cohort and other studies that looked at diet, demonstrate that women tend to adopt a more health-conscious diet when they are seeking to become pregnant. Looking at the results of studies like MoBa and the wider research effort on probiotics, I think it’s clear that probiotics and foods like yoghurt should have a place in your diet; or be on your list for discussion with your doctor.