Man eat yoghurt

Probiotics or Prebiotics? Which is Best?


Probiotics is one of the fastest growing industries, with millions of new sales of both probiotic supplements and probiotic food products sold every year. But are they just a waste of your hard-earned cash or are they worth every cent you spend? New research may hold the answer!

What are probiotics?

You would not be alone if you got confused between probiotics and prebiotics. These technical words have become freely used in the public domain, often interchangeably – but they mean very different things.

We are going to talk about probiotics – supplements or foods that contain live bacteria! Specifically, bacteria that is found naturally in our gut, and we believe that by eating more, it can only help keep our gut healthy.

As disgusting as this sounds, we as a complete human being are actually made up of two types of cells: human cells and non-human cells. The non-human cells may well outnumber the human – and they are largely bacteria!

Most of these bacteria live in our gut and on our skin, and many of these bacteria are not only safe and friendly, but actually contribute to our health in a good way!

There is a staggering amount of scientific evidence being published every year showing how bacteria inside of us is contributing to so much of our health state: how fat we’re likely to get, whether we’re prone to diabetes or inflammatory diseases, whether we’re more likely to get cancer, even how our mood state will be!

Bacteria that live in our gut talk to us in very complex ways – in ways we never knew about until just recently. Collectively, we call these types of bacteria microbiota or the microbiome – the latter actually refers to the bacteria’s genetic make-up.

This discovery has lead to a boom in probiotics, with claims that adding to the natural bacteria that live inside of us can only be a good thing.

We’re now consuming more yoghurt than ever, and started exploring foods that only 10 years ago few of us had heard of: kefir, kombucha, and pickles such as kimchi.

So are these claims valid? If the bacteria really do make it to the gut alive and are not nuked by the acid in our stomach or the immune system – do they get to the gut and colonise there?

The research

A lot of exciting and highly influential research in the realm of microbiota is coming from Israel.

Israeli researchers were the first to discover how different foods can affect us all in very different ways, which is leading science toward a personalised a approach to nutrition and medicine.

The same institute performed new tests to see whether probiotics actually do what they claim they do – and carried out the most comprehensive research yet on whether probiotics colonise the gut.

They decided to test, once and for all, do probiotics that we buy as supplements in health stores actually make it to the gut and, once there, do anything at all for our health?

To do this, they abandoned older methods of proving whether probiotics work by using stool samples. They decided to go straight to the gut and have a look directly inside the colon.

They did this by using cameras attached to long flexible tubes that can be inserted into the colon – a method known as colonoscopy.

They recruited 25 people and split them into two groups: one group took a probiotic supplement and the other a placebo (a substance that has no active properties – but will look identical to a probiotic supplement).

They investigated the subjects twice during the treatment stage: once shortly after taking the supplement and again at the end of the experiment – which took 2 months.

What they found was, some people just pooped out the probiotic supplement – this group of people became known as resisters, because their bodies rejected the probiotic.

The others welcomed the probiotic and allowed them to colonise the gut! This successful group were termed persisters because their bodies were open to the idea of having microbial visitors.

What was particularly interesting about this study was that the researchers were able to predict who would be persisters and who would be resisters by examining the genetic profile of the resident gut bacteria prior to the experiment.

So this experiment did two things:

  • it showed that existing research that uses stool samples to prove that probiotics make it to the gut and survive are using imperfect methods to prove that probiotic products work. Some people just poop them out!
  • it opens the world up to brand new research into gut microbiota, because some people have guts that are very unwelcoming to visitors! AND that this can be predicted.

So that was the first study!

What if you take antibiotics and delete all the existing bacteria that live in the gut?

Antibiotics and Probiotics

The same team decided to go one step further – what happens if you eradicate the residents and then introduce a probiotic?

In western medicine, it’s often the advice to take probiotics at different times to an antibiotic (if you took them at the same time, the antibiotic just neutralises the probiotic!).

The gut does recover its microbial population after antibiotics, but can take up to six months and not all the species come back – in fact, some nasty ones can make a sudden appearance according to research.

In the second study, the team found that the probiotic does populate the gut – and successfully so.

However, it takes a very long time for the gut to return to normal because its original native bacteria struggle to thrive with the new population now resident.

They found that the most successful recovery from antibiotics was to remove a sample of the gut’s original microbiota, and then transplant it back in after the antibiotic treatment.

So using probiotics with antibiotics might actually put the gut in a worse state than it was before!

To read more about this research and about the Institute itself, click here for the original press release and link to their website.


The best way to improve the bacteria in your gut is not by taking expensive probiotics, but by changing your diet.

Prebiotics are foods that we eat that the bugs also eat. Typically, we refer to prebiotics as food that the good bacteria want, not the bad.

So give the gut bugs that you already have the food they want, and starve the bad bugs of the foods they want – their diets are different!

Aim for a plant-based diet such as a flexitarian diet (if you prefer to eat meat, fish or dairy)

Do eat:

  • High fibre, wholegrain foods such as oats, barley, wheat and rye if you can tolerate them. Some people have an adverse reaction to these foods.
  • Lots of foods rich in phytonutrients: this means a varied palette of colours from the plant world. Reds (such as peppers, strawberries, cherries), purples (blueberries, blackberries, aubergine, purple cabbage), orange (sweet potato, squashes, carrots), greens (chards, spinach, kale, herbs) etc
  • Foods that feature inulin such as the onion family: onions, leeks, garlic as well as Jerusalem artichokes and asparagus
  • Seeds such as chia seeds or flax
  • A small amount of dark chocolate now and then

However, there is a word of warning for people who suffer from a condition known as irritable bowel syndrome (IBS) – changing your diet to include more of these foods could make your symptoms worse!

These foods are high in FODMAPs, and need to be included in the diet slowly and in small incremental amounts to see how much you are able to tolerate.


  • Meat
  • Dairy
  • Refined carbohydrates (white bread, white pasta)


  • High fat foods: lots of oil, lots of saturated fat in meat or dairy.
  • High sugar foods: sweets, cakes, biscuits, processed foods

Image Credit
Nappy at

One comment

So what do you think?

This site uses Akismet to reduce spam. Learn how your comment data is processed.