What are prebiotics vs probiotics?

What are probiotics?

Most people have now heard of probiotics and many have bought and consumed probiotic products in the hope of benefiting from consuming them. The word probiotic derives from the Greek language, meaning ‘for life’. Today, a lot of evidence exists on the effectiveness of consuming probiotics across a range of health issues from enhancing immunity to the control of weight and preventing unwanted side effects of prescription medicines. So what exactly are probiotics, why should we take them and what benefits might we expect from their use.

Our gut

To begin with it’s important to know that the human gut is host to billions of microbes, which are collectively called the ‘gut microbiota’. The majority of these are found in the large intestine and, actually outnumber all the cells of the human body which contain them!  While most of the microbes in the gut are bacteria, there are also viruses and fungi in the mix that makes up the microbiota. In a normal human gut you can expect to find around 400 species of bacteria!

The Science of Probiotics

The science of probiotics therefore is based on the idea that adding to or changing this mix of microbes in our gut can have specific health benefits to us. While foods that contain bacteria such as yogurts and fermented foods such as sauerkraut have been eaten for thousands of years, today you can select from a wide variety of food products which deliver known strains and numbers of bacteria (usually lactobacilli and/or bifidobacteria) which have been developed and tested with the specific aim of boosting your microbiota with ‘friendly bacteria’. The ‘friendly’ or ‘good’ bacteria are those which are claimed to have positive health benefits and can displace or reduce in number those ‘bad’ bacteria (such as Salmonella and Shigella) that may be lurking in your intestines.

The history of products with the specific aim of boosting good gut bacteria goes back some 80 years to the original Japanese Yakult probiotic product which delivers around 6.5 billion lactobacilli (L casei Shirota) per bottle. Over the decades, promising research showing benefits to gut health and also immune function have spurred many other producers of related products to emerge supplying a wide range of different bacterial strains in a variety of drinks, yogurts, capsules and powders. Today the probiotic business is a global multi-billion dollar marketplace, and it is still growing. So do these products really work and if so are some better than others?

What’s the evidence on probiotics?

Well, the research evidence is mixed, but even the most sceptical observers must now concede that studies do show benefits in terms of helping with the bloating and discomfort of IBS . Furthermore, other studies have shown reductions in allergic symptoms and the duration of episodes of cold and flu the when using probiotics. Taken together, it seems that boosting positive gut bacteria could help not just the intestines, but also the whole body in terms of immunity and overall resistance to illness. It is difficult to determine whether all probiotics work for people, as there are many different bacteria taken at many different doses in the studies available. It is likely that the amount and mix of probiotic bacterial taken is important here. For example, studies using the VSL3 product have indeed shown that ulcerative colitis may be helped by using this product. VSL3 contains a blend of 8 different strains of bacteria which are known to survive the acid of the stomach and make it to the large intestine (the part of the gut affected by ulcerative colitis).

What are prebiotics?

Over the years, a growing body of scientific evidence has emerged to support the idea that probiotics can have positive health effects. In addition to this, the microbiota and health concept has been expanded and now we are looking at ‘prebiotics’ in addition to probiotics. Prebiotics are the foods we eat that provide nourishment to the probiotic bacteria in the gut. So the theory goes that by eating the right prebiotics (typically non-digestible fiber compounds) we are allowing the probiotics to flourish and do their job. It is thought that prebiotics significantly support the growth and effectiveness of probiotics and that is the correct balance between pre and pro biotic intake is necessary to get the best out of the probiotics.

What are the most popular prebiotics?

The most popular prebiotics currently are the fructo-oligsaccharides (FOS) derived largely from fruits and vegetables, and the galacto-oligosaccharides (GOS) derived from milk sugars. Both can support the ‘good bacteria’ in the gut and may be consumed for this specific reason. Currently research seems to be indicating that in supplemental form at least, the GOS have the most favourable profile, promoting the growth of bifidobacteria and lactobacilli in the large intestine while food sourced FOS prebiotics can be obtained readily through eating garlic, onions, leaks, bananas and Jerusalem artichokes.

Prebiotics vs Probiotics

What is the ideal balance between the foods and supplements supplying probiotics and the foods and supplements supplying prebiotics? This is the subject of much current interest and research, and has promoted a new term ‘synbiotics’, referring to the consumption of pre and probiotics simultaneously. Synbiotics have actually been around for hundreds if not thousands of years in the form of yogurts which naturally supply ‘good bacteria’ and the fuel they need to survive at the same time. In this regard it is probably worth mentioning the traditional yogurt drink Kefir, which contains GOS and multiple strains of bacteria that live in this beneficial yogurt preparation. For people with problems digesting milk products, probiotics and prebiotics can easily be consumed via separate foods and products.

In summary

Overall then, the balance of evidence is that probiotics and prebiotics, especially when combined, can have positive effects on human health. We now know that the gut microbiota has an important influence on our overall health and that we can modify the balance of microbes in this gut flora through diet and supplements. Fruits and vegetables, yogurts and fermented foods, all foods that are part of a healthy balanced diet, can deliver prebiotics and probiotics to support a healthy gut and immune system. Additional benefits may be obtained through topping up these effects with specially designed pro and prebiotic supplements and functional foods. Research continues into the best strains of bacteria, doses and prebiotic supports to optimize the benefits of probiotics on a wide range of measures of health and wellbeing. Exciting recent research even suggests that this may include lowering stress levels through consumption of the correct pre/probiotic mix.

For a great source of synbiotics, check out Zaggora’s Protein Super Smoothies, containing the right amount of both pre-and probiotics.

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Adam graduated from Queen Mary College London with a first class degree in physiology. Having completed an MSc in Nutrition at King’s College London he went on to research towards his PhD at the Royal London Hospital. He then established a career as a researcher and educator, teaching at major London Universities.
With expertise in anti-ageing, weight loss, clinical nutrition, sports nutrition and management of stress and fatigue, Adam has been featured on CNN, BBC TV & Radio and in UK national and local press.
Adam has published his research findings on multiple aspects of diet and health including diabetes, obesity, fatigue states, human performance and nutrition for healthy ageing.