Skip main navigation

New offer! Get 30% off your first 2 months of Unlimited Monthly. Start your subscription for just £29.99 £19.99. New subscribers only. T&Cs apply

Find out more

Probiotics and prebiotics

Both prebiotics and probiotics have a direct effect on our gut bacteria. In this video we discuss these concepts, and how they relate to our health.
[music] - Hello everybody, and welcome back. As we already stated during this week, superfood is not a regulated term, and it can be applied to very different foods with different properties and nutritional content. There are a few terms that are often associated with superfoods. In some cases, the meaning is intuitive such as for antioxidants, anti-inflammatory or vitamins. The meaning of other words can be less clear, and they can lead to confusion. It is the case, for instance, of prebiotics and probiotics. Probiotic is probably the term we are most familiar with, and it refers to microorganisms that can provide health benefits to their host organisms.
This concept was introduced by a Russian biologist, Elie Metchnikoff, who used it to relation to one of the most common sources of probiotics, yogurt. Yogurt is produced by the fermentation of milk by specific strains of bacteria such as Lactobacillus delbrueckii bulgaricus. Other similar products such as kefir are produced with analogous processes by different genera of bacteria. Both yogurt and other fermented products can contain more than a single bacterial strain. Different bacteria are added either for the characteristics they give to the final product, or for the supposed beneficial effect. Why should probiotics be good for our health?
The idea behind these claims is that when we consume them, bacteria can survive the acid in our stomach, reach our gut, and form colonies there. These colonies of good bacteria could then perform a number of useful functions such as synthesizing vitamins, and short-chain fatty acids, competing with pathogens for resources and stimulating the immune system. In order to thrive, these probiotic bacteria need both a viable habitat and an abundant source of food. This is where the second term of this lecture, prebiotic, comes into play. As probiotic bacteria live in our gut, they can benefit from the components of our diets that are not digested and absorbed in the stomach.
Therefore, the term prebiotic indicates the molecules that can reach undigested our gut where they’re metabolized by the probiotic bacteria. Most of these substances are a specific kind of fibers and they can be found, for instance, in unrefined wheat, and barley, as well as in some vegetables such as Jerusalem artichoke, and chicory root. Therefore, both prebiotics and probiotics would improve our health by modifying the population of bacteria living in our gut. Both have been associated to a range of health benefits. Are these health claims proven? As often is the case in Science, the answer is not clear-cut.
On one hand, multiple studies found that specific strains of probiotic bacteria are linked with positive effects on health such as activity against traveler’s diarrhea or antibiotic-associated diarrhea. Other studies showed an effectiveness of a mixture of probiotics on the symptoms of irritable bowel syndrome, and linked the consumption of probiotics to increased absorption of some minerals, and regulation of bowel movements. On the other hand, the overall evidence in support of the health claims of pro and prebiotics is not very strong. When the entire body of research is analyzed, there are few proven health benefits. This is why, to the best of our knowledge in mid-2018, the European Food Safety Authority approved a health claim linked to probiotics in just one case.
Products such as yoghurt, kimchi, kefir, and sauerkraut have been consumed traditionally for hundreds of years, and they have good nutritional properties. They are already part of traditional eating habits in many countries, and there is no reason to either abandon them, or to think of them as a solution to some of our health problems, regardless of their labeling.

Our gut microbiome is linked with our health.

It is therefore of no surprise that foods that can influence our gut bacteria, by increasing the number of beneficial ones, received attention from scientists and consumers alike.

Yogurt and kefir are two very common sources of probiotics and both have been named as superfoods, but is their beneficial effect proven?

In contrast, prebiotic-rich foods can be consumed by humans, but we may be more likely to consume them in the form of supplements or nutraceuticals. They can also help support gut health alongside probiotics. So what evidence is there on both of these?

In this video, we discuss the differences and links between the two concepts, and briefly review the scientific literature to find whether they can be said to be effective in improving our health.

This article is from the free online

Superfoods: Myths and Truths

Created by
FutureLearn - Learning For Life

Reach your personal and professional goals

Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates.

Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas.

Start Learning now