Written by Charlotte Green
In recent years, it has become increasingly clear that looking after our gut health is not only important for our digestion but our overall health as well. In fact, it is thought that the health of our gut could impact our weight (1), immune function (2) and even our mood (3).
This is largely due to the influence of the gut microbiota, the community of trillions of microorganisms that live along the digestive tract. The composition of the gut microbiota can be influenced by a variety of lifestyle-related factors including diet, sleep, and stress. It is thought that dysbiosis, an imbalance of the “good” and “bad” bacteria, can contribute to the emergence of a variety of diseases including obesity, IBS and autoimmune diseases such as coeliac disease (4). However, there are simple changes that can be made to improve gut health, including adding in sources of prebiotics to your diet.
What are Prebiotics?
The term “prebiotic” has become increasingly popular, particularly in food marketing, but it can be difficult to navigate the facts from the fads. Essentially, prebiotics are a source of food for the “good” bacteria in the large intestine. They are a type of plant-based fibre, obtained from the diet, that are broken down by the gut microbiota. The most beneficial prebiotics are inulin, fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS) (5).
Where can you find Prebiotics?
Prebiotics are found in plant-based foods. Good sources of prebiotics include:
Leeks
Oats
Onions
Garlic
Artichokes
Chicory
Bananas (6)
Some food products, such as breakfast cereals, have also been fortified with inulin, which can act as an additional source of prebiotics (7).
How do they work?
The gut microbiota uses prebiotic fibre as an energy source, which allows the “good” bacteria to grow (5), whilst preventing the growth of harmful bacteria (8), which can have far-reaching effects to improve our overall health. This is because fermentation of prebiotics produces beneficial chemicals such as short-chain fatty acids (SCFAs). SCFAs are anti-inflammatory and can leave the digestive system and travel in the bloodstream to confer a number of health benefits around the body (8).
Health benefits of Prebiotics
Digestion
Consuming foods high in prebiotics regularly to increase the number of “good” bacteria is important for effective digestion. There are certain food components, particularly dietary fibre from plant-based foods, that our body cannot digest on its own. We rely on the assistance of the gut microbiota. Therefore, a healthy gut microbiota allows us to obtain the maximum amount of energy and nutrients from the food we eat (5).
Furthermore, the gut microbiota assists in the breakdown of other important plant chemicals, such as polyphenols, found in berries, olive oil, tea, and coffee. Polyphenols are important for our health as they are potent antioxidants, preventing excessive damage to our cells (9).
Prebiotics could also be beneficial as part of the treatment of some gut disorders like IBS, although research in this area is still in its early stages (10).
Metabolic Health
Gut microbiota dysbiosis has been linked to both obesity and type 2 diabetes, largely due to increased inflammation (11). However, prebiotics have a potential role in the prevention and treatment of these conditions.
Prebiotics can increase the number of beneficial bacteria such as Bifidobacterium species (11), which may regulate appetite via various communication pathways. This was demonstrated in a study of obese children who showed reduced food consumption following treatment with the prebiotic inulin (12).
Furthermore, the increase in beneficial bacteria has been shown to improve insulin resistance, a key feature of type 2 diabetes (13). Research in this area is promising but has mostly been performed in animals, so much longer-term studies are required in humans before prebiotics are utilised for type 2 diabetes.
Brain Health
There is a two-way communication system between the gut and the brain, known as the gut-brain axis. Essentially, it means that the gut and brain can “talk” to each other via the nervous system and the transport of chemical messengers such as hormones.
Therefore, the gut microbiota has the potential to influence brain health (14). In fact, it is thought that the gut microbiota could play a role in a variety of disorders, from anxiety and depression (which we often see alongside eating disorders) to Alzheimer’s Disease.
Although research into the use of prebiotics for depression is in its early stages, it is thought that prebiotics could be helpful. They can increase the number of short-chain fatty acid producing bacteria, which could help reduce inflammation, a known risk factor for depression (15).
Similarly, early studies looking at supplementation with FOS prebiotics has been shown to reduce various markers of Alzheimer’s Disease and maintain the diversity of the gut microbiota, which is often lowered in Alzheimer’s Disease patients (16) .
What about prebiotic supplements?
In general, for those wanting to improve their gut health and general wellbeing, prebiotic supplements are not necessary. In fact, it is often more beneficial to consume prebiotics from whole foods because they contain many other vitamins, minerals and plant chemicals that are beneficial for our health. It is important to remember that no nutrient in isolation is revolutionary for health, it is all about variety and balance. Our free guide How To Build a Balanced Plate explains more on why all foods have a place in a balanced diet.
That being said, research is progressing into the use of prebiotic supplements for specific medical conditions, which could open up exciting new treatment options.
At TCN our specialist eating disorder dietitians can offer online consultations to support your health journey! Book a free 15 minute discovery call here with one of our dietitians.
Charlotte Green
Charlotte Green is a postgraduate Dietetics student at the University of Chester, after graduating with a degree in Biological Sciences from Durham University. She is passionate about the role of nutrition in health and longevity, the gut microbiome and the link between food and mood. Charlotte looks forward to supporting others live a healthier life in her future role as a registered Dietitian.
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