Exploring the role of gut bacteria in digestion

When we hear the word bacteria, it generally conjures up negative connotations, but bacteria are particularly important when it comes to our health.

Nutritional therapist Penny Shaw, brand quality manager at G&G Vitamins, explains: “Gut bacteria are responsible for building the body’s immune system, digestion, normalise bowel movement, influence weight and mental performance.”

“100 trillion bacteria populate the human gut, a number that is 10 times greater than the number of cells in the human body,” comments Jenny Bodenham, nutritional therapist at Higher Nature. “Some of these bacteria such as E. coli and salmonella are bad for us, as they can cause acute or chronic illness. Others however, live symbiotically within us in a mutually beneficial relationship that has evolved to enhance their life and ours. These ‘friendly’ bacteria play an important role in health, as they are essential for many functions in the body including supporting the immune system, supporting digestion and absorption of nutrients, aiding the manufacture of many vitamins including B vitamins and vitamin K, and helping to regulate peristalsis and bowel regularity

“These beneficial bacteria are so important for our health that an imbalance, also known as dysbiosis, may cause various symptoms such as diarrhoea, constipation, bloating, wind, skin problems and thrush and could contribute to health conditions such as IBS, eczema, Crohn’s and diverticulitis. Healthy gut function has also been linked to normal function of the central nervous system.”

Our gut microbiota is linked to our mood and brain health too. Michela Vagnini, nutritional therapist at Natures Plus, explains: “The gut-brain axis (GBA) consists of bidirectional communication between the central and the enteric nervous system, linking emotional and cognitive centres of the brain with peripheral intestinal functions. Recent advances in research have described the importance of gut microbiota in influencing these interactions. This interaction between microbiota and GBA appears to be bidirectional, namely through signalling from gut-microbiota to brain and from brain to gut-microbiota by means of neural, endocrine, immune and humoral links.That is why when you suffer from dysbiosis (imbalance between good and bad gut flora) it can slow your ability to think, trigger depression and affect your memory retention.”

What role does it play in our digestion?
Egzona Makolli, technical and commercial nutritionist at Kinetic Enterprises, answers: “Gut bacteria has many roles within digestion as its essential in breaking down food molecules into useable fuel and produces vitamins to help protect the body. They are also important in breaking down substances that cannot be digested such as fibre, some starches and sugars. Bacteria also produce enzymes which help digest carbohydrates in plant walls and without bacteria these valuable nutrients would be lost, for example Lacobacillus bacteria produces lactic acid which helps the release of digestive enzymes and increases the absorption of essential minerals such as calcium, magnesium and iron. Certain strains of gut bacteria are essential to producing vitamin K and certain B vitamins which cannot be manufactured by humans.”

“One of the key roles of a healthy gut flora is the synthesis of essential nutrients, support food digestion and protect the delicate mucosal lining of the GI tract (the Gut mucosal membrane),” comments Vagnini. “Enzymes produced by intestinal bacteria are important in the metabolism of several vitamins.”

“Gut bacteria make up gut flora. Different strains have different properties,” explains Shaw. “The bacteria help to maintain a healthy gut lining where food is absorbed, normalise bowel movements and a balanced ecosystem of bacteria can avoid occurrence of inflammation.”

Nutritional therapist Katherine Pardo, head of nutrition at Nutri Advanced, adds: “New research suggests that maintaining a healthy balance of bacteria in the gut may help to support reduced cravings, weight loss and reduce the risks of metabolic problems such as type 2 diabetes.”

“Symptoms that tell you your gut bacteria may be out of balance include gas and bloating, nausea, headaches, constipation, diarrhoea, fatigue, sugar cravings, low mood, weight gain, low immune health and allergies and intolerances,” explains Pardo.

How can we support a healthy balance of bacteria?
“There are many factors that can compromise the health of our gut flora,” comments Vagnini. “Environment, pollution, infections, chronic low grade (silent) or acute inflammation, stress, certain foods, medications and alcohol can all affect the delicate balance of our gut microbiome. An excess of unfriendly intestinal microorganism can result in gas, bloating, indigestion, dysbiosis, diarrhoea and other digestion problems.”

To help support a healthy balance of bacteria, Shaw recommends repopulating your stomach with beneficial bacteria: “Repopulating the gut with beneficial bacteria can contribute towards rebalancing the microflora in the gut. This may involve the use of probiotics or fermented foods. Reduce intake of sugar which feeds the bad bacteria that encourage yeast and candida. Prebiotics can help feed good bacteria, digestive enzymes can help break down food when digestion becomes sluggish. Manage stress levels is key due to the gut-brain axis which indicates a close relation between the two.”

Vagnini also suggests eating fermented foods: “Fermented foods like kimchi, kefir, saurkraut and pickles, miso, natto and live yogurt can help to nourish and maintain a good gut flora. Traditional fermented foods are rich in beneficial lactic acid-producing bacteria. These bacteria are what naturally make milk products go sour and cause vegetables to ferment. Consuming naturally fermented foods not only supplies the gut with more of these desirable microorganisms, but the extra acidity they create helps to support the bacteria that are already there. Some drinks are also good for your gut: kombucha, naturally fermented and unpasteurised beer (occasional use) and kefir water.”

Bodenham suggests increasing your intake of probiotic foods: “To support a healthy balance of bacteria it is important to eat plenty of ‘probiotic’ foods to provide fuel for the ‘friendly’ bacteria. These may include garlic, onions, leeks, asparagus, artichokes, bananas and apples. A nutrient dense fibre-rich diet promotes the growth of beneficial gut bacteria so eat plenty of fibrous wholegrains such as brown rice, oats and quinoa as well as a variety of beans and legumes. Additionally, fermented foods such as natural yoghurt, kefir and sauerkraut will benefit gut bacterial balance.”

In terms of a probiotic supplement, Bodenham suggests looking for one which is backed by clinical research: “It is important to choose a strain that can survive stomach acid and the digestive juices found in the intestinal tract. They should have the ability to adhere to gut epithelial tissue and be backed up by proven clinical research. Some of the most well used and researched strains of probiotic bacteria include Lactobacilli, Bifidobacteria and Bacillus coagulans.”

“There are many factors to take into consideration when choosing a pre or probiotic,” comments Makolli. “It’s essential to pick a reputable brand which has been tested by a third party and that the product comes with a full strain probiotic identification and safety data. Clinical studies are essential when picking a product as these ensure that the strain has been tested in a robust controlled study and has been fully reviewed prior to being sold. Always look at the CFU count with a potency claim at ‘end of expiration date’ versus the ‘at time of manufacture’ as many may not contain the same CFU count it did at the time of manufacturing. It’s also worth looking at the different types of strains as current research suggests that it’s more beneficial to purchase a wide variety of strains versus just a few to provide a variety of health benefits.  Similarly, ensure that the prebiotic picked has clinical studies to show to have true prebiotic effects.”