London Clinic of Nutrition
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Our bodies are populated by trillions of bacteria of differing species, found on the skin, in the gut and all mucous membranes such as the mouth, vagina, nose and lungs.



While bacterial cells may be small, experts estimate that they outnumber our human cells 10:1 and as such they contribute hugely to our overall health.

Focusing on our enteric (intestinal) bacteria, we know that these bacteria form a vitally important and delicately balanced community, which is constantly influenced by our diet and lifestyle choices. Disruption to this microbiome is likely to be contributing to the huge increase we have seen in digestive-related illnesses such as IBS, Crohn’s disease, reflux and constipation. But beyond maintaining a healthy digestive tract and assisting in digestion and absorption, we also now know that the health of the digestive tract is closely linked with health throughout the body. Justin Sonnenberg, associate professor in the Department of Microbiology and Immunology at the Stanford School of Medicine, believes that there is a major connection between what is happening in the gut, and the risk of chronic disease. Imbalanced flora, gut damage and the systemic inflammation that can ensue contribute to autoimmune disease, cardiovascular disease, problems with metabolism, obesity, detoxification, and the health of the brain via the gut-brain axis.

It stands to reason that supporting the balance of our existing bacterial population and taking in beneficial strains will improve health. This is especially true because while some species become resident in the gut, others are transient, meaning that despite their positive contribution to the health of the GI tract, they don’t colonise and won’t remain after supplementation is stopped. These transient strains include lactobacillus plantarum and bulgaricus, and streptococcus thermophilis. Another transient good-guy is a probiotic yeast called Saccharomyces Boulardii, found to improve mucosal immunity, reduce inflammation and help flush out pathogenic strains of bacteria while improving the efficacy of beneficial strains.

There are several ways to improve and increase the beneficial bacterial population in the gut and throughout the body. The first, and most popular way is by taking oral probiotic supplements. This area of supplementation has grown hugely and an enormous number of products are available. Some bacterial strains have been more widely researched than others, and as a result most probiotic supplements include a range of bacteria featuring several lactobacillus strains, for example lactobacillus acidophilus, as well as bifidobacterial strains. It’s worth looking out for certain superior ‘sticker strains’, such as lactobacillus acidophilus DDS, which have been studied and found to have a superior ability to move through the digestive tract and adhere to the intestinal wall, where they can destroy harmful bacteria.

More recently, soil-based organisms have become available in supplement form, containing symbiotic strains selected to mimic the flora found in traditional and Paleolithic diets. Manufacturers claim these bacterial strains are naturally adapted to survive the conditions in the human GI tract. Research suggests that soil-based organisms help promote a healthy GI environment and alleviate IBS symptoms such as flatulence, bloating and nausea.

As well as directly supporting overall digestive function and the health of the GI tract, probiotic supplements may benefit a diverse range of health conditions not only through their relationship with the gut, but because so much of the body is colonised by bacteria that help maintain the function of their environment. These areas of health include cognitive conditions such as depression and memory problems; sinus infections; oral health conditions like tooth decay and gum disease; and inflammatory skin conditions like eczema and acne. Using a specific blend of probiotic bacteria can even help with allergies because certain strains help downgrade histamine in the body, including lactobacillus plantarum and rhamnosus, plus bifidobacterium longum.

There are also more novel methods for maintaining and restoring gut health. Dr David Perlmutter, a neurologist and author of Grain Brain and Brain Maker, recommends administration of probiotics via an enema, whereby a dose of probiotics in a watery solution is inserted directly into the large intestine through the rectum. He also recommends fecal microbial transplantation, a more controversial procedure becoming increasingly popular in America, typically used when a patient is suffering with clostridium difficile infection, but also for inflammatory conditions and autoimmunity.

Another way to increase and support beneficial strains in the intestines is to consume prebiotic foods that feed them. Many probiotic supplements also contain a prebiotic ingredient, but making specific food choices may help to keep the beneficial bacteria thriving and healthy. There are several types of prebiotic, but resistant starch appears to be particularly beneficial for the human gut compared to other prebiotics. We can’t digest or benefit from it as a food source, but the prebiotics within these foods can travel through the digestive system and reach the large intestine intact, where they act as fuel for the beneficial bacteria that reside there.


Written by Emma Rushe

Selecting probiotics for health is best done with the help of an expert.

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