How Can I Improve My Microbiome?


The gut microbiome refers to the community of microorganisms, including bacteria, viruses, fungi, and protozoa, that live in the digestive tract. 


The majority of these microorganisms reside in the large intestine and play a crucial role in maintaining human health. They help with the digestion of food, the absorption of nutrients, and the regulation of the immune system. They also play a role in the production of certain vitamins and neurotransmitters – think mood and anxiety! 


Imbalances in the gut microbiome, also known as dysbiosis, have been linked to a variety of health conditions including obesity, inflammatory bowel disease, and certain types of cancer. Additionally, the gut microbiome plays a role in mental health, influencing mood and behaviour.



There are several ways to work on improving the quality of your gut microbiome. Why not pick one or two to start with?

FIBRE– Eat a diet high in fibre, which can feed the beneficial bacteria in the gut. There are two types of fibre, soluble fibre and insoluble fibre which are both important for gut health.  Soluble fibre dissolves in water and forms a gel-like substance that slows down the movement of food through the digestive system. This can help regulate blood sugar levels and lower cholesterol, whilst keeping bowel movements regular and is found in fruits, veggies, psyllium and oat bran. 

Insoluble fibre, does not dissolve in water and provides bulk to stools, helping to prevent constipation and promote regular bowel movements. This type of fibre is found in foods such as wheat bran, whole grain breads, and vegetables.

Then you also have prebiotic fibre- this is a type of non-digestible carbohydrate that serves as a food source for the beneficial bacteria in the gut. These bacteria ferment the prebiotic fibres, producing short-chain fatty acids that can improve gut health and enhance the function of the digestive system.(1)

Examples of prebiotic fibres include bananas, onions, garlic, leeks, asparagus, and whole grains.

You should be aiming for 30g of fibre per day, which includes all types of fibre such as soluble fibre, insoluble fibre, and prebiotic fibre. It is important to have a balanced intake of different types of fibre in your diet to ensure that you are getting the full range of benefits for your gut health. (2)

FERMENTED FOODS- Include fermented foods such as live yogurt, kefir, sauerkraut, and kimchi in your diet, as they contain probiotics which can help to balance the gut microbiome. Aim to include these fermented foods into your diet on a regular basis as they can provide a good source of probiotics and support overall gut health. A few times a week is a good place to start, and ideally rotate between different types of fermented foods to get a variety of probiotics. 

POLYPHENOLS– Polyphenols are a type of antioxidant found in many plant-based foods. They have been shown to support gut health by promoting the growth of beneficial gut bacteria and improving the diversity of the gut microbiome, which is important for overall gut health. Polyphenols may also improve the function of the gut barrier, which helps prevent harmful substances from entering the body and causing inflammation. (3) Aim to eat a diet rich in polyphenol-containing foods, such as berries, green tea, organic red wine, dark chocolate, and good quality olive oil – as much as possible!

30 PLANT FOODS- Eating 30 different types of plant foods a week  is a great way to support gut health due to the variety and richness of the nutrients they each provide. Plant foods are a source of fibre, prebiotics, probiotics, antioxidants, and phytochemicals, all of which play important roles in maintaining a healthy gut microbiome as you expose your gut microbiome to a wider range of nutrients, fibres, and other beneficial compounds. This can help improve the diversity and balance of the gut microbiome, which is fundamental for maintaining gut health. (4)

PROCESSED FOODS- Avoid ultra-processed foods when possible as they often contain a lot of added sugars, unhealthy fats, preservatives, and artificial ingredients, which can negatively impact the gut microbiome.

If you see ingredients that you cannot recognize or pronounce, the food is likely to be highly processed. Ultra-processed foods also often contain high levels of added sugars, which can be listed under several different names, including corn syrup, high fructose corn syrup, and dextrose. They often have a smooth and uniform texture, which is often achieved through the use of emulsifiers, stabilisers, and other artificial ingredients.


Common ultra-processed foods include:

  • Soft drinks and energy drinks
  • Packaged snacks such as chips, crackers, and cookies
  • Convenience foods such as pre-packaged meals and instant soups
  • Sweetened breakfast cereals
  • Processed meat products such as hot dogs, ham, and sausages
  • Candy and sweets
  • Baked goods such as cakes and pastries
  • Margarine and spreads
  • Sweetened yoghurt
  • Energy and protein bars

ARTIFICIAL SWEETENERS- Artificial sweeteners have been shown to alter the gut microbiome, promoting the growth of harmful bacteria and reducing the number of beneficial bacteria (5). Limiting your consumption of artificial sweeteners and opting for naturally occurring sweeteners, such as raw honey or maple syrup, in moderation is best.  Always check food labels and watch out for the following ingredients to avoid artificial sweeteners:

  1. Aspartame: A low-calorie artificial sweetener often used in diet drinks and sugar-free gum.
  2. Saccharin: A low-calorie artificial sweetener that is hundreds of times sweeter than sugar and used in diet soft drinks and other sugar-free products.
  3. Sucralose: A no-calorie artificial sweetener that is 600 times sweeter than sugar and used in diet soft drinks, baked goods, and other sugar-free products.

PROBIOTICS- Take a probiotic supplement, which can help to introduce beneficial bacteria into the gut. But remember that quality is key! Check out my Probiotics Guide blog article here 

STRESS REDUCTION- Stress can alter the balance of bacteria in the gut, leading to an imbalanced gut microbiome. This can contribute to the development of various gut-related health problems, such as irritable bowel syndrome. Stress can also impact the movement of food and waste through the gut, leading to constipation or diarrhoea. Aim to reduce stress levels through exercise, meditation, or other stress-reduction techniques. 

The vagus nerve is a key component of the parasympathetic nervous system, which is responsible for regulating functions such as digestion, heart rate, and blood pressure. Relaxing the vagus nerve can support gut health by improving digestive function and reducing inflammation. (6) I am a big fan of the Sensate device, a resonance device that emits vibrations that works by toning the vagus nerve, sending you into a state of pure relaxation and calm in just 10 minutes. Use the code CLARISSA for £30 off here

ANTIBIOTIC USE- Antibiotics can kill off both the harmful and beneficial bacteria in the gut, leading to an imbalanced gut microbiome and reducing the diversity of gut bacteria. An imbalanced gut microbiome can increase the risk of various gut-related health problems, such as irritable bowel syndrome, inflammatory bowel disease , and Clostridium difficile infections. Avoid the overuse of antibiotics unless necessary, as they can kill off beneficial bacteria in the gut. (7)

But do not fear, if you have taken antibiotics try to incorporate probiotics into your diet through a good quality supplement and by eating some yummy fermented foods. And don’t forget those prebiotic rich foods to feed the good bacteria!

EXERCISE– Exercise can help to stimulate the movement of food and waste through the gut, reducing the risk of constipation and other gut-related health problems. It has also been shown to reduce levels of stress and anxiety, which can have a positive impact on gut health by reducing inflammation and promoting the growth of beneficial bacteria in the gut. (8)



There are several diets that have been shown to support and even improve gut health, however it is important to note that each person will have a different requirement from diet.  What works for one person may not necessarily work for another, and  individual needs and tolerances may vary.  Therefore, it’s always best to consult with a gut health nutritionist before starting any new diet.

The Mediterranean diet: This diet is rich in fruits, vegetables, whole grains, legumes, and healthy fats. It also includes moderate amounts of fish and poultry, and low volumes of red meat. This diet has been shown to promote a healthy gut microbiome and reduce inflammation in the body. (9)

​​The Low FODMAP diet: This diet is designed to reduce the intake of certain fermentable carbohydrates that can cause digestive symptoms in those with IBS or other gut-related disorders. The diet involves eliminating certain types of fruits, vegetables, dairy products, and grains, and then gradually reintroducing them to see which ones trigger symptoms. The low FODMAP diet should only be done alongside working with a nutritionist, as long term this diet can negatively impact the microbiome. (10) 

The High-fibre diet: Fibre is essential for gut health, it helps to feed the beneficial bacteria and maintain bowel regularity. Eating a diet high in fruits, vegetables, whole grains, and legumes can help to promote a healthy gut microbiome. Your microbiome can change by the month, by the week, or even by the meal. And if you eat a large array of fresh fruits, grains, and vegetables, your gut health will reflect that. Always aim for a minimum of 30g of fibre a day. (11) However, too much fibre can actually worsen symptoms, so always go low and slow when increasing your fibre intake. 

The Palaeolithic diet (Paleo diet): This diet is based on the idea that the human body is best suited to the diet of our ancestors. It includes meats, fish, fruits, vegetables, nuts, and seeds. It excludes processed foods, grains, legumes, and dairy products. It  can help support your gut health by reducing inflammation and promoting the growth of beneficial gut bacteria. The paleo diet focuses on whole, minimally processed foods and eliminates highly processed foods, which often contain artificial ingredients and preservatives that can be harmful to the gut.



Processed foods may have a negative impact on gut health in several ways. Processed foods often contain added sugars, which may disrupt the balance of the gut microbiome by promoting the growth of harmful bacteria and reducing the growth of beneficial bacteria.

They also often contain artificial ingredients and preservatives, which can irritate the gut lining and contribute to inflammation. Always check food labels and look out for:

  1. Artificial sweeteners: Artificial sweeteners, such as aspartame, saccharin, and sucralose, have been shown to have a negative impact on the gut microbiome and can disrupt the balance of gut bacteria. (5)
  2. Emulsifiers: Emulsifiers are commonly added to processed foods to improve texture and stability. However, some studies have suggested that certain emulsifiers, such as carrageenan and polysorbate 80, may have a negative impact on gut health by promoting inflammation and altering the composition of the gut microbiome. (12)
  3. Preservatives: Preservatives, such as sodium benzoate and potassium sorbate, are commonly added to processed foods to extend shelf life. However, some studies have suggested that these preservatives may have a negative impact on gut health by promoting inflammation and disrupting the balance of gut bacteria. (13)
  4. Artificial food colours: Artificial food colours, such as Red 40 and Yellow 5, have been shown to have a negative impact on gut health by promoting inflammation and altering the composition of the gut microbiome.(14)

Processed foods often lack fibre, which is key for maintaining a healthy gut microbiome. Fibre helps to feed the beneficial bacteria and promote bowel regularity. Processed foods also tend to lack the vitamins, minerals, antioxidants, and phytochemicals that are found in whole foods, which are essential for maintaining good gut health.

It’s important to remember that not all processed foods are the same and some can be part of a healthy diet when consumed in moderation. However, I always recommend reading the label and choosing options with minimal ingredients, added fillers, artificial ingredients, emulsifiers and preservatives.



Probiotics are live microorganisms, similar to the beneficial bacteria that naturally live in the gut. They can be taken as a dietary supplement or found in fermented foods. Taking a probiotic supplement can improve gut health by restoring the balance of the gut microbiome, which can be disrupted by factors such as antibiotic use, a poor diet, or stress.

  • They can help to improve digestion and nutrient absorption by breaking down food and producing enzymes, whilst helping to boost the immune system by promoting the production of antibodies and white blood cells.
  • A probiotic may help to reduce inflammation in the gut, which can help to alleviate symptoms of gut-related disorders such as inflammatory bowel disease and irritable bowel syndrome.

It’s important to note that not all probiotics are the same and some strains are more effective than others for specific health conditions. Probiotics work best when combined with a healthy diet, stress management techniques, and regular exercise. It is best to consult with a healthcare professional before starting a probiotic supplement, particularly if you have a chronic condition or are taking other medications. Take a read of my Probiotics Guide article for more details and my top recommendations here.



There are several signs that may indicate you have an imbalance in your gut microbiome:

  • Gastrointestinal symptoms such as bloating, gas, constipation, diarrhoea, or abdominal pain
  • Skin issues such as eczema, acne, or rosacea
  • Food sensitivities or allergies
  • Fatigue or brain fog
  • Mood changes such as anxiety or depression
  • Autoimmune disorders such as rheumatoid arthritis or lupus
  • Unexpected weight gain or weight loss
  • Joint pain
  • Nutritional deficiencies such as low vitamin B12 or iron levels

It’s worth noting that these symptoms can also be caused by other factors, so it’s important to consult a healthcare professional for an accurate diagnosis. 



When working with a gut health nutritionist, they may also undertake some diagnostic tests such as a comprehensive stool analysis, breath test for methane and hydrogen, or blood test for zonulin to confirm gut dysbiosis. This will then guide them on the best course of action to support your gut and microbiome health.

Overall, it is always best to work with a professional who can help you get to the root cause of your gut problems. If you are interested in working with myself or one of my team, please email info@clarissalenherr.com for more info and to set up a FREE discovery call.





https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5390821/ (1)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8153313/ (2)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770155/ (3)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6478664/ (4)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6363527/ (5)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5859128/ (6)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8756738/ (7)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5357536/ (8)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359750/ (9)

https://pubmed.ncbi.nlm.nih.gov/28707437/ (10)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7589116/ (11)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6899614/ (12)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6835893/ (13)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2957945/ (14)

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Hi there

London Nutritionist Clarissa Lenherr

I’m Clarissa, a registered nutritionist (mBANT) and workplace wellness expert. In my practice, I have helped hundreds of clients reach optimal health through creating sustainable, effective habits and dietary adjustments. My aim is to empower people with the skills, tools and knowledge to take their health into their own hands and feel the happiest, healthiest versions of themselves. Featured in The Daily Mail, Women’s Health, The Telegraph, and more.




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