Lifestyle Factors That Could Impact Gut Health

We are beginning to understand the pivotal role the gut microbiota plays in human health, and this is an essential element to bring into our everyday practice as healthcare practitioners. The intricate balance of microorganisms within the gastrointestinal tract not only influences digestion but also has far reaching effects on immunity, metabolism and mental health. This delicate ecosystem is highly susceptible to disruption by various lifestyle factors, which can lead to microbial imbalances that can compromise gastrointestinal health and contribute to a range of conditions.

In this blog we will delve deeper into the key lifestyle factors that can impact the microbiome, as well as practical advice and strategies to help you support your patients. This blog will cover advice for patients with gastrointestinal disease, and those who would benefit from lifestyle advice to prevent gastrointestinal upset and disease.

Diet

Diet is one of the most potent modifiable lifestyle factors in shaping the microbial community. We know dietary changes can rapidly and reproducibly create changes in the gut microbiome, with some of the key factors which positively influence the microbial community being:

• Diversity of plant-based products within the diet [1]

• Fermented foods and probiotics [2]

• Total fibre intake (30g/day recommended by the government, studies show greater benefit with 50g/day) [3]

Dietary fibre is involved in modulating host immunity. It does this via a few proposed mechanisms. Dietary fibre selectively fuels bacteria within the gut, with short chain fatty acids (SCFAs, a type of postbiotic) promoting the differentiation of Tcells within the immune system which control the immune systems response to foreign objects, as well as substances produced by the body. SCFAs also downregulate pro-inflammatory cytokines and upregulate anti-inflammatory cytokines, to reduce or prevent chronic low-grade inflammation.[5]

We know a high fibre diet can also be protective against colorectal cancer, as well as other cancers including breast cancer and stomach cancer.[6-7] Some studies have shown a 44% reduced risk of stomach cancer with a 10g/day increase in dietary fibre.[8]

A high fibre diet is also protective against type two diabetes mellitus (T2DM)[9-10] and cardiovascular disease, [11] with the NHS spending around 9% of its entire budget on diabetes care,[12] implementing simple preventative strategies can have huge benefits for not only the individual but the wider population.

The average UK citizen gets just 19.7g of fibre within their diet,[13] just 2/3rds of the government’s recommended 30g/day. There are studies to show we see greater improvements in metabolic markers and gastrointestinal health with even higher levels of fibre, around 50g/day.[1-2]

I recommend spending a few minutes listening to your patient’s current diet, and suggesting small and actional swaps, for example:

• Swap white bread... for wholemeal or seeded bread, 50/50 bread if taste is a challenge

• Swap white pasta... for wholemeal pasta, chickpea pasta, brown rice pasta

• Swap biscuits... for oat-based biscuits or bars

• Swap sweets... for dried fruits or dark chocolate coated fruits/nuts

• Swap Crisps... for popcorn or roasted chickpeas

You can also recommend resources such as the British Dietetic Association, who provide a range of food facts sheets on fibre, gastrointestinal health and specific nutrients as well as nutritional guidance in relation to specific health conditions.

As well as fibre, we know that fermented foods and probiotic foods* can positively influence gastrointestinal health. Fermented foods (foods which are produced via desired microbial growth and enzymatic conversions of food components), are thought to have the potential to modulate the immune system via impacting the microbiome and the presence of bioactive compounds that can impact intestinal as well as systemic function. Probiotic foods are different in that they contain specific strains of bacteria which have been shown to confer a health benefit to the host. For example, a trial showed that consuming Activia, a probiotic yogurt, twice daily for 4 weeks (2 x 125g) reduced digestive discomfort when consumed as part of a healthy diet.[4]

To learn more about the evidence behind fermented and probiotic foods, read this blog post by Sophie Bell RD.

Stress

The gut-brain-axis (GBA) is a well-established bidirectional communication network between the central nervous system (CNS) and the enteric nervous system (ENS); linking cognitive and emotional centres within the brain, with gastrointestinal movement and function. This can include motility, permeability and secretion of mucus, resulting in abdominal pain, bloating and changes in bowel movements when the gut-brain-axis is negatively impacted.

This can be really challenging to discuss with patients who have a disorder of the gut-brain-axis. It is important we do not put the cause of their gastrointestinal symptoms down to stress, but recognise that nervous system regulation is an essential element of treatment. In fact, management of stress, anxiety or depression are listed as a key management strategies for Irritable Bowel Syndrome within NICE guidelines.[15]

Tips for management:

• I like to talk through a range of techniques and choose 1-2 which may work for the individual. For example:

• Regular exercise, especially exercise such as hatha yoga which has been directly linked with improvements in gut function[16][17]

• Maintaining sleep hygiene

• Practising breathwork. Diaphragmatic breathing can be particularly effective for upper GI symptoms such as reflux
  

Antibiotics

Whilst antibiotics may be clinically required at times, excessive antibiotic use has been associated with the development of antimicrobial resistance, a reduction in alpha diversity (the number of species within a single sample) and an altered microbiome structure which can promote the growth/overgrowth of opportunistic pathogens such as Clostridioides difficile, Klebsiella pneumoniae and enterococcus faecium.[18-20]

These changes in the microbiome can result in chronic gut conditions such as IBS, and infections such as c.difficile.

Recommendations for antibiotic use and how to mitigate its impact on the microbiome:

Prescribe cautiously, using the narrowest spectrum and shortest duration feasible. It is however important to emphasise to the patient, the importance of completing the full course, even if they feel better, as this helps eliminate harmful bacteria, preventing the infection from returning

Recommend a specific probiotic backed by clinical evidence alongside to prevent antibiotic associated diarrhoea. There is strong evidence for this.[21-22]

Encourage patients to increase prebiotic and fibre intake alongside antibiotics, as well as fermented foods.

Educate patients that microbiome recovery can take months and encourage strategies to enhance resilience, such as a balanced and high fibre diet, regular exercise and stress management.

Gut health and disease

There are a number of autoimmune conditions such as coeliac disease and Inflammatory Bowel Disease (IBD), where we know there is an altered microbiome, to a less favourable and less diverse subset of bacteria. We don’t know if this is cause or effect, however there are hypothesis that some treatment strategies (e.g. exclusive enteral nutrition for Crohn’s disease) work in-part by targeting the microbiome.[23-25]

These are an important subset of patients as they are much more likely to be following a low fibre or restrictive diet. We know those who follow a gluten free diet tend to have a lower fibre diet, and in cases of IBD, dietary restriction and deliberate fibre restriction may occur during a flare of their condition, with much less emphasis on the importance of re-integrating fibre into the diet. Studies suggest that when IBD patients are in remission, as long as it is not contraindicated (e.g. fibrotic stricturing or significant levels of bowel removal), they benefit from a re-integration of fibres in their diet. Furthermore, in many of these conditions where there is temporary damage to the gut mucosa, we see temporary intolerances, especially lactose intolerance as the lactase enzyme is produced right at the end of the mucosal tissue within the small intestine. Often patients are nervous to re-introduce foods which have been poorly tolerated in the past, however it is important to trial a re-introduction of lactose-containing products when their condition is well controlled medically, to prevent an unnecessary restriction of nutrients, like calcium and products which can support their microbiome (e.g. yogurt, kefir).[23-24]

IBS is a chronic gut condition which is a disorder of the gut-brain-axis. In the long-term, working on strategies to improve and diversify the diet is essential, however dietary triggers should be identified first so that the diet can be selectively diversified.

Tips for patients with chronic gut conditions:

• Begin re-introducing fibres slowly

• Begin with plant-based products which are easy to digest (e.g. hummus before chickpeas or ground flaxseeds before whole linseeds)

• Encourage long-term re-integration of fibres, diversity and fermented foods

• Charities such as Guts UK, Crohn’s & Colitis UK and the IBS Network can be a great starting point for dietary advice in relation to specific gastrointestinal conditions.
  
  

We are learning more and more about the gut microbiota and the huge impact that dietary and lifestyle changes can have as both a preventative and treatment method for patients. This is a topic we should be broaching with all of our patients, as modulating the microbiota can have a powerful effect in terms of preventing gastrointestinal and systemic illness, as well as helping in the direct treatment of certain medical conditions and even influencing patient’s responses to some medical treatments.[26]

There are a number of dietary and lifestyle factors which can impact gut health and therefore wider health; here are a few key take homes we should be considering with all patients:

• Diet: how to increase fibre intake, diversity ,fermented foods and specific probiotics as appropriate

• Diet: minimising restrictions where able and appropriate with disease and autoimmune conditions

• Stress: the importance of prevention and regulating the nervous system

• Antibiotics: prescribing with caution and recommending specific probiotics, backed by clinical evidence alongside

• Directing towards a dietitian or reputable websites such as the British Dietetic Association (BDA) for further guidance
  

If your patients want to learn more about how their own lifestyle may impact their gut health, you can direct them to the Activia Gut Health Tracker, which provides guidance on simple changes to help support their gut health.