Gastroenterologist Dr. Alan Desmond and Clint Paddison discuss in this podcast:

• Western culture’s approach to food
• The importance of a healthy gut
• How microbiome plays a key role in the digestive process
• Foods and inflammatory states
• The TMAO experiment
• Assessing the bowel
• The connection between gut health and RA
• Crohn’s disease
• Aspirin and inflammation
• Prednisone and it’s risk of usage from a Gastroenterologist’s perspective

In this week’s podcast, we spoke to Dr. Alan Desmond, a Consultant Gastroenterologist and General Physician who is also a leading nutrition expert. Dr. Desmond is a dedicated advocate of the unparalleled health benefits of achieving optimal gut health. We have been passionate about chatting with Dr. Desmond since he presented at the sell-out Doctors for Nutrition Conference in Melbourne in February 2019. 

Understanding the Digestive Process

Dr. Desmond began by discussing how the body’s digestive process works. He explained how digestion starts when we chew food in our mouths. The amylase enzyme in our saliva breaks down protein in the food. The chewing process turns our ingested food into a ball-like mixture called a ‘bolus’. 

The bolus is swallowed into our throat and transferred through our oesophagus, which is about 30 to 40 centimetres long. It then carries on down into the stomach, which acts like a cement mixer, continually churning up the food. In addition, the stomach contains a powerful acid, hydrochloric acid, which helps break up the food further. As a result, the food changes into a liquid consistency within the stomach and is referred to as ‘chyme.’

The chyme then passes through a little hole called the pylorus and heads into the small intestine. Despite only being a couple of centimetres wide, the small intestine is essential because so much absorption of nutrients occurs there. The remaining residue is transferred to the large intestine following the absorption of carbohydrates, fats, proteins, and other nutrients. This residue contains all the broken-down food particles that are not needed by the body and a liquid known as ‘succus entericus’, which includes water, digestive enzymes, and mucoproteins. 

The Final Journey

The final journey is to the colon, or your large bowel, which is much broader and shorter. The liquid that arrives here has already taken on the characteristic brown colour of stools, thanks to the digested bile mixed in with it. As the digested liquid passes through, the large bowel absorbs water, resulting in the drier and more formed stool we recognise. 

We also know that the large bowel is home to the gut microbiome, consisting of trillions of bacteria, viruses, and yeasts. Interestingly, the microbes that make up our gut microbiome are like the close relatives of the Earth’s very first living organisms. 

Over recent years, we have realised that gut microbiome composition plays a crucial role in human health. Furthermore, we can influence what goes on in our gut microbiome and how it interacts with our body by altering the food we eat. 

According to Dr. Desmond, “all health does begin in the gut and in a way that comes back to the vital role of the human gut microbiome”.

How Does Gut Health and Microbiome Influence the Immune System?

So how does the microbiome modulate the functioning of the immune system and the body’s inflammatory response?

Firstly, it is important to remember that not all inflammation is harmful. Dr. Desmond reminds us that acute inflammation is a healthy response. For example, if you hit your finger with a hammer, there’s damage. Your thumb will become inflamed because of increased blood flow, lymphocytes, and repair cells. This is a normal response and will help the body to repair itself. 

However, long-term, chronic inflammation is not healthy. Chronic inflammation is common in many diseases, including ulcerative colitis, Crohn’s disease, rheumatoid arthritis (RA), heart disease and depression. 

How Is Gut Health and Microbiome Related to Inflammation?

The foods we eat greatly influence how much inflammation resides within our bodies. A recent systematic review and meta-analysis adds weight to this statement. The study reports that consuming a vegetarian dietary pattern is associated with lower systemic markers of inflammation compared to a non-vegetarian-based diet. 

So why is that? Suppose you eat a diet rich in antioxidants, phytonutrients, carotenoids, polyphenols, fibre, and healthy unsaturated fats. In that case, you are reducing your food’s inflammatory burden. Whereas with a non-vegetarian diet, you are consuming pro-inflammatory animal protein. 

One of the critical mechanisms whereby an animal-based diet promotes inflammation is through its influence on the human gut microbiome. Indeed, a study published in 2014 described how the short-term consumption of either a purely animal- or plant-based diet could alter the gut microbiome composition in healthy volunteers. 

Researchers observed an outgrowth of pro-inflammatory bacteria when volunteers consumed an animal-based diet. The opposite occurred with a plant-based diet; they saw an increase in healthy bacteria. These bacteria help to reduce inflammation, control blood sugar levels and maintain the health of the gut lining. 

Animal-sourced food, including meat and eggs, may contribute to diseases such as heart disease, diabetes, and colon cancer by raising levels of a substance produced naturally in the body by gut bacteria. This substance is TAMO (trimethylamine N-oxide) and is created when we consume food rich in choline (concentrated in eggs) or carnitine (concentrated in meat).

Research has shown that diets high in animal protein have been found to increase TAMO levels, while plant-based diets can reduce them. 

Can Bacteria in the Gut Cause Joint Pain?

So, we know that gut health is associated with inflammation within the body, but is it also explicitly associated with joint pain? The short answer is yes.

In support of this, research has shown that obesity-related dysbiosis of the gut microbiome leads to an inflammatory process and rapid joint deterioration. This was reversed by dietary supplementation, which positively altered the gut microbiome.

Assessing the Gut Health

Dr. Desmond then talked with us about how, as a gastroenterologist, he assesses gut health. Initially, he would perform a non-invasive test using a stool sample, where he checks the levels of various chemicals. One of the most important is faecal calprotectin, a marker of intestinal inflammation. Interestingly, in a healthy population of patients consuming a Western diet, a certain baseline level of gut inflammation is normal. Although patients’ responses to plant-based diets indicate that this ‘normal’ level of gut inflammation may not be the baseline, it may just be a symptom of a standard Western diet.

To assess the health of the bowel visually, Dr. Desmond would use a colonoscopy to perform an endoscopic examination. Before the colonoscopy, a patient would be prescribed laxatives to clean out the bowel and improve visibility for the test. The colonoscope (a flexible tube) is then inserted up the bottom, producing a high-definition, real-time picture of the inside of the bowel. 

According to Dr. Desmond, a healthy gut lining looks like the inside of our cheeks, pink and shiny, with a healthy layer of mucus covering it. However, a diseased gut lining can look red, sore, and even ulcerated, with an underlying whitish area. The lovely pink glossiness is either reduced or completely absent. 

Does Gut Health Affect Rheumatoid Arthritis?

How does our gut health impact other parts of our body?

Dr. Desmond reminds us of the importance of treating the body as one entire system. In this way, all our individual bodily systems, such as digestive, respiratory and rheumatology, are connected and influence each other. For example, we know that patients with Crohn’s disease or ulcerative colitis are commonly affected by extraintestinal complications, such as pain and inflammation of the joints. Research suggests that compositional changes in the microbiome may play a role in this. 

Dr. Desmond has identified co-existing mild Crohn’s disease and ulcerative colitis when performing colonoscopies and gastroscopies on RA patients. This highlights the overlap between these conditions. 

RA-specific medications may also modify the gut microbiome. Notably, Dr. Desmond reports that examining individuals with chronic inflammation who are taking non-steroidal anti-inflammatory drugs (NSAIDs) often identifies adverse effects from the medication, such as damage to the gut lining, a reduction in the protective mucosal layer, and even ulceration. 

Steroid use also leads to various negative adverse effects, including damage to the gut lining and chronic formation of ulcers and bleeding. Within his practice, Dr. Desmond only prescribes steroids as a short-term intervention. From a gastroenterology perspective, he prescribes many newer immune-modifying medications, such as infliximab, adalimumab, and methotrexate. He states, “although we worry a lot about the side effects of these new expensive biologics, the medications that cause the most damage are corticosteroids”. 

The Power of a Plant-Based Diet and Exercise

This is why Dr. Desmond remains so passionate about dietary modifications. Suppose you have a patient with a chronic inflammatory gut or joint problem. In that case, plenty of evidence supports the positive effects of an unprocessed, predominately plant-based diet in reducing their inflammatory burden and their need for medication. Combining a whole food plant-based diet with the best available medicines can achieve the best outcome for the patient. For example, a study investigated the remission rates of patients with Crohn’s disease when combining infliximab with a plant-based diet. The researchers found that the combination treatment achieved a staggering 96% remission rate. 

Dr. Desmond also advocates for exercise’s positive effects on the microbiome’s diversity. In support of this, he mentions research published in BMJ in 2014, which shows elite rugby players have a much more diverse gut microbiota than the general population. 

Does the Microbiome Affect RA?

While routine microbiome analysis does not yet have a place in Dr. Desmond’s clinical practice, he is aware of the literature describing a level of gut dysbiosis in patients with RA, obesity, heart disease, colitis, and Type II Diabetes.

Research by Mayo Clinic’s Center for Individualized Medicine, published in Genome Medicine in 2021, shows that gut microbiome composition may be used to estimate RA disease progression. This suggests that the two are intricately liked. 

Is RA Caused by a Leaky Gut?

As gut health plays a role in RA, so too does the integrity of the gut wall. Microbial balance is essential for maintaining the health of the gut wall and preventing intestinal permeability, which can trigger RA flare-ups. 

Research has shown that RA patients present with increased serum markers for gut permeability. The same study also showed increased gut permeability in arthritic mice from an early stage of their disease.

Can Probiotics Cure RA?

Dr. Desmond tells us that he rarely recommends probiotics to his patients, with very few clinical scenarios being the exception. Although he agrees with the evidence for positive change as probiotics pass through the gut, this remains incomparable with the massive positive change resulting from implementing a wholefoods plant-based diet. 

Do Oils Disrupt the Microbiome?

According to Dr. Desmond, oils are energy dense and a source of unnecessary calories that we could eliminate if seeking to improve our health and reduce our body weight. However, he believes that if individuals wish to use one or two tablespoons of extra virgin olive oil per day, combined with a whole food plant-based diet, they should do so. Interestingly, olive oil is rich in polyphenols, shown in various population and mechanistic studies to help reduce atherosclerosis and possibly inflammatory markers. 

Contacting Dr. Desmond

You can follow Dr. Desmond via his Instagram account to learn more about his fascinating and exciting work. Also, check out the Plant Based Health Professionals UK website. Dr. Desmond is a former advisory board member and ambassador for PBHP UK.