Gut check: The role of clinical nutrition in managing digestive diseases

We’re told to trust our guts — but sometimes we’re not exactly sure what our stomachs are trying to tell us. People suffering from digestive diseases may experience serious pain, discomfort, and distress. And according to a recent American Gastroenterological Association survey, forty percent of Americans report their daily lives are disrupted by digestive troubles. 

May is National Digestive Disease Awareness Month, and Levi Teigen, PhD, RD, assistant professor in the U of M’s College of Food, Agricultural and Natural Resource Sciences Department of Food Science and Nutrition, shares some insights on the role clinical nutrition can play in managing digestive diseases. 

What are some of the most common digestive diseases affecting people today and why are they so problematic?

The most common digestive disorder seen in clinics is irritable bowel syndrome (IBS). Abdominal pains and cramps constitute the major symptoms of IBS, but symptoms also include bloating and diarrhea or constipation (or both). Experiencing symptoms of IBS reduces quality of life and can often be particularly frustrating for patients because of difficulty in management. The main driver of IBS is thought to be a disorder of gut-brain communication, where normal activities of the gut are perceived as pain and discomfort. There may be other factors, such as bile acid malabsorption or altered activities of gut microbes. 

IBS is distinct from inflammatory bowel disease (IBD), of which ulcerative colitis and Crohn’s disease are the most common. IBD affects ~ 1% of the US population. In IBD there is gut inflammation, which is thought to be driven by an imbalance in the interactions of the immune system with the gut microbes. Common symptoms of ulcerative colitis include diarrhea, fecal urgency, and rectal bleeding. The same symptoms can be also seen in Crohn’s disease, although patients commonly experience more abdominal pain and develop complications requiring multiple surgeries.

Finally, colon cancer unfortunately remains a big problem. It is second only to lung cancer in cancer deaths in the U.S., and its incidence is increasing particularly in younger people. The timing to initiate colon cancer screening has already moved from 50 years of age to 45. 

How can clinical nutrition be applied to address digestive diseases?

Clinical nutrition plays a critical role in supporting patients impacted by digestive diseases. There are generally two primary roles for clinical nutrition. The first is support of a patients’ nutritional status, which includes calorie and protein intake as well as any potential vitamins or minerals of concern based on symptoms. The second role for clinical nutrition is to help minimize symptoms. Oftentimes these two things are addressed independently of each other. We are developing and studying diet therapies that address the metabolic demands of disease while considering symptom management as well (and health of the gut microbes).

Can clinical nutrition prevent digestive diseases from occurring? 

The role of nutrition in prevention of disease (including but not limited to digestive diseases) is something that we are particularly interested in studying. We are uniquely well positioned to study the preventative role of nutrition in digestive diseases at the level of the gut microbiota here at the University of Minnesota because of clinician researchers like Dr. Alexander Khoruts and Dr. Byron Vaughn and the Microbiota Therapeutics Team. Dr. Khoruts has been a pioneer in microbiota transplant therapy (often referred to as fecal microbiota transplant). Microbiome transplant therapy trials can provide direct evidence for the role of the gut microbiome in health and disease and offer unique insight into the potential role of, and targets for, gut-microbiota targeted diet therapies. 

Could you talk about the role of the gut microbiome and how gut microbiome targeted diet therapies work? 

The gut microbiome is metabolically active and exists in a symbiotic relationship with the rest of our bodies. We can influence the activity of the microbiome, in part, through the food that we eat. In essence, whatever doesn’t get absorbed in our small intestine makes its way to our large intestine and represents food for the microbes. This nutrient flow helps shape the activity and metabolic output of the microbes. This can be harnessed to either increase certain outputs by the microbes or, similarly, reduce outputs. For example, hydrogen sulfide is a metabolite produced by the gut microbiota that has been implicated in ulcerative colitis and development of colon cancer. We demonstrated that hydrogen sulfide production can generally be decreased with increased fiber intake. However, this effect was not consistent across participants, which is where this gets more complicated. Everyone has a very distinct microbiome composition, which poses a challenge to studying gut microbiome targeted diet therapies. Fortunately, our unique access to microbiome transplant therapy recipients allows us to study the role of diet on microbiome composition and function on a defined microbiome coming from a select number of donors.  

Is there anything else people should know about clinical nutrition's role in managing digestive diseases?

We have barely begun to scratch the surface of the role of nutrition in managing digestive diseases. Unfortunately, it has not received much in the way of attention or funding historically, but it has enormous potential to improve patient care. Through continued research we hope to advance the paradigm of clinical nutrition management of digestive diseases and improve patient outcomes and quality of life.