GUT MICROBIOTA AND NUTRITION NEWSLETTER #27
March 2021
Dear friends,
This month’s newsletter looks in depth at the concept of “gut health”, starting with a new publication on what it really means. We then share two articles on diet for reducing uremic toxins, a review on salt and cardiovascular health, and study on intestinal permeability in IBD. This is followed by two great resources: a newly published continuing education course package on probiotics, prebiotics and fermented foods -- as well as a great summary of the research on gut microbiota and IBS by leading gastroenterologist, Dr. Eamonn Quigley
Grab a big salad and enjoy reading! Your gut will thank you.
Natasha and Kristina
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Boosting your ‘gut health’ sounds great. But this wellness trend is vague and often misunderstood
"Gut health" is a term that we hear (and use!) a lot lately. And without a doubt, our gut health is critically important to overall health. But the definition of gut health is still somewhat vague. Should we define it simply as the lack of diagnosed digestive disease, or should we specify that gut health requires being free of digestive symptoms or having some 'optimal' gut microbiota composition? Heidi Staudacher & Amy Loughman just published an article in The Lancet Gastroenterology & Hepatology on the meaning of gut health -- and while the article itself is paywalled, they summarized their discussion nicely for an article in The Conversation.
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The Role of Dietary Fiber Supplementation in Regulating Uremic Toxins in Patients With Chronic Kidney Disease: A Meta-Analysis of Randomized Controlled Trials
Research has suggested that, in general, increased dietary fiber is beneficial for those with chronic kidney disease (CKD) -- but how does it work, and how should it inform recommendations in clinical practice? A new meta-analysis of trials shows dietary fiber supplementation indeed reduces levels of several uremic toxins: indoxyl sulfate, p-cresyl sulfate, blood urea nitrogen, and uric acid. The form of fiber supplementation included resistant starch, inulin, fructo-oligosaccharides, and polydextrose.The dosages varied from 90 mL/day to 25 g/day. The duration of the intervention varied from 4 to 12 weeks, with a median length of 7 weeks. The authors concluded that supplemental dietary fiber can be used as an auxiliary method to reduce uremic toxins in patients with CKD with a modest benefit in CKD patients on dialysis or without diabetes.
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Associations Among Plant-Based Diet Quality, Uremic Toxins, and Gut Microbiota Profile in Adults Undergoing Hemodialysis Therapy
Keeping to the topic of uremic toxins: diet is a potential way to influence uremic toxin production by the gut microbiota in people undergoing hemodialysis. A small trial (n=22) of older adults receiving hemodialysis treatment found that better adherence to a plant-based diet was associated with lower levels of indoxyl sulfate, an important uremic toxin. In fact, those who showed higher adherence to a plant-based diet had lower abundances of Haemophilus species in their guts -- species which tend to correlate with levels of indoxyl sulfate. This was an association study, so authors suggest follow-up dietary intervention trials to determine whether the plant-based diet caused the reduction of uremic toxins in this population.
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A cross-talk between gut microbiome, salt and hypertension
It's well established that high salt intake is associated with poor cardiovascular health -- but how are they linked on a biological level? The authors of this review try to reconcile dietary data with emerging data on how gut microbiota affect the emergence of coronary artery disease. They propose a three-way relationship between diet (in this case, salt intake), the gut microbiota, and hypertension. It's possible that the situation with salt intake could parallel emerging perspectives on red meat & cardiovascular disease, in that the gut microbiota may (partially) determine the effects of dietary components on disease development.
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Functional Food Components, Intestinal Permeability and Inflammatory Markers in Patients with Inflammatory Bowel Disease
Intestinal permeability & gut inflammation are intricately linked in inflammatory bowel disease, but scientists are still sorting our cause-and-effect as well as which dietary components might have an effect on excess gut wall permeability. This small study explored the effects of food components on both intestinal permeability and inflammation in people with and without IBD -- and while the researchers didn't find any specific foods that clearly improved intestinal permeability, they saw a (non-significant) trend toward reduced digestive symptoms with their dietary intervention. This area is worthy of more study.
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ISAPP publishes continuing education course for dietitians
What are the latest evidence-based uses of probiotics, prebiotics, and fermented foods? Find it all here in this Special Continuing Education Supplement in Today’s Dietitian. The International Scientific Association for Probiotics & Prebiotics offers this continuing education course and bundle of resources, which is accessible online for everyone -- and worth 2.0 CPEUs for US dietitians.
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The Microbiome — Can it aid in the diagnosis and therapy of irritable bowel syndrome (IBS)?
As dietitians know, diagnosing and treating irritable bowel syndrome (IBS) can be challenging -- not least because each case of IBS looks very different from the next. Can the gut microbiota research to date give us insights into better managing this condition? Gastroenterologist Dr. Eamonn Quigley provides an excellent summary of the research about gut microbiota in IBS, including how the microbiota-gut-brain axis relates to the psychological symptoms (anxiety, depression) that often occur. Quigley explains recent research progress, including lessons from multi-omics (molecules produced that contribute to symptoms); food-related symptoms; other microorganisms besides bacteria; and fecal microbiota transplantation.
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Microbiome, inflammation, gut health & disease
Doug Cook, RDN, interviews Natasha on this podcast covering the topic of microbiome, inflammation, and gut health. Hear more about their discussion on prebiotics, probiotics and fermented foods with tips on how to improve your overall gut health.
The podcast is available here on Spotify.
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Gut health: A key to unlocking better health and wellbeing
If you work with clients who have inflammatory bowel disease, check out this recent lecture for UBC Healthy Living & Chronic Disease Prevention, given by Natasha, along with her PhD supervisor Dr. Deanna Gibson of UBC Okanagan and patient advocate Gerald deVeer. The webinar contains practical advice for diet in IBD and summarizes what we're learning about gut microbes and inflammation.
The webinar is available here on YouTube.
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Natasha’s Opinion: What do you tell clients looking to improve their gut health?
As the researchers continue their quest to determine the diet for optimizing “gut health”, in parallel our clients want to know what they can do now. Personalized nutrition advice based on one’s microbiome is in its early stages, so what can nutrition professionals safely recommend?
My PhD work looks at the effects of diet on the microbiome in patients with Ulcerative Colitis. Through extensive review of the literature in this field, I believe the concepts of a Mediterranean-like eating pattern could be recommended to improve gut health – at least until we have the information to create personalized nutrition plans.
The Mediterranean-like eating pattern is rich in vegetables, fruits, legumes, nuts, and olive oil, and limited in red meats and refined grains. The diet has been associated with reduced risk of developing a variety of diseases, including cancer, inflammatory bowel disease, cardiovascular disease and Alzheimer’s to name a few. The increase in plant-based foods in the Mediterranean-like eating pattern, generally leads to a higher fibre intakes which are associated with the degradation of fibers by the microbes with subsequent production of short-chain fatty acids in the gut, specifically increased production of butyrate.
Although more research is needed, I have provided a few tips, based on the current state of evidence, that nutrition professionals can provide their clients asking how to improve their gut health.
- Change the way you think about fats. Include sources of healthy fats in daily meals, especially monounsaturated fats, or MUFA (i.e., extra-virgin olive oil) and limit omega-6 fats (e.g., soybean, corn, safflower, sunflower oils). Goal: 1 tbsp of MUFA at each meal.
- Encourage omega-3 fatty acid intake from food, not supplements. Fish such as tuna, herring, salmon, and sardines are rich in omega-3 fatty acids, and shellfish including mussels, oysters, and clams have similar benefits for gut health. Goal: 2 meals from fish or seafood per week.
- Change the way you think about meat. Red meat once every two weeks, white meat twice/week, vegetarian dish minimum once/week.
- Enjoy two servings of dairy products. The Mediterranean diet includes full-fat dairy from milk, yogurt or cheese.
- Increased intake of vegetables. Goal: 2 servings at each main meal.
- Cook a vegetarian meal one night a week. Build these meals around beans, whole grains and vegetables. When one night becomes comfortable, try two nights per week.
- Switch to whole grains. Cook traditional Mediterranean grains such as bulgur, barley, farro and brown, black or red rice, and favor products made with whole grain flour. Goal: legumes 2 servings per week with 1-2 servings of whole grains per meal.
Resources:
If you are looking for some fantastic resources, I highly recommend Old Ways.
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