Updated: Feb 12
Gut health is a popular topic in nutrition nowadays for several reasons: Increased prevalence of gut associated health conditions such as IBS, IBD, celiac; common digestive issues such as constipation or diarrhea; newly discovered communication pathways between the brain and gut; as well as relationships between gut bacteria
and a typical Western diet and lifestyle. For example, the damaging effects on gut health via a diet low in fibre, and high in processed foods, as well as non-dietary factors like frequent broad spectrum antibiotic and antimicrobial product use. That said, many factors have been identified that improve gut health by increasing beneficial bacteria types and amounts, which in turn may positively impact health.
It is indeed reasons such as these, that the food and medical industry are rapidly creating products with prebiotic (the food bacteria eat), probiotics (the live bacteria), and more recently postbiotics (the beneficial metabolic molecules produced from microbes), to enhance the health of your gut microbiome. But there is more to this story, which is explored below.
1. The gut microbiome is the collection of bacteria that live in your gut, and contribute to many aspects of health.
2. Add more fibre, prebiotic, and probiotics to your diet from a variety of whole foods to improve gut health.
3. Optimize health of your gut by including other beneficial activities such as mindfulness-based stress reduction and physical activity.
What is the gut microbiome?
Consider this, there are more bacterial cells in your gut than human cells that make up your body. If you stretched out the entire surface area of the human intestine, you would get the size of half a badminton court. That’s a lot of real estate. This is the home for your gut microbiome - the collective community of microbes that inhabit your gut.
The story on how your gut health evolves starts from birth, differing if you were born by cesarian or traditional delivery. For example, the first bacteria that colonize the gut of those born by cesarian have been noted to be the same found on the skin cells of the doctor delivering the baby. In traditional delivery, the first bacteria to colonize baby’s gut come from the birth route and surrounding area. Interestingly we also see those born by cesarian have increased prevalence of allergy and asthma. An association, not a definitive causation, but what could gut bacteria have to do with the immune system?
During the first year of life, your immune system develops together with the bacteria populating your gut, creating the initial “fingerprint” of gut microbes. As this dynamic relationship evolves, an ecosystem of bacteria finds their niche along your gut. They are not only tolerated by your immune system, but in many cases are symbiotic, or mutually beneficial to you and your health. Over the lifespan, this microbiome “fingerprint” evolves based largely on your environment, including diet.
It’s a lifelong partnership
These little microbes form an interdependent relationship with your body, taking advantage of living in your nutrient rich gut, and in turn providing benefits such as stimulating your immune system, improved digestion and absorption of food, preventing “bad” bacteria from causing infections, and maintaining the integrity of
your gut. The benefits don’t stop there. Researchers have identified that the molecules these microbes produce participate in two-way communication with many of your organs including your lungs, skin, and brain.
Furthermore, when there is an imbalance of bacteria in your gut, something known as dysbiosis, researchers are seeing evidence towards development of allergic or autoimmune diseases, influences on chronic disease, weight and obesity, as well as psychological conditions including mood and anxiety disorders. Research is still new and expanding regarding these complex relationships, but sufficed to say this is an area that fascinates researchers and medical professionals from many fields. It is an area that is still relatively poorly understood, abundant with misinformation on the web, and an area most individuals would benefit from learning more about in their health journey.
What do beneficial gut bacteria eat?
All the foods that you do, and their favourite food is fibre! Fibre (plural) is a diverse type of nutrient found in many types of whole foods. Adult women need 25 grams of fibre per day and men need 38 grams of fibre per day, and on average most Canadians do not meet even half of this.
And perhaps this is part of the reason why researchers are seeing a massive decrease in microbe abundance and diversity in those who consume a typical Western diet high in processed foods, and low in fibre. Indeed, indigenous populations in places such as Papa New Guinea who consume a diet entirely consisting of whole foods rich in fibre have almost triple the diversity of gut bacteria as those in the West, and enjoy a life without non-communicable diseases we see in the West such as diabetes, obesity, heart disease, and more. Caveat is they have higher prevalence of communicable infectious diseases, so just like everything in life, we sacrifice one thing for another. Necessitating a need for balance. There is also a “too clean hypothesis” existing among researchers suggesting that in our attempt at controlling the bad bacteria out there, we inadvertently do damage to the good, such as those in our gut. This warrants ongoing investigations how our diet and lifestyle impacts gut health, and even how this relates to society and culture.
What does gut health have to do with weight management?
A persisting idea in diet culture as it relates to weight management is the concept of “calories in must equal calories out”. This assumes that each calorie we eat, we absorb and either store or use for energy. But consider, if the trillions of bacteria in your gut also eat what you do, where does this fit in to the equation? How does this impact the calories we absorb if bacteria are standing (figuratively speaking) at the in-between?
Research has not uncovered all the answers, but there are numerous studies implicating specific gut bacteria populations as higher or lower in individuals who are obese or overweight vs. those who are not.
There are also many proposed biological mechanisms, such as regulating our hunger and satiety hormones. So having specific types of beneficial microbes in your gut may play a role in metabolism, appetite, and consequently weight. While there is still more research needed in this area, most researchers agree that a high fibre diet is the number one way to ensure health of your microbiome. Additionally, fibre contributes to
satiety and feelings of fullness independent of gut bacteria, and are an important dietary component of any sustainable weight loss strategy. Double bonus for increasing fibre in your diet!
What else does the research say?
Gut health research has exploded, with research papers growing exponentially since the early 2000’s implicating lifestyle aspects, even including the importance of physical activity in supporting a healthy microbiome. Exercise can determine changes in your gut bacteria that play a positive role in energy homeostasis and regulation.
We are seeing a role for the gut microbiome in anxiety and mood disorders, which are also on the rise. The gut-brain axis is a two-way communication that needs to be further understood in relation to holistic interventions that go beyond medications and diet. Since this connection is two-way, mindful based lifestyle strategies may be beneficial.
We are also seeing cures for life-threatening conditions such as C. difficile infections by performing what is known as fecal transplantation aka the poop pill. While this therapy is not exciting, if not disgusting to consider to most, it nonetheless underpins rationale for further investigative research on novel therapies in medicine.
The research and academic literature is expanding, and with any field that is (relatively) new in its inception, there is many contradicting or unclear relationships that require further research. Until then, enjoy colourful, fibre rich foods in abundance, speak with a dietitian versed in gut health, and be amazed at the incredible symbiotic relationship that you can support through your diet and lifestyle.
Should I take a supplement of probiotic or fibre?
Certainly, if your diet is low, supplements such as Metamucil, psyllium husk, or bran buds may help. Fibre has many functions that go beyond supporting bacterial happiness and health. Fibre can aid in digestion, keep you regular, help to lower cholesterol, help control blood sugars, and regulate appetite. While supplementing fibre can be a good strategy, I do recommend to try and get your recommended fibre intake from consuming a diet rich in whole unprocessed foods. There is really no supplement that can substitute for all the diverse fibre types and nutrition we find from having a balanced diet.
High fibre foods include: Vegetables, fruits, whole grains, legumes, nuts, and seeds.
Probiotic supplementation is also presenting as an interesting strategy. For example, probiotic therapy is sometimes warranted in treatment and or management of digestive conditions such as IBS, a syndrome affecting an estimated 1 in 7 people. But probiotics (in food or supplements) are to be taken regularly. Your microbiome “fingerprint” is relatively static at any given point. So the takeaway is that eating probiotic foods
can improve your gut health transiently during the times you consume them, and regularly if you consume them often as part of your lifelong dietary approach.
Probiotic foods include: Yogurt, kefir, kombucha, sauerkraut, kimchi, miso.
How to improve gut health – Top 7 Tips
Eat a variety of fibre rich foods including vegetables, fruits, whole grains, legumes, nuts and seeds.
Include more prebiotics (fibre) and probiotics in your diet.
Include more antioxidant and polyphenol-rich foods, found in colourful fruits and vegetables, and green tea.
Avoid ultra-processed foods.
Exercise regularly to enhance the number of beneficial microbes.
Take antibiotics only when necessary and prescribed by your doctor.
Book an appointment with your resident Preventous dietitian – let’s find strategies unique to you and your diet!
Variety is key, and a good rule of thumb is the more colourful your plate of whole foods, the more diverse nutrition you are feeding your gut microbes.
One last practical tip - I often highlight to clients the benefits of legumes, due to them being an excellent source of plant based protein and fibre. Try a legume-focused dinner once per week. I can recommend the Alberta Pulse Growers recipes for ideas. They have a great selection of vegetarian and non-vegetarian recipes that incorporate legumes.
One last disclaimer – there are medical indications where increasing fibre is not indicated. If you have a specific medical condition, speak with your medical provider if you have questions about whether or not you should be adding more fibre to your diet.
Thanks for reading!
Are you looking for ways to improve your gut health? Would you like to learn more about this evolving area of nutrition science as it relates to your health?