The gut microbiome is composed of trillions of beneficial and potentially harmful bacteria (such as E. coli), viruses, and fungi. Dietary choices and lifestyle habits are two of the most influential aspects to a person’s health and disease status, but emerging research on the gut microbiome is challenging how we think illness and disease develop.
From the moment we’re born we are exposed to a variety of bacteria and organisms. Babies born vaginally are introduced to various bacteria as they pass through the mother’s birth canal, and then through skin-to-skin contact with each parent and from breast milk. All of these exposures are pivotal in building a diverse community of bacteria, viruses and fungi throughout the body. Our eyes, nasal cavity, and mouth each have a unique microbiome. Different parts of the digestive tract contain different types of bacteria present, based upon the conditions they are suited to survive in. One of our most important microbiomes lies within the large intestine, otherwise known as the gut.
Here are some common health concerns that doctors believe are linked to our gut microbiome:
Understandably, it can be hard to appreciate, or care about, the vital role our gut microbiome plays if it doesn’t have an obvious impact on our daily life. However, digestion is something most people have at least had some experiences with. Issues with bloating, constipation, diarrhea or having a diagnosis of Irritable Bowel Syndrome (IBS) or Irritable Bowel Disease (IBD) are all linked to gut health. Gut bacteria eat fiber from plant foods, resulting in the production of a group of compounds called short chain fatty acids (SCFA). These SCFA then feed your colon cells, keeping them alive and well.
Obesity and Metabolic Disorders
Multiple factors will determine how much a person weighs, but one of the more interesting pieces to the obesity epidemic is the role of the microbiome. Gut bacteria can affect a person’s metabolism by several mechanisms including the production of certain SCFA which affect how hungry someone feels, insulin resistance, and increased extraction of energy from food.
Have you ever had a “gut feeling” about something? That’s your brain and gut talking with each other through a complex network of neurons. 90% of serotonin (a “happy” chemical) and other important neurotransmitters that control mood are produced by gut bacteria, and we are seeing a link between poor gut health and lack of diversity in gut bacteria and mood disorders like depression and anxiety.
One of the most exciting areas of research, for me personally, is around sleep and the gut circadian rhythm. Many people who are night shift workers or experience frequent interruptions in sleep are at increased risk of being overweight, obese, or suffer from a number of digestive issues. While the exact mechanism is unclear and certainly multifactorial, research suggests these disruptions in sleep change the microbiome.
Eating more fiber and less saturated fat is one of the hallmark recommendations for preventing cardiovascular disease and type 2 diabetes. But, we now understand nutrients in food impact the diversity of our microbiome. For example, the Standard American Diet which is high in animal protein and fat and low in fiber decreases bacterial diversity and allows certain less beneficial bacteria to grow in numbers. In addition to changing the ratio of helpful-to-harmful, the bacteria themselves produce compounds which further help or harm our health.
What if I told you that the REAL way to support your immune health was through a healthy gut? Yep. Gut bacteria help regulate a person’s immune system. It’s complex and external factors, such as antibiotic use, also contribute to the health of someone’s immune system, but the bacterial balance in your gut is critical to immune health. Does this mean you need to run out and buy probiotics? NO!
How Do We Maintain a Healthy Microbiome?
We can’t yet say what the ideal balance of bacteria looks like, but one thing we do know is each strain of bacteria plays a role in our health so a diversity of species is critical. Here are three things you can do to get your gut back on track:
1. Eat a whole-foods plant-based diet!
Fiber doesn’t get enough credit, but it truly is a superfood and you only find it in plants. A well-planned whole-foods plant-based (WFPB) diet can provide the diversity and adequacy of fiber needed to feed various types of gut bacteria. Furthermore, a WFPB diet by nature excludes the foods and ingredients that negatively impact gut bacteria.
A note about prebiotic fiber: Gut bacteria need prebiotic fibers to survive and thrive. You find prebiotics fibers in: garlic, onions, leeks, asparagus, chicory, artichokes, bananas, whole grain corn, whole grain wheat, oats, and soybeans.
2. Probiotics from Fermented Foods
Fermentation is a food preservation method that allows bacteria to grow. It is a way to ingest beneficial bacteria, often referred to as probiotics. Any naturally fermented product will contain these “good guys”. Here are a few plant-based options:
- Fermented vegetables
- Sauerkraut & pickles (not the kind made with vinegar)
- Sourdough bread
- Cultured non-dairy yogurt
3. Maintain a Healthy Lifestyle
Remember, poor sleep and too much stress negatively impact your gut. Be kind to yourself and find ways to include self-care and gentle exercise in your daily routine. If you’re having trouble sleeping for a long period of time, it may be wise to check in with your doctor.
What Negatively Alters Our Microbiome?
So we know what we can do to feed the “good guys” in our gut, here are some things that can have a negative impact on your flora:
- Not enough dietary fiber – Most Americans only consume half of the recommended 25-35 grams of dietary fiber per day.
- Limited variety of dietary fibers – prebiotic fibers
- High-fat diets: increases the ratio of certain bacteria that promote inflammation
- Stress: the stress hormone, cortisol, can weaken the intestinal lining making it more permeable to bacteria
- Poor sleep or altered sleep patterns
- Too much animal protein
- Some ingredients found in processed foods, like emulsifiers and sweeteners
The role of the gut microbiome and our health is becoming increasingly important. With more research we are seeing just how complex and important diet and health are. We can also see how vital a whole foods plant-focused diet is! Research on the microbiome offers even more insight as to WHY certain nutrients affect our body in certain ways. I’m excited to see what future research on the microbiome will reveal.
by Christina Archer
Christina Archer is a registered dietitian with a master’s degree in Nutritional Science, board certification in Integrative and Functional Nutrition through the Integrative and Functional Nutrition Academy and currently works for Sansum Clinic where she provides individualized medical nutrition therapy as well as nutrition and lifestyle recommendations to optimize health.
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National nutrition guidelines are continuing to shift plant-forward! The American Cancer Society recently updated its...
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