By Cliona Byrnes, RD
The composition of our gut microbiome is continuously shaped by a variety of factors such as diet, stress, antibiotic use and even the seasons. It’s normal to have some “bad” or disease-causing bacteria. In a healthy gut, the good bacteria outweigh the bad. However, when there is an imbalance of bacteria, it can lead to dysbiosis of the gut microbiome which has been linked to issues such as obesity, cardiovascular disease, diabetes and gastrointestinal diseases such as irritable bowel syndrome. Read ahead for the top tips on supporting gut health.
1. Fill up on fiber
Studies have shown that dietary fiber intake influences the composition of the gut microbiota. While most nutrients are digested and absorbed in the small intestine, fiber is resistant to digestion and passes through to the large intestine where it is fermented by the microorganisms, increasing the number and diversity of the microbiota. The by-products of the fermentation also support the health of the cells lining the gut. The Dietary Guidelines for Americans recommend that adult women get at least 25g fiber per day, and men should aim for at least 31g, although over 90% of adults fail to achieve that target. You can read more on the benefits of fiber here and check out this article for our top tips on increasing your fiber intake.
2. Eat a variety of plant-based foods
Eating a range of plant-based foods such as fruit, vegetables, pulses, nuts, seeds, grains can increase the diversity of your gut microbiota. In fact, the American Gut Project found that people who ate 30 different types of plant per week had greater microbial diversity than those who ate 10 or fewer. Research has also found that there is a significant difference in the gut microbiomes of vegetarians and in those of meat eaters. Even if you don’t quite hit that level of variety, including a range of foods from plant sources in your diet is beneficial to your gut health...and maybe even your taste buds!
3. Consider probiotics and fermented foods
Probiotics are live organisms that have been shown to support gut health. Probiotics typically do not colonize your gut however, as they move through the gut, probiotics and their by-products interact with the cells in our gut which delivers health benefits. Fermented dairy products e.g. kefir and yogurt are some of the most common food sources of probiotics in our diet. While all fermented dairy products are made using live or active cultures, many products now have added probiotics e.g. Bifidobacteria or Lactobacillus that have been proven to have a beneficial impact on gut health. While fermented foods like kimchi, miso and tempeh are produced using live microbes, the method of processing e.g. pasteurization or baking may kill the beneficial microbes. However, eating fermented foods can still be beneficial to the health of the gut microbiota as fermentation leads to the formation of bio-available end products that have been linked to better gut health.
4. Don’t forget about prebiotics
Prebiotics are a form of dietary fiber that can be used by microorganisms in our gut, essentially “feeding” the good bacteria which leads to beneficial changes in the composition of the gut microbiota. While there are many types of prebiotics, the most common are found in resistant starches, inulin and pectin. Inulin rich foods include onion, leek, asparagus and garlic. Pectin is found in apples, raspberries, tomatoes and green beans. As the name would suggest, resistant starches resist digestion and are fermented by microorganisms in our gut to produce short-chain fatty acids like butyrate which play an important role in the maintenance of gut and metabolic health. Resistant starch is found in foods like oats, legumes, and cooked and cooled potatoes and rice.
5. Other lifestyle considerations
Managing stress is important to supporting gut health as stress can negatively affect the microbiome. Interestingly, the composition of our gut microbiome can also impact how we handle stress due to the gut-brain axis, or the system of communication between the gut and the brain. This explains why you may experience butterflies in your stomach when you feel nervous or why we sometimes have a “gut instinct”. As alcohol can be an irritant to the gut, drinking in moderation will support your overall health and wellbeing, as well as your microbiome. Exercise helps to support gut health by keeping your bowel movements regular, and research has found that frequent physical activity is associated with increased microbial diversity.