Humans are complex organisms with bones, organs, and tissues that are made up of trillions of individual cells. What many people don’t realize, though, is that our cells aren’t alone; in fact, our bodies also contain an equal or greater number of single-celled microorganisms called bacteria. While bacteria are present all around the body, the largest concentration is found in the large intestine and other parts of the gastrointestinal system.
It is because of this connection with digestion that recent research has been focused on the impact of our lifestyle choices on the health of these naturally present “good bacteria,” collectively referred to as microbiota or the microbiome. Studies have shown that the foods and beverages we consume can all have an effect on our gut health. Some foods hamper the growth or function of bacteria, but some can actually improve the microbiome. One specific area of research that seems promising is in probiotic foods.
Facts About the Microbiome
To understand probiotics and their potential benefit, it’s first helpful to look at the gut microbiome and its symbiotic relationship with the human body. As this is a relatively new avenue of research, scientists don’t yet have a complete picture of that relationship. However, there are some benefits that have been identified:
- Pathogen defense: Our “good bacteria”can actually help us by defending against harmful bacteria by crowding out pathogens. By simply existing in larger numbers, our beneficial gut bacteria essentially starve some types of harmful bacteria by fully utilizing the substances that fuel their growth. Some beneficial bacteria can even produce enzymes that specifically seek out and eliminate pathogens.
- Improved immune function: Though the immune system uses inflammation to help eliminate pathogens, sometimes it backfires and accidentally causes additional health problems. Some kinds of microbiota have been shown to improve this process and decrease the chances of having inflammation problems.
- Synthesizing Nutrients: Part of the reason we eat food is to get nutrients our cells can’t get from anywhere else. Amazingly, the microbiome can actually synthesize some of these necessary nutrients that might be lacking in terms of dietary sources. Examples include: vitamin B12, vitamin K, and short chain fatty acids (SCFA).
- Gut-brain axis: The function of the gastrointestinal system is controlled by a part of the autonomic nervous system called the enteric nervous system. Research into the microbiome in recent years has revealed a deep connection between the central nervous system and the digestive system that doctors refer to as the “gut-brain axis.” Mounting evidence suggests that the health of the microbiome is strongly related to digestive health and overall health.
What are Probiotics?
Probiotics are live microorganisms that can be introduced to the gastrointestinal tract in order to supplement the naturally occurring bacteria. In a sense, probiotics are the opposite of antibiotics; where antibiotics are meant to eliminate or counteract harmful bacteria, probiotics aim to bolster or restore beneficial bacteria. Though research is ongoing, there currently is no scientific consensus about the purported benefits of probiotics.
What some studies have shown, however, is that probiotics can add to the total amount of gut bacteria while also spurring the growth and activity of the microbiome. The most effective types are those that are the same or similar to existing gut bacteria. Two of the most common strains used are part of the Lactobacillus and Bifidobacterium groups. While questions about the benefits of probiotics remain, side effects are exceedingly rare and should therefore be safe for most people.
Because of the nature of the microbiome and the gut-brain axis, the potential benefits of probiotics are wide-ranging. There has already been evidence that probiotics improve intestinal health and immune response as well as reduce cholesterol and prevent some types of cancer. But even beyond particular gastrointestinal problems, probiotics may even indirectly have a positive impact on neurological or psychological conditions.
More research needs to be done to further establish the benefits of probiotics, and that is particularly true for probiotic supplements that often come in pill form. This is partly because of the difficulty in selecting the right combination of bacterial strains. But this is less of a concern when dealing with probiotic bacteria that are naturally found in certain cultured foods. Below are some food and beverage options that contain probiotics:
- Yogurt: Perhaps the most famous source of probiotics, yogurt is produced by fermenting milk with yogurt cultures. The strains of bacteria involved in yogurt fermentation are similar to our microbiome, so it can have a restorative effect and help reduce the symptoms of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD).
- Kefir: Kefir is a fermented milk drink that originated in Eastern Europe and has the consistency of very thin or watery yogurt. The kefir grains added to milk are actually cultures of lactic acid bacteria. Kefir is thought to have similar benefits as yogurt.
- Sauerkraut: Lactic acid bacteria is also the agent used to ferment the shredded cabbage in sauerkraut, a national dish of Germany that has a distinctive sour flavor. In addition to digestive health benefits, sauerkraut contains antioxidants and valuable nutrients.
- Tempeh: This traditional Indonesian food is made from fermented soybeans and served in the form of a flat cake. The fermentation process improves the nutritional value of the soybeans in part through the synthesis of vitamin B12, an important vitamin involved in metabolism.
- Kimchi: Kimchi is a spicy, fermented Korean side dish that is commonly made with cabbage or other vegetables. The bacteria involved in fermentation make it beneficial for digestive health in multiple ways.
- Miso: Miso is a Japanese seasoning that is also made from fermented soybeans, in this case with salt and the koji fungus. Studies have linked miso with a number of health benefits, including reduced risk of stroke and breast cancer.
- Kombucha: Made from fermented black or green tea, kombucha is purported to have numerous health benefits, but little evidence supports these claims.
- Pickles: The skin of cucumbers naturally contain the Lactobacillus bacteria necessary for the fermentation of pickles. Like other foods that feature this bacteria, they can have a positive impact on digestion.
- Natto: Like tempeh and miso, natto is made from fermented soybeans. In this case, however, whole soybeans are fermented with Bacillus bacteria. Natto contains vitamin K2 and may improve bone and cardiovascular health.
- Cheese: Some types of cheese, typically those that have been aged but not heated afterwards, have live cultures of beneficial bacteria that have health benefits. Examples include mozzarella, gouda, and cottage cheese.
- Sourdough: The starter dough of sourdough bread involves a fermentation process that gives the bread its unique flavor. Yet the probiotic bacteria that thrive during fermentation are destroyed in the baking process. Nevertheless, sourdough bread still is beneficial for digestion since it contains more fiber and improves nutrient absorption.
Be Proactive About Digestive Health
Eating more foods with probiotics can only be beneficial, in part because of the other nutritional value these foods tend to have. But if you have significant digestive health problems, minor diet changes may not be sufficient. If you have been experiencing significant symptoms and would like to speak with a gastroenterologist, please contact us at Cary Gastro to request an appointment. Our staff is dedicated to providing high quality, compassionate health care.