The gut microbiome is the trillions of microscopic organisms that live inside your gut including thousands of species of fungi and bacteria. Your gut is your gastrointestinal (GI) tract with most of your microbiome being found in your large intestine. Every person has their own unique microbiome. First you inherit your gut microbiome from your mother and later your diet and other environmental exposures introduce new microbes to your biome. Some of these exposures can harm and reduce the quality of your gut microbiome while others can be beneficial. In other words, your lifestyle, especially your diet, directly impacts the health of your gut microbiome. A healthy gut microbiome is highly important to overall health.
Many of the microorganisms in our guts have a symbiotic relationship, a relationship that is mutually beneficial to people and the microorganisms that they host. Our bodies provide microorganisms with food and shelter and in exchange, they protect our health through important services such as keeping potentially harmful microorganisms in check. When your gut microbiome is healthy and thriving, you thrive, too and vice versa. An important function that the gut microbiome performs is that the bacteria within it helps to break down certain complex carbohydrates and dietary fibers that humans can’t break down on their own. They also produce short-chain fatty acids, an important nutrient, and the enzymes necessary to synthesize certain vitamins, including B12 and K. Deficiencies in micronutrients significantly impact overall health. Short fatty acids also benefit the immune system by maintaining your gut barrier. They keep the bacteria and bacterial toxins inside from escaping into your bloodstream and have anti-inflammatory properties. Additionally, gut bacteria help to metabolize bile in your intestines. In a process called enterohepatic circulation, your liver sends bile to your small intestine to help you digest fats and then bacteria and bacteria enzymes help to break down the acids for reabsorption and recycling in your liver. If this process stopped working, your body wouldn't have enough bile acids to produce new bile. In that case, your digestive system wouldn’t get the bile it needs to digest and absorb fats. The leftover cholesterol, one of the components of bile, would build up in your blood, leading to high cholesterol.
Your gut microbiome benefits your immune system by training it to tell beneficial microbes apart from the unhelpful, pathogenic types. Your gut is your largest immune system organ, containing immune cells that clear out many harmful pathogens daily. Healthy microbes compete with unhealthy microbes for nutrients so when the microbiome is diminished, chronic bacterial infections affecting the GI tract become more common. Your gut microbes also impact your nervous system through the gut-brain axis. The gut microbiome can influence our mental as well as our physical health through the gut-brain axis. Studies have shown a link between gut health and emotional well-being. It has been found that certain gut bacteria help produce neurotransmitters such as serotonin in the brain. Further, short-chain fatty acids appear to have positive effects on the nervous system, while bacterial toxins might damage nerves. Additionally, gut microbes and their products also interact with endocrine cells in your gut lining. Gut microbes secrete hormones that regulate parts of your metabolism, including blood sugar, hunger, and satiety. Your gut microbiome also impacts your risk of certain diseases such as Inflammatory Bowel Disease (IBD) and diabetes as well as the development of food allergies.
To have a thriving gut microbiome, a diet including a variety of plant fibers is necessary. A common American diet is high in processed foods, and is especially high in red meat, dairy, sugar, and saturated fats, which is less helpful to gut microorganisms. The typical American diet is low in fiber rich foods such as fruits, vegetables, and whole grains instead which reduces the variety of microbes in the digestive system. A diet based on highly processed foods can be problematic to your gut microbiome because they often lack fiber and micronutrients, vitamins and minerals. Highly processed foods also typically are made with many additives and preservatives that can be harmful to your microbiome. While some cases of a damaged microbiome are more severe than others, you can improve your microbiome by improving your diet. It has been found that a Mediterranean diet, a diet that is high in plant-based fiber from fruits, vegetables, nuts, and whole grains, can help to restore and maintain a healthy gut microbiome.
Not only does eating nuts increase microbiome diversity, but it has been found to have a prebiotic effect on the gut microbiota that can benefit gut function and gut symptoms. Eating nuts is also associated with a reduced risk of chronic diseases such as cardiovascular disease and type 2 diabetes. Nuts are especially important because they help fuel be slowly released to the gut. The unique structure of nuts means that valuable nutrients will reach the lower regions of the digestive tract where the majority of your microbiome is. Nuts are also rich in fiber and micronutrients such as magnesium and vitamin E which are important to a healthy gut microbiome. Further, nuts are an excellent source of both soluble and insoluble fibre which help the gut microbiome.
