Written by Azadeh Khiabani, Ph.D. in Food Biotechnology
What is the microbiome?
The microbiome is the collection of all microorganisms, including bacteria, fungi, and viruses. Trillions of these microbes exist mainly in the gut and on the skin, with the majority found in the large intestine, known as the gut microbiome.
While various types of microbes inhabit the human body, most research has focused on bacteria. Surprisingly, the number of bacterial cells in the body exceeds human cells, with approximately 40 trillion bacterial cells compared to 30 trillion human cells. Furthermore, there are over 1,000 bacterial species in the human gut microbiome, each playing a unique role in the body. Many of these bacteria are crucial for maintaining good health, while others have the potential to cause disease. Collectively, these microorganisms may weigh around 1 to 2 kilograms, nearly equivalent to the weight of the human brain. Acting as an additional organ in the body, they play a significant role in human health.
How does the microbiome benefit the body?
Humans have evolved to coexist with microbes for millions of years. Microorganisms play vital roles in the body, and without the gut microbiome, survival would be challenging. The gut microbiome begins to impact the body from birth, with exposure to microorganisms occurring during passage through the birth canal. As humans grow, the diversity of the gut microbiome expands, creating different types of microbial species. This increase in diversity is beneficial for human health, with the food consumed directly influencing the variety of intestinal bacteria.
How does the microbiome impact the body?
The intestinal microbiome can affect the key functions of the body and thus human health in various ways. In this section, we will explain some of these impacts.
- Digestion of breast milk
Some of the bacteria that initially grow in a baby’s gut are called Bifidobacteria. These bacteria play a crucial role in digesting the healthy sugars present in breast milk, which are essential for growth.
- Fiber digestion
Certain bacteria in the gut are responsible for digesting fiber and producing short-chain fatty acids that are vital for gut health. Consuming fiber may help prevent weight gain, diabetes, heart disease, and the risk of cancer.
- Regulation of the immune system
The gut microbiome is involved in regulating the immune system. It can influence the body’s response to infections by communicating with immune cells.
- Impact on brain health
Recent research suggests that the gut microbiome can also influence the central nervous system, which controls brain function. Some bacteria can produce neurotransmitters in the brain, such as serotonin, which is important for mood regulation. The gut is connected to the brain through millions of nerves, allowing the gut microbiome to affect brain health by controlling the messages sent to the brain. Additionally, certain probiotics can improve symptoms of depression and other mental health disorders.
- Influence on body weight
The balance of different types of bacteria in the gut is crucial for overall health. An imbalance, known as dysbiosis, can lead to weight gain and various diseases.
- Impact on gut health
The microbiome plays a role in gut health and may contribute to gut diseases like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Imbalances in the gut microbiome can cause symptoms like bloating, cramping, and abdominal pain. However, certain healthy bacteria, like bifidobacteria and lactobacilli found in probiotics, can improve gut health and prevent disease-causing bacteria from adhering to the intestinal wall.
- Contribution to heart health
The gut microbiome may also affect heart health by influencing cholesterol levels and triglycerides. Some unhealthy bacteria in the gut microbiome can produce a chemical called TMAO, which may increase the risk of heart disease. However, probiotic bacteria like lactobacilli, can help lower cholesterol levels and support heart health.
- Regulation of blood sugar and diabetes risk
The gut microbiome plays a role in controlling blood sugar levels and reducing the risk of type 1 and type 2 diabetes. Studies have shown that changes in the microbiome composition may precede the onset of diabetes. Additionally, variations in gut bacteria may explain differences in blood sugar levels among individuals, even when consuming the same foods.
How to improve the gut microbiome?
- There are several ways to improve the gut microbiome:
- Consume a variety of foods.
- Consume fermented foods.
- Limit intake of artificial sweeteners.
- Consume prebiotic
- Breastfeed for at least six months.
- Consume whole grains.
- Try a plant-based diet.
- Consume foods rich in polyphenols.
- Take probiotic supplements.
- Take antibiotics only when necessary and as prescribed by a doctor.
For more information, please refer to the articles on (Prebiotic), (Probiotics), (Synbiotics), and (Postbiotics).
