Why Are Gut Bacteria So Important for Health? Can Microbiota Health Be Tested?

In recent years, studies showing that gut health plays an active role in many aspects of health, including obesity, depression and the immune system, have attracted attention. So how do the microorganisms other than human cells that occupy an important place in the human body and live mostly in our gut affect our health? What exactly does microbiota mean? How can we improve gut health, and how do we know whether our gut microbiota is healthy?

What Are Microbiota, the Microbiome and Gut Flora?

Microbiota are the communities of microorganisms living together with an organism. Microbiota are found on the internal and external surfaces of all multicellular organisms studied, from plants to animals. They include bacteria, archaea, protists, fungi and viruses.

Microbiome refers to all the genetic information (genomes) of microorganisms in a particular environment. Microbiota means the community of microorganisms. There are approximately 100 trillion microorganisms in the human gastrointestinal system. When microbiota are in the gut, they are called gut flora / microbiota; on the skin, they are called skin flora / microbiota. In scientific language, “microbiota” is preferred to “flora.”

The human genome consists of 23,000 genes. In contrast, the microbiome produces thousands of metabolites to perform some of the body’s main functions and influence health, using more than 3 million genes that it encodes.

An adult’s gut microbiota weighs approximately 2 kg and is larger than the human brain. In addition to containing trillions of bacteria, viruses, archaea and fungi, it contains at least 150 times more genes than the human genome.

Professor Tim Spector, an epidemiologist at King’s College London and author of two books on diet and gut health, says that the microbiota does not work only on the digestive system, as many people think, but is key to both physical and mental health, including depression, anxiety and strengthening the immune system. Many scientific studies support Professor Spector’s approach.

A leading scientific journal worldwide, Nature reports that two scientific developments shaping the last 10 years are microbiome science and artificial intelligence technology.

Can Gut Health Be Tested through the Microbiota?

Symptoms such as irregular bowel movements, overly soft or hard stools, and abdominal bloating or pain may indicate an unhealthy gut. Monitoring bowel movements can help us gain an idea of how healthy our gut is. The blue dye method can also provide information about gut activity. In recent years, it quickly became popular on social media under the hashtag #BluePoopChallenge (blue stool challenge). This project, also initiated by Professor Spector, was proposed as a quick, inexpensive and enjoyable indicator of gut health. Participants eat cake colored with blue food dye and track how many hours it takes for the color to appear in their stools. Professor Spector says the dye appears in stools after an average of 28.7 hours and that the ideal time is close to this. However, he also states that 14-58 hours is within the healthy range.

What Factors Adversely Affect Gut Health?

Professor Jack Gilbert, an award-winning microbiome scientist at the University of California San Diego, says that good gut health requires a variety of beneficial bacteria and that antibiotic use, which began 80 years ago, may have caused a loss of healthy gut bacteria.

Antibiotics, together with water chlorination and vaccines, are among medicine’s 3 most important discoveries for preventing premature deaths. However, indiscriminate antibiotic use has adversely affected the gut microbiota. He notes that factors other than antibiotics, such as lifestyle (smoking, alcohol and inactivity), a low-fiber diet, obesity and genetics, also play a role in the loss of healthy bacteria. Diet is thought to be the most influential factor. In terms of nutrition, the foods’ composition plays an important role rather than total calorie intake.

Prepared and Packaged Foods Are Major Enemies of Gut Health

Processed and ultraprocessed foods adversely affect gut health. Examples of these chemicals include artificial sweeteners derived from the paraffin and petroleum industries and emulsifiers, substances added to mix two or more phases that do not mix naturally, such as fat and water in foods. Many enzymes not listed on packaged-food labels may also contribute.

What Health Problems Are Associated with Reduced Gut Microbiota Diversity?

Reduced diversity and/or disruption of balance in the gut microbiota has been associated with the development or progression of many conditions, including food allergies, endocrine disorders such as obesity and diabetes, autoimmune diseases such as ulcerative colitis, and skin allergies.

Although epidemiological proof is difficult, studies over the last 50 years show that people with reduced gut diversity are more prone to developing the conditions mentioned above.

Is Using Probiotic Yogurt, Tablets or Powders Enough to Improve Gut Health?

As studies investigating the relationship between the gut and health have increased in recent years, production and marketing of products supporting the gut microbiota have also grown rapidly. Many advertisements suggest that consuming probiotic supplements is sufficient for a healthy gut. Professor Spector, however, says that we are still at the very beginning of understanding how to improve gut health, that fully understanding it is very difficult and that we have only completed 10% of the journey. Using the right products will, of course, be helpful, but gut health should be approached holistically. Many factors are involved, including diet, lifestyle, antibiotics, tobacco use, physical activity and genetics. When John Cryan, head of anatomy and neuroscience at University College Cork, was asked his opinion of probiotics, he said, “Just as there is no pill that cures every disease, the same is true for probiotics” and added, “Painkillers are given for migraine, while other medicines are used for other conditions. The same logic should apply to probiotics. The type of probiotic each person needs may differ”. To tailor the bacterial species and dietary patterns people need, in 2017 scientists including Professor Spector, working at prestigious institutions such as Oxford and Harvard University, designed an app called ZOE for this purpose.

What Is the ZOE App and Exactly How Does It Work?

The ZOE app’s main aim is to design a completely personalized dietary program. It evaluates blood sugar, blood fats and gut health through at-home tests to prepare a dietary pattern suited to the individual’s general and gut health. The #BluePoopChallenge mentioned earlier was also a ZOE project. Its founding team argues that people respond differently to foods and that this may be closely related to gut health. For example, one person may consume far more calories than needed without gaining weight, while another gains weight despite much lower calorie intake. The ZOE team argues that, to treat conditions such as obesity and type-2 diabetes, gut health needs to be restored to the desired healthy state.

Many biotechnology companies worldwide are developing applications linking the gut microbiota to general health. There are also notable initiatives in Turkey; for example, ENBIOSIS offers artificial intelligence solutions for gut microbiome analysis.

7 Recommendations for Improving Gut and Overall Health

1. Consume adequate fiber  and fluids: At least 30 grams of fiber should be consumed daily. However, studies indicate that people consume, on average, half this amount. Vegetables, fruit and legumes help increase fiber intake. Water intake is important for removing toxins from the body. At least 2-2.5 L of water should be consumed daily.
2. Eat a rainbow: Choose different colors rather than vegetables and fruit of the same color. Each color provides different benefits.
3. Eat a polyphenol-rich diet: Polyphenol-rich foods include oranges, cherries, plums, blackberries, strawberries, apricots, grapes, dark chocolate, spinach, onions, olives, broccoli, whole wheat, walnuts, almonds, hazelnuts and olive oil.
4. Eat fermented foods: Tim Spector recommends unpasteurized cheeses and kefir.
5. Consume omega 3: New research shows a relationship between gut microbes, omega 3 and brain health. Eating fish several times a week would be beneficial.
6. Let children play outdoors and with pets such as cats and dogs: Jack Gilbert’s research argues that gut microbiota diversity is seeded early in life. Allowing young children to dig in soil and play with pets is proposed to improve the damage modern lifestyles cause to microbiomes. 
7. Avoid processed foods: Greatly limit foods such as salt and sugar that affect microbial diversity in the gut.

Comment and Summary

We can say that a balanced diet is essential for improving gut health and maintaining a healthy body. One of the dietary patterns that most effectively improves gut health is Mediterranean-style eating. A Mediterranean-style dietary pattern can improve both gut and general health. A good mood also positively affects gut health, so enjoyable activities such as hobbies, and exercise, can be beneficial. Newly developed apps that test gut health may also help. However, they cost money, and their benefits have not yet been confirmed by comprehensive clinical research. We are only at the beginning of understanding the microbiome’s effects on health, and we know the future holds greater discoveries in this field.