Role of Probiotics in Improving Mental Health

Probiotics are live bacteria, and when you consume it regularly in adequate quantity, they provide various health benefits. ⁽¹⁾ For a certain species of bacteria to be labeled as being probiotic, there needs to be a lot of scientific evidence to show that they provide some health benefits. Research shows that probiotics may benefit people with medical conditions such as eczema, irritable bowel syndrome (IBS), dermatitis, liver disease, and high cholesterol levels. Many chronic lifestyle disorders may also benefit from the regular intake of probiotics. ^{(2, 3, 4)}

Lactobacillus and Bifidobacteria are the two most common types of bacteria that are found in probiotics. However, there are many other species and strains present within these groups itself that have many kinds of different effects on the body.

There is a close link between the gut and the brain, with the gut even being known as the second brain of the body. The brain and the intestines are not only connected physically but also chemically. Due to this, any type of change in the gut can affect the brain.

The primary connection between the gut and the brain is the vagus nerve, which is the longest nerve in the body, which is a large nerve present in the central nervous system. The vagus nerve is responsible for sending signals between the gut and the brain.

The brain and your intestines also communicate through the presence of gut microbes, which manufacture the molecules that carry information to and fro from the brain. ⁽⁵⁾

Statistics show that there are nearly 30 trillion human cells and 40 trillion bacteria present in the body. This means that there are more bacteria than the number of cells present in our bodies. ⁽⁶⁾ The majority of these bacteria can be found in the gut, meaning they come into direct contact with the cells that line the walls of your intestines. They also come into direct contact with pretty much everything that enters your body. This includes medications, microbes, and even food.

Apart from the gut bacteria, there are many other types of microbes as well that live inside the gut, including fungi and yeasts. Together these microbes are referred to as the gut microbiome or gut microbiota. ⁽⁷⁾

Each of these microbes is known to produce different types of compounds that have an impact on the brain. These also include amino acids, neurotransmitters, and short-chain fatty acids. ⁽⁸⁾

Gut bacteria is thereby known to have an influence on the brain as well as the central nervous system and is believed to play a role in controlling hormone production and inflammation. ⁽⁹⁾

There is a term used to refer to a health condition wherein both the intestines and the gut bacteria are in a diseased state. Known as ‘gut dysbiosis,’ this condition is believed to develop due to the presence of disease-causing bacteria, which also cause chronic inflammation within the body.

Researchers have found evidence that indicates the development of gut dysbiosis in people who have: ^{(10, 11, 12)}

• Heart disease
• Type 2 diabetes
• Obesity
• Other chronic health conditions

Many studies show that certain probiotics can help restore the gut microbiome to a healthy state and also reduces the symptoms of many various health conditions ^{(13, 14)}

At the same time, several studies have also shown that people with certain types of mental health conditions have also been found to have an altered and unbalanced gut microbiome. It is yet unclear as to if this imbalance of microbiome has caused the mental health condition, or if the condition is a result of lifestyle and dietary factors. ⁽¹⁵⁾

Since there is a known connection between the gut and the brain, and the production of various compounds by the gut bacteria is known to impact the brain, so it is believed that probiotics can benefit the brain and a person’s mental health. Probiotics that are known for helping a person’s mental health are known as psychobiotics. ⁽¹⁶⁾

Several studies have investigated this, but most of these studies have been conducted in animals.

Anxiety and stress are today widespread, and nearly every person is fighting a daily battle with stress. Depression is also another common mental health problem around the world. ⁽¹⁷⁾

Stress, anxiety, depression, and many other such disorders are known to cause high levels of cortisol in the bloodstream. Cortisol is the stress hormone in humans, and chronic high levels of cortisol in the blood are known to increase the risk of many diseases. ^{(18, 19)}

Many studies have explored how probiotics can affect people who have clinically diagnosed with depression. One such study found that taking a combination of three Bifidobacteria and Lactobacillus strains for a period of eight weeks dramatically decreased the symptoms of depression. They also had lower levels of inflammation. ⁽²⁰⁾

Several other studies have also explored how probiotics impact the symptoms of depression in people who do not have clinically diagnosed depression such as: ^{(21, 22, 23)}

• Depressive symptoms
• Academic stress
• Symptoms of anxiety
• Psychological distress

Irritable bowel syndrome is a group of intestinal symptoms that occurs together. These symptoms can vary in severity and duration and can even cause intestinal damage in some cases. ⁽²⁴⁾ The common symptoms of irritable bowel syndrome include:

• Abdominal pain
• Abdominal cramping
• Constipation
• Diarrhea
• Bloating and gas

It is common for people with irritable bowel syndrome to experience bouts of both constipation and diarrhea, with the symptoms of gas and bloating typically going away on their own immediately after having a bowel movement. ⁽²⁵⁾

While irritable bowel syndrome is directly associated with the functioning of the large intestine, but there are many researchers who believe that irritable bowel syndrome is a psychological disorder. ⁽²⁶⁾

Depression and anxiety are also commonly found in people with irritable bowel syndrome. At the same time, it is interesting to note that people with irritable bowel syndrome also have an altered microbiome. ^{(27, 28)} Several studies have also found that certain probiotics can decrease symptoms of irritable bowel syndrome, such as bloating and abdominal pain. ⁽²⁹⁾ All this evidence has made researchers believe that probiotics are associated with aiding digestive health.

When a person experiences a traumatic brain injury, they are likely to remain in an intensive care unit in a hospital. Doctors will need to feed them through tubes, and they will probably need tubes for breathing as well. All these increase the risk of developing infections, and in the case of traumatic brain injuries, such infections may lead to further complications as well.

Some studies have shown that adding certain probiotics into the food that is being delivered through the tube than help lower the number of infections and also cut down the length of time a person has to spend in the intensive care unit. ^{(30, 31)}

Probiotics are believed to bring about these positive effects due to the many benefits they have on the immune system.

While there is not enough evidence at the moment to show that probiotics have a definite benefit on the brain, but this does not mean that probiotics cannot help your brain. If you have any brain-related disorders, then you should discuss the possibility of adding probiotics to your diet with your doctor.

At the same time, there is plenty of evidence to show that probiotics have many other health benefits, including digestive disorders, eczema, dermatitis, and heart health. ⁽³²⁾

Scientific evidence has also demonstrated a clear link between your gut and the brain. This area of research is also growing rapidly, with new developments coming forward very quickly.

People can definitely get a healthy gut microbiome by following a healthy lifestyle and diet, and there are many foods that contain beneficial bacteria that function just like probiotics. These include:

• Kimchi
• Kefir
• Probiotic yogurt
• Unpasteurized sauerkraut

If needed, you can also take probiotic supplements to help increase the number of beneficial bacteria in your intestines. Taking probiotics has been found to be safe for almost everyone, and there are very few side effects known for taking probiotics. However, if you suffer from a health condition, then it is best to first discuss the possibility of taking probiotics with your doctor.

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Also Read:

• What are the Health Benefits of Probiotics?
• Can Probiotics Really Help My Digestive Health?