Image: iStock.

For most of us, our gut area tells us two things; when we’re hungry and when we need to erm, visit the bathroom.

But while we look to other areas of our body for signs of our health, the digestive system – which is often called ‘the second brain’ – is actually an excellent communicator of what’s going on inside.

“Our gastrointestinal system plays an incredibly important role in our health. What we put into our bodies via our gut has a significant influence on both our physical and also our emotional health,” says gastroenterologist Dr John Halliday .

Pretty important then, huh? Here are five things your gut is can tell you about your health.

1. How your digestion is working.

According to Jay Pasricha, M.D., director of the John Hopkins centre for Neurogastroenterology, the gut’s main role is to control digestion, right from the swallowing to the elimination process.

As a result, if you’re suffering from constipation, diarrhoea, bloating, irritable bowel syndrome, pain or an upset stomach (functional bowel problems that 30 to 40 per cent of the population will at some point experience), your gut is indicating that something could be amiss and needs attention.

2. Whether you’re anxious or depressed.

The past few years have seen a growing interest in the connections between microbiome (the microrganisms in a particular part of the body) and the brain.

According to a study published earlier this year in Nature Communications by scientists at McMaster University, there could be a link between the microbes in your gut and whether you suffer from anxiety or depression.

Researchers tested how the gut microbiome affected stressed mice, by separating baby mice with different gut bacterial conditions from their mothers for three hours a day.

One group was kept completely free of bacteria in their guts while the other group of regular mice was exposed to an ordinary, complex range of bacteria. The baby mice with normal gut microbiomes showed a significant increase of the stress hormone corticosterone and exhibited signs of depression and anxiety, while the germ-free mice did not.

After exposing the germ-free mice to bacteria taken from the stressed group, the scientists found that after a few weeks they also started to show signs of depression as their bacterial composition changed, suggesting that there’s a link between gut bacteria and depression.

“ We need to obtain some human data to be able to say with confidence that bacteria are really inducing anxiety or depression. I think it’s very likely that for at least a percentage of patients with psychiatric disorders, the microbiota is playing an important role,” lead author Premysl Bercik told IFL Science. (Post continues after gallery.)

Celebrities who have battled Anxiety Disorder

Kate Moss

Emma Stone

Emma Stone has had a long history of panic attacks, and told USA Today "I just started meditating in January... It's changing my life completely. I'm pretty into it. Once or twice a day, I meditate. That has been the best thing for my mind."

Adele

Adele told The Rolling Stone in 2011 "I'm scared of audiences... I get shitty scared. One show in Amsterdam, I was so nervous I escaped out the fire exit. I've thrown up a couple of times. Once in Brussels, I projectile-vomited on someone. I just gotta bear it. But I don't like touring. I have anxiety attacks a lot."

Kristen Stewart

Selena Gomez

Selena Gomez sought help in January 2014 for her severe anxiety, telling fans in a statement: It has become clear to me and those close to me that after many years putting my work first, I need to spend some time on myself in order to be the best person I can be."

Oprah Winfrey

Kim Basinger

Hollywood Actress, Kim Basinger, has had a history of social anxiety, agoraphobia and panic disorder. Basinger has been open about her mental health issues, and in an interview with Charlie Rose stated: "Fear has been something I've lived with my entire life, the fear of being in public places - which led to anxiety or panic attacks... I stayed in my house and literally cried every day."

Barbra Streisand

Olivia Munn

Actress Olivia Munn has been very public about her battle with anxiety, revealing to Marie Claire in 2013 that she is "trying to overcome my social anxiety. Its manifested in trichotillomania, a disorder that gives me the urge to pull out my eyelashes."

3. It can influence your feelings.

According to David Perlmutter, author of the New York Times bestselling book Brain Maker, the gut actually makes more than 90 per cent of extremely essential neurotransmitters, including serotonin, also known as ‘the happy chemical’. See – we always knew the stomach was the key to happiness.

4. It can signal early indicators of serious disease.

Early symptoms for a range of conditions such as Parkinson’s, osteoporosis and autism have been found to be displayed in the gut.

A 2014 study published in the journal Movement Disorders by University of College London, researchers suggested that certain brain diseases could be caused by an unhealthy gut because of the signals that travel between the gut and the brain.

certain brain diseases could be caused by an unhealthy gut

They discovered that sufferers of Parkinson's disease had a higher prevalence of a condition called SIBO, or Small Intestinal Bacterial Overgrowth. Symptoms of SIBO include excess gas, abdominal bloating, diarrhoea and abdominal pain.

"We now think that neurological diseases such as MS and Parkinson’s are linked to the gut being more leaky, permitting pathogens into the bloodstream and causing an antibody response," co-author Dr Anton Emmanuel told the Daily Mail .

5. It can influence your weight.

In her best-selling book Gut: The Inside Story of Our Body's Most Under-Rated Organ, microbiologist Giulia Enders suggests that intestinal bacteria can determine whether we're a healthy weight or obese.

"There are some bacteria that can be found in people with higher weight. I like to call them the 'chubby bacteria' because we see that they can actually harvest more calories out of the food you eat. And we see that overweight people, when they go to the toilet, there are less calories that they excrete and other people, they just excrete more of the calories they take up," she told the ABC's Lateline earlier this year.

"Having a more diverse ecosystem will actually be a very protective thing for people struggling with weight. We see that some diets, when they work on a person and they don't work in another person, there was a study that showed that it worked when it altered the gut flora."

Your gut bacteria could affect your weight. Image via iStock.

6.  It could hold the secret to preventing allergies.

Research from the Human Microbiome Project, a project attempting to create a map of all the microbes in and on your body, has found that even a imbalance in your gut microbiomes could lead to certain allergies and even diseases.

The Washington Post reports that research company Second Genome have isolated a link between allergic diseases and the bacteria in your gut, opening up the possibility of a drug that could inject bacteria based on certain gut microbiomes - or 'good bacteria' - to prevent allergies or minimise allergic reactions.

It's based on the 'hygiene hypothesis' that suggests we're so conscious about getting rid of all the nasty bacteria in every day life that we've also eradicated some of the helpful bacteria that help to keep us healthy.

When do you "listen to your gut"?