“We are what we eat.” – Anthelme Brillat-Savarin
“All disease begins in the gut.” – Hippocrates
These famous quotes of all times are much recognized by the modern-day scientists. Our gut is home to trillions of microbes and their genes, collectively known as the “gut microbiome.” The role of this “forgotten organ” — the gut microbiome — is critical in health and disease. In fact, the experts say that a human body is made more of bacterial cells than human cells. Whatever we eat governs —what kind of microbes will go into our digestive tract — and eventually what is their impact on our entire well-being. It’s thus, important that we only fill our body with stuff that is beneficial for us in the long-term.
The key to remaining physically active may simply lie in a healthy gut. If your digestive tract and/or the bugs residing in it are not in their optimal shape, a number of disease processes can emerge throughout the body as follows:
1. Mental health issues
More than 50% of individuals with IBS tend to suffer from at least one mental disorder in their lifetime.  An altered gut microbiome and/or intestinal inflammation can be a precursor for several mental ailments.
Regarded as the “second brain,” the gut if messed up, can lower your mood or upset the levels of chemicals in your brain, make you more anxious, and spark off those “negative gut feelings.” The two-way communication through the “gut-brain-microbiome axis” is responsible for the mental health problems experienced by the IBS sufferers. A disturbed tummy can send anxious signals to the brain just like a disturbed mind can deliver painful signals to the gut.
A healthy digestive tract is, thus, critical to attaining and then maintaining a peaceful mind.
2. Autoimmune conditions
A deranged microbiome and gut can sow the seeds for autoimmunity. This is a condition in which your immune system goes haywire and begins to attack your own body tissues.
Remember, more than 80% of your immune system resides in your gut. The antibodies in the gut interact with the gut bacteria to protect against environmental toxins and foreign agents like bacteria and viruses. 
Moreover, the gut lining forms a protective barrier that prevents the entry of harmful agents into your body. Factors like unfavorable gut ecology, an unhealthy diet, and stress can cause the barrier to become leaky, allowing the toxins to find their way into your bloodstream.  These toxins may then provoke autoimmune diseases, including but not limited to:
- Inflammatory bowel disease
- Celiac disease
- Diabetes mellitus
- Multiple sclerosis
- Autoimmune hepatitis
That is the reason, experts are now not only studying but also recommending probiotics to avert as well as reverse leaky gut and the impending autoimmunity. 
3. Compromised immunity
Similar to triggering autoimmune diseases, poor digestive health can weaken the immune defenses, predisposing to harmful bacteria or viruses.
The gut and its microbiome health largely determine if an individual will be obese or slim and smart.
An imbalance of the gut microbiome has been linked to weight gain, obesity, and related metabolic problems. This is because the composition of the gut microbiome can affect the extent of calories you burn and the energy stores in your body. Studies show that obese people have a higher amount of bad bacteria called Firmicutes but a lower percentage of friendly bugs. 
5. Heart disease
It’s obvious if poor gut and microbiome health can make you gain extra pounds, it can also lead to heart disease — obesity being a major risk factor for heart disease.
A study published in the New England Journal of Medicine found that certain microbes churned out a compound named TMAO (trimethylamine N-oxide) after the participants’ ingested hard-boiled eggs. TMAO puts a person at risk of heart attack and stroke, indicating the link between microbiome and heart disease.  Which bacteria yield more TMAO is not known, but replacing good microbes with a healthy diet and probiotic supplements may help address the risk factors for heart disease.
6. Skin problems
Your digestive tract and skin are connected through the gut-brain-skin axis. So, it’s no surprise that an unhealthy, leaky intestinal barrier and an imbalanced gut microbiome may herald skin diseases like acne, psoriasis, and eczema. In contrast, a healthy digestive tract and its microbiome may keep skin issues at bay. 
A French study shows that beneficial gut bacteria may suppress early cancers located not only in the gut lining but even at distant places such as the breast and prostate gland. A decrease in substances that promote inflammation, a decline in the number of inflammatory cells, a strong, healthy gut barrier, and a robust immune system may account for this protective effect.  On the contrary, long-standing inflammation and a shift in the makeup of the gut microbiome may drive cancerous changes in your body cells.
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