Your body hosts trillions of bacteria, viruses, and fungi, collectively known as the microbiome. While some bacteria are linked to disease, many play essential roles in supporting your immune system, heart health, weight management, and overall well-being. This article delves into the significance of the gut microbiome and its impact on health.

What Is Gut Microbiome?

Interestingly, bacterial cells outnumber human cells in the body, with approximately 40 trillion bacterial cells compared to 30 trillion human cells. With up to 1,000 species of bacteria present in the gut, each plays a distinct role. While most bacteria contribute positively to health, some can be harmful. Together, these microbes weigh around 1–2 kilograms, functioning almost like an additional organ essential for overall well-being.

How Does Gut Microbiome Influence Your Health?

The relationship between humans and microbes has evolved over millions of years, with the gut microbiome playing a crucial role from birth. Initial exposure to microbes occurs during birth, and some evidence suggests that exposure begins in the womb. As the microbiome diversifies, it starts influencing key bodily functions:

Digestion of breast milk: Beneficial bacteria like Bifidobacteria help break down essential sugars in breast milk, supporting infant growth.

Fiber digestion: Some bacteria process fiber into short-chain fatty acids, which contribute to gut health and reduce risks of obesity, diabetes, and heart disease.

Immune system regulation: The gut microbiome interacts with immune cells, influencing how the body responds to infections.

Brain health: Emerging research suggests a link between the gut microbiome and brain function, potentially affecting mental health and neurological processes.

Gut Microbiome And Weight Management

An imbalance between beneficial and harmful microbes, known as gut dysbiosis, may contribute to weight gain. Studies on identical twins—one with obesity and the other without—suggest that microbiome composition plays a role in body weight independent of genetics. Additionally, animal studies indicate that gut bacteria can influence weight gain, even when calorie intake remains constant.

Probiotics, beneficial bacteria found in supplements and certain foods, can help restore gut balance and support weight loss, though their effects may be modest.

Gut Health And Disease Prevention

The gut microbiome plays a vital role in preventing and managing conditions like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Imbalances in gut bacteria may lead to bloating, cramps, and digestive issues. On the other hand, beneficial bacteria like Bifidobacteria and Lactobacilli help strengthen the intestinal lining, reducing the risk of gut-related disorders.

Impact On Heart Health

Research suggests that the gut microbiome influences heart health by affecting cholesterol levels and blood pressure. Certain harmful bacteria produce trimethylamine N-oxide (TMAO), a compound linked to blocked arteries and heart disease. However, probiotics, particularly those containing Lactobacilli, may help reduce cholesterol levels and promote cardiovascular health.

Blood Sugar Regulation And Diabetes Risk

The gut microbiome also plays a role in regulating blood sugar levels. Research on infants genetically predisposed to type 1 diabetes indicates that gut microbiome diversity declines before disease onset. Furthermore, individual variations in gut bacteria may explain why people experience different blood sugar responses to the same foods.

Connection Between Gut And Brain

The gut is physically connected to the brain through nerves, and certain bacteria help produce neurotransmitters like serotonin, which influence mood and mental health. Studies indicate that people with mental health disorders often have different gut bacteria compared to those without such conditions. Additionally, some probiotics have shown promise in alleviating symptoms of depression and anxiety.

Tips For Healthier Gut Microbiome

Maintaining a balanced gut microbiome is crucial for overall health. Here are some strategies to support gut health:

• Eat a diverse range of foods: A varied diet rich in fiber, legumes, and fruits promotes microbial diversity.
• Consume fermented foods: Yogurt, kefir, and sauerkraut contain probiotics that enhance gut health.
• Limit artificial sweeteners: Some artificial sweeteners can encourage the growth of harmful bacteria.
• Include prebiotic foods: Bananas, oats, and asparagus contain fibers that nourish beneficial bacteria.
• Breastfeed infants when possible: Breastfeeding promotes a healthier gut microbiome in babies.
• Choose whole grains: Whole grains contain fiber and beneficial compounds that support digestive health.
• Opt for a plant-based diet: Vegetarian diets may reduce inflammation and support a healthier gut microbiome.
• Consume polyphenol-rich foods: Green tea, dark chocolate, and olive oil contain compounds that foster beneficial bacteria.
• Take probiotics if needed: Probiotic supplements can help restore gut balance after disruptions, such as antibiotic use.
• Use antibiotics cautiously: While antibiotics can be life-saving, overuse can harm beneficial gut bacteria.

A study of more than 700 individuals found distinct differences in the mix of bacteria in the mouths and lungs of those with severe long COVID.

Published in the European Respiratory Journal, the study found that differences in the lung microbiome were linked to respiratory problems, cognitive difficulties and digestive symptoms associated with long COVID.

The findings may help researchers understand why some people develop long COVID and identify potential treatments, according to the team from the University of Dundee, UK.

"The microbiome is important to maintain health throughout the body, so it is a strong candidate for something that may contribute to long COVID,” said lead author Dr. Daniela Alferes de Lima Headley.

What Did The Study Find?

The observational study included 771 adults who had been hospitalized for COVID-19 between February 2020 and March 2021. Researchers grouped participants according to the severity of their ongoing health problems and symptoms.

The participants had an average age of 57.5 years, and 38.5% were women.

Six months after hospital discharge, researchers collected saliva samples to examine microbes in the mouth and sputum samples to study the lung microbiome. They used DNA sequencing to identify the microbes and analyze their diversity. Participants also completed questionnaires about their symptoms.

The results showed that people with very severe long COVID had distinct differences in their oral and lung microbiomes compared with those who had fewer ongoing symptoms.

Microbiome differences were also associated with:

• • Respiratory problems: Reduced lung function.
  • Cognitive symptoms: Brain fog, memory problems, and difficulty with attention and concentration.
  • Digestive issues: Abdominal pain, nausea, diarrhea and loss of appetite.

Bacterial Changes Linked To Inflammation

Further, the changes associated with long COVID symptoms also included an increased abundance of bacteria that produce lactic acid. These changes were also linked to signs of inflammation in participants' blood samples.

James Chalmers, chair of respiratory research at the University of Dundee, said the greatest microbiome changes were found in people with the most severe symptoms five to six months after COVID-19.

"We also found that changes in the airway microbiome were linked not just to lung problems, but also to symptoms like brain fog and gut symptoms, suggesting the lung microbiome could have effects on health more broadly," he added.

However, the researchers do not yet know whether these microbiome differences existed before COVID-19 or developed after infection. The long-term effects of these changes also remain unknown.

Could The Findings Lead To New Treatments?

Chalmers said more research is needed to understand what causes long COVID, which continues to affect many people worldwide.

Because the microbiome can be altered through interventions such as antibiotics and probiotics, understanding its role could help researchers explore potential treatment options.

What Is Long COVID?

Long COVID refers to new, returning or ongoing health problems that persist four or more weeks after the initial COVID-19 infection. Symptoms can last for months or even years.

Common symptoms include fatigue, brain fog, memory problems, difficulty concentrating and slowed thinking.

Research has also suggested that brain inflammation may persist even after the virus is no longer detectable.

For some women with endometriosis, getting a diagnosis is only the beginning of a long struggle to access treatment and navigate management.

In Canada, long waitlists for specialist appointments are pushing patients to consider expensive surgery abroad, highlighting how delays in care can prolong pain and disrupt everyday life.

Noelle Menu, 37, from Calgary, said her symptoms intensified after she stopped taking birth control while trying to conceive at 26.

Years of pain, emergency room visits, surgery and delays in specialist care eventually led her and her husband to seek private treatment in Tijuana, Mexico.

After being told that waiting several years to see a specialist in Canada was possible, Menu said: “We can’t deal with it in Canada.”

The couple used their savings and went into debt to pay for treatment at EndoGlobal in Mexico. The total cost was approximately $35,000, including travel, accommodation and other expenses, according to CBC News.

Her experience highlights the delay in addressing endometriosis that can intensify debilitating symptoms.

What Is Endometriosis And Why Can It Be Difficult To Diagnose?

Endometriosis is a chronic condition in which tissue similar to the lining of the uterus grows outside it, potentially affecting the ovaries, bowel, bladder and other areas. The resulting inflammation and scar tissue can cause severe menstrual cramps, persistent pelvic pain, painful sex, bowel or urinary symptoms and difficulties conceiving.

The World Health Organization estimates that endometriosis affects around 10% of reproductive-age women worldwide, or approximately 190 million people.

Diagnosis can be challenging because symptoms vary and may overlap with other conditions. There is no single definitive test that identifies every case. Doctors may use a detailed medical history, pelvic examination, ultrasound or MRI, with surgery sometimes needed to investigate or treat suspected disease.

The WHO estimates that diagnosis commonly takes between four and 12 years, leaving many patients managing symptoms without a clear explanation for prolonged periods.

Also read: Endometriosis: Repurposed Anti-Parasite Drug Shows Promise In Mouse Study

How Do Delays Affect Patients?

For patients with severe disease, waiting for specialist care can mean continuing to live with pain that interferes with work, relationships, sleep and fertility plans.

Another Canadian patient, identified in CBC's report as Papiernik, described discovering that endometriosis had infiltrated her colon after a colonoscopy detected a mass. She was referred for specialist care but faced further waits for an appointment and surgery.

“Living like this for two years was just not an option for me,” she said.

Canada's House of Commons health committee has identified gaps in endometriosis care, while the condition's economic impact includes lost productivity and healthcare costs. The issue is not simply whether treatment exists, but whether patients can access appropriate care before symptoms and complications become harder to manage.

Also read: Urine & Vaginal Samples May Help Detect Womb Cancer: Lancet Study Suggests Less Invasive Way To Triage Patients

Does Surgery Cure Endometriosis?

Surgery can remove endometriosis lesions, adhesions and scar tissue, reducing pain and treating complications. However, it is not a guaranteed cure. Symptoms may persist or return, and treatment decisions depend on disease severity, the organs involved, fertility goals and previous treatment.

Hormonal medicines and pain management can also help control symptoms. Some patients benefit from a combination of medical treatment, surgery and ongoing follow-up.

Travelling abroad may offer faster access to specialist treatment, but it comes with financial costs and other challenges. Patients should consider the surgeon's experience, the facility's standards, the possibility of complications and arrangements for follow-up after returning home.

A routine heart scan helped doctors detect pancreatic cancer in a 72-year-old US woman before it was too late. Vicky Titcomb, a Cape Cod bookstore owner and great-grandmother, underwent the scan at Mass General Brigham in March 2025, before traveling to New York City to visit her son.

Although she felt healthy, the scan revealed an abnormality on her pancreas. Further testing confirmed pancreatic cancer, one of the deadliest forms of cancer, CBS News reported.

“I felt like my life just switched in that moment,” Titcomb said. “It was a very weird feeling.”

Titcomb had undergone treatment for breast cancer in 2012.

In 2025, she was diagnosed with stage 1 breast cancer as well as pancreatic cancer. Doctors also found a mass on her ovary, which proved benign after the ovary was removed.

Why Early Detection Matters In Pancreatic Cancer

Pancreatic cancer is often diagnosed after it has spread to other organs. Its five-year overall survival rate is 13%.

The American Association for Cancer Research noted in its 2026 Cancer Progress Report that pancreatic cancer survival rates have shown little improvement despite advances in cancer care.

Doctors at Mass General Brigham planned chemotherapy and radiation to shrink Titcomb’s pancreatic tumor before surgery.

“I was told the size of the (pancreatic) cancer was about the size of a grape. The goal, to me, was trying to make this cancer a raisin,” she said. “That's the way I visualized it.”

The plan was to perform a Whipple procedure, a complex operation that removes the head of the pancreas, part of the small intestine, the gallbladder and the bile duct. Only about one in five pancreatic cancer patients is eligible for this surgery.

Titcomb’s early diagnosis made the operation possible.

“If I had not had that scan when I did, the outcome would have been bad,” she said.

Chemotherapy, Radiation And Surgery

Titcomb began chemotherapy in June 2025, receiving eight doses over four months. She then underwent three weeks of radiation and additional chemotherapy.

Surgical oncologist Dr. Thomas Clancy said she tolerated the treatment “very well.” The therapy shrank the pancreatic tumor enough for surgery.

On November 4, Titcomb underwent surgery to treat her breast cancer. Just over two weeks later, Clancy performed a robotic Whipple procedure to remove the affected part of her pancreas and other structures.

The operation was successful, and Titcomb said she was walking that night. She returned home after several days in the hospital.

Although she was recovering well, Clancy recommended two more months of chemotherapy because pancreatic cancer can be aggressive.

“There was a lot going on,” Titcomb said. “I just tried to cope with the day-to-day.”

No Evidence Of Cancer After Treatment

In March 2026, after further treatment, Clancy told Titcomb she had no evidence of cancer. She will continue to undergo scans every three months.

“She’s living her life. I generally tell patients at this point, ‘You’re done with therapy ... you go about your days,’” Clancy said. “The goal is to not be thinking about it all the time.”

Titcomb is returning to running her bookstore, which family members helped manage during her treatment. She is also spending time with her children, grandchildren and great-grandchildren, keeping in touch with those who live far away through photos, videos and phone calls.