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.

Breastfeeding is important not only for babies' health and nutrition but also for protecting mothers from serious diseases, the World Health Organization (WHO) said.

It urged governments to strengthen access to services and interventions that support breastfeeding as part of World Breastfeeding Week, observed annually from August 1–7.

The 2026 theme, "Breastfeeding for a Sustainable Start in Life: Strengthen What Works," focuses on tracking progress, evaluating impact, and scaling proven approaches that improve breastfeeding outcomes.

Breastfeeding Could Save Hundreds of Thousands of Lives

"Scaling up breastfeeding could prevent almost 400,000 child deaths and around 140,000 maternal deaths each year," said UNICEF Executive Director Catherine Russell and WHO Director-General Dr. Tedros Adhanom Ghebreyesus in a joint statement.

"Every US$1 invested in breastfeeding promotion generates an estimated US$59 in economic returns through lower health-care costs, improved cognitive development, higher educational attainment, and increased lifetime earnings," they added.

Health Benefits for Babies and Mothers

The experts noted that breastfeeding is one of the simplest and most powerful ways to protect a child's health. It provides infants and young children with essential nutrition, boosts immunity, helps protect against serious illnesses, and supports cognitive development.

For mothers, breastfeeding also offers significant health benefits by reducing the risk of noncommunicable diseases such as breast and ovarian cancers, and type 2 diabetes.

Global Breastfeeding Rates Have Improved

The WHO said breastfeeding rates have improved globally due to sustained investments in policies and programs supporting mothers and families.

Exclusive breastfeeding during the first six months increased from around 37 per cent in 2012 to more than 47 per cent today. Over the past five years, the prevalence of breastfeeding up to two years of age has risen from 38 per cent to 50 per cent.

Progress Remains Uneven

Despite these gains, the WHO said many countries continue to lag behind global targets.

"Coverage of services supporting breastfeeding remains low, policies are inconsistently enforced, and service quality is often inadequate, especially in low-income, fragile, and humanitarian settings," the WHO said.

The agency noted that cost-effective interventions include skilled breastfeeding support within health systems, community-based counselling, maternity protection policies, and protection from the exploitative marketing of commercial milk formulas.

WHO, UNICEF Call for Stronger Support

WHO and UNICEF called on governments, health systems, workplaces, communities, civil society organizations, and families to strengthen the "Warm Chain of Support" for breastfeeding.

During World Breastfeeding Week, the agencies urged countries to:

• Strengthen health systems to provide quality breastfeeding support for mothers and newborns.
• Expand community-based counselling and peer support programs.
• Fully implement and enforce the International Code of Marketing of Breast-milk Substitutes.
• Invest in paid maternity leave and supportive workplace policies.
• Integrate breastfeeding interventions into antenatal, perinatal, and postnatal health-care services.
• Sustain breastfeeding support in humanitarian and fragile settings.

"Breastfeeding is vital. By investing in proven solutions, we can give every child the best possible start in life and ensure every mother gets the care and services she needs," the agencies said.

A new study published in The Lancet Regional Health–Southeast Asia has found that India accounts for 68% of all childhood cancer cases in the SAARC region.

While the country's large child population contributes to the high numbers, experts say underdiagnosis and incomplete cancer registration may mean the actual burden is even greater.

An international team of researchers, including from the US, India, and Canada, estimated that nearly 37,700 children aged up to 14 years were diagnosed with cancer across South Asia in 2022, with 17,700 deaths reported. India alone accounted for an estimated 25,939 cases and 12,028 deaths.

The researchers noted that because cancer registration remains incomplete, particularly in rural areas, the true number of childhood cancer cases in India could exceed 50,000 annually.

India's Large Child Population Drives Numbers

India is home to more than 380 million children, accounting for nearly 69% of the child population in the SAARC region. This naturally contributes to the country's higher share of childhood cancer cases and deaths.

However, experts emphasize that population size is only part of the explanation. Delayed diagnosis, limited access to specialized treatment, and gaps in cancer registration continue to affect both disease estimates and patient outcomes.

Leukemia Most Common Cancer

Dr. Narendra Agrawal, a leading Hematologist and Bone Marrow Transplant Physician and Senior Consultant and Unit Head of Haemato-Oncology at Rajiv Gandhi Cancer Institute & Research Centre, told HealthandMe that childhood cancer remains a major public health concern in India.

"Current estimates suggest that around 70,000–80,000 children and adolescents develop cancer each year, although the exact number remains uncertain due to expanding cancer registration systems". The most common childhood cancers in India include:

• Leukemia
• Lymphomas
• Brain tumors
• Bone tumors

What Causes Childhood Cancer?

Unlike many adult cancers, most childhood cancers do not have a clearly identifiable or preventable cause. Dr. Agrawal explained that, in most children, cancer develops because of genetic changes that occur during early development. These changes are usually not linked to lifestyle factors or inherited from parents.

Recognized Risk Factors

Although the causes of most childhood cancers remain unclear, some well-established risk factors include:

• Ionizing radiation: High-dose exposure before birth or during childhood increases the risk of leukemia and certain other cancers.
• Genetic syndromes: Conditions such as Down syndrome, Li-Fraumeni syndrome, and neurofibromatosis increase susceptibility to specific childhood cancers.
• Certain infections: Epstein–Barr virus (EBV) is associated with some lymphomas, HIV increases lymphoma risk, and chronic hepatitis B infection raises the risk of liver cancer.
• Environmental and parental exposures: Tobacco smoke, certain chemicals, pesticides, and some occupational exposures have been investigated as possible risk factors, although evidence remains inconclusive.

Challenges Beyond Disease Burden

Dr. Agrawal said India's substantial childhood cancer burden is largely driven by its population size. However, improving outcomes requires addressing several systemic challenges.

Key issues include:

• Delayed diagnosis
• Limited access to specialized pediatric oncology services in some regions
• Treatment abandonment
• Incomplete cancer registration

Marketed as a "harmless" alternative to cigarette smoking, vaping is increasingly emerging as a health concern, particularly for lung health, doctors warned ahead of World Lung Cancer Day on August 1.

Traditional cigarettes remain strongly linked to lung cancer, chronic obstructive pulmonary disease (COPD), and several other life-threatening illnesses. However, growing laboratory, animal, and population studies suggest vaping may also damage lung tissue, alter DNA, and potentially increase lung cancer risk—especially among people who both smoke and vape.

A recent study published in the peer-reviewed journal ERJ Open Research found that vaping may offer far less protection than many users believe when it comes to cardiovascular fitness, breathing efficiency, lung function, and blood vessel health in young adults.

"E-cigarettes are often advertised as a safer choice and as a way to help people quit smoking. But the evidence behind these claims is weak. We still don't fully know what long-term damage e-cigarettes can do to the lungs, including whether they can cause lung cancer," Dr. Shiba Kalyan Biswal, Head of Pulmonology at Shalby International Hospital, Gurugram, told HealthandMe.

Why E-Cigarettes May Raise Lung Cancer Risk

The vapor produced by e-cigarettes contains several harmful chemicals, including substances that can damage cells and DNA—the genetic material inside the body's cells.

Animal studies have found that mice exposed to e-cigarette vapor for about a year developed a type of lung cancer. Ingredients commonly used in e-cigarette liquids, such as propylene glycol and benzoic acid, may also irritate cells and trigger inflammation in the lungs.

"There have also been outbreaks of a serious vaping-related lung disease that has sent people to hospital with severe breathing problems. This shows that the risks of vaping can be unpredictable, especially when products are poorly regulated or contain unknown ingredients," Dr. Biswal explained.

She urged doctors to routinely ask patients about e-cigarette use, particularly those with breathing problems or those at higher risk of lung cancer.

"Since evidence suggests that e-cigarettes add to the risk for people who used to smoke, it may be worth including vaping history when deciding who needs lung cancer screening," she said.

Why Dual Users Face Even Greater Risk

According to Dr. Biswal, lung cancer risk appears to be even higher among people who use both e-cigarettes and conventional cigarettes, often referred to as "dual users."

Many smokers who turn to e-cigarettes intending to quit end up continuing to use both products rather than switching completely.

"This means they stay addicted to nicotine and may be exposed to even more harmful substances."

Lung Cancer Rising Among Young Non-Smokers

Doctors are also reporting more lung cancer cases among young people who have never smoked, particularly women.

Indoor air pollution, biomass fuel exposure, second-hand smoke, occupational hazards, and genetic susceptibility are increasingly contributing to the disease, said Dr. Akshay Budhraja, Senior Consultant and Head of Respiratory and Sleep Medicine at Aakash Healthcare.

"It's no longer just the lifelong smoker in his sixties—we are seeing younger patients, more women, and a growing number who have never touched a cigarette. Air quality, occupational exposure and genetic predisposition are all playing a bigger role than they used to, and that means our screening approach has to widen well beyond the traditional smoker profile," Dr. Budhraja said.

Experts said early detection through low-dose CT screening remains crucial for high-risk individuals. However, symptoms such as a persistent cough or breathlessness are often mistaken for pollution-related irritation or a lingering infection, leading many people to delay getting screened.

They also noted that lung cancer affects more than the lungs, with potential impacts on men's sexual health and women's reproductive health.

Lung Cancer Remains a Global Health Challenge

According to the World Health Organization (WHO), lung cancer remains one of the world's biggest public health challenges due to its high incidence and mortality. In 2024, it was the leading cause of cancer-related deaths globally, with an estimated 2.6 million new cases and 1.8 million deaths.

Lung cancer develops when abnormal cells grow uncontrollably in the lungs. Treatment depends on a person's medical history and the

stage of the disease.

The doctors stressed that avoiding tobacco remains the most effective way to reduce lung cancer risk.

"Smokers face nearly 20 times the risk of non-smokers, though the rising non-smoker caseload complicates that picture," said Dr. Budhraja. "Second-hand smoke is the third leading cause of lung cancer among non-smokers; radon gas, seeping in from soil, is the leading one, and home testing kits can catch it."