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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.
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.
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.
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.
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.
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.
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.
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.
Maintaining a balanced gut microbiome is crucial for overall health. Here are some strategies to support gut health:
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When patients first hear the term "bone marrow transplant," they often picture a complex surgery involving the bones or spine. This is perhaps the most persistent misconception surrounding one of modern medicine's most remarkable achievements.
Unlike other organ transplants (kidney/ heart/ liver, etc), a bone marrow transplant is not a surgery at all! It is administered much like a blood transfusion, through a simple intravenous line. Yet this deceptively simple procedure can rebuild an entire blood-forming and immune system from scratch, offering a genuine cure for blood cancers and other serious blood disorders.
Bone marrow is the body's blood factory, producing the red cells that carry oxygen, the white cells that fight infection, and the platelets that prevent bleeding. At its heart lie blood-forming stem cells or the "parent cells" capable of generating every blood cell the body will ever need.
In leukemia and related cancers, these stem cells turn rogue, crowding out healthy ones. In several inherited disorders, the marrow simply fails to manufacture healthy cells at all. A transplant addresses the problem at its root, replacing defective stem cells with healthy ones.
I often explain this to patients using the language of farming. Before sowing fresh seed, a farmer clears the field of weeds. Similarly, before healthy stem cells can be transplanted, doctors must prepare the marrow through chemotherapy and, in select cases, radiation, a stage called conditioning. Once this was punishingly intensive, limiting transplants to the young and fit. Today, reduced-intensity regimens, which are carefully tailored to suit even the old or frail patients, have extended this option to older adults and those with other health conditions.
The transplant itself is almost anticlimactic in its simplicity: stem cells are infused through an IV, with no incision or operating theatre required. These cells possess a natural ability doctors call "homing": they find their own way into the bone marrow and settle there. Over two to four weeks, they begin producing healthy blood, a process called engraftment.
For decades, the greatest obstacle to transplantation was finding a matched donor. Traditionally, only a fully matched sibling would do, leaving many patients, particularly in a genetically diverse country like India, without options. That has changed decisively. Half-matched family transplants and unrelated donors identified through registries now succeed at rates that rival matched-sibling transplants. Nearly every patient today has a realistic path to a suitable donor.
Technology is reshaping this field further. Gene therapy is opening a new chapter for disorders such as sickle cell disease and thalassemia, correcting a patient's own stem cells in the laboratory rather than relying on a donor, though such therapies remain costly and available only in select countries for now.
Recovery, however, is a marathon, not a sprint. It can take months as the immune system rebuilds, requiring vigilant monitoring for infection and for graft-versus-host disease, in which transplanted immune cells attack the patient's own tissues. Advances in immunosuppressive and targeted therapies have greatly improved our ability to manage this complication, allowing most survivors to gradually return to work, education and family life.
A blood cancer diagnosis remains frightening, but treatment has advanced tremendously in two decades. Bone marrow transplantation is no longer experimental or exceptionally hazardous: it is established, evidence-based, and growing safer and more accessible across India.
Its truest achievement is not simply extending life, but restoring it: another birthday, another child watched growing up, another future reclaimed. For these patients, a transplant is quite literally a chance to begin again.
(Dr. Narendra Agrawal, Hematologist and Bone Marrow Transplant Physician and Senior Consultant and Unit Head of Haemato-Oncology at Rajiv Gandhi Cancer Institute & Research Centre.)
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A six-in-one (hexavalent) vaccine could make India's Universal Immunization Program more efficient, convenient for families, and cost-effective if it becomes widely available at an affordable price, according to a study led by the Ministry of Health and Family Welfare.
The study found that while the hexavalent vaccine has higher upfront procurement costs, it could reduce the number of injections, improve operational efficiency, lower healthcare workload, and save time for caregivers.
The hexavalent vaccine protects children against six diseases with a single injection:
Combining multiple vaccines into one shot reduces the number of injections infants receive during routine immunization visits.
Also read: India Records 20,138 Organ Transplants In 2025; Deceased Donor Transplants Reach 3,526
Researchers found that the vaccine's price is the biggest factor determining the overall cost of introducing it into India's immunization program.
The study estimated that:
The findings were published in the peer-reviewed journal Human Vaccines & Immunotherapeutics.
According to the study, introducing the hexavalent vaccine could:
Read More: India's National Hepatitis Program Screens Over 210.6 Million, Treats 612,000 Patients
India runs one of the world's largest immunization programs, vaccinating nearly 26 million babies every year.
The program protects children against 12 vaccine-preventable diseases, including:
A team of researchers, including from The George Institute for Global Health India, The Gates Foundation, and Gavi, The Vaccine Alliance, assessed two implementation scenarios:
The analysis considered costs from both government and household perspectives, including:
The researchers noted that replacing the current pentavalent, fIPV and DTP booster vaccines with the hexavalent vaccine would initially increase vaccine procurement costs. However, these would be partially offset by savings from:
The team added that based on previous vaccine procurement trends, a 50% reduction in the hexavalent vaccine price would make the switch economically favorable under the primary immunization schedule. Further price reductions could also generate cost savings for the booster-dose scenario.
"Our study demonstrates that although the hexavalent vaccine carries a higher upfront procurement cost, it also generates important efficiencies by reducing injections, easing pressure on frontline health workers, lowering cold-chain requirements and saving caregivers' time. These findings provide important economic evidence that can inform future policy discussions on strengthening India's immunization program," Dr. Susmita said.
Blockbuster GLP-1 drugs, with semaglutide as the key ingredient, have shown promise in treating conditions ranging from diabetes and obesity to certain cancers.
Now, US researchers are set to test whether semaglutide can also help treat alcohol use disorder (AUD), particularly among veterans. AUD affects an estimated 400 million people worldwide, or about 7% of people aged 15 years and older.
The US Department of Veterans Affairs (VA) has announced a new clinical trial to evaluate the effectiveness of semaglutide in treating AUD and is aimed directly at benefiting Veterans.
"By exploring emerging treatment options like the use of a GLP-1 for AUD, we aim to expand the tools available to help Veterans take control of their health and recovery," said VA Secretary Doug Collins.
Currently, more than 400,000 US veterans have been diagnosed with AUD, while an estimated 11% of US adults are affected by the condition.
Also read: GLP-1 Weight-Loss Drugs Show Promise for 17 Million With Binge Eating Disorder, Suggests Study
The study, called the Cessation or Reduction of Alcohol Consumption in Veterans (CRACV) trial, will enroll more than 600 veterans across 18 VA medical centers in the US.
Participants aged 18 to 80 with moderate or severe AUD will receive weekly injections of either semaglutide or a placebo for 24 weeks, followed by a safety follow-up period.
Researchers will assess changes in alcohol consumption, overall health, and quality of life to determine whether semaglutide could become a new treatment option for alcohol use disorder.
Evidence is also emerging that GLP-1 medications may influence alcohol consumption. A Phase 2 clinical trial published in the American Journal of Psychiatry in July suggests that oral semaglutide may help reduce heavy and harmful drinking, even among people who are not trying to quit alcohol completely.
The trial included 50 adults with moderate to severe alcohol use disorder who wanted to reduce or stop drinking. Participants were randomly assigned to receive either daily oral semaglutide or a placebo for eight weeks.
The semaglutide dose increased from 3 mg per day during the first four weeks to 7 mg per day during the remaining four weeks.
While semaglutide did not significantly reduce laboratory-assessed craving or the average number of drinks per day compared with placebo, it significantly reduced heavy drinking days.
Compared with participants receiving placebo, those taking semaglutide had fewer heavy drinking days during the final four weeks of treatment. They also consumed fewer drinks on drinking days and reported greater reductions in everyday alcohol cravings and alcohol-related negative consequences.
"It could represent a new treatment option for alcohol use disorder, particularly for those who have not benefited from existing medications, and may reduce alcohol-related health and social harms. Importantly, even reducing heavy drinking can lead to meaningful improvements for patients and families," said Joseph Schacht, PhD, professor of psychiatry at the University of Colorado Anschutz School of Medicine.
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