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.

With flu season setting in across countries, including the US and the UK, doctors are urging people to get their annual flu shots. October offers an opportunity to build protection before winter flu activity increases.

The UK Health Security Agency (UKHSA) reported above-average flu activity and urged at-risk groups to get vaccinated. England's flu vaccination program last winter is estimated to have prevented about 100,000 hospital admissions and 7,000 deaths.

The US Centers for Disease Control and Prevention (CDC) recommends annual flu vaccination for everyone aged six months and older. The seasonal vaccine targets influenza A(H1N1), A(H3N2) and B/Victoria viruses.

In September, the Indian Medical Association (IMA) also highlighted annual influenza vaccination and gaps in adult immunization.

Why Is October A Good Time To Get Vaccinated?

Also read: Flu Activity Rises Early In US, UK And Japan: Why Experts Urge Vaccination Before Winter

The flu vaccine takes about two weeks to build protection, making October a good time to get vaccinated before winter, Dr. Bhawna Malik, Senior Consultant-Neonatologist and Pediatric Intensivist at Motherhood Hospitals, Greater Noida, told HealthandMe.

In India, flu activity can increase between January and March. Vaccination in October allows time for immunity to develop before this period.

However, October is not the only option. Dr. Vikas Maurya, Senior Director and HOD, Pulmonology, Fortis Hospital, Shalimar Bagh, told HealthandMe that vaccination can also be taken between April and mid-June, ahead of another period of flu activity from July to September.

He said one dose annually is generally sufficient, with timing depending on local flu patterns and the vaccine used.

Who Should Get The Flu Vaccine?

Healthy adults and children, as well as people with underlying conditions, can benefit from flu vaccination. Influenza can cause pneumonia, hospitalization and other severe complications.

Older adults, particularly those aged 65 and above, and people with diabetes, heart disease, kidney or liver disease, asthma or chronic obstructive pulmonary disease (COPD) face a higher risk of complications.

“Flu vaccination doesn't protect just yourself against the risk of having influenza but it also prevents transmission of infection to other vulnerable people around ourselves like little ones, elderly family members and people with medical conditions,” Dr. Malik said.

Dr. Mohit Bhardhwaj, Consultant, Pulmonology, PB Health, Gurugram, told HealthandMe that annual vaccination helps protect individuals and reduce transmission, as flu viruses change and vaccine protection can decrease over time.

Flu Vaccine Schedule For Children And Adults

Read More: Flu 2026: Symptoms To Watch For As New Season Begins

The vaccine can be administered from six months of age. The schedule depends on age and previous vaccination history.

• Children aged six months to eight years: Some children receiving the vaccine for the first time need two doses at least four weeks apart.
• Children aged nine and above: Annual vaccination is generally recommended.
• Adults: One dose each flu season is generally recommended.
• Infants younger than six months: Cannot be vaccinated directly.

Dr. Malik recommends vaccination for parents, siblings and caregivers to help reduce the risk of transmitting influenza to infants who are too young to receive the vaccine.

Are There Any Side Effects?

Most flu vaccine side effects are mild and may include injection-site pain, redness or swelling, fever, headache, body aches and tiredness. These generally settle within a few days, Dr. Bhardhwaj said.

A cooling pack or an ice pack wrapped in cloth may help relieve injection-site discomfort. Nasal vaccines may cause a stuffy nose, cough or headache, Dr. Maurya noted.

The injected flu vaccine cannot cause influenza. Anyone experiencing persistent fever, breathing difficulty or unusual symptoms should seek medical advice. Those with a history of serious allergic reactions to a previous flu vaccine should consult their doctor before vaccination.

A migraine attack is characterised by nausea, vomiting and sensitivity to light and sound. But early symptoms may surface long before the headache itself. Signs like fatigue, mood changes, food cravings and difficulty focusing may appear hours or even days before the pain.

The symptoms that occur during the attack reflect a complex neurological process that involves several interconnected brain networks, rather than just a headache.

A new Lancet Seminar review, looks deeper into how migraine develops, why its symptoms extend beyond head pain and how the better understanding of its biology are affecting treatment.

The study authors describe migraine as a chronic neurovascular disorder shaped by genetic susceptibility and interactions between the brain’s sensory networks, nerves, and blood vessels.

What Happens In The Brain During A Migraine Attack?

Also read: These Yoga Asanas Could Cure Your Migraine

Migraine is the result of the interaction of multiple systems responsible for processing sensory information and transmitting pain. Researchers are focusing more on other factors that drive migraine rather than just blood vessel narrowing or widening.

An important concept is the trigeminovascular system, which is a network involving the trigeminal nerve, tissues sensitive to pain that surrounds the brain and blood vessels. When this system gets activated, the patient experiences the peculiar head ache.

Chemical messengers called neuropeptides also play a key role. One of the most important is calcitonin gene-related peptide (CGRP), which participates in pain signalling in migraine. Treatments that target CGRP is an important development in migraine treatment and management.

The condition also involves changes in how the brain processes sensory information. This explains why light, sounds or smells can become intolerable during an migraine attack, and why some patients experience nausea, dizziness or difficulty concentrating along with severe headache.

Not an isolated abnormality triggering every symptom, migraine involves interactive neurological and vascular processes whose contributions can vary between individuals and across different phases of an attack.

Symptoms May Begin Before The Headache

Also read: Saba Ali Khan Opens Up About Brain Tumour: Can It Go Unnoticed If You Walk, Talk And Work Normally?

Migraine attacks typically occurs through several phases mostly:

1. Prodrome: Hours or days before the pain

The earliest phase can involve fatigue, yawning, mood changes, food cravings, neck stiffness and difficulty concentrating. The involvement of brain regions linked with homeostasis, including the hypothalamus, may help explain why an approaching attack can affect sleep, appetite, mood and other bodily functions.

2. Aura: Temporary neurological symptoms

Some people experience an aura before or during the headache. This can include flashing lights, zigzag patterns, blind spots, tingling or temporary difficulties with speech. Aura is associated with a phenomenon called cortical spreading depression, a wave of changing electrical activity that moves across the brain’s cortex.

3. Headache: Pain and sensory sensitivity

During the headache phase, activation of the trigeminovascular system contributes to pain signalling. Patients may experience moderate-to-severe, often throbbing pain, alongside nausea, vomiting and sensitivity to light, sound or smells.

Movement can aggravate the pain, making routine activities difficult. The headache phase can last several hours to as long as 72 hours.

4. Postdrome: After the pain subsides

The end of an attack does not necessarily mean the attack is over. Some people experience exhaustion, dizziness, body aches and difficulty concentrating for hours or days afterwards. These phases can overlap, and their timing and severity differ from person to person.

The Lancet review also highlights the role of genetic and epigenetic factors that contribute to migraine risk. They interact with complex neurological networks, helping explain why some people experience occasional attacks while others develop frequent or chronic migraine.

Episodic migraine is characterised by fewer than 15 headache days per month. Chronic migraine involves headaches on at least 15 days per month for more than three months, including migraine features on at least eight days each month.

Breast cancer is the most common cancer among women in India. According to various estimates, it accounts for about 26% of all cancers diagnosed among women, with nearly 2,00,000 new cases estimated in India each year.

Family history is not the only risk

Family history is an important risk factor, as some women inherit genetic changes that can increase their risk of developing breast cancer. Hereditary breast cancers can result from inherited genetic susceptibility, including mutations in high- or moderate-penetrance genes. BRCA1 and BRCA2 are among the best-known genes associated with hereditary breast cancer. Therefore, knowing family history is important.

But the absence of a family history does not mean that women are free from risk. In fact, around 80-85% of breast cancer cases occur in women with no known family history. These are generally referred to as sporadic cases.

The risk factors

Breast cancer risk factors can broadly be divided into those that cannot be changed and those that can potentially be modified.

Among the non-modifiable factors are age and certain reproductive and hormonal factors. Longer lifetime exposure to hormones such as oestrogen and progesterone can increase breast cancer risk. Early menstruation, later menopause and having a first pregnancy at a later age are some factors associated with longer hormonal exposure.

Potentially modifiable risk factors are largely lifestyle-related and include alcohol consumption, physical inactivity, excess body weight (particularly after menopause) and tobacco exposure. Maintaining a healthy weight, staying physically active, avoiding tobacco and limiting alcohol can help reduce the risk.

Also read: Amanda Peet’s Breast Cancer Wasn’t A Lump: What Was Her First Sign?

Five signs that should never be ignored

The five important warning signs include:

• A new, hard lump in the breast or armpit, particularly if it is increasing in size.
• A change in the size or shape of one breast, especially when it creates a new difference in breast symmetry.
• Unusual nipple discharge, particularly spontaneous discharge that is clear or bloody.
• Changes involving the nipple, such as a newly inverted nipple.
• Changes in the breast skin, including thickening, dimpling, puckering or a change in its appearance or texture.

These signs do not automatically mean cancer. But they should not be ignored.

Also read: Mammogram May Spot Hidden Heart Risk That Doctors Miss In Women

Get checked if you notice a change

If you notice any of these signs, particularly a new or persistent change in your breast, do not ignore it or try to diagnose it yourself. Seek medical evaluation promptly. A doctor will assess the breast and, if necessary, recommend what is known as a triple assessment: a clinical examination, breast imaging such as ultrasound or mammography, and tissue diagnosis when required. In selected cases, an MRI may also be recommended.

Tissue sampling may involve Fine Needle Aspiration Cytology or a core/true-cut biopsy. Together, these assessments help determine whether a breast abnormality is benign or malignant. It is important to distinguish this from screening. Screening is done in women who do not have symptoms, with the aim of detecting breast cancer at an early stage. When a woman has a symptom or notices a new breast change, she needs diagnostic evaluation rather than simply screening.

Don't panic: most breast lumps are benign

Finding a lump can understandably cause anxiety. However, most breast lumps, particularly in younger women, are benign. Common causes include fibroadenomas, breast cysts and fibrocystic changes.

Fibrocystic changes are often influenced by hormonal fluctuations. A lump may become more prominent or painful one to two weeks before menstruation and become smaller or less uncomfortable after the period. Some women may also experience a feeling of heaviness or tenderness in the breast.

An injury to the breast can also result in tissue damage and inflammation, producing a lump-like area. Therefore, a lump should not be assumed to be cancer, but neither should it be dismissed without appropriate evaluation.

Early detection can make a significant difference in the successful management of breast cancer. Women should remember that having no family history does not mean they are not at risk. At the same time, a breast lump or other change does not necessarily indicate cancer. The key is to know your own breasts, be aware of the warning signs and seek timely medical evaluation whenever a new or persistent change is noticed.

By Dr Megha B - Surgical Oncologist in Trichy - Breast, GI & Cancer Surgery Specialist, Kauvery Hospital