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.

Women who skip their first breast cancer screening may face a 40% greater risk of dying from the disease over the long term, according to a new study. The research, published in September in The BMJ, followed more than 400,000 women in Sweden over a span of up to 25 years.

When Should Women Begin Breast Cancer Screening?

The study raises important questions: at what age should women start screening, why does missing the first appointment increase long-term risk, and what other tests or self-checks might help? Dr. Leana Wen, an emergency physician and adjunct associate professor at George Washington University, weighed in on these points.

As per CNN, Wen explained that in the United States, breast cancer is the second most common cancer among women and the second leading cause of cancer death. In 2022, over 279,000 new cases were reported in women, and more than 42,000 women died from the disease in 2023.

Globally, a report from February, as per CNN, indicated that 1 in 20 women will develop breast cancer in their lifetime. Researchers estimate that by 2050, annual diagnoses could reach 3.2 million, with 1.1 million deaths worldwide.

When breast cancer is found and treated in its earliest stage, the five-year survival rate exceeds 99%, according to the American Cancer Society. Once cancer spreads to other organs, the survival rate drops to around 32%.

When Should Women Start Screening For Breast Cancer?

Last year, the U.S. Preventive Services Task Force recommended that most women begin mammograms at age 40 and continue every two years until age 74. Women over 75 should decide in consultation with their primary care provider.

For women at higher risk, screening may need to start earlier or occur more frequently. High-risk factors include prior chest radiation, certain genetic mutations, and having a first-degree relative, such as a mother or sister, with breast cancer.

The Swedish study tracked 432,775 women over up to 25 years. Nearly one-third of women invited for their first mammogram did not participate. Those who skipped the first screening were also less likely to attend future screenings and more likely to be diagnosed at advanced stages.

The study found that women who missed the initial mammogram were 1.5 times more likely to be diagnosed with stage 3 cancer and 3.6 times more likely for stage 4, compared to those who attended. After 25 years, death rates from breast cancer were significantly higher among the initial nonparticipants.

Researchers noted that while the findings reflect Sweden’s healthcare system, the principle that missing initial screenings increases long-term risk likely applies worldwide. An editorial in the same journal emphasized that attending the first mammogram is a long-term health investment, not just a routine check.

Why Does Delaying First Breast Cancer Screening Increase Long-Term Risk?

Wen highlighted that women who skip the first screening often continue to miss subsequent exams. Factors such as lack of awareness, access challenges, fear, and cultural influences may contribute. Late-stage diagnosis leads to lower survival rates and higher mortality.

Mammograms remain the standard screening tool for women at average risk. Higher-risk women may benefit from additional tests, such as genetic testing, breast MRI, or ultrasound. Women with dense breast tissue should discuss supplemental tests with their healthcare provider, as mammograms are less effective for detecting cancer in dense tissue.

What About Breast Self-Exams?

Self-exams are not a replacement for mammograms but can help women notice changes in their breasts. If a lump or other unusual symptoms appear—such as nipple discharge, pain, swelling, color changes, inward-turning nipple, enlarged lymph nodes, or skin changes—women should consult a healthcare provider immediately.

How Can Women Reduce Their Risk Of Breast Cancer?

Lifestyle factors play a major role. Smoking, excessive alcohol consumption, and obesity increase risk. Maintaining a healthy weight, staying physically active, eating a nutritious diet, quitting smoking, and moderating alcohol intake can all lower the risk and improve overall health.

We all indulge in tasty meals from time to time and with the holiday season approaching, many of us will be enjoying larger-than-usual meals. But going overboard can raise the risk of certain health problems, including heart attacks, especially for those with chronic health conditions.

“If you’re young and healthy, a single large meal is unlikely to trigger a heart attack, but for the right population, it can certainly increase the risk,” said Ameya Kulkarni, a cardiologist at Kaiser Permanente, as per The Washington Post.

Heart disease is the top cause of death in the United States, with someone experiencing a heart attack roughly every 40 seconds. That adds up to over 800,000 people annually, according to the CDC.

Heavy Meals Can Trigger Heart Risk

In 2000, a study abstract presented at an American Heart Association conference revealed that an “unusually heavy meal” may increase the risk of a heart attack by about four times in the two hours after eating, which the authors called the “hazard period” - particularly in those with pre-existing heart disease.

The participants described their meals as “heavy.” The abstract wasn’t published in a peer-reviewed journal.

Similarly, a 2005 analysis of 17 studies found that heavy physical activity, eating, and emotional stress were some of the common triggers reported before a heart attack. Men were more likely to report exertion and eating, while women often reported emotional stress.

Big Meals Stress The Heart

Eating a large, high-fat, high-calorie meal is similar to extreme physical exertion for your heart. To digest all that food, blood is redirected to your digestive system. Blood vessels tighten, heart rate and blood pressure rise, and blood flow to the heart can be limited, said Steve Kopecky, a cardiologist and professor at Mayo Clinic.

That spike in blood pressure can rupture cholesterol plaques in the arteries, forming clots. Even the fatty meal itself — think buttered potatoes, gravy, and heavily marbled meats — can make your blood more prone to clotting.

“These factors together can lead to a heart attack a few hours later,” Kopecky explained.

Who Is Most At Risk?

Certain conditions raise heart attack risk, including diabetes, high cholesterol, high blood pressure, and obesity, as well as lifestyle habits like poor diet, inactivity, or smoking history. For people with these risk factors, a large meal could act as a trigger, just like emotional stress or heavy physical activity, such as shoveling snow, said Kulkarni, also president of the AHA’s Greater Washington Region Board of Directors.

Heart Attack Warning Signs

• Chest pain or pressure in the center or left side of the chest that persists for several minutes or comes back.
• Pain or discomfort in one or both arms, jaw, neck, back, or above the stomach.
• Shortness of breath without physical activity.
• Weakness, dizziness, lightheadedness, or sudden cold sweats.
• Nausea or vomiting.
• Fast or irregular heartbeat.

Tips For Safer Indulgence

• Enjoy indulgent foods, but balance your plate with healthy options. Aim for half your plate to be fruits and vegetables, a quarter protein, and a quarter starch, Kulkarni said. Start with a salad, then add whole foods like turkey with a modest portion of stuffing, beans, or sweet potatoes.
• Eat slowly. It can take up to 20 minutes for your brain to register fullness, so eating quickly can lead to overeating. Treat meals as a social event and savor the time with family and friends.
• Limit alcohol. Drinking can increase appetite and reduce self-control, leading to eating more.
• Stop when you feel full. Skip that second helping once you’ve had enough.
• Take a walk after meals. Walking can help reduce triglycerides, regulate blood pressure, and lower blood sugar, Kopecky said.

Large meals high in saturated fats, calories, and processed carbs can increase heart attack risk for people with underlying health conditions. But with moderation, adding healthy foods to your plate, and skipping extra servings, you can enjoy your meals while lowering your risk.

Bird flu viruses pose a particular danger to people because they can continue multiplying even at temperatures that would normally stop most infections. Fever is one of the body’s natural ways to slow viruses, yet new research from the universities of Cambridge and Glasgow shows that avian strains can survive what should be a hostile environment.

The study, published in Science, identifies a key gene that influences how well a virus copes with heat. This same gene moved into human flu strains during the 1957 and 1968 pandemics, allowing those viruses to spread more easily.

How Flu Viruses Thrive In The Body

Human influenza viruses infect millions each year. The seasonal strains we see most often fall under influenza A and tend to do well in the cooler temperatures of the upper respiratory tract, which is close to 33°C. They are less suited to the warmer, deeper parts of the lungs, where temperatures reach about 37°C.

As per Science Daily, when the body cannot slow an infection, the virus continues to multiply and spread, which can lead to more serious illness. Fever acts as a protective response, pushing body temperature as high as 41°C. Until now, the exact reason why fever slows some viruses but not others has been unclear.

Avian influenza behaves differently. These viruses usually grow in the lower respiratory tract, and in their natural hosts, such as ducks or seagulls, they often infect the gut. Temperatures in these areas can reach 40°C to 42°C, which helps explain their greater tolerance to heat.

How Fever Limits Infection and Why Bird Flu Can Resist It

If left unchecked, a virus can move through the body and cause significant harm. Fever is one of the body’s most familiar defence responses and can raise the core temperature to levels that inhibit many pathogens. Scientists have long known that some viruses withstand these temperatures, but the reason behind this resistance has remained uncertain.

Avian flu strains show a clear advantage in hotter environments. They thrive in the lower airways and, in birds, survive in the high heat of the gut. These features distinguish them from human influenza strains, which prefer cooler tissue.

Earlier studies in cell cultures hinted that avian flu copes better with fever-range temperatures than human strains. The new research offers direct evidence from animal experiments, helping explain why fever is effective against some types of influenza but far less useful against others.

Experiments Show Why Fever Slows Human Flu but Not Avian Flu

Researchers from Cambridge and Glasgow recreated fever-like conditions in mice to examine how different viruses responded. They worked with a lab-adapted human influenza strain known as PR8, which does not pose a threat to people.

Mice do not typically develop a fever from influenza A, so the scientists raised the temperature of the environment to lift the animals’ body temperature.

The findings were striking. When body temperature rose to fever levels, the human-origin virus struggled to replicate, and the infection weakened. Avian influenza behaved very differently. Raising the temperature did not stop the virus from multiplying, and a small increase of only 2°C was enough to turn a normally severe human-origin infection into a mild one.

The PB1 Gene Helps Bird Flu Withstand Fever

The study also identified the PB1 gene as a major reason why bird flu can tolerate heat. PB1 helps the virus copy its genetic material inside infected cells. When viruses carried an avian-type PB1 gene, they were able to endure high temperatures and still cause severe disease in mice. This matters because avian and human flu viruses can exchange genes when they infect the same host, such as pigs.

Dr. Matt Turnbull, the study’s first author from the Medical Research Council Centre for Virus Research at the University of Glasgow, explained that this gene swapping remains a major concern for emerging influenza strains. He noted that similar exchanges occurred in 1957 and 1968, when human flu viruses replaced their PB1 gene with one from an avian strain. According to the researchers, this may help explain why those pandemics were so severe.