A stomach virus, often colloquially referred to as the "stomach flu" or "stomach bug," is a microscopic organism that infects your digestive system. Unlike the common flu, which is caused by a respiratory virus, stomach viruses target the gastrointestinal tract. These viruses can cause inflammation and irritation of the stomach and intestines, leading to a range of unpleasant symptoms.

It's important to note that stomach viruses are not caused by bacteria. While bacteria can also cause food poisoning or other gastrointestinal illnesses, viruses are a different type of infectious agent. This distinction is crucial because antibiotics, which are effective against bacterial infections, are ineffective against viruses.

What are Some Common Stomach Viruses?

Norovirus, a highly contagious virus, is notorious for causing outbreaks in communal settings like schools, hospitals, and cruise ships. It can lead to severe vomiting and diarrhea, often resulting in rapid dehydration. Rotavirus, primarily affecting young children, is a major cause of severe diarrhea globally. However, widespread vaccination has significantly reduced its impact in many developed countries. Adenovirus is a versatile virus capable of causing various illnesses, including respiratory infections, eye infections, and gastrointestinal issues. While it can lead to stomach illnesses, symptoms are often milder compared to those caused by norovirus or rotavirus. Astrovirus is another common culprit of childhood diarrhea, causing vomiting, diarrhea, and fever.

What are The Symptoms?

The symptoms of a stomach virus typically manifest within 12 to 48 hours post-exposure. Common symptoms include nausea, vomiting, diarrhea, abdominal cramps, headache, fever, and fatigue. In severe cases, dehydration can occur, leading to dizziness, lightheadedness, and reduced urine output. While most individuals recover without complications, it's crucial to seek medical attention if you experience severe dehydration, persistent vomiting or diarrhea, blood in your stool, high fever, or severe abdominal pain. Dehydration, especially in vulnerable groups like young children and the elderly, can be dangerous and may necessitate intravenous fluid therapy. If you're concerned about your symptoms or experience severe dehydration, consult a healthcare provider.

Ways to Prevent It

While there's no foolproof way to avoid stomach viruses entirely, adopting these preventive measures can significantly reduce your risk of infection.

Frequent Handwashing

This is the single most effective way to prevent the spread of stomach viruses. Wash your hands thoroughly with soap and water, especially after using the bathroom, changing diapers, and before eating.

Sanitize Surfaces

Regularly clean and disinfect frequently touched surfaces, such as doorknobs, countertops, and toys, to eliminate viruses.

Avoid Contaminated Food and Water

Cook food thoroughly, avoid raw or undercooked foods, and drink clean water. Be cautious when traveling to areas with poor sanitation and consider boiling water before drinking it.

Practice Good Hygiene

Avoid touching your face with unwashed hands and cover your mouth and nose when coughing or sneezing. This helps prevent the spread of respiratory droplets that may contain viruses.

Millions of people around the world undergo blood tests every year to measure LDL, commonly known as "bad" cholesterol. But researchers now suggest that this standard test may not always provide the most accurate picture of heart disease risk.

A new study from Northwestern Medicine found that a blood test measuring apolipoprotein B (ApoB) may be better than LDL cholesterol testing for identifying people who need more intensive treatment to reduce their risk of heart attacks and strokes.

The researchers also found that using ApoB to guide treatment decisions could prevent more cardiovascular events while remaining cost-effective for healthcare systems. The findings were published in the journal JAMA.

"We found that ApoB testing to intensify cholesterol-lowering medication would prevent more heart attacks and strokes than current practice, and that these health benefits were achieved at a cost that represents good value for US healthcare payers," said study lead author Ciaran Kohli-Lynch, Assistant Professor of Preventive Medicine in the Division of Epidemiology at Northwestern University Feinberg School of Medicine.

ApoB vs LDL: What's the Difference?

Also read: Confused By Your Cholesterol Report? Here's What LDL And ApoB Really Mean

Doctors have traditionally relied on LDL ("bad") cholesterol and non-HDL cholesterol levels to assess heart disease risk and decide when patients should begin or intensify cholesterol-lowering treatment. While these tests provide useful information, researchers say they do not tell the whole story.

The difference lies in what the two tests measure:

• LDL cholesterol test: Measures the amount of LDL cholesterol in the blood.
• ApoB test: Measures the number of cholesterol-carrying particles—including LDL and other potentially harmful particles—that can enter artery walls and contribute to plaque buildup.

"Research strongly shows that apolipoprotein B (ApoB) is better at identifying who is at risk because it counts the total number of harmful particles in the blood," Kohli-Lynch said.

According to the researchers, the number of harmful particles may provide a more accurate measure of cardiovascular risk than LDL cholesterol levels alone.

What Is ApoB?

Read More: US Cardiologist Explains Why 2026 AHA Cholesterol Guidelines Recommend Starting Young

In a post on X, Dr. Sudhir, Senior Consultant Neurologist at the Institute of Neurosciences, Apollo Hospitals, Hyderabad, explained that ApoB is a protein found on potentially harmful cholesterol-carrying particles such as LDL and VLDL (very low-density lipoprotein).

"Think of ApoB as a count of the particles capable of entering artery walls and causing plaque. One ApoB is equal to one potentially harmful particle," he said.

Dr. Sudhir explained that two people can have the same LDL cholesterol level but very different numbers of cholesterol-carrying particles. The person with more particles will usually have a higher ApoB level and, potentially, a greater risk of cardiovascular disease.

He added that ApoB often provides a more accurate assessment of heart disease risk than LDL cholesterol alone.

Despite growing evidence supporting ApoB, the test is still not widely used in routine clinical practice because it generally requires an additional blood test beyond the standard cholesterol panel, increasing both cost and inconvenience.

"Our study asked: Is it worth spending extra money to use ApoB instead of LDL to guide treatment intensification?" Kohli-Lynch said.

Dr. Sudhir suggested that ApoB testing should be considered for:

• people with diabetes,
• prediabetes,
• metabolic syndrome,
• obesity,
• elevated triglycerides,
• strong family history of heart disease.

New Cholesterol Guidelines

Earlier this year, the American Heart Association and 10 other medical organisations released updated guidelines recommending that many people begin cholesterol-lowering therapy at younger ages.

"This means it is increasingly important to accurately identify who would benefit most from intensive treatment," Kohli-Lynch said.

The updated guidelines also recommend measuring ApoB, particularly in people with high triglycerides, diabetes or in situations where LDL cholesterol levels may underestimate the number of harmful cholesterol-carrying particles.

Do you often forget where you kept your keys or glasses and worry that it could be a sign of Alzheimer's disease? While many people become more forgetful with age, doctors say that occasional memory lapses are a normal part of ageing. Alzheimer's disease, however, causes a different pattern of decline that affects memory, thinking and the ability to function in everyday life.

HealthandMe spoke to two neurologists who explained how to tell the difference between normal age-related forgetfulness and the warning signs of Alzheimer's disease.

"Many people worry when they start becoming more forgetful with age. While some changes in memory and thinking are a natural part of growing older, Alzheimer's disease causes a different pattern of decline that affects everyday life," said Dr. Rajneesh Kummar, Vice Chairman & Unit Head, Neurology, Max Super Speciality Hospital, Dwarka.

Dr. Praveen Gupta, Chairman, MAIINS, Marengo Asia Hospitals, Gurugram, added, "Alzheimer's is not a normal part of ageing. It's a neurodegenerative disease that affects memory, thinking and how you function each day. Recognising the difference can help people get medical evaluation and treatment sooner."

Also read: India Gets Its First Alzheimer’s Drug: Know All About Eli Lilly’s Lormalzi

The experts advised that persistent memory concerns should not be ignored. If symptoms become more noticeable or begin affecting day-to-day functioning, a medical assessment can help identify the cause and guide appropriate treatment and support.

They outlined six key differences that can help distinguish normal ageing from Alzheimer's disease.

1. Occasional Forgetfulness vs Repeated Memory Loss

According to the doctors, it is common to occasionally misplace items, forget a name or an appointment, and remember the information later.

However, people with Alzheimer's disease may repeatedly forget recent events, conversations, appointments or newly learned information and may not recall them even after reminders.

2. Slower Thinking vs Difficulty With Everyday Tasks

Normal ageing may mean taking longer to learn new technology or complete routine tasks.

In Alzheimer's disease, people may struggle to manage bills, prepare meals, follow directions, learn to use a new phone or remember instructions given only moments earlier.

3. Misplacing Things vs Forgetting They Were Ever There

Occasionally losing keys or glasses is considered a normal part of ageing, and most people can usually retrace their steps and find them.

By contrast, people with Alzheimer's disease may not remember putting an item down or even recall recently getting or buying it.

Read More: Anti-Inflammatory Diet May Help Lower Dementia Risk, Even In Those Who Show Early Signs Of Alzheimer’s: Study

4. Temporary Confusion vs Disorientation

Older adults may occasionally lose track of the day or date but usually remember it shortly afterwards.

According to the doctors, Alzheimer's disease can cause confusion about time, dates and places. People may repeatedly ask the same questions or become disoriented, even in familiar surroundings.

5. Searching for Words vs Difficulty Communicating

Everyone experiences occasional "tip-of-the-tongue" moments.

With Alzheimer's disease, people may frequently lose their train of thought, repeat themselves, struggle to follow conversations or have difficulty finding the right words.

6. Remaining Independent vs Needing Increasing Support

The doctors said one of the biggest differences is that normal ageing generally does not prevent a person from living independently.

Alzheimer's disease, however, gradually affects a person's ability to carry out everyday activities, adapt to changes in routine and maintain self-care without assistance.

Bryan Johnson, the billionaire biohacker and longevity enthusiast, has been diagnosed with an incurable autoimmune disease called Autoimmune Gastritis (AIG).

Johnson is known for his radical longevity experiments, including measuring the biological age of his organs in an effort to reverse aging, injecting himself with ketamine, taking over 50 pills a day, undergoing fat transfers, and receiving blood transfusions from his teenage son.

In a recent post on X, he made the shocking announcement of his autoimmune conditions, which went undetected for years: Autoimmune Gastritis.

Calling it "bad news," Johnson wrote: "I have an autoimmune disease. My stomach is eating itself."

"2-5 per cent of people have this, too. Likely more, because it hides," he added.

According to Johnson, his stomach had been attacking itself without causing noticeable symptoms. The condition was only discovered in May.

Also read: Bryan Johnson Blames Sugary Cereals, Soda and Stress for His Autoimmune Disease; Shares Treatment Plan

The Early Warning Sign: Low Ferritin

Autoimmune Gastritis, a condition in which the immune system attacks the stomach's acid-producing cells, also impairs the absorption of iron and vitamin B12.

Johnson said one of the earliest signs of the condition was persistently low ferritin levels over the past 11 years despite not having anemia.

"We continually tried to raise my iron levels with food and supplementation, but nothing would work."

He said he followed a plant-based diet, trained intensely, used a sauna and hyperbaric oxygen therapy, and took iron supplements, yet his iron levels remained low.

Ferritin stores the body's iron. Iron is essential for transporting oxygen and producing energy, and low iron levels can lead to fatigue, weakness, and dizziness.

Johnson said autoimmune gastritis is difficult to diagnose because its earliest clue is often overlooked.

"The earliest clue, low ferritin, is the one standard medicine waves through. Low iron stores get normalized and rarely investigated at all when anemia hasn't shown up yet. That blind spot is what hid mine for a decade."

While initially it wasn't clear why his iron levels were continuously dipping, after further testing, Johnson's team identified three interconnected issues.

Read More: Bryan Johnson Battles Autoimmune Gastritis: Which Parts Of His Longevity Guide Are Actually Worth Copying?

Autoimmune Gastritis was preventing normal iron absorption by damaging the stomach cells that produce acid. He also discovered autoimmune thyroid disease.

"The iron deficiency, the autoimmune gastritis driving it, and the autoimmune thyroid disease alongside it. Iron and thyroid feed each other both ways; low iron impairs the conversion of thyroid hormone into its active form, and an underactive thyroid impairs how the body uses iron," Johnson explained.

Iron Deficiency May Be More Common Than Many Realize

According to research published in JAMA Network Open, about one in four Americans may have inadequate iron intake or absorption.

As per the study of more than 8,000 Americans, 14 per cent of adults had absolute iron deficiency, reflecting depleted iron stores.

Even after excluding common causes such as anemia, pregnancy, heart failure, and chronic kidney disease, 11 per cent remained iron deficient. Another 15 per cent had functional iron deficiency, where iron levels appear normal but the body cannot use the mineral effectively.

How Bryan Johnson Is Managing The Condition

Since receiving the diagnosis, Johnson has begun iron infusions, which deliver a full dose of iron in a single treatment.

He said his team will continue routine monitoring of his ferritin and iron levels.

Johnson ended his post with a warning that hidden health conditions can go unnoticed for years.

"You too may have a lurking health issue that is undiagnosed and could increase in severity from unhealthy life choices, without your knowing… A gentle nudge that minding your health, no matter your situation in life, is a good decision-making."