A new study published in The Lancet Digital Health suggests that biological age of different organs could predict a person's risk of diseases such as cancer, dementia, and heart disease than their actual chronological age. The research analyzed long-term data from Whitehall II study, which had been followed by over 10,000 British adults for more than 35 years.

The blood plasma samples were collected between 1997 and 1999 from participants between ages 45 to 69. Researchers have now examined a follow up data from 6,235 participants, who were by then aged 65 to 89. This was done to see how aging of specific organ may correlate with the development of diseases over two decades.

What Organs Were Studied?

The study measured the biological age of nine key organs, including:

• Heart
• Blood vessels
• Liver
• Immune system
• Pancreas
• Kidneys
• Lungs
• Intestines
• Brain

The researchers were able to find that different organs aged at different rates in different people. In many of the cases multiple organs showed signs of faster aging within the same individual. What is important to note is that those with accelerated aging in certain organs had a higher risk of developing 30 out of the 40 age-related diseases the study had tracked.

Organ Aging And Disease Risk

Some organ-disease connections were expected—people with rapidly aging lungs were more likely to develop respiratory diseases, and those with aging kidneys had an increased risk of kidney-related conditions. However, the study also found less obvious associations.

For example, individuals with fast-aging kidneys were more prone to diseases in other organs, such as the liver and pancreas. Additionally, multiple fast-aging organs were linked to an increased risk of kidney disease.

One of the most surprising findings was that dementia risk was not best predicted by an aging brain but rather by the immune system’s biological age. This suggests that factors such as chronic inflammation and immune health may play a critical role in neurodegenerative diseases.

What Is Organ Specific Blood Tests?

The study also highlights the important of the potential of developing blood tests that could assess the biological age of specific organs. Unlike previous complex methods that measured the organ health, this new approach could make things simple to detect early signs of disease.

The leader author of the study Mika Kivimaki, who is also a professor at the University College London's Faculty of Brain sciences pointed out that such tests could be helpful when it comes to guiding personalized healthcare. In a news release, Kivimaki said, "They could advise whether a person needs to take better care of a particular organ and potentially provide an early warning signal that they may be at risk of a particular disease."

The study reinforces the idea that aging does not affect all organs equally and that looking beyond chronological age could offer better insights into disease prevention. By understanding which organs are aging more rapidly, medical professionals may be able to recommend targeted interventions for individuals at higher risk of specific conditions. Future advancements in organ-specific blood testing could revolutionize how we detect and manage age-related diseases, potentially leading to more personalized healthcare strategies.

Even a mild case of COVID-19 may trigger long-lasting eye problems, with new research revealing that persistent inflammation and nerve damage could be responsible for symptoms that standard eye tests often fail to detect.

The study, led by researchers at Linköping University in Sweden and published in Nature Communications, sheds light on why some COVID-19 survivors continue to experience debilitating vision issues months or even years after infection.

The research began after people who had recovered from mild COVID-19 sought medical help for persistent eye complaints. Many reported:

• Severe eye pain
• Light sensitivity (photophobia)
• Difficulty reading and focusing
• Extreme eye fatigue

Many participants said the condition significantly disrupted their daily lives, preventing them from working or continuing their education.

What the Study Found

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Researchers evaluated 100 people who developed eye problems after mild COVID-19 but had never been hospitalized. Their symptoms had persisted anywhere from three months to three years.

The findings were compared with those of 32 people who had recovered from mild COVID-19 without developing eye symptoms.

Using advanced imaging and laboratory techniques, researchers identified several abnormalities that conventional eye exams failed to detect.

Persistent Inflammation and Nerve Damage

The study found evidence of:

• Long-term inflammation in the eyes
• Damage to nerves controlling multiple eye functions
• Abnormal immune activity involving T cells
• Changes in proteins found in tear fluid

Lead author Petros Moustardas, senior research associate at Linköping University, said the findings indicate that COVID-19 may trigger a severe immune reaction in the eyes, resulting in chronic inflammation and nerve dysfunction.

Why Light Sensitivity Happens

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One of the most common complaints among participants was extreme sensitivity to light. Researchers found that their pupils were allowing too much light into the eyes because of impaired nerve control.

This abnormal pupil function was also associated with:

• Headaches
• Difficulty reading
• Trouble maintaining focus

An Unusual Eye Movement Disorder

The study also identified impaired coordination between the two eyes.

Some participants developed adult-onset strabismus—commonly known as crossed eyes—a condition that is rare in adults.

Researchers believe this occurred because COVID-19 affected the nerves responsible for controlling eye muscles.

A New Way to Diagnose COVID-Related Eye Problems

Because routine eye tests often miss these abnormalities, the research team developed two diagnostic models.

The first relies on specialized ophthalmic tests available at advanced eye clinics, while the second combines these examinations with tear fluid protein analysis to improve diagnostic accuracy.

Researchers hope these models will help doctors recognize COVID-related eye syndrome earlier and pave the way for future treatments.

"We found that the problems experienced by those affected were not detectable by standard tests. We had to perform specialised examinations to detect deviations. The puzzle pieces then fell into place, and we found explanations for the symptoms," said Neil Lagali, professor of experimental ophthalmology at Linköping University.

He added that while the findings provide important clues about how COVID-19 affects the eyes, more research is needed to develop effective treatments for those living with persistent vision problems.

Plant-based Vitamin D3 is often marketed as a healthier or superior alternative to traditional supplements, but doctors say that's not necessarily the case.

According to Dr. Murtaza S. Bagwala, Head of Emergency Medical Services at Saifee Hospital in Mumbai, existing research shows that plant-based Vitamin D3 is just as effective as conventional Vitamin D3 in increasing the body's vitamin D levels.

"Current evidence suggests that plant-based Vitamin D3 performs similarly to conventional Vitamin D3 supplements. For people who prefer vegan or plant-based products, it is a suitable alternative," he told HealthandMe.

Echoing this view, Dr. Sudhir Kumar, Neurologist at Apollo Hospitals in Hyderabad, said that plant-derived Vitamin D3—usually obtained from lichen, algae, or modern fermentation methods—provides an animal-free option without sacrificing effectiveness.

In a post on X, he noted that while plant-based Vitamin D3 is welcome news for vegans and those seeking cruelty-free supplements, both forms work equally well. He added that there is no medical need for people to switch if they are already taking conventional Vitamin D3 supplements.

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India has approved its first plant-based Vitamin D3 (cholecalciferol) ingredient, a move that could expand options for food fortification and dietary supplements while addressing the country's widespread Vitamin D deficiency.

The Food Safety and Standards Authority of India (FSSAI) has cleared VITADEE Green, developed by Fermenta Biotech, for use in health supplements, nutraceuticals and food products.

The company stated that the ingredient is produced using an India-patented process and offers a sustainable, scalable and vegetarian-friendly source of Vitamin D3.

The approval allows Indian manufacturers to incorporate the ingredient into fortified foods, beverages and dietary supplements.

It is particularly significant for vegetarians and vegans, who have traditionally had limited access to Vitamin D3 because most supplements are derived from lanolin, a by-product of sheep's wool.

The approval also supports India's broader efforts to improve nutrition through food fortification, an area where experts say Vitamin D remains a major gap.

What Is Vitamin D3?

Vitamin D3, often called the "sunshine vitamin," is produced by the body when the skin is exposed to sunlight.

It helps the body absorb calcium, maintain healthy bones and teeth, and lowers the risk of fractures. In children, severe deficiency can lead to rickets, while in adults it increases the risk of osteoporosis, muscle weakness, and falls.

Beyond bone health, Vitamin D3 also supports immune function. Research suggests low Vitamin D levels may be associated with increased susceptibility to infections and higher levels of inflammation.

Who Should Take Vitamin D3 Supplements?

The experts said the key question is whether supplementation is needed, not whether the source is plant- or animal-derived.

"The source matters mainly for ethical, dietary or personal preference—not for efficacy," Dr. Sudhir said.

Dr. Bagwala cautioned against taking high-dose Vitamin D without medical advice, as excessive intake can raise calcium levels and increase the risk of kidney stones and other complications.

Yawning has a certain fact attached to it, which is without a doubt a reason for curiosity and amazement among people. Many of you must have noticed that when someone nearby yawns, you often end up yawning too. Even in some cases, a person yawns just after hearing the word yawn or watching someone yawn on screen.

Yawning itself is a natural physical process that involves taking a deep breath and stretching the muscles used for breathing. Some experts suggest that it may help increase alertness and leave us feeling refreshed. However, while scientists have proposed several theories about the purpose of yawning, one question continues to intrigue researchers: why are yawns so contagious?

Dr. Debanjan Pan, Consultant Psychiatrist at Saltlake Mindset, told Health and Me, "Contagious yawning may be linked to mirror neurons, which help us understand and imitate the behavior of others. Humans have survived by living in groups, and our brains are naturally wired to synchronize with the people around us. When we see someone yawn, the same neural networks in our brains may become activated, prompting us to yawn as well."

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Yawning involves taking a very deep breath, which increases oxygen intake and stimulates several parts of the respiratory system. This deep inhalation can temporarily raise the heart rate and boost blood circulation to the spinal cord and the brain, making a person feel calmer and more relaxed afterward.

According to Dr. Pan, this sense of relaxation may also explain why yawning is contagious. When we see someone else yawn, the brain's empathy circuits, particularly those linked to mirror neurons, become active. As humans are highly social beings, we often unconsciously mimic the behaviour and emotions of people around us, causing a yawn to spread from one person to another.

But there might be a question: if yawning is contagious because humans are social animals and human brains are naturally wired to synchronize with the people around them, then why doesn't coughing and sneezing have the same effect?

Dr. Vikas Mittal, Director - Pulmonologist, CK Birla Hospital, Delhi, addressed this very issue and explained, "Yawning is different than coughing and sneezing. Coughing and sneezing are protective reflexes that protect you from irritants. They can be contagious, but that contagion comes after one or two days, not immediately as is with yawning. Yawning occurs because of the brain's automatic self-mirroring networks."

Dr. Mittal further added, "What it means is when somebody yawns, then your brain starts imitating that unintentionally. Not only yawning, but other emotions like a smile, laugh, and fear can trigger the same emotion in the people around you. This is because of the same brain's automatic self-mirroring networks."

Contagious yawning appears to be more than a simple reflex, offering insights into empathy, social bonding, and the human brain.