Why Do Some People Live Past 100 in Good Health?
Parkinson’s disease, dementia, and cancer, do you think these are unavoidable as we age? Surprisingly, some individuals live past 100 in remarkable good health. When researchers examined their blood, they found an astonishing common trait:
They have a high number of specialized immune cells that help maintain cellular balance.
What Are Senescent (“Zombie”) Cells?
A special forces unit that clears out “zombie cells”
Our bodies accumulate aging cells, often called “zombie cells.” These cells no longer divide, yet they refuse to die. Instead, they release inflammatory substances that damage surrounding tissues. As we age, these cells increase, leading to chronic inflammation and various age-related diseases.
In October 2025, a research team from Ben-Gurion University in Israel published a major discovery in Nature Aging. They found that among our immune cells, CD4 T cells transform into “killers” as we get older. These transformed cells are called CD4-Eomes cells.
When immune cells from young mice were transplanted into old mice, the aged environment transformed these cells into “clean-up units” (CD4-Eomes, shown in red).
Source: Elyahu et al., Nature Aging (2025)
The researchers analyzed the blood of elderly humans, skin tissue, and laboratory animals.
Remarkably, they found that CD4-Eomes cells detect environments rich in aging cells, migrate to those areas, and selectively eliminate only the problematic cells, much like a special forces unit seeking out and removing enemies.
What’s even more surprising is the experiment that followed: When these cells were eliminated through genetic engineering, the mice aged rapidly and had shorter lifespans. Conversely, when senescent (“zombie”) cells were removed with medication, the number of CD4-Eomes cells also decreased.
This shows that the body produces exactly the amount of these “clean-up units” that it needs, no more, no less.
How Aging Impacts Our Immune System
As we age, our immune system gradually changes:
- The production of new immune cells slows down.
- Chronic low-level inflammation (“inflammaging”) increases.
- The ability to fight infections and remove senescent cells declines.
CD4-Eomes cells represent the body’s adaptive response, creating a protective mechanism to maintain immune balance despite these age-related changes.
The Answer Isn’t Youth—It’s Balance
Many people believe that to slow aging, the immune system must be restored to a youthful, twenty-year-old state. But this research tells a different story.
Professor Monsonego, who led the study, explained:
“People think we need to reset the immune system to make it young again, but our findings show that may not be the correct answer.”
The key is an appropriate immune balance for your age.CD4-Eomes cells increase as we grow older, but this is not a problem; it is a protective mechanism the body develops to adapt to aging. In fact, these cells were found in high numbers among people who live past 100 in good health.
What are CD4-Eomes cells?
Basic identity: CD4 cells (commanders/helpers)
In our immune system, CD4 T cells usually act as coordinators or helpers. They don’t directly fight viruses themselves. Instead, they direct other powerful immune cells signaling, “Attack over there!” or “Boost your strength!” essentially managing the battle plan.
Special upgrade: Eomes (attack switch/weapon)
Eomes is a kind of internal switch inside the cell. When this switch turns on, the cell gains the ability to directly kill harmful cells and acquires “killer instinct.” Normally, this switch is found in frontline attacker cells known as CD8 T cells.
Maintaining Immune Balance in Daily Life
Aging cannot be avoided, but aging healthily is absolutely possible. Based on current research, here are practical ways to maintain immune balance:
Reducing inflammation through diet: Antioxidants found in berries, leafy green vegetables, and oily fish help reduce the formation of aging cells. Green tea, olive oil, and dark chocolate are also beneficial. On the other hand, processed foods and refined carbohydrates increase inflammation.
Appropriate exercise matters: About 150 minutes of moderate exercise per week, plus strength training 2–3 times a week, is recommended. Excessive exercise can increase oxidative stress, so maintain an intensity that suits your body.
Deep sleep protects immunity: During 7–8 hours of deep sleep, the body repairs damaged cells and removes waste. Irregular sleep patterns weaken immune function.
Stress management is essential: Chronic stress suppresses immunity and increases inflammation. Meditation, yoga, and deep breathing help maintain autonomic nervous system balance, and relationships with family and friends are equally important. Loneliness is linked to increased inflammation.
Your environment matters too: Minimize exposure to fine dust, plastics, and chemical pollutants, and check your inflammation markers through regular health screenings.
Top 5 Habits for Immune Balance
For a quick takeaway, here are the most effective actions to support immune cells:
- Eat antioxidant-rich, anti-inflammatory foods
- Exercise moderately and consistently
- Get 7–8 hours of deep, restorative sleep
- Reduce stress through meditation, yoga, or breathing exercises
- Avoid environmental toxins and pollutants
Wisdom Our Immune Cells Can Teach Us
The discovery of CD4-Eomes cells changes how we think about aging. Aging is not simply a decline; it is a process of adaptation. As we grow older, our immune system creates new types of cells that take on new roles, eliminating senescent cells and protecting our health.
The fact that these cells were abundant in the blood of centenarians delivers a powerful message: The secret to healthy aging is not making the immune system stronger, but making it balanced.
As the researchers emphasized, “People don’t need a supercharged immune system. They need one that works properly and is appropriate for their stage of life.”
Aging is natural. What matters is helping our immune cells do their best throughout that process. An anti-inflammatory diet, regular exercise, sufficient sleep, and stress management are the keys to maintaining immune balance.
Conclusion: Aging Gracefully Is About Balance
The secret to living past 100 in good health is immune balance, not immortality. CD4-Eomes cells show us that the body adapts to aging by creating protective mechanisms. Supporting these natural processes through lifestyle diet, exercise, sleep, stress management, and environment can help you age gracefully and maintain vitality.
Healthy aging is not about chasing youth; it’s about creating the conditions in which your immune system can work efficiently, adaptively, and effectively throughout your life.
Take Action: Support Your Immune System Today
Adopt an anti-inflammatory diet, exercise wisely, prioritize sleep, and manage stress to help your immune cells work at their best, your body’s natural defense system against aging.
