Stem cells – the things people talk about in network groups sometimes, claiming X and Y can help etc. But what exactly are stem cells, how do they work and, more importantly, what can you do to keep them sprightly as you age?
Stem cells are the Swiss Army knives of your biology: versatile, resourceful and endlessly busy behind the scenes. They build, they repair, they regenerate and they are so interesting IMO. At their core, stem cells are undifferentiated cells, blank slates with potential. They can become many different types of specialised cells, from muscle to nerve to blood, depending on what your body needs, but with certain limitations – read on if this is of interest.
There are several types of stem cells, but the two most talked about are:
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Embryonic stem cells, which can morph into any cell type. These are pluripotent and mainly used in research, not hanging around your body unless you’re developing in utero.
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Adult (or somatic) stem cells live in various tissues and help maintain and repair them. These are multipotent, meaning they can become a few different cell types, but they have their limits. They can’t turn into a spleen cell if they were born to be muscle cells.
Then there’s the trendy cousin, induced pluripotent stem cells (iPSCs). These are adult cells reprogrammed to act like embryonic stem cells. Think of them as midlife crisis cells. They’ve gone back to being 21 and now insist they can do anything – interesting.
You can think of stem cells are your body’s in-house repair service. When tissues are damaged, whether from injury, disease or just the ravages of daily life, they are activated to regenerate what’s been lost or broken.
For instance, hematopoietic stem cells in the bone marrow replenish your blood cells constantly. Neural stem cells in your brain can, in theory, replace damaged neurons, although the adult brain is rather stingy with its generosity. Muscle, skin and gut tissues are constantly refreshed by their own resident stem cells.
However, like many things in life (your metabolism, your memory of where you put your keys), stem cell function declines with age.
Dr David Sinclair at Harvard Medical School, one of the more recognisable faces in the field of ageing, started much of his trailblazing work not on humans but on yeast calls. That might sound underwhelming until you realise yeast has been a reliable model organism for studying cell biology for decades.
(At this point I have to detour because I found this fascinating: David Sinclair’s research at Harvard revealed that yeasts are far more socially complex. In his early studies, he discovered that yeast cells have sexes (yes, male and female), and they even recognise family members, choosing to cooperate with kin while competing with unrelated cells. This primitive social behaviour is driven by genetic signals that bear striking resemblance to the systems in higher organisms. Also we humans share about 31 percent of our genes with yeast, making them a surprisingly effective model for studying fundamental biological processes like ageing, DNA repair and cellular communication.)
And yeast also makes wine and bread, so frankly, deserves some respect, especially from a French viewpoint!
Back to the science part: Dr Sinclair’s work on yeast revealed that ageing isn’t just about things breaking down randomly. He showed that sirtuins, a group of proteins involved in cellular health, play a major role in how cells age. In yeast, activating the SIR2 gene (the yeast version of our SIRT1) extended their lifespan. This line of research helped establish a whole new field exploring how epigenetic changes, not just DNA mutations, drive ageing.
Think of it this way: your DNA is like the piano, but the epigenetic system is the pianist. Over time, the pianist starts getting a bit tired and hitting more wrong notes, and the music of your cellular function gets a bit… dissonant.
His research lab went on to explore how NAD+ (a molecule that supports sirtuin activity) declines with age. Boosting it with precursors like NMN (nicotinamide mononucleotide) or NR (nicotinamide riboside) has shown promise in improving mitochondrial function and even stem cell activity in mice.
So how do you look after your stem cells as you age? Thankfully, you don’t need to live like a monk in the Himalayas and drink endless green smoothies (though it probably wouldn’t hurt). There’s an increasing body of clinical research pointing towards tangible, practical things you can do, many of which rely solely on your will power and not your debit card.
1. Exercise: A 2019 study published in “Cell Metabolism” by researchers at the University of Copenhagen showed that aerobic exercise increases muscle stem cell number and function in older adults. In mice, regular running increased the number of neural stem cells and improved cognitive function. Exercise literally tells your body, “We’re not dead yet, keep repairing!”
2. Fasting (Or at Least Pretending to): Studies from the University of Southern California’s Longevity Institute, led by Dr Valter Longo, show that intermittent fasting or mimicking fasting diets can promote stem cell regeneration, particularly in the gut and immune system.
In one mouse study, periodic fasting caused the regeneration of old, damaged white blood cells. The researchers concluded that fasting flips a regenerative switch in stem cells by lowering IGF-1 (an ageing-related growth factor) and glucose levels.
No, this doesn’t mean starvation. But periods of low nutrient intake, done safely, may help reawaken stem cells that had dozed off in your digestive tract sometime in your late 30s. (Please refer to previous ramblings on intermittent fasting and time restricted eating)
3. NAD+ and Sirtuin Activation: Back to David Sinclair’s work. Several studies suggest that boosting NAD+ levels improves stem cell function. A 2018 paper in “Nature Communications” found that raising NAD+ in aged mice restored the number and function of muscle stem cells, essentially rejuvenating muscle tissue.
Sinclair himself takes NMN and resveratrol daily. Though human trials are still ongoing, with mixed results, the early signs are promising. If you’re tempted to join him, know that this is not yet mainstream clinical advice, and more evidence is needed. However, I would recommend looking him up on Utube; there is a lovely story behind his motivation to do research in this area.
4. Sleep: The Free Treatment You’re Ignoring: Sleep supports stem cell maintenance, particularly in the brain. A 2020 study in “Science Advances” showed that disrupted sleep patterns reduce neurogenesis (birth of new neurons) in the hippocampus. Chronic sleep deprivation increases inflammation and oxidative stress, which harms stem cell niches — the microenvironments where stem cells live and work.
Basically, if you’re burning the candle at both ends and also skipping sleep to read blogs like this one, you might be actively evicting your neural stem cells. Matt Walker is a well known researcher in this field – again worth listening to his onlline lectures which I think are now on Utube.
5. Avoid Smoking and Excessive Alcohol: A 2021 paper from the University of São Paulo found that alcohol impairs mesenchymal stem cell differentiation, particularly into bone cells. This is one of the reasons chronic drinkers have higher risk of osteoporosis.
Smoking? Worse. A 2022 meta-analysis in the journal “Stem Cell Research & Therapy” concluded that tobacco exposure damages stem cell DNA, disrupts their repair mechanisms and accelerates their depletion. In summary, no surprises here. Your stem cells hate parties.
6. Anti-inflammatory Diets: Less Glamorous Than Kale Juice, But Real. Chronic inflammation is a known driver of stem cell dysfunction. A 2023 study from the University of Oxford showed that high levels of TNF-alpha (a pro-inflammatory cytokine) disrupted hematopoietic stem cell quiescence and led to premature exhaustion.
Eating anti-inflammatory foods, like oily fish, leafy greens, berries and olive oil helps. And avoiding ultra-processed foods is even better. Yes, we’re back to the Mediterranean diet. Again. Because it just keeps winning.
7. Exposure to Cold: Yup, cold showers and ice baths – my kind of nightmare… Cold exposure is nature’s brutally honest personal trainer. A few minutes in icy water boosts norepinephrine by up to 530 percent; not bad for something that also makes you question all your life choices. Scientists call it hormetic stress, but let’s be honest, it’s just your mitochondria waking up and screaming.”It’s bl00dy freezing!!”
Stem cell therapy is a rapidly evolving field. Clinics worldwide are offering regenerative treatments for everything from arthritis to erectile dysfunction, but many are unregulated and not backed by solid science.
That said, stem cell banking (freezing your own cells now for use later) is gaining traction, particularly for younger adults. It’s speculative, but the idea is that your youthful stem cells may be a valuable personal resource down the line when regenerative medicine catches up with science fiction.
As of 2025, most effective stem cell therapies are still in the clinical trial or experimental stage, especially for neurodegenerative diseases. But trials at institutions like Stanford, the Mayo Clinic and King’s College London are making real headway in areas like Parkinson’s, spinal cord injury and diabetes. I’ve even heard Dr Sinclair speak about new eye nerves re-orientating themselves to head towards the brain…
Stem cells are your body’s silent repair squad. They don’t ask for recognition, but they absolutely deserve your care. Whether it’s through exercise, rest, diet or the responsible use of emerging supplements like NMN, the science is clear: you have more power than you think to support the regeneration happening within you.
And if nothing else, remember this. Your body is still running software written in the Palaeolithic age. It’s not looking for either lab grown burgers (gross) or Blue Spirulina sprinkles. Just give it movement, real food and enough sleep to finish the updates overnight.
As for the new networking products promising to reactivate your stem cells –
