As a science writer, longevity specialist, and host of the globally top-200-ranked podcast Pushing the Limits, I recently had the privilege of sitting down with my dear friend, mentor and teacher, regenerative medicine extraordinaire, Dr. Elizabeth Yurth, for an episode that left me buzzing with excitement.

Known as the "GOAT" (Greatest of All Time) in her field, Dr. Yurth is the founder of the Boulder Longevity Institute and a pioneer in cellular medicine. Our conversation dove deep into the science of immunosenescence—the ageing of the immune system—and its sinister partner, chronic inflammation, often dubbed "inflammaging." This isn’t just a topic for older people; it’s critical for anyone navigating autoimmune diseases, post-viral syndromes even young people, or those simply aiming to optimize their health in a world full of immune stressors.

This blog post is crafted for Health professionals but also longevity enthusiasts like you—those who like scientific depth with a personal touch. I’ll weave in my own journey, from ultra-endurance athlete to health optimization advocate, while unpacking Dr. Yurth’s cutting-edge strategies to combat immune ageing. We’ll explore the role of the gut, the thymus gland, and a revolutionary formulation we’ve co-developed at Aevum Labs called Rejuvenate Pro. Buckle up—this is a science-packed ride with actionable insights to transform your health.

The Personal Backdrop: Why This Matters to Me

Before we plunge into the science, let me share why this topic hits home. For over 25 years, I pushed my body to the limits as a professional ultra-endurance athlete—racing through the Himalayas, Death Valley, and even surviving an illegal crossing of the Libyan Desert. I logged over 70,000 km of running in that time. Resilience was my currency. But life threw curveballs: my mother suffered a devastating brain aneurysm, and my father passed away in a hospital where I couldn’t intervene with therapies I knew could have perhaps saved his life. These tragedies shattered my trust in conventional medicine and ignited a relentless pursuit of functional medicine, cellular medicine, genetics and longevity science.

Through years of research and trial, I helped my mother defy medical odds over and over again. That journey birthed my podcast, Pushing the Limits, and Aevum Labs, where I collaborate with brilliant minds like Dr. Yurth and a world class scientific advisory team. This episode, aired on May 18, 2025, at 8:34 PM NZST, isn’t just a discussion—it’s a culmination of my quest to empower others with knowledge to take control of their health.

Meet Dr. Elizabeth Yurth: The Cellular Medicine Maverick

Dr. Yurth’s credentials are as inspiring as her mission. Trained in orthopedics, she pivoted to regenerative medicine after realizing she was merely "patching people up" rather than healing them. Her journey led her to found the Boulder Longevity Institute and the Human Optimization Academy (check it out at bli.academy), where she educates both professionals and the public. With fellowships in anti-ageing medicine and epigenomics, she’s faculty at Seed Scientific Research and Performance, teaching cellular medicine—the art of fixing health at its root: the cell.

Her philosophy? Disease begins with cellular dysfunction, and the immune system is the linchpin. This perspective drives her work and our collaboration on Pushing the Limits.

Immunosenescence Unveiled: The Immune System’s Silent Decline

So, what is immunosenescence? It’s the gradual deterioration of your immune system as you age, and it starts earlier than you might think—around puberty. Here’s why it’s a big deal:

• Thymus Gland Shrinkage: The thymus, a gland in your chest, trains immune cells like T-cells to distinguish friend from foe. It’s massive in infants but begins turning to fat after puberty. By your 60s, it’s largely inactive, leaving your immune system without its master regulator.

• Gut Health Erosion: Your gut houses 70-80% of your immune system. Modern insults—poor diets, antibiotics, toxins—disrupt the microbiome and weaken the gut lining, leading to "leaky gut" and chronic inflammation.

• Pathogen Overload: Viruses like Epstein-Barr, CMV, and even C-19 linger in your body, taxing your immune system. Add environmental toxins, and it’s a recipe for immune dysfunction.

When your immune system falters, it struggles to fight infections, clear cancer cells, and manage inflammation. This sets the stage for inflammaging—a state of persistent low-grade inflammation that fuels age-related diseases like cancer, arthritis, and neurodegeneration.

The 1000 Immunomes Project: Proof in the Data

Dr. Yurth and I went deep into the findings and research of the 1000 Immunomes Project(see my podcast with project director Dr David Furman , a 15-year study by Stanford University and the Buck Institute. Using AI and big data, it’s the longest human immune study ever, and its findings are game-changing: immune ageing underpins all the 12 hallmarks of ageing (think mitochondrial dysfunction, cellular senescence, etc.). Key markers like CXCL9—a chemokine—spike with immune decline, signalling trouble. This study inspired us to target immune health as the foundation of longevity rather than trying to tackle the 12 hallmarks of ageing one at a a time in a whack-a-mole fashion.

The Gut-Immune Axis: Your Body’s Frontline

Dr. Yurth emphasized the gut as the immune system’s powerhouse. It’s not just about digestion—it’s a barrier teeming with soldiers: immunoglobulins (IgA, IgG), the microbiome, and mucosal layers. When this barrier breaks down (hello, leaky gut), pathogens slip through, triggering inflammation and immune chaos.

But here’s the catch: fixing it isn’t as simple as swallowing probiotics. In a damaged gut, probiotics often don’t survive. Prebiotics—fiber that feeds good bacteria—help, but repairing those tight junctions (the seals between gut cells) is the real challenge. Enter nature’s secret weapon: colostrum and not just any sort of colostrum.

Colostrum: The Evolutionary Superfood

Colostrum, the first milk produced post-birth, is a marvel of evolution. Packed with antibodies, growth factors, antimicrobial peptides, and immune cells, it jumpstarts a newborn’s immune system and seals their gut. Studies show it outperforms flu vaccines threefold for respiratory infections and trumps pharmaceuticals in some immune applications.

But adults can benefit too—especially those with compromised immunity. The problem? Standard colostrum supplements contain lactose and casein, which some can’t tolerate, and their bioactive potency varies. Dr. Yurth and I wanted more—a concentrated, standardized solution.

IDP and Immunel two next generation Colostrum and whey extracts.

Cue IDP (Immune Defense Protein), a breakthrough from Quantec in New Zealand. Derived from bovine serum, IDP isolates 50 synergistic bioactive molecules from colostrum, minus the fluff (lactose, casein, fat). It’s like colostrum on steroids—10 liters of milk condensed into 1 gram of pure immune power.

Why IDP Rocks:

• Gut Repair: Strengthens tight junctions across mucosal barriers (gut, lungs, brain).

• Pathogen Defense: Outperforms lactoferrin and vaccines against viruses (influenza, COVID-19) and selectively kills harmful bacteria (e.g., Staphylococcus) while sparing beneficial ones like Lactobacillus.

• Inflammation Control: Lowers pro-inflammatory cytokines like IL-6 and TNF-alpha.

IDP’s origins trace to lactoferrin research, but purifying lactoferrin alone reduced its efficacy. The magic lies in the synergy of all 50 components—proof that nature often beats isolated extracts.

Beyond IDP: Supercharging the Thymus and More

IDP tackles gut and inflammation, but what about the thymus? We turned to Immunel a concentrated and standardized colostrum extract again, isolating:

• Proline-Rich Peptides (PRP): Thymic regulators that modulate immunity.

• IGF-1 (Insulin-Like Growth Factor-1): A growth hormone byproduct for tissue repair.

• Transforming Growth Factor (TGF): A prebiotic and brain-protective immune enhancer.

These peptides, boost natural killer (NK) cells—your cancer and pathogen fighters—by upregulating markers like CD69 and cytokines like IL-2. Studies show Immunel clears Streptococcus pneumoniae in mice within 24 hours and outperforms antibiotics in humans by 70%.

Targeting Immune Ageing Markers: Rosemary and Kawakawa

The 1000 Immunomes Project flagged CXCL9 as a critical immune ageing marker. Enter rosemary extract (carnosic acid), a potent CXCL9 inhibitor. It’s a natural powerhouse for curbing immune decline.

Then there’s Kawakawa, a Maori medicinal plant I grew up with. Harvested at full moon (a tradition science is starting to validate), it lowers NF-κB—the inflammation cascade’s master switch—while boosting IL-10, an anti-inflammatory cytokine that dwindles with age. My dad made Kawakawa tea regularly; now, modern data confirms its immune-balancing prowess.

Rejuvenate: The Ultimate Immune Optimizer

After two years of research, we launched Rejuvenate Pro at Aevum Labs aevumlabs.co.nz. It combines:

Immune Defense Proteins (IDP®)
IDP® is a bioactive whey protein complex derived from pasture-fed New Zealand cows, rich in over 50 immune-active components, including lactoferrin, lactoperoxidase, and immunoglobulins. These proteins exhibit selective antimicrobial activity, targeting harmful pathogens while sparing beneficial probiotics, thereby supporting gut health and the immune system. IDP® exerts anti-inflammatory properties by modulating cytokines such as TNF-α and IL-6, and enhancing mucosal immunity, which contributes to tissue healing and protection against infections and inflammation.

Immunel® Colostrum Extract
Immunel® is a concentrated, fat-free, lactose-reduced colostrum extract sourced from New Zealand pasture-fed cows. It contains potent bioactive compounds like Proline-Rich Peptides, Sialic Acid, Nucleotides, and Growth Factors. These components support immune function by enhancing phagocytosis, Natural Killer (NK) cell activity, and immune cell infiltration. Immunel® modulates immune responses by influencing cytokines such as TNF-α and IL-6, leading to coordinated immune modulation and comprehensive health benefits, including intestinal integrity and upper respiratory tract support.

Rosemary Extract (20% Carnosic Acid)
This extract is standardized to contain 20% carnosic acid, a potent antioxidant that protects cells from oxidative stress and inflammation. Carnosic acid neutralizes free radicals and reduces pro-inflammatory cytokines like TNF-α and IL-6. Additionally, it boosts macrophage and NK cell activity, enhancing immune function. Its neuroprotective properties further support overall health by strengthening the immune system and promoting effective defense against infections and diseases.

Kawakawa (Piper excelsum)
Kawakawa is a native New Zealand plant traditionally used in rongoā Māori medicine. It contains bioactive compounds such as myristicin, diayangambin, elemicin, and piper methysticum. Kawakawa modulates immune health by influencing cytokines and chemokines involved in inflammation. It lowers pro-inflammatory cytokines like TNF-α and IL-6 and affects chemokines such as CCL2, which recruits immune cells to infection sites. These anti-inflammatory properties help regulate immune responses and enhance overall wellness, particularly beneficial with aging.

Collectively, these ingredients in Re:juvenate Pro work synergistically to modulate key immune pathways, reduce inflammation, and support cellular repair, contributing to improved immune function and longevity. Safe for most people except during pregnancy and caution if on immunosuppressants or blood thinning medications—from fragile elderly to those with IgA deficiencies—Rejuvenate tackles immunosenescence holistically. My mum’s lymphocytes jumped into the normal range for the first time post-Rejuvenate—a personal win backed by science allbeit an N of 1 at this stage.

Actionable Strategies to Beat Immune Ageing

Here’s how you can apply these insights:

1. Prioritize Gut Health: Eat high-fiber, fermented foods; consider prebiotics and postbiotics over probiotics.

2. Leverage Rejuvenate Pro: Concentrated immune support without the supplement overload.

3. Incorporate Tradition: Kawakawa or rosemary tea can complement your regimen.

4. Minimize Toxins: Opt for clean, grass-fed sources (New Zealand’s a gold standard).

Why This Matters Now

Our healthcare system is reactive—treating symptoms, not causes. But you can act proactively. Immune ageing drives every chronic disease; optimizing it is your ticket to a longer, healthier life. Listen to the full episode on Pushing the Limits or YouTube youtube.com/user/lisatamati—Dr. Yurth and I cover even more ground.

For me, this is about self-sovereignty—reclaiming health through science and nature. Rejuvenate isn’t just a product; it’s a philosophy.

Get your Rejuvenate Here

Listen to the full episode here: