Blood Markers That Flag Cancer and Alzheimer's Risk Decades Before Symptoms
Surgeon-turned-longevity-physician Dr Darshan Shah joins Louisa Nicola to explain why standard blood panels are built to confirm disease, not to see it coming. Together they walk through the screening and biomarker layers - colon screening, full-body MRI, liquid biopsy, brain markers like p-tau 217 and the amyloid ratio, ApoB, blood pressure and fasting insulin - that can shift the picture decades earlier.
Overview
Dr Darshan Shah trained as a general, trauma and reconstructive surgeon before his own health collapsed under stress, poor sleep and an unstructured routine - high blood pressure, metabolic trouble and an autoimmune condition affecting the tissue of his forehead and skull. That experience pushed him toward the science of health rather than the science of disease, and eventually into building a large longevity clinic network.
In conversation with Louisa Nicola he argues that the classic CBC and metabolic panel are excellent in an emergency room and nearly useless for seeing a chronic disease forming. The episode maps out what a more forward-looking panel can include: colon screening earlier than the standard age, at-home stool blood tests, full-body MRI for solid tumours, and liquid biopsy that reads cell-free tumour DNA fragments in blood. On the brain side, Nicola walks through p-tau 181 and 217, the beta-amyloid 42 ratio, GFAP and neurofilament light - markers that now correlate with what a PET scan shows, without the radiation.
Shah adds the levers he considers most controllable: blood flow through exercise and nitric oxide, treated blood pressure, and metabolic health tracked through fasting insulin and HbA1c rather than fasting glucose alone. Both stress that a single odd result should be repeated before anyone panics, because assay method and blood source change the number. The conversation closes on what makes longevity worth having - relationships, social life, not turning a protocol into isolation.
Key quotes
5The problem with traditional blood work is that it's only useful for diagnosing bad problems. There's very little there predicting if you're going to head towards a chronic disease.
Cancer's biggest enemy is being diagnosed at stage one, because then you're talking cure rates. You're not talking five-year survival rates.
No longer do we need to wait for symptoms or radiographic changes.
As you put lifestyle changes into place, you can see those levels come down. You can actually track and measure it over time.
If your longevity routine is causing loneliness, is causing distance from friends and family, is causing more stress - what is the point?
Key ideas
9The doctor who became the patient
Years of long operating days, chronic stress and broken sleep left Shah with high blood pressure, metabolic disease and an autoimmune condition. His own decline, not his training, sent him looking into nutrition, sleep and exercise as a science.
Chronic disease is multifactorial, not one broken part
Shah argues clinicians are trained to hunt for a single cause - one gene, one hormone, one hammer. Autoimmune and neurodegenerative conditions touch every system, which is why a systems view fits them better than a single specialty.
Standard panels are built for emergencies
A complete blood count and metabolic panel are invaluable in the ICU or ER. They were never designed to tell a healthy person whether they are drifting toward chronic disease over the coming decades.
Colon cancer is no longer an older person's disease
Around one in ten colon cancers now appears in younger people, and the number is climbing. Shah's working theory points at toxic exposure, ultra-processed food, microbiome disruption and inflammation acting on rapidly replicating gut cells.
From preventive to hyper-preventive
National screening guidelines are built for populations and budgets, not individuals. The individual layer adds full-body MRI for solid tumours and liquid biopsy that detects cell-free tumour DNA fragments circulating in blood.
The brain finally has blood markers
P-tau 181 and 217, the beta-amyloid 42 ratio, GFAP and neurofilament light can now be read from plasma. P-tau 217 tracks especially closely with PET scan changes, and these markers move decades before symptoms.
ApoE4, cholesterol transport and blood flow
ApoE4 carries fats and cholesterol through the brain; when it works poorly, blood flow and toxin clearance suffer. Nicola notes two copies carry roughly sixteen times the risk, one copy about four times - and that genetic risk is not a verdict.
Blood pressure is the cheapest high-value lever
Both point to the SPRINT trial: from 130/80 upward, every ten-point rise tracks with meaningfully higher all-cause mortality. Home measurement, done correctly and repeatedly, beats a single reading in a clinic.
ApoB as the number to memorise
Shah simplifies cardiovascular tracking down to ApoB, hs-CRP and HbA1c. He notes ApoB is causal for vascular disease and that vessels run through the brain too - though high ApoB alone does not equal existing disease.
Practical takeaways
7- 1
Add a yearly stool blood test 24:00
An at-home FIT test costs roughly twenty dollars and checks for blood in stool. It is a floor, not a ceiling - bleeding usually appears once a lesion is already established, so it does not replace scope-based screening.
- 2
Layer your screening rather than picking one 35:30
Mammogram plus breast ultrasound gives far better resolution, especially with dense tissue. Full-body MRI sits on top for solid tumours elsewhere, and skin mapping catches what a rushed visit misses.
- 3
Treat an odd result as a question, not a diagnosis 44:00
Both describe wildly different lipid results from the same person a week apart. Anything that would trigger a treatment decision should be confirmed with a second draw, ideally from the same blood source and method.
- 4
Learn to measure blood pressure properly at home 53:00
Seated, still, correct arm position, first thing in the morning, recorded over time. Shah suggests at least monthly self-measurement from age forty, and notes that morning readings can hide hours of daytime elevation.
- 5
Watch fasting insulin, not just glucose 1:02:00
Insulin rises before HbA1c does, and HbA1c moves before fasting glucose. Shah points at HbA1c around 5.2 or lower and fasting insulin around eight or lower as orientation points.
- 6
If weight is coming off, keep it slow 1:04:30
Shah's rule of thumb is roughly a pound a week. Faster than that and muscle mass, micronutrient levels and skin quality struggle to keep up with the loss.
- 7
Get the base right before stacking 1:06:00
Nutrition, sleep, exercise and stress management come first. Red light, sauna and similar tools sit near the top of the pyramid - useful additions once the foundation is actually in place.
Topics & chapters
17From the operating room to longevity
Shah's path through general, trauma and reconstructive surgery, and what pulled him toward the science of health.
When the surgeon got sick
Stress, poor sleep and no real routine led to high blood pressure, metabolic disease and an autoimmune condition.
Autoimmunity as a whole-body story
Why one specialty cannot own a condition that touches the immune, neurological, gut and cardiovascular systems at once.
What standard blood work does and doesn't do
The complete blood count and metabolic panel as emergency tools rather than forecasting tools.
Colon cancer at 31
Nicola describes a stage-four diagnosis with almost no warning signs, and the two ask what could have surfaced it earlier.
FIT tests, Cologuard and the colonoscopy
The available options, their limits, and why bleeding is already a late signal.
Population screening versus individual screening
Why national guidelines cover only a handful of cancers, and what the individual layer adds.
Full-body MRI and liquid biopsy
Imaging for solid tumours and blood-based detection of cell-free tumour DNA fragments.
Skin, breast and prostate
Mole mapping, mammogram plus ultrasound, dense breast tissue, and earlier PSA tracking for men.
Brain biomarkers in blood
P-tau 181 and 217, the amyloid ratio, GFAP and neurofilament light - and how they compare with PET imaging.
ApoE4 and cerebral blood flow
What the gene does, what carrying one or two copies means, and why blood flow sits at the centre of the story.
Blood pressure done properly
SPRINT trial numbers, home measurement technique, and continuous monitoring revealing hidden daytime elevation.
ApoB, LDL and the brain
Why Shah has patients memorise ApoB, the vascular argument, and a measured view on statins.
Assays, labs and repeat testing
Capillary versus venous blood, method differences, and why a single strange result should be confirmed.
Metabolic markers and GLP-1 caution
Fasting insulin, HbA1c, HOMA-IR, and what fast weight loss costs in muscle, micronutrients and skin.
Red light, and what longevity is for
Mitochondria, nitric oxide and blood flow - plus the reminder that a protocol causing isolation defeats itself.
Dashboards and nerve regeneration
A unified biomarker dashboard, and research on engineered Yamanaka factors aimed at regenerating nerve tissue.