Brain scans and blood tests that reveal brain health

What factors most influence brain health over time? A conversation between Dr. Mark Hyman and the scientist behind the ENIGMA consortium, a global brain mapping collaboration with 2,500 scientists across 47 countries, gives a surprising answer: the body shapes the brain more than most doctors assume. The project has gathered about 200,000 brain scans across more than 30 brain disorders, together with blood biomarkers.

Seeing disease on a scan

Brain imaging first showed its value in Alzheimer's, where repeated scans revealed tissue loss spreading like wildfire from the memory system to language and then planning areas. Incidence doubles every five years after 70: about 5% at 70, 10% at 75 and 20% at 80. Imaging was later used in schizophrenia drug trials to see whether treatment slowed tissue loss.

A standard structural MRI works like a fancy X-ray. It finds tumors, bleeds or aneurysms. Functional MRI and PET look at blood flow and metabolism, which matters more in depression, bipolar disorder and addiction. Depressive disorders often show metabolic changes in the limbic system, the brain's gas pedal, while compulsive disorders and addiction often show damage in the frontal lobes, the brakes.

The body drives the brain

The strongest message is about cardiometabolic health:

• Scans of people who were overweight or obese made their brains look about 8 years older.
• People with below normal estrogen, testosterone or thyroid hormone showed faster brain aging.
• Around 60% of people diagnosed with dementia have cardiometabolic issues.
• In depression, bipolar disorder and schizophrenia, brain differences were larger when metabolic or cardiovascular disease was present.

Recovery also shows up. In people with anorexia, the disorder with the largest brain effect the team studied, brain systems were restored once nutrition returned. Dr. Hyman describes a personal anecdote of brain changes after taking ibogaine in Mexico, with higher cortical thickness and fewer white matter lesions on quantitative MRI. It is one person's experience, not a recommendation, but it supports the idea that the brain can change. The message: do not be pessimistic about brain recovery. Think of it like a bank account. Medication is one way to top it up, but metabolic, nutritional and lifestyle routes can replenish it too, and a scan can show whether the balance actually improved.

Sleep and shared patterns

Sleep matters too. During sleep, the glymphatic system acts like a car wash that clears waste from the brain. Poor sleep and brain disease feed each other, and when sleep or lifestyle improves, some of these markers come back into line. Many disorders also share patterns such as inflammation, mitochondrial dysfunction and sluggish switching between brain networks like the default mode network involved in rumination. Treatments range from medication and TMS to neurofeedback, therapy and lifestyle changes.

Genes tilt the scales

Only about 2% of Alzheimer's is directly genetic, through genes such as presenilin. For most people the APOE gene matters. About a quarter of people carry one APOE4 copy, which roughly triples risk, and about 6% carry two, raising risk 9 to 10 times. Yet it is not deterministic, and its effect differs by ancestry. Polygenic scores, AI and genome guided drug repurposing aim to match treatments to a person's biology.

Brain charts, brain age and blood markers

Like a pediatric growth chart, a brain chart compares your brain measures with a large reference population. Tools such as NeuroQuant analyze an MRI, and a brain age score combines hippocampus size, white matter connections and more. You can retest after changes and see whether you moved.

Blood adds another layer. New Alzheimer's markers include amyloid beta 42/40, p tau 217, neurofilament light and GFAP. Broader markers such as vitamin D, iron, omega 3, heavy metals, insulin, thyroid, sex hormones, homocysteine and methylmalonic acid also affect mood and cognition. Within 5 to 10 years, the researcher expects major neurological and psychiatric conditions to be diagnosed with scans plus blood tests. Function Health offers a panel of about 160 tests and brain MRI options.

AI and subtypes of dementia

Alzheimer's is a label for a syndrome with many causes. Autopsies show amyloid in some people, but others have Lewy bodies, alpha synuclein or TDP 43 changes. AI can spot patterns across millions of scans, helping refine diagnosis so treatment fits the subtype, whether amyloid, vascular or metabolic.

Products mentioned

The episode includes sponsor segments for a Bon Charge red light face mask, Paleovalley dark chocolate chip superfood bars, Timeline Mitopure gummies, Seed DS 01, BiOptimizers Magnesium Breakthrough and Fatty15. Treat them as promotions, not evidence.

Conclusion

The brain does not live apart from the body. Metabolic health, hormones, nutrition and sleep leave visible marks on scans and blood work, and many of them can be corrected. Measure early, track trends over time and treat the system, not only the symptom. Ask your doctor which baseline tests make sense for your age and family history.