Systems-Over-Organs Model
Trace a symptom through connected body systems instead of isolating one organ
- Difficulty
- Moderate
- Time to result
- ~weeks to results
- Steps
- 5
- Confidence
- 90%
The Systems-Over-Organs Model reframes the body from a collection of separate specialties into interacting functional systems. Start with the symptomatic organ, then map every system in which it participates and the other organs connected through those systems. This reveals pathways by which a disturbance in one location can produce symptoms elsewhere. Junger uses the intestines as an example: they contribute not only to digestion and absorption, but also to immune defense and nervous-system activity. Because several systems physically meet there, the gut can become a leverage point for broad investigation. The model does not establish a diagnosis by itself; it creates a more complete map for asking questions, selecting tests, coordinating practitioners, and tracking whether an intervention improves the whole pattern rather than one isolated measure.
Origin
Junger describes functional medicine as teaching a modern physician to think more like practitioners of Chinese or Ayurvedic medicine: retain modern knowledge while replacing organ silos with a systems view.
Core principles
- 01The body functions as connected systems
- 02One organ can participate in several systems
- 03A symptom location does not necessarily reveal its driver
- 04System intersections are high-leverage investigation points
How to run it
- 1
Locate the presenting problem
Record the main symptom, the organ where it appears, and its time course. Keep this as the starting point rather than assuming it is the cause.
Pro tip Separate where a symptom appears from where its driver may originate.
Watch out Do not delay acute assessment while building a systems map.
- 2
Map participating systems
List the functional systems that involve the affected organ, such as digestion, absorption, immune defense, repair, or nervous regulation.
Pro tip Ask what jobs the organ performs beyond the specialty most associated with it.
Watch out A broad map is a hypothesis tool, not proof of causation.
- 3
Trace connected organs
For each system, identify other organs and processes that could influence the presenting symptom. Look for shared pathways rather than isolated abnormalities.
Pro tip Pay special attention to organs where several systems intersect.
Watch out Avoid expanding the map so far that every possible factor becomes equally important.
- 4
Find the leverage point
Prioritize a plausible, high-connectivity driver that can be assessed or changed safely. Use professional evaluation and testing when needed.
Pro tip Prefer a factor that explains several observations over one that explains only a single symptom.
Watch out Do not force all symptoms into one fashionable explanation.
- 5
Measure system-wide response
Track the original symptom and related functions across the mapped systems. Revise the map if the expected pattern does not improve.
Pro tip Use changes in the whole pattern to update the working hypothesis.
Watch out A temporary symptom change can be misleading without broader follow-up.
In the wild
A patient presents with bloating plus skin and mood symptoms. Instead of treating the intestine only as a digestive organ, a practitioner maps its roles in absorption, immune defense, and nervous regulation, then evaluates plausible shared drivers with appropriate clinical support.
→ The assessment produces a coordinated hypothesis and measures effects across several symptom domains.
Common mistakes
Confusing symptom site with cause
The organ displaying the symptom may be downstream of another process in the same system.
Turning the map into a diagnosis
Systems mapping organizes investigation; it does not prove a mechanism without suitable evidence.
Mapping everything at once
An unlimited list of connections creates noise instead of identifying a useful leverage point.
Is it for you?
Best for
Persistent, multi-symptom problems that cross digestive, immune, nervous, metabolic, or repair functions.
Not ideal for
It is not the first tool for an acute emergency that needs immediate stabilization.
From the transcript
“modern medicine divides and conquers, meaning there's specializations. They divide the body in organs.”
“the body is not really a set of divided organs. Actually, it's a set of systems. So in functional medicine, we think in systems.”
“They they are part of the digesting and absorbing system. They are also part of the immune, repair, and defense system. They're also part of…”
From the episode
Episode 413: Dr. Alejandro Junger: The Gut's Impact on Depression, Skin and Allergies + a Gut Repair Program
Dr. Alejandro Junger