The Gut-Brain Axis: Signal, Hype, and the Gap Between
The anatomy is uncontested and the human trial evidence is thinner than the headlines. Here is where each part of the claim actually stands.
Section
Supplements
Magnesium Forms Compared: What the Absorption Data Show
Oxide, citrate, chloride, amino acid chelate. Absorption has been compared directly across forms. The laxative effect has not, and the difference between those two statements matters.
The American Fiber Gap, in Numbers
Adequate Intake is 25 to 38 grams a day. Measured US intake sits closer to 16. What the surveys and the trials actually show.
Leaky Gut: What Is Measured, and What Is Sold
Intestinal permeability is a real, quantified research variable. 'Leaky gut syndrome' is a marketing category. The distance between the two is the story.
The CFU Number Is the Wrong Thing to Compare
Labels advertise 50 billion, then 100 billion. The published dose-response evidence does not support reading that number as a ranking.