Ben Greenfield on health: what the evidence says · JRE #1069

“there's this cat up at University of Washington named Dr. Gerald Pollack, and he has done this research that shows like in plants or vessels, like blood vessels, for example, there's an exclusion zone of water.”

What the evidence says

Gerald Pollack, a biomedical engineer at the University of Washington, has published peer-reviewed work, including a 2024 study in Scientific Reports, documenting a real, reproducible phenomenon: a particle-free "exclusion zone" (EZ) that forms in water near certain hydrophilic surfaces, including plant xylem vessels. The existence of this exclusion zone near materials like Nafion has been independently replicated by multiple laboratories. However, Pollack's further claim that EZ water constitutes a distinct, more-ordered "fourth phase" of water with altered molecular structure is disputed among physical chemists; a 2020 critical review in the International Journal of Molecular Sciences found the experimental evidence (including birefringence measurements) does not support a genuine phase change and argued that conventional mechanisms, such as diffusiophoresis, better explain the observations. Critically, no controlled human studies show that passing tap water through a "structuring" device changes its biological hydration properties inside the human body; water crosses cell membranes via aquaporin channels on femtosecond timescales, a mechanism unaffected by any claimed pre-treatment "structuring." Even Pollack himself has publicly stated skepticism toward commercial "structured water" products, saying he has "yet to see the demonstrated evidence" that such devices produce what they claim. The claim therefore selectively cites a narrow, real physical observation to support a much broader and unsupported commercial health claim.

1. Exclusion Zone Phenomena in Water: A Critical Review of Experimental Findings and Theories (Elton, Spencer, Riches & Williams, Int J Mol Sci, 2020) · government
2. Exclusion-zone water inside and outside of plant xylem vessels (Wang & Pollack, Scientific Reports, 2024) · journal