Ben Greenfield on health: what the evidence says · JRE #1069
“you use a reverse osmosis water filter because it's a really, really fine filtration. But it takes everything out. Like, it takes the bad stuff and the good stuff out.”
What the evidence says
Reverse osmosis (RO) is a fine-pore membrane filtration process that removes a broad range of dissolved substances from water, including contaminants such as heavy metals, nitrates, and many organic chemicals, but also strips out naturally occurring minerals like calcium and magnesium; this part of the claim is accurate and consistent with how the technology works. Research on very-low-mineral (demineralized) water, including RO output, has found associations with adverse changes in mineral metabolism and cardiovascular markers in some populations, though drinking water is a minor source of dietary minerals compared to food for most people, and RO-treated water is not generally considered harmful by health authorities when a normal diet is maintained. The claim also implies a causal chain linking golf-course pesticide or fertilizer runoff, municipal tap water contamination, and a local cancer cluster; no peer-reviewed study, health department investigation, or epidemiological report was found establishing such a specific cluster or a runoff-to-cancer link, and this portion of the claim appears anecdotal rather than evidence-based. Overall, the mechanical description of RO removing both contaminants and minerals is well-supported, while the implied causal cancer-cluster narrative remains unverified.