Does RO water pull vitamins out of your body?
Executive summary
Recent studies and media reports link reverse osmosis (RO) drinking water to lower mineral content and an association with vitamin B12 deficiency in some Indian studies: one hospital study reported RO users had a 50.6% B12 deficiency versus 17.5% in others and found RO use an independent risk factor [1]. RO filtration does remove dissolved minerals like calcium, magnesium and trace metals including cobalt—which some authors and local press say could plausibly affect B12 status—while other outlets and commentators argue the evidence is weak or incomplete [2] [3] [4].
1. What RO does to water: near-total demineralization is documented
Reverse osmosis systems produce very low‑mineral water by design; multiple consumer and technical writeups state RO removes dissolved salts and minerals such as calcium and magnesium from water [2] [5]. Public-facing articles and NGO pages warn that RO water “lacks minerals” and can reduce the mineral content people receive from drinking water [6] [5]. Scientific interest in mineral differences in RO consumers has produced studies comparing serum electrolytes and vitamin D in children drinking RO versus other water [7].
2. The B12 connection: one epidemiological study reports an association
A cross‑sectional study cited in news coverage found 50.6% of RO users (40 of 79) were vitamin B12 deficient versus 17.5% (30 of 171) among people using other water sources, and the authors reported an independent association between RO use and B12 deficiency after analysis [1]. Local hospital researchers and regional press reported the finding and suggested RO systems remove cobalt—an element in cobalamin (vitamin B12)—as a possible mechanism [3] [8].
3. Mechanism claims: cobalt removal is hypothesized but not firmly proven in reporting
Several outlets repeat the hypothesis that RO removes cobalt from water and that cobalt loss could reduce B12 availability [3] [9]. Consumer sites and vendors also claim RO strips trace metals and hence could affect micronutrient intake [5]. However, available sources do not present direct measurements showing that typical drinking‑water cobalt losses from RO produce clinically meaningful reductions in bodily cobalt or B12 absorption in well‑fed populations; the mechanism remains a suggested explanation in coverage rather than a fully established causal chain [1] [3] [9].
4. Contrasting viewpoints: some sources call the link weak or unsupported
Health commentary pieces challenge the idea that RO causes B12 deficiency, noting B12 largely comes from dietary animal products and that poor diet, absorption disorders, or medications are established causes of deficiency [4]. Lifehack-style coverage and other consumer articles assert the belief that RO causes B12 deficiency is “not based on scientific evidence,” arguing diet and medical causes explain most deficiencies [4]. Thus the literature and press present competing interpretations: an observed association in at least one study versus skepticism about causality and mechanism [1] [4].
5. Broader evidence: mineral‑status studies and public health context
Larger efforts examine calcium, magnesium, phosphate and vitamin D levels in children consuming different water types, showing researchers are investigating whether low‑mineral water affects bone‑related markers and electrolytes [7]. Other commentary and historical reports cite episodes (e.g., concerns in Czech/Slovak populations) where demineralized water coincided with complaints about magnesium/calcium deficiency, but these accounts are cited in advocacy and opinion pieces rather than as definitive, controlled trials in the sources provided [6] [10].
6. What this means for individuals: practical, evidence‑based takeaways
If you rely heavily on RO water, sources advise attention to overall diet and routine medical checks for micronutrient status because RO removes minerals from water and at least one study found a statistical association with B12 deficiency [2] [1]. Other commentators stress that dietary intake of B12 (animal products or fortified foods/supplements) and known medical causes of poor absorption are primary determinants of B12 status and argue the RO hypothesis is not conclusively proven [4].
7. Limitations and where reporting falls short
Available sources show an association from one cross‑sectional study and extensive commentary about mineral removal, but they do not provide randomized trials, population‑level causal proof, or consistent mechanistic data proving RO water directly “pulls vitamins out” of the body or depletes bodily B12 via cobalt loss [1] [3] [4]. The reporting mix includes hospital study claims, consumer vendor messaging, and skeptical health writeups; motives vary—some pieces are product‑adjacent or advocacy oriented—which should temper interpretation [11] [5].
Bottom line: RO filtration does remove minerals from water (documented in product and scientific reporting), and at least one study in India found a substantial association between RO use and vitamin B12 deficiency [2] [1]. The causal mechanism—whether RO‑removed cobalt or demineralized water meaningfully reduces B12 in people with normal diets—remains contested in the available sources and is not definitively proven by the material provided [3] [4].