What clinical trials exist testing oral food‑grade diatomaceous earth for human or veterinary parasitic infections?
Executive summary
Clinical testing of orally administered food‑grade diatomaceous earth (DE) has been conducted primarily in livestock and poultry, not humans, and the results are mixed: some controlled trials in laying hens report reduced parasite loads, while a broader set of controlled trials in ruminants (sheep, goats, cattle, bison) generally show no meaningful anthelmintic effect compared with standard treatments or controls [1] [2] [3] [4] [5]. No large, well‑controlled clinical trials support oral DE as an effective antiparasitic in humans, and mainstream clinicians urge caution [6] [7].
1. What veterinary clinical trials exist and what did they measure?
Published and conference reports document controlled feeding trials of food‑grade DE in poultry (e.g., Bennett et al., 2011 and related 2019 ScienceDirect entry) that measured fecal/intestinal parasite loads, egg production and egg quality, and reported statistically significant reductions in some parasite indicators in hens receiving dietary DE versus untreated birds [2] [1] [3]. Conversely, a suite of controlled studies in ruminants — including feedlot beef steers, sheep, goats and bison — measured fecal egg counts and growth/performance and largely found DE no different from untreated controls and markedly inferior to conventional anthelmintics in reducing parasite egg counts (Fernandez et al. 1998 and later sheep/cattle work summarized in reviews) [5] [8] [4] [9].
2. How consistent are the results across species and trials?
The evidence is inconsistent by species and study: poultry trials show some positive signals for reduced parasite incidence and improved production metrics in specific trials [1] [2], while most controlled ruminant trials show no significant impact on gastrointestinal nematode indicators such as fecal egg counts [4] [5] [8]. Reviews and extension‑type summaries conclude information is “sparse and unconvincing” for internal parasite control in ruminants, even as DE’s insecticidal efficacy for external pests is well established [4] [10] [5].
3. Limitations and methodological caveats in the published trials
Several trial limitations appear repeatedly in the reporting: small sample sizes, low baseline fecal egg counts that reduce statistical power, breed or flock differences in parasite resistance, variable DE formulations/doses and trial durations, and frequent absence of blinded or placebo controls — all of which complicate interpretation and generalization [9] [4] [1]. Reviews note that DE products marketed as feed supplements are not regulated as drugs and therefore rarely come with rigorous efficacy data required for pharmaceutical approvals [11] [7].
4. Human clinical trials — what exists and what doesn’t?
Searchable reporting and consumer‑health reviews indicate an absence of large‑scale, controlled human clinical trials demonstrating DE’s efficacy as an oral antiparasitic; mainstream medical voices warn that claims for gut “detox” or deworming in people are unsupported by clinical evidence and should be scrutinized [6] [7]. Popular how‑to pieces and anecdotal testimonials promote dosing regimens for people and pets, but these are not substitutes for randomized clinical trials and are noted as non‑peer‑reviewed marketing or folklore [12] [13].
5. Balanced take: where the science currently stands and what to watch for
The scientific balance is simple and practical: veterinary trials provide some species‑specific evidence (notably limited positive findings in hens) but a preponderance of controlled studies in ruminants show no reliable internal‑parasite control from oral DE [1] [2] [4] [5]. There are no robust human clinical trials supporting oral DE for parasitic infections, and clinical authorities recommend proven anthelmintic drugs when treatment is indicated [6] [7]. Readers should watch for well‑designed randomized trials (clear dosing, adequate power, blinding, and clinically relevant parasite outcomes) if DE proponents seek to change this evidence base; until then, reliance on DE as a substitute for validated antiparasitic medications lacks solid clinical support [4] [11].