Supplement
Potato
A nutritious food whose medicinal file contains one laboratory report from 2012 and nothing since.
Potato is a starchy staple food. We grade Potato D+ on evidence and C- for worth-it at about $3-6 per month.
Evidence
Worth it
Typical cost: $3-6/month
What it does
Potato is a starchy staple food. In natural-health teaching it appears as raw juice for stomach complaints and as poultices and slices for sprains, inflammation, and eye irritation. It entered this library's queue through that teaching, and this record grades those uses, plus the one genuinely studied potato product, its raw resistant starch.
What the research says
Raw potato juice against stomach bacteria: a laboratory finding that never became a trial
Evidence: weak. In 2012, University of Manchester researchers reported that molecules in potato juice inhibited H. pylori (the ulcer bacterium) in the laboratory without harming beneficial bacteria, and hoped to develop a supplement from it. More than a decade later there is still no human trial of potato juice for ulcers, gastritis, or anything else. The raw-potato-juice tradition in naturopathic practice, echoed in the teaching that queued this record, rests on this and on anecdote.
Potato poultices for sprains, inflammation, and eye complaints: no evidence at all
Evidence: weak. Grated or sliced raw potato applied to skin is a long folk tradition (drawing poultices for sprains and boils, slices for tired or infected eyes). No study tests any of it. A cool slice on closed eyes is a cool compress, and it works exactly as well as one.
Raw potato starch is a real resistant starch, with small gut trials behind the starch, not the poultice
Evidence: emerging. Uncooked potato starch resists digestion and feeds butyrate-producing gut bacteria; small trials of the isolated starch show increased fecal butyrate and mild metabolic effects. That evidence belongs to the purified starch as a fiber supplement. It does not transfer to juice, slices, or poultices.
Potato's file is the emptiest in this grading run: a dish-level antibacterial observation from 2012 that was never followed into humans, a fiber literature belonging to an isolated ingredient, and folk applications with no studies behind them at all. What keeps it at D+ rather than D is that the food is nutritious and the traditions are mostly harmless, provided the potato itself is sound (see safety). Nothing about the promoted uses is established, plausible-by-mechanism alone does not grade, and the record says so.
The week's longevity and biohacking news.
This grade for Potato rests on the record above. When a new result changes that record, the grade changes with it, and the Thursday email is where the change lands first: the week's longevity and biohacking news, in plain English, linked back to the reasoning on this page.
The week's longevity and biohacking news. Every story graded against the evidence. Free. Unsubscribe anytime.
Every grade follows a published rubric, and sponsors never change one. When the evidence moves a grade, Thursday is where you hear it first, before you renew a stack that stopped earning its cost.
Is it worth it?
Evidence (D+) sits far below the leaderboard floor, so the worth-it grade is capped at C+; the derived value lands at C- on food-level cheapness alone. About $4 a month at food amounts. Derived from the October 2026 worth-it model.
Typical cost
$3-6/month
Common form, not a brand recommendation
Dosage context established
No studied dose exists for juice or poultice use. Raw potato starch trials used about 24 to 48 g/day of the isolated starch, a different product from anything in a kitchen preparation. Juicing raw potatoes concentrates whatever is in them, including the glycoalkaloids in the safety notes.
Worth-it leaderboard
Potato sits outside the worth-it top 20.
Potato sits outside the current top 20 on the gated leaderboard. The leaders below clear an evidence floor of B- before price counts at all, so cheap alone never earns a rank.
See the full worth-it leaderboard →
When the evidence moves a grade, this ranking moves with it. Thursday is where you hear it first.
Safety notes
Never juice or eat green, sprouted, or bitter potatoes. Light exposure and sprouting raise glycoalkaloids (solanine and chaconine), which cause nausea, vomiting, diarrhea, and in larger amounts neurological symptoms, and they are not destroyed by cooking or juicing. Ordinary sound potatoes are safe food. Diabetics should note that potato, cooked and cooled or otherwise, is a meaningful carbohydrate load; raw juice concentrates sugars less than starch but still counts. Poultices on broken skin or near infected eyes risk introducing contamination to exactly the wrong place.
Longevity Lab Report
Potato news. Graded when it happens.
The grade on this page stays free. The email carries the news on potato: expert moves, dose changes, and what is working, in plain English every Thursday.
Changelog
Last updated 2026-10-23
- 2026-10-23|Graded from the H. pylori laboratory report and the raw potato starch literature, and from a direct search for human trials of potato juice or poultices: none exist. The record separates the food, the starch, and the folk preparations, because the little evidence that exists attaches to exactly one of them.
- 2026-10-23|Not listed under any goal: this record's graded findings do not map onto the library's ten goals.