Calcium
What the European Food Safety Authority and the United States National Institutes of Health have published about calcium intake, and what the catalogue records. Reference figures and citations only.
Stacky is an organisational tool, not a medical device. It does not provide medical advice, and nothing on this page says what calcium does. Talk to a doctor or pharmacist before starting, stopping or changing what you take.
Published intake references
Each figure is one authority’s published value, with the kind of figure and the people it applies to as that authority stated them. Where the EU and the US differ, both are shown and neither is averaged or converted. Only a tolerable upper intake level sets a ceiling. A recommended or adequate intake is context, not a limit.
EUEuropean Union — EFSA
USUnited States — NIH ODS / IOM
To cite a figure, cite the authority’s document linked on its card, and this page as where you read it: stacky-app.com/substances/calcium, retrieved 13 November 2026. Every card has its own address: add #eu-rda-2 to the page URL for the first one.
Products in Stacky’s catalogue containing Calcium
3 products whose label declares calcium, listed by brand and drawn as the app draws them. Amounts are the manufacturer’s printed figures; Stacky has measured nothing and ranks nothing.
How it is recorded
What the app records so it can schedule a dose. None of it is advice.
Default time of day in the app: Morning, Evening. A person can move it; the app never changes a dose.
Default food note in the app: with food.
Recorded interactions
How Stacky summarises what a named source says about calcium taken alongside another substance: absorption and nutrient status only. The category and the summary are Stacky’s words; each row links to the source, and the source’s own wording governs. A row without one is not published, and neither is one whose source description names a disease or clinical condition. None of these says whether a combination is good or bad.
| Stacky’s category | Summary, in Stacky’s words | Source |
|---|---|---|
| Documented relationship with Caffeine | Net absorption of dietary calcium is reduced to a small extent by caffeine intake. Scope the source gave: described as a small effect on net absorption. |
NIH ODS Checked 6 Aug 2026 |
| Documented relationship with Inulin | Evidence from animal studies and limited human research suggests that inulin and oligofructose may enhance calcium absorption. | Linus Pauling Institute Checked 6 Aug 2026 |
| Reduces absorption or status of Iron | Calcium can reduce the bioavailability of both heme and non-heme iron when the two are taken together. NIH ODS notes the effect has not been definitively established, and that calcium supplementation over several weeks has not been shown to change iron status. Scope the source gave: calcium and iron taken at the same time; applies to both heme and non-heme iron. |
NIH ODS Checked 6 Aug 2026 |
| Reduces absorption or status of Manganese | In one set of studies, supplemental calcium at 500 mg a day slightly decreased manganese bioavailability in healthy adults, with the size of the effect varying by the form of calcium. Several other studies found minimal effects of supplemental calcium on manganese. Scope the source gave: 500 mg a day of supplemental calcium; effect varied by calcium form, smallest with milk and largest with calcium carbonate and calcium phosphate. |
Linus Pauling Institute, Manganese Checked 6 Aug 2026 |
| Reduces absorption or status of Phosphorus | Calcium from foods and supplements binds some of the phosphorus in food and prevents its absorption. The competition runs both ways: net absorption of dietary calcium is reduced to a small extent by phosphorus intake, and the two minerals are co-regulated by vitamin D and parathyroid hormone. | NIH ODS Checked 6 Aug 2026 |
| Documented relationship with Potassium | Low potassium intakes impair calcium reabsorption in the kidney and increase urinary calcium excretion. Potassium supplementation has been found to reduce urinary calcium excretion in trials in older adults. | NIH ODS Checked 6 Aug 2026 |
| Documented relationship with Sodium | Dietary sodium is a major determinant of urinary calcium loss: higher sodium intake increases the amount of calcium excreted in urine. Each gram of sodium excreted by the kidneys has been found to draw about 26 mg of calcium into the urine. | Linus Pauling Institute, Calcium Checked 6 Aug 2026 |
| Documented relationship with Vitamin D3 | Vitamin D promotes the absorption of calcium in the gut and helps maintain serum calcium concentrations. The two are commonly formulated together in bone-health products. | NIH ODS Checked 6 Aug 2026 |
Indexed studies
Stacky has 5 papers indexed against calcium, and none of them is published here. A study reaches this page only if its own title names Calcium and does not name a disease or clinical condition. None of the 5 passes that rule. They remain in the app. How this list is built →
About this page
Stacky is a supplement tracking app. It renders what you take and what published sources say about it; it does not tell you what to take. Every figure on this page names the authority that published it and links to that authority’s own page.
Not on this page: a dose of our own, a grade, a verdict on whether calcium works, or any statement that it treats, prevents or improves a condition. How these pages are built →
Figures are read from the authorities’ published tables and can go out of date when those tables are revised. If one here is wrong, tell us at support@stacky-app.com and we will check it against the source.