Minerals for Older Adults: Needs, Absorption, Kidney Function and Medicines
Mineral needs in older adults with official figures, why kidney function and medicines matter for magnesium, potassium, calcium, iron and zinc, and what to ask a pharmacist.
Content last updated . This page has not been medically reviewed.
Seek care first
- If you feel suddenly unwell after starting or changing a supplement, contact your clinician or urgent care, and call 911 in the US for an emergency. Bring the product label.
- If you take several medicines or have kidney disease, ask your pharmacist or doctor before any mineral supplement. Some minerals build up when the kidneys work less well. Do not stop or change a prescribed medicine yourself.
The short answer
Older adults often take more medicines and may have reduced kidney function, and both change what is safe. The NHS says older people should not take potassium supplements unless a doctor advises, because their kidneys may be less able to remove potassium. [1] MedlinePlus says magnesium side effects are uncommon except in people with significantly reduced kidney function. [2] This page is information only. For vitamins see Vitamins and supplements for older adults.Official intake levels
Figures are for adults in the stated age band and are published reference levels, not advice for one person.| Mineral | Reference intake per day | Upper level per day | Source and year |
|---|---|---|---|
| Calcium | US: women 51 to 70 1,200 mg, men 51 to 70 1,000 mg, both sexes over 70 1,200 mg | US: 2,000 mg "considered safe" over 50. Canada: 2,000 mg (51 and over) | MedlinePlus 2025; Health Canada 2025 |
| Iron | US: 8 mg for men and women 51 and over | Canada: 45 mg (51 and over). UK: 17 mg or less from supplements "unlikely to cause any harm" for adults | MedlinePlus 2025; Health Canada 2025; NHS 2020 |
| Zinc | US: men 11 mg, women 8 mg (19 and over) | Canada: 40 mg (51 and over). UK: do not take more than 25 mg from supplements unless advised by a doctor | MedlinePlus 2025; Health Canada 2025; NHS 2020 |
| Magnesium | US: men 420 mg, women 320 mg (31 and over) | Canada: 350 mg from supplements only. EU: 250 mg from supplements and added sources | MedlinePlus 2025; Health Canada 2025; EFSA 2025 |
| Potassium | UK: 3,500 mg (adults 19 to 64) | UK: 3,700 mg or less from supplements unlikely to have obvious harm, but older people should not take supplements unless advised | NHS 2020 |
[3] [4] [5] [2] [6] [7] [8] [1]
The NHS also says that for older people, who may be more sensitive to manganese, 0.5 mg or less a day from supplements is unlikely to cause harm, compared with 4 mg for most people. [1] Check Understanding minerals for how label amounts relate to these tables.
Medicines and minerals
Evidence labels: established means documented in official drug or health pages; limited means small studies.| Medicine or condition | What the source says | Strength |
|---|---|---|
| Levothyroxine (thyroid) | The NHS lists antacids, calcium and iron supplements, and stomach-acid medicines among things that may not mix well. [9] | Established |
| Doxycycline (antibiotic) | The NHS lists antacids and medicines or supplements containing iron or zinc among things that may not mix well. [10] | Established |
| Stomach-acid medicines (PPIs) and low magnesium | Case reports led the FDA and MHRA to issue warnings. A prospective study found clinically relevant low magnesium was not readily identifiable on regular blood testing, and people also taking diuretics were at higher risk. [11] | Limited |
| Reduced kidney function | The NHS says older kidneys may be less able to remove potassium, and MedlinePlus names reduced kidney function as the main setting for magnesium side effects. [1] [2] | Established |
Do not skip or move doses yourself. A pharmacist can check your list; see Spacing supplements and medicines, Medication interactions and Multiple medicines, kidney function and supplement burden.
What is not well established
- Does absorption fall with age? Proper evidence not found in the sources we read (NHS, MedlinePlus, EFSA, Health Canada and PubMed reviews on magnesium and stomach-acid medicines). Do not assume you need more of a mineral because you are older.
- Do mineral supplements prevent fractures or frailty in healthy older adults? For calcium and fractures, trial evidence is weak; see Minerals for women over 50.
- Blood tests. A single test may not show total body stores, and illness and medicines can change results; see Deficiency testing and its limits.
Frequently asked questions
Do older adults need more minerals?
Reference intakes change with age: US calcium rises for women over 50 and everyone over 70, while iron falls for women after 50. [3] [4] Needs are individual, so ask your clinician.
Is magnesium safe if my kidneys are weaker?
MedlinePlus says magnesium side effects are uncommon except in people with significantly reduced kidney function. [2] Ask your clinician before taking any magnesium product.
Can older adults take potassium supplements?
The NHS says older people should not take potassium supplements unless advised by a doctor. [1]
Can minerals affect my medicines?
Yes. The NHS lists calcium, iron and zinc among supplements that may not mix well with levothyroxine or doxycycline. [9] [10] Ask a pharmacist.
Can stomach-acid medicines lower magnesium?
FDA and MHRA warnings followed case reports of low magnesium with PPIs; a prospective study advised regular magnesium testing for people also on diuretics. [11]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Other cautions
References
- NHS (UK). Vitamins and minerals: Others (magnesium, potassium, selenium, zinc and others). Page last reviewed 3 August 2020. Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Magnesium in diet. Review date 1/21/2025. Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Calcium in diet. Review date 1/21/2025. Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Iron in diet. Review date 1/21/2025. Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Zinc in diet. Review date 1/21/2025. Read 2026-10-23.
- Health Canada, Dietary reference intakes tables: Reference values for elements, page dated 2025-11-19. Read through the WebFetch tool, whose output is a model-made extract of the table, so these figures should be treated as (WebFetch extract). Read 2026-10-23.
- European Food Safety Authority (EU), version 11, August 2025. EFSA, Overview on Tolerable Upper Intake Levels (SCF and EFSA NDA Panel), Tables 1 and 2. Read 2026-10-23.
- NHS (UK). Vitamins and minerals: Iron. Page last reviewed 3 August 2020. Read 2026-10-23.
- NHS (UK). Levothyroxine (medicine page). Page last reviewed 6 July 2026. Read 2026-10-23.
- NHS (UK). Doxycycline: how and when to take it. Page last reviewed 5 September 2025. Read 2026-10-23.
- Proton pump inhibitor associated hypomagnesaemia: a cause for concern? Br J Clin Pharmacol 2016;81:753-758. PubMed abstract (PMID 26613375). Read 2026-10-23.