Nutrition basicsMineralsDoses & safety
Minerals are inorganic elements that build your skeleton, carry oxygen, fire your nerves and balance your fluids. They split into major minerals (needed in hundreds of mg/day) and trace elements (mg or µg) — "trace" means small quantity, never small importance.
Read first — about the doses on this page. The therapeutic doses listed are what is used in research and clinical practice — they are information, not a prescription. Minerals interact and several are dangerous in excess (iron, potassium, selenium). Always involve a doctor or pharmacist before using a mineral therapeutically, in pregnancy, for a child, with kidney disease, or alongside medication. "Upper limit" is the official Tolerable Upper Intake Level (UL) where set.
Major minerals
Calcium
Adult need ≈ 800–1000 mg/day
What it does: ~99% is in bones and teeth (also a calcium reserve); the rest runs muscle contraction, the heartbeat, nerves and clotting. Where: dairy, fortified plant drinks, calcium-set tofu, tinned fish with bones, kale, broccoli. Needs vitamin D to be absorbed.
DeficiencyShort-term low blood calcium → muscle cramps and tingling (tetany); long-term low intake → weak bones and osteoporosis.
Therapeutic useOsteoporosis prevention/treatment, usually with vitamin D (≈ 500–1000 mg supplemental calcium); correcting low dietary intake.
Upper limit2,500 mg/day (both EFSA and US; the US limit drops to 2,000 mg from age 51). Too much from supplements: constipation, kidney stones, and possibly raised cardiovascular risk.
Magnesium
Adult need ≈ 280–350 mg/dayCommon modest shortfall
What it does: a cofactor in 300+ reactions — energy, muscle and nerve function, blood-sugar control, building bone; part of how muscles and the mind relax. Where: leafy greens, nuts, seeds, whole grains, legumes, dark chocolate.
DeficiencyMuscle cramps and twitches, weakness, fatigue, and — when severe — an irregular heartbeat.
Therapeutic useConstipation (magnesium oxide/citrate as an osmotic laxative); evidence for migraine prevention (≈ 300–400 mg — note this exceeds the supplemental upper limit below, so it belongs under medical supervision); IV magnesium for pre-eclampsia and severe asthma (hospital). Not effective for ordinary night-time leg cramps in older adults — Cochrane rates that null with high certainty.
Upper limit250 mg/day from supplements (EFSA) — magnesium from food is not capped. Excess from supplements: diarrhoea; dangerous only in kidney failure.
Potassium
Adult need ≈ 3500 mg/dayMost people get too little
What it does: the main mineral inside cells; balances sodium to control fluid, nerves and muscle, and helps keep blood pressure down. Where: potatoes, bananas, beans, lentils, leafy greens, tomatoes, avocado, dairy.
DeficiencyWeakness, cramps, constipation and irregular heartbeat — often triggered by vomiting, diarrhoea or diuretic medicines.
Therapeutic useA higher-potassium, lower-sodium diet is well-proven to lower blood pressure; prescription potassium replaces medical losses.
Upper limitNo UL from food. Danger: in kidney disease or on certain heart/BP medicines, potassium can rise to life-threatening levels (hyperkalaemia) — never supplement without medical advice.
Sodium
Target: <2 g sodium (<5 g salt)/dayMost people get too much
What it does: essential for fluid balance and nerve/muscle signalling — but needed only in small amounts a normal diet easily supplies. Where it hides: bread, processed and cured meats, cheese, ready meals, snacks and sauces — far more than the salt shaker.
DeficiencyRare from diet; low blood sodium (hyponatraemia) comes from illness or over-hydration → headache, confusion, in severe cases seizures.
Therapeutic useThe health goal is almost always the opposite — cutting salt to lower blood pressure and heart/stroke risk.
Upper limitKeep salt under 5 g/day (≈ 2 g sodium). High intake raises blood pressure across the population.
Phosphorus
Adult need ≈ 550–700 mg/day
What it does: partners with calcium in bones and teeth, and is built into DNA and into ATP, the cell's energy molecule. Where: protein foods (meat, fish, eggs, dairy), whole grains, legumes, nuts.
DeficiencyRare on a normal diet; can cause bone pain, weakness and fatigue when it occurs.
Therapeutic useLimited; mainly correcting low levels in specific medical conditions.
Upper limit4,000 mg/day (US). High intake — largely from cola drinks and additives — is a real problem mainly in kidney disease.
Chloride
Comes with sodium
What it does: works with sodium for fluid balance, and is a component of stomach acid (needed for digestion). Where: table salt (sodium chloride) and most foods.
DeficiencyRare; mostly seen with prolonged vomiting or certain medicines, disturbing the body's acid balance.
Therapeutic useNo standalone role — managed together with sodium and fluids.
Upper limitTracks sodium; reducing salt reduces both.
Trace elements
Iron
Women ≈ 15–18 mg · Men ≈ 9 mg/dayWorld's most common deficiency
What it does: the core of haemoglobin, which carries oxygen in red blood cells; also part of energy enzymes. Where: well-absorbed heme iron in meat/fish; non-heme iron in legumes, tofu, greens, fortified grains — absorbed better with vitamin C, worse with tea/coffee.
DeficiencyIron-deficiency anaemia — fatigue, pallor, breathlessness, brittle nails. Highest risk: menstruating and pregnant women, blood donors, some plant-based eaters.
Therapeutic useOral iron for anaemia (≈ 65 mg elemental iron; alternate-day dosing can absorb better and be gentler); IV iron under medical care.
Upper limit45 mg/day (US; EFSA sets none). Excess: constipation and GI upset; acute overdose is a leading cause of poisoning in children; chronic overload (haemochromatosis) damages the liver and heart. Don't supplement without a confirmed low test.
Zinc
Adult need ≈ 7–11 mg/day
What it does: cofactor for hundreds of enzymes; essential for immunity, wound healing, growth, taste/smell and fertility. Where: meat, shellfish (oysters very rich), pumpkin and other seeds, legumes, nuts, whole grains.
DeficiencyMore frequent infections, slow wound healing, hair loss, reduced taste, poor growth in children.
Therapeutic useZinc lozenges may shorten a cold's duration; supplementation corrects deficiency; WHO uses zinc to treat childhood diarrhoea.
Upper limit25 mg/day (EFSA) · 40 mg (US). Excess: nausea; and chronic high doses cause a secondary copper deficiency.
Iodine
Adult need ≈ 150 µg/dayKey in pregnancy
What it does: the building block of thyroid hormones, which set the body's metabolic rate; critical for fetal and infant brain development. Where: dairy, fish and seafood, eggs, and iodized salt (a main dietary source in many countries).
DeficiencyEnlarged thyroid (goitre), underactive thyroid, and impaired development in pregnancy.
Therapeutic useTreating deficiency/goitre; potassium iodide protects the thyroid in a radiation emergency.
Upper limit600 µg/day (EFSA) · 1,100 µg (US). Paradoxically, too much can itself trigger thyroid over- or under-activity — care with kelp/seaweed supplements.
Selenium
Adult need ≈ 55–70 µg/day
What it does: built into antioxidant enzymes that protect cells, and needed to activate thyroid hormone and support immunity. Where: Brazil nuts (very rich — 1–2 cover a day), fish and seafood, eggs, meat, whole grains. Soils in many parts of Europe are low.
DeficiencyRare; severe lack is linked to a heart-muscle disease (Keshan) and thyroid problems.
Therapeutic useLimited — mainly correcting genuine deficiency; routine high-dose supplements are not advised.
Upper limit255 µg/day (EFSA, revised 2023 — the critical effect is hair loss) · 400 µg (US). Narrow safety margin — excess (selenosis) causes hair and nail loss, garlic breath and nerve problems.
Copper
Adult need ≈ 1–1.3 mg/day
What it does: helps the body use iron, builds connective tissue and nerve coatings, and is part of antioxidant and energy enzymes. Where: shellfish, nuts and seeds, whole grains, legumes, dark chocolate, offal.
DeficiencyAnaemia, low white blood cells and nerve problems — often caused by too much zinc rather than too little copper.
Therapeutic useCorrecting deficiency, including zinc-induced copper deficiency.
Upper limit5 mg/day (EFSA) · 10 mg (US). Excess: stomach upset and, at high levels, liver damage.
Manganese
Adult AI ≈ 2–3 mg/day
What it does: a cofactor for enzymes in energy metabolism, the formation of bone and cartilage, and a key antioxidant enzyme (manganese superoxide dismutase) that protects cells. Where: whole grains, nuts, leafy greens, legumes and tea (a notably rich source).
DeficiencyVery rare in humans on a normal diet — the everyday diet easily supplies enough.
Therapeutic useNo established supplement role; only relevant for correcting a genuine (uncommon) deficiency.
Upper limitNo EFSA UL · 11 mg/day (US). Notably, the real risk is inhaling manganese dust (welding/industry), which can cause a Parkinson-like nerve disorder — dietary excess is rare. Care in liver disease, which slows its removal.
Chromium
Adult AI ≈ 25–35 µg/dayGlucose-metabolism link
What it does: the dietary form — trivalent chromium (Cr III) — is thought to help insulin act on cells, so its best-known role is in glucose (blood-sugar) metabolism. (This food form is harmless and completely different from the toxic industrial form, Cr VI.) Where: whole grains, meat, broccoli, nuts and brewer's yeast.
DeficiencyOnly severe deficiency (seen with long-term intravenous feeding) clearly causes insulin resistance and high blood sugar. In ordinary diets a deficiency state isn't well defined — EFSA has even questioned whether chromium is strictly essential.
Therapeutic useChromium picolinate is widely marketed for blood sugar and weight. Honest evidence: it may modestly improve glucose control in some people with type 2 diabetes, but trials are mixed and it is not an established treatment — and it does not reliably help weight loss.5
Upper limitNo UL set for trivalent chromium — toxicity from food and supplements is low. (The industrial Cr VI form is a separate, toxic, carcinogenic substance — not what is in food or supplements.)
Molybdenum
Adult need ≈ 45–65 µg/day
What it does: a cofactor for enzymes that break down sulfur-containing amino acids and process the body's waste products (including forming uric acid). Where: legumes (a top source), whole grains, nuts and organ meats.
DeficiencyEssentially unknown from diet — it occurs only in rare genetic disorders or prolonged artificial feeding.
Therapeutic useNo role in general use; supplementing it is not needed for healthy people.
Upper limit600 µg/day (EFSA) · 2,000 µg (US). Excess is rare from food.
Fluoride
Dental mineral · AI ≈ 3–4 mg/day
What it does: hardens tooth enamel and helps it resist decay, and is incorporated into bone. It is the one "mineral" here that is not strictly essential for life — its value is dental. Where: tea, fish and seafood, and fluoridated drinking water. Note: where drinking water isn't fluoridated, fluoride toothpaste (plus tea and fish) is the main everyday source.
DeficiencyMore dental cavities (tooth decay), especially in children.
Therapeutic useThe mainstay of caries prevention — fluoride toothpaste, and dental varnishes or rinses applied by a dentist.
Upper limit10 mg/day (US). EFSA withdrew its adult upper limit in 2025, replacing it with a safe intake of 3.3 mg/day for everyone over 8 and in pregnancy — about half the old figure, and now set on fetal brain development rather than bone. Too much during childhood causes dental fluorosis (white-flecked or mottled enamel); very high lifelong intake can affect bone.
Silicon (silica)
Ultratrace · not officially essentialBone & connective tissue
What it does: silicon is not officially classified as essential for humans — no defined biochemical requirement has been proven — but it is linked to collagen and connective-tissue formation and to bone. The well-absorbed dietary form is orthosilicic acid (OSA). Where: whole grains and cereals (oats, barley), green beans, bananas and mineral water (in plants much of the silicon is locked in poorly-absorbed silica, so overall absorption is limited).
DeficiencyNo defined deficiency state in humans — there is no established requirement to fall short of.
Therapeutic useMarketed for hair, skin, nails and bone. Honest evidence: higher dietary silicon is associated with greater bone mineral density (observational), and a small RCT of ~10 mg/day orthosilicic acid over 20 weeks improved skin elasticity and reduced hair/nail brittleness6 — promising but limited. Herbal "horsetail" is a traditional silicon source but quality varies (it contains thiaminase) — stabilised OSA from a reputable brand is more reliable.
Upper limitNo UL set as a nutrient; dietary silicon and the anti-caking food additive silica (E551) are considered low-risk.
Boron
Ultratrace · not officially essentialBone & hormones
What it does: like silicon, boron is not officially classified as essential (EFSA finds no proven biochemical function in humans) — but it is clearly bioactive: it appears to support bone, improve how the body handles calcium, magnesium and vitamin D, and to influence sex hormones (estrogen and testosterone). Where: nuts (the richest source), dried fruit (raisins, prunes), legumes, fresh fruit and vegetables, avocado and coffee; animal foods contain very little. Most people get 1–3 mg/day from food.
DeficiencyNo defined deficiency state in humans — there is no established requirement.
Therapeutic useMarketed for bone, testosterone and joints. Honest evidence: small short trials of ~3 mg/day suggest support for bone and modest rises in estradiol and testosterone (e.g. in postmenopausal women), and 10 mg/day raised these hormones in men7 — but the studies are small and brief, so treat it as preliminary, not proven.
Upper limit10 mg/day (EFSA) · 20 mg (US). Safe within these limits; very high doses cause GI upset (and, in animal studies, reproductive harm).
The honest bottom line: a varied diet covers nearly all minerals. In our region the ones worth real attention are iron (menstruating/pregnant women), iodine (use iodized salt; vital in pregnancy), calcium + vitamin D for bone health, and a little care with selenium/zinc on plant-based diets. Cut sodium, lift potassium. Several minerals are genuinely harmful in excess — supplement a specific mineral only when a test or clinician points to a real need.
✓
Bodil Isaksson, Licensed Biomedical Scientist (Sweden)
At Food Health Lab we explain what the science says in plain language, and we cite our sources so you can check for yourself.
References
Reference intakes and upper limits are general adult values from official bodies, rounded for clarity; exact values vary by age, sex and life stage. "Upper limit" = Tolerable Upper Intake Level (UL).
- EFSA. Overview on Tolerable Upper Intake Levels — consolidated UL summary for vitamins and minerals (2024). efsa.europa.eu (UL summary PDF) · DRV topic
- US NIH, Office of Dietary Supplements. Individual mineral fact sheets — functions, food sources, recommended intakes, upper limits, deficiency and therapeutic uses. ods.od.nih.gov/factsheets
- Nordic Council of Ministers. Nordic Nutrition Recommendations 2023 — reference values and Nordic-specific guidance (iron, iodine, selenium, calcium). pub.norden.org
- World Health Organization. Salt reduction — keep salt below 5 g/day (≈ 2 g sodium). who.int
- Trumbo PR, Yates AA, et al. Chromium picolinate intake and risk of type 2 diabetes: an evidence-based review by the US FDA (qualified/mixed evidence). Nutrition Reviews, 2006. Nutr Rev 64(8):357 · NIH ODS Chromium
- Araújo LA, et al. Use of silicon for skin and hair care (An Bras Dermatol, 2016) PMC4938278; and Jugdaohsingh R. Silicon and bone health. PMC8283247. Note: silicon is not officially recognised as an essential nutrient.
- Nielsen FH, Meacham SL. Growing evidence for human health benefits of boron. J Evid Based Complementary Altern Med, 2011. SAGE. EFSA tolerable upper intake level for boron = 10 mg/day (adults); boron is not officially classed as essential.
This article summarizes nutrition science from official health authorities for education. It is not a substitute for individual medical advice, and the doses given are not prescriptions — always consult a professional before therapeutic supplement use, in pregnancy, or alongside medication.