What it does in the body
- Bone and teeth mineralization
- Muscle contraction and relaxation
- Nerve impulse transmission
- Blood clotting cascade (Factor IV)
- Intracellular signaling and enzyme activation
How much you need (Daily Value)
| Group | Recommended | Source |
|---|---|---|
| Adult male | 1000 mg | NIH/IOM |
| Adult female | 1000 mg (19-50), 1200 mg (51+) | NIH/IOM |
| Pregnancy | 1000-1300 mg | WHO |
| Children | 700 mg (1-3y), 1000 mg (4-8y), 1300 mg (9-18y) | NIH/IOM |
| Older adults | 1200 mg (women >50, men >70) | NIH/IOM |
Richest food sources
| Food | Amount | Where |
|---|---|---|
| Parmesan cheese | 1184 mg per 100g | Europe |
| Sardines with bones | 382 mg per 100g | Mediterranean |
| Milk (whole) | 125 mg per 100ml | global |
| Yogurt | 110 mg per 100g | global |
| Tofu (calcium-set) | 350 mg per 100g | East Asia |
| Bok choy (cooked) | 105 mg per 100g | East Asia |
| Kale (cooked) | 150 mg per 100g | global |
| Ragi (finger millet) | 344 mg per 100g | South Asia/Africa |
In our food database, per 100 g
Highest among our free foods — open the Food Explorer to compare.
If you don't get enough
Mild: Muscle cramps, perioral numbness, brittle nails, dental problems
Moderate: Tetany, Chvostek and Trousseau signs, QT prolongation on ECG, paresthesias
Severe: Seizures, laryngospasm, cardiac arrhythmias, heart failure, osteomalacia, rickets in children
Time to onset: Acute hypocalcemia: hours to days. Chronic deficiency bone effects: months to years
Too much
Upper limit: 2500 mg/day (adults 19-50), 2000 mg/day (adults >50)
Hypercalcemia causing nausea, vomiting, constipation, kidney stones, nephrocalcinosis, cardiac arrhythmias, confusion, milk-alkali syndrome
How well you absorb it
25-35% from diet on average; varies significantly by source and physiological state
Helped by: Vitamin D, Lactose, Acidic pH in stomach, Casein phosphopeptides, Moderate protein intake
Hindered by: Oxalate (spinach, rhubarb), Phytate (whole grains, legumes), High sodium intake, Caffeine, High phosphorus intake, Fiber excess
Cooking & storage
Calcium is heat-stable and not destroyed by cooking. Boiling vegetables may leach calcium into cooking water; using that water in soups preserves it. Soaking beans reduces phytate, improving calcium bioavailability.
Nutrisize Health totals every nutrient from what you actually eat, against targets set for your age and sex, and flags what's short — across 4,995 foods, on your device.
