💊 What it does
Calcium is the most abundant mineral in the body — 99% is stored in bones and teeth, providing structural strength. The remaining 1% circulates in blood and is essential for muscle contraction (including the heart), nerve signalling, blood clotting, and hormone secretion. The body regulates blood calcium tightly — if dietary intake is too low, it draws calcium from bones, gradually reducing bone density over years and decades.
👤 Who needs it
Post-menopausal women — oestrogen protects bone density and its decline accelerates calcium loss from bones. People who avoid dairy products and do not eat calcium-rich plant foods consistently. Those with low vitamin D status (vitamin D is required for calcium absorption). Older adults whose absorption efficiency declines with age. Teenagers and young adults during peak bone mass development.
🥦 Food sources first
Plant sources: fortified plant milks (calcium-set tofu is excellent — 350 mg per 100g), broccoli, kale, bok choy, almonds, sesame seeds (tahini), white beans, edamame, dried figs, fortified cereals. Absorption from plant sources varies — calcium from kale and broccoli is actually better absorbed than from dairy; spinach and rhubarb contain oxalates that bind calcium and reduce absorption. Fortified plant milks with calcium carbonate or tricalcium phosphate provide comparable calcium to dairy milk.
🗓 When to supplement
Only if dietary calcium is genuinely insufficient after assessment. Many plant-based eaters who include calcium-set tofu, fortified plant milks, and plenty of leafy greens meet their needs without supplementing. Nutriofia's tracking will show you your daily calcium intake — use that data before reaching for a supplement.
🏷 Best form to look for
Calcium citrate is better absorbed than calcium carbonate, can be taken on an empty stomach, and is better for older adults with lower stomach acid. Calcium carbonate requires stomach acid — take with meals. Avoid mega-dose calcium supplements — 500 mg is a reasonable upper limit per dose as absorption drops sharply above this.
⏰ When to take it
Calcium carbonate: always with food. Calcium citrate: with or without food. Split doses across the day rather than taking all at once — the body can only absorb around 500 mg efficiently at one time.