Calcium

Calcium is an essential mineral that plays a vital role in maintaining bone health, muscle function, and nerve signalling. Over 99% of the body’s calcium is stored in bones and teeth, providing structural strength, while the remaining amount supports blood clotting, heart rhythm regulation, and cellular communication. Research highlights its importance in preventing osteoporosis, particularly in postmenopausal women, and suggests potential benefits for reducing hypertension and colorectal adenoma recurrence. Though primarily associated with dairy, calcium can be sourced from leafy greens, fortified foods, and supplements. Balancing intake with vitamin D is crucial, as it enhances calcium absorption and supports overall skeletal health.

Key Facts

  • Adults aged 19–50 require 1,000 mg of calcium daily, rising to 1,200 mg for women over 50 and men over 70.
  • Postmenopausal women lose bone density faster due to reduced oestrogen, increasing calcium needs.
  • Non-dairy sources like kale, almonds, and fortified plant milk provide bioavailable calcium.
  • Vitamin D, magnesium, and phosphorus are essential for optimal calcium absorption and utilisation.
  • Excessive supplementation (over 2,500 mg/day) may increase kidney stone and cardiovascular risks.
  • Chronic deficiency can lead to osteopenia, osteoporosis, and neuromuscular issues like muscle spasms.

What does the research say about calcium and its function in the body?

Calcium is critical for bone mineralisation, muscle contraction, and nerve transmission. Studies link adequate intake to reduced fracture risk and slower bone loss in ageing adults. Emerging evidence suggests it may lower blood pressure and recurrent colorectal adenomas, though findings on cardiovascular benefits remain mixed.

What are the primary food sources of calcium?

Dairy products like milk, cheese, and yoghurt are rich sources. Non-dairy options include fortified cereals, tofu, sardines with bones, kale, and sesame seeds. Plant-based sources often require larger portions due to lower bioavailability.

How can I supplement calcium?

Common forms include calcium carbonate (cost-effective, best taken with meals) and calcium citrate (easier absorption, ideal for low stomach acid). Pairing supplements with vitamin D enhances efficacy. Avoid exceeding 500 mg per dose to maximise absorption.

What are the main symptoms of calcium deficiency?

Early signs include muscle cramps, fatigue, and tingling in extremities. Severe deficiency (hypocalcaemia) may cause brittle nails, dry skin, arrhythmias, or seizures. Long-term low intake raises osteoporosis risk, particularly in older adults.

Are there any known side effects of supplementing calcium?

High doses can cause bloating, constipation, or kidney stones. Excessive intake from supplements (not food) has been associated with arterial calcification in some studies. Stick to recommended limits unless advised otherwise by a healthcare provider.

How long does it take to see the benefits of calcium supplementation?

Bone density improvements may take 6–12 months to manifest, though muscle cramps or tingling might resolve within weeks. Consistency is key, as benefits accumulate gradually over time.

What should consumers look for on the supplement label when supplementing calcium?

Check for elemental calcium content, which indicates the actual absorbable amount. Opt for brands with third-party certification (e.g., USP, NSF). Labels should specify whether vitamin D or magnesium is included to aid absorption.

Can calcium interact with medications?

Yes, calcium can hinder the absorption of antibiotics like tetracycline and thyroid medications. Take supplements 2–4 hours apart from these drugs. Long-term corticosteroid use also increases calcium excretion, raising deficiency risk.

Do calcium needs change with age?

Absolutely. Adolescents, pregnant women, and adults over 50 often require higher intake. Postmenopausal women and older adults may need 1,200 mg daily due to reduced absorption efficiency and hormonal changes.

Does calcium only benefit bones?

No—it also supports heart muscle contraction, blood vessel dilation, and neurotransmitter release. Low calcium levels may contribute to mood disorders like depression, though more research is needed in this area.

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