Calcium

Calcium is one of those nutrients most people recognise, even if they’re not entirely sure how much they need or whether they’re getting enough. In pharmacies across the UK, it’s common to hear questions about bone strength, supplements, and whether calcium clashes with prescription medicines.

While calcium is best known for keeping bones and teeth strong, its role in the body is broader than many realise. Understanding the basics doesn’t require medical training. This guide explains what calcium does, where it comes from, who may need to pay closer attention to intake, and how supplements can be used safely when they’re genuinely needed.

What Calcium Does in the Body

Most of the calcium in your body is stored in your bones and teeth, where it provides structure and strength. Bone isn’t a static material - it’s constantly being broken down and rebuilt. Calcium is essential to that process, helping bones stay dense and resilient over time. When intake is consistently low, bones can gradually weaken and become more prone to fractures.

A much smaller amount of calcium circulates in the bloodstream, but this fraction is just as important. It supports everyday processes such as muscle movement, nerve signalling, normal blood clotting, and keeping the heart beating in a steady rhythm. The body tightly controls blood calcium levels, which is why long-term shortages are often taken from the skeleton rather than showing immediate symptoms.

Where We Get Calcium From

For most people in the UK, calcium comes from ordinary foods rather than supplements. Dairy products remain a major contributor, but they’re far from the only option. Fortified foods now play an increasingly important role, particularly for those who avoid milk.

A single glass of calcium-fortified soya or oat milk can provide a similar amount of calcium to cow’s milk, but not all plant-based alternatives are fortified - checking labels matters. Tofu made with calcium salts, leafy green vegetables such as kale and broccoli, canned fish with edible bones, nuts, seeds, and some breads and cereals can all contribute meaningfully to daily intake.

Food remains the most reliable and safest way to meet calcium needs, as it spreads intake naturally across the day and avoids excessive doses.

Who Might Struggle to Get Enough Calcium

Most healthy adults need around 700 mg of calcium per day, and many reach this without difficulty. However, some groups may fall short more easily.

Adolescents need more calcium while bones are developing rapidly, and post-menopausal women often experience accelerated bone loss due to hormonal changes. Older adults may eat less overall or absorb nutrients less efficiently, particularly if vitamin D levels are low.

Dietary patterns also matter. Vegan and dairy-free diets can meet calcium requirements, but only when fortified foods or suitable alternatives are included consistently. Certain medical conditions, such as coeliac disease or inflammatory bowel disease, can reduce calcium absorption, while long-term steroid use increases calcium needs. Limited sun exposure can compound the issue by reducing vitamin D, which helps the body absorb calcium effectively.

a bottle label Solgar Calcium Citrate

Calcium Supplements: What the Evidence Really Says

The NHS advises that most people do not need calcium supplements if they eat a balanced diet. Supplements are most useful when dietary intake is persistently low or when medical circumstances increase requirements.

They may be appropriate if:

  • You cannot meet needs through food alone due to diet or illness
  • You have osteoporosis or are taking bone-protective medication
  • You have a condition that reduces calcium absorption

For people already getting enough calcium from food, supplements do not appear to provide extra protection and can cause side effects when taken unnecessarily.

Two main forms are commonly found in pharmacies:

  • Calcium carbonate, which provides more calcium per tablet but is best taken with food and may cause constipation in some people
  • Calcium citrate, which is gentler on digestion and absorbed more easily, especially in people with lower stomach acid

Many products also include vitamin D to support absorption.

Safety, Interactions, and Practical Advice

Taking more calcium than needed doesn’t strengthen bones further and can cause problems. Regularly exceeding recommended amounts may lead to digestive discomfort or increase the risk of kidney stones in susceptible individuals.

Calcium can also interfere with the absorption of certain medicines, including thyroid medication, some antibiotics, iron supplements, and treatments for osteoporosis. Timing matters - spacing doses by a few hours can prevent reduced effectiveness. Anyone taking regular prescription medicines should check before starting supplements.

Seek professional advice if you have kidney disease, a history of kidney stones, conditions affecting calcium levels, or symptoms such as persistent muscle cramps or tingling.

Pharmacist Comment

"Calcium is one of those supplements people often start taking ‘just in case’, but in practice it’s not always necessary. Most adults who eat a varied diet will already be getting enough, especially if they include dairy or fortified alternatives. Where calcium supplements can be helpful is for people with restricted diets, absorption issues, or diagnosed bone conditions. The important thing is checking for medicine interactions and avoiding taking more than you need - that’s where a quick conversation with a pharmacist can make a real difference." -Alessandro Grenci, Superintendent Pharmacist

Conclusion

Calcium plays a vital role in bone strength, muscle movement, and nerve function, but more isn’t always better. Most adults in the UK can meet their needs through food alone, particularly when diets include dairy or fortified alternatives.

Supplements have a place, but mainly for people who genuinely cannot reach adequate intake through diet or who have specific medical needs. If you’re unsure whether you need one, a pharmacist can help assess your intake, review medicines, and suggest the most suitable option. For most people, food remains the best foundation for long-term bone health.

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