Calcium Deficiency: How to Spot It and What to Do

If you’ve had leg cramps at night, brittle nails, or unexpected fractures, low calcium could be the reason. Calcium does more than build bones — it helps your muscles, nerves, and heart work right. Missing it quietly over months can cause vague symptoms that people ignore until a fracture or a lab test reveals the problem.

Symptoms & Causes

Common signs of low calcium include muscle cramps or spasms, tingling or numbness around the mouth and fingers, weak nails, dental issues, and frequent bone fractures. Severe shortages can cause confusion, seizures, or an abnormal heartbeat. Don’t assume occasional cramps are harmless — if they’re new, frequent, or come with numbness, get checked.

Why does calcium drop? The usual reasons are low dietary intake, not enough vitamin D (which your body needs to absorb calcium), or problems with the parathyroid glands that control calcium balance. Kidney disease can make it hard to keep calcium steady. Certain medicines — long-term corticosteroids, some anticonvulsants, or loop diuretics — can lower calcium too.

How to Fix Low Calcium — Practical Steps

Eat calcium-rich foods first. Good choices are dairy (milk, yogurt, cheese), fortified plant milks, canned salmon or sardines with bones, tofu set with calcium, and low-oxalate greens like kale and bok choy. Be careful with spinach and beet greens — they have lots of calcium, but oxalates make it harder for your body to use that calcium.

Vitamin D matters. If you don’t get sunlight or you have low vitamin D, your body won’t absorb calcium well. Ask your doctor for a simple 25(OH)D blood test. If it’s low, a D supplement (often vitamin D3) is an easy fix and improves calcium uptake.

Supplements: Many adults need about 1,000 mg of calcium a day; older adults (often women over 50 and men over 70) commonly need around 1,200 mg. If you use supplements, calcium carbonate is cheaper but should be taken with food. Calcium citrate is easier on an empty stomach and for people with low stomach acid. Don’t take more than recommended — excess calcium can raise the risk of kidney stones and interfere with other minerals.

Watch interactions: calcium can reduce absorption of some antibiotics (tetracyclines, fluoroquinolones) and thyroid meds. Take those drugs at least two hours apart from calcium supplements. If you’re on multiple prescriptions, check with your pharmacist.

When to see a doctor: get tested if you have persistent cramps, sudden numbness, new fractures, or signs of severe deficiency like fainting or heart irregularities. A blood calcium test, corrected calcium (for albumin), PTH, and vitamin D level usually give a clear picture. Treatment depends on the cause — diet and supplements help most, but some conditions need specific medical care.

Fixing low calcium is usually straightforward: eat better, check vitamin D, mind interactions, and follow up with your doctor when symptoms point to a real problem. Small changes in diet and a short course of supplements often make a big difference fast.