Do you need calcium and vitamin D tablets?
Most adults just need the vitamin D, in autumn and winter. Calcium usually comes from food. But in trials in older people, the pair did something vitamin D alone didn’t.
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Who needs calcium and vitamin D tablets?
Most adults need the vitamin D, not the calcium. The NHS says adults need 10 micrograms (400 IU, another unit you’ll see on packs) of vitamin D a day.
From October to early March, the sun is too weak to make enough. So everyone should consider a 10 microgram supplement in autumn and winter.
Calcium is different. Adults need 700mg a day, and the NHS says you should be able to get it all from food.
| Who | Vitamin D | Calcium |
|---|---|---|
| Most adults | 10 micrograms a day in autumn and winter. | 700mg a day, usually from food. |
| Rarely outdoors, in a care home, or skin mostly covered outside | 10 micrograms a day all year. | 700mg a day, usually from food. |
| Dark skin, such as an African, African-Caribbean or south Asian background | Consider 10 micrograms a day all year. | 700mg a day, usually from food. |
| At risk of osteoporosis (bones that get weak and break easily) or on a bone medicine | Your doctor may advise 20 micrograms a day. | Your doctor may advise around 1,000mg a day. |
Sources: NHS: vitamin D; NHS: calcium; ROS; ROS: vitamin D
Think of calcium as bricks and vitamin D as the van that brings them in. Vitamin D helps your body absorb and use calcium.
But extra bricks don’t build a stronger wall. The Royal Osteoporosis Society (ROS) says more calcium than you need is unlikely to improve your bone strength.
Your next step: find your row. If it’s the last one, ask your GP before you buy.
How much calcium do I need a day?
Most adults need 700mg, including in pregnancy. Food usually covers it. Good sources, from the NHS:
- milk, cheese and other dairy foods
- curly kale and okra
- soya drinks with added calcium
- bread made with fortified flour
- sardines or pilchards, eaten with the bones
Don’t count on spinach. It’s high in calcium, but your body can’t digest it all. Low-fat dairy has just as much calcium as full-fat.
- 1500 mg or belowNHS: unlikely to cause any harm.
- Above 1500 mgCould cause stomach pain, diarrhoea and kidney stones.
Add up every supplement you take. Other supplements may contain calcium too.
No dairy? Pick plant milks and tofu with added calcium, and check the label.
Cutting dairy for protein too? See dairy-free protein.
A blood test won’t settle it. The ROS says a calcium blood test doesn’t show if you get enough from food. See calcium blood test results.
Which calcium and vitamin D supplement is best?
No single brand wins. Read the back of the pack, not the front.
Calcium carbonate and calcium citrate are both good for your bones, says the ROS. Vitamin D3 is thought to be slightly more effective than D2. Packs called calcium D3 pair calcium with vitamin D3.
Before you buy calcium and vitamin D tablets
- Find the calcium per daily dose. Most supplements give 300mg to 1,000mg.
- Find the vitamin D per dose. 10 micrograms is the same as 400 IU.
- Add any other supplement that has calcium or vitamin D in it.
- Keep calcium from supplements to 1,500mg a day or less.
- Keep vitamin D to 100 micrograms (4,000 IU) a day at most. Some medical conditions mean you may not be able to safely take this much. If your doctor advises a different amount, follow their advice.
- Vegan? Check your D3 isn’t made from lamb’s wool.
Sources: ROS: calcium; ROS: vitamin D; NHS
Calcium can cause constipation, diarrhoea or feeling sick. If it does, ask a pharmacist or doctor about trying a different type.
Seen D3 sold with K2? Read vitamin D3 and K2 first.
Do calcium and vitamin D tablets prevent fractures?
A little, in older people. A Cochrane review, a big summary of trials, pooled 53 trials in 91,791 people. They were women after the menopause and men over 65.
Vitamin D alone, in the doses tested, was unlikely to prevent hip fractures. Vitamin D plus calcium slightly cut them. That’s the thing vitamin D alone didn’t do: fewer broken hips.
| Older adults living | Hip fractures per 1,000 a year | With vitamin D plus calcium |
|---|---|---|
| At home | About 8 | 1 fewer |
| In care homes and other institutions | About 54 | 9 fewer |
Source: Cochrane
There was no rise in deaths. There was a small rise in stomach symptoms and kidney disease.
Heard calcium tablets cause heart attacks? Some reviews found a link. The ROS says there’s not enough evidence to prove it.
Past the menopause, over 65, or caring for someone in a care home? Ask the GP whether both tablets are right.
Can I take calcium and vitamin D with other medicines?
Often, but timing matters. On a bone medicine called a bisphosphonate? Take calcium and vitamin D at a different time.
| Medicine | Why it matters |
|---|---|
| Alendronic acid | Wait at least 30 minutes after it before another medicine by mouth. |
| Digoxin, a heart medicine | You may get too much calcium in your blood, which may cause an abnormal heartbeat. |
| Some water tablets, such as bendroflumethiazide or indapamide | You may get too much calcium in your blood. |
| Epilepsy medicines, such as phenytoin or carbamazepine | You may need a larger dose of vitamin D. |
| Steroids, such as prednisolone | These may reduce the effect of vitamin D. |
Sources: NHS: alendronic acid; NHS: colecalciferol
Already prescribed vitamin D? Don’t add other calcium or vitamin D supplements without talking to your doctor.
Prescribed calcium? Take the number of tablets your doctor advises. Stopping when food doesn’t cover you can harm your bones, so tell your doctor if you stop.
Never stop or change a prescribed medicine without your prescriber.
When to speak to a GP
Get advice if:
- You have kidney stones, kidney disease, high blood calcium or a gut condition, or you’re at risk of heart disease. Cochrane says get medical advice first.
- You’re at risk of osteoporosis or take a bone medicine. Your doctor may advise more calcium and vitamin D.
- You need to pee more often, get swelling, or are sick, confused, or get bone or joint pain or an irregular heartbeat. Call your doctor or 111. Some could be signs of too much calcium.
- You get a high temperature and a sharp pain in your side or one side of your lower back. Call your doctor or 111. It could be the start of kidney stones.
- These can be signs of a serious allergic reaction. Call 999 if your lips, mouth, throat or tongue suddenly swell, or your throat feels tight or you struggle to swallow. Call too if you’re breathing very fast or struggling to breathe. The same goes if your skin, tongue or lips turn blue, grey or pale, or you suddenly feel very confused, drowsy or dizzy. Call if someone faints and can’t be woken, or a child is limp, floppy or not responding like normal.
You don’t normally need a blood test to check your vitamin D, says the ROS. Worried yours is low? See vitamin D deficiency and can you take too much vitamin D.