Calcium rich foods: a UK list

Which foods are rich in calcium?

Milk, yoghurt and cheese are the most familiar sources, and tinned sardines or pilchards eaten with their bones, curly kale and watercress, calcium-set tofu and fortified plant drinks also give useful amounts. The table uses McCance and Widdowson's Composition of Foods Integrated Dataset (CoFID), the UK's official food composition data, published by Public Health England in 2021. The per-100 g figures are CoFID's. Portion sizes come from the British Dietetic Association (BDA), and the per-portion figures are our own arithmetic, rounded to the nearest milligram.

A glass of milk, a pot of yoghurt and a glass of fortified soya drink each give about 240 mg, so any one of them covers about a third of an adult's day. Low-fat dairy has as much calcium as full-fat: CoFID gives 120 mg per 100 g for whole and semi-skimmed milk and 125 mg for skimmed.

White and brown bread have more calcium than wholemeal because UK law requires calcium carbonate to be added to wheat flour that isn't wholemeal. The sardine figure is for the whole contents of the tin, bones included, which is where the calcium is. CoFID's boiled kale value is higher than the BDA's (150 mg per 100 g), so read the kale figure as a range.

Does spinach count as a calcium food?

Not much, despite its number. CoFID lists 160 mg of calcium per 100 g of boiled spinach, but the NHS says the body can't digest all of it. The BDA explains that oxalates in spinach, and phytates in seeds, nuts and beans, reduce how much calcium you absorb, so sesame seeds and almonds shouldn't be your main sources either.

Tofu has no calcium value in CoFID. The BDA gives about 300 mg per 100 g for tofu set with calcium chloride or calcium sulphate, but not for tofu set with nigari, so check the label.

How much calcium do you need?

The NHS says adults need 700 mg of calcium a day and should be able to get all of it from a varied diet. The BDA lists 800 mg for girls and 1,000 mg for boys aged 11 to 18, and 1,200 mg for women after the menopause and men over 55. The Royal Osteoporosis Society says people at risk of osteoporosis, or taking an osteoporosis medicine, may be advised to aim for around 1,000 mg. If you have osteoporosis, ask your GP or a dietitian for your own target.

Most adults reach 700 mg. In the National Diet and Nutrition Survey for 2016 to 2019, average intakes were above the reference nutrient intake in every group except 11 to 18 year olds, and 9% of women aged 19 to 64 were below the lower reference nutrient intake, the level enough for only the few people with the lowest needs.

A dairy-free day can still reach about 700 mg: 200 ml of fortified soya drink (240 mg), 80 g of boiled kale (185 mg), two slices of white bread (128 mg), baked beans (63 mg) and a handful of almonds (81 mg).

Who might need calcium tablets?

Most adults in the UK don't need calcium supplements, because the NHS says a varied diet should provide the 700 mg a day. The Royal Osteoporosis Society says that if you can't get enough calcium from food, a supplement can top you up, and that calcium supplements are sometimes prescribed with vitamin D. If you're at risk of osteoporosis or take an osteoporosis medicine, a GP or dietitian can say how much of your target should come from a supplement. The BDA advises asking a pharmacist, doctor or dietitian first if you take medicines or think you need more than 500 mg of extra calcium. The upper amount to remember is 1,500 mg a day from supplements: the NHS says more could cause stomach pain and diarrhoea, and the Royal Osteoporosis Society adds kidney stones. Count every product, including antacids and multivitamins.

What are good vegan sources of calcium?

Fortified plant drinks, calcium-set tofu, green leafy vegetables such as kale and okra, and bread are the main vegan sources. The NHS lists unsweetened soya, pea and oat drinks with added calcium, tofu set with calcium, brown and white bread (UK law requires calcium to be added to flour that isn't wholemeal), sesame seeds and tahini, pulses and dried fruit. It names curly kale, okra, broccoli and cabbage among the greens and leaves out spinach, because the body can't absorb all of its calcium. The BDA gives 120 to 190 mg per 100 ml for fortified plant drinks and about 300 mg per 100 g for tofu set with calcium chloride or calcium sulphate, and warns that many organic plant drinks aren't fortified, so read the label. The dairy-free day above shows how these add up to about 700 mg.

Does oat milk have calcium?

Only if it's fortified. An oat drink made from oats and water contains little calcium. The BDA gives 120 to 190 mg per 100 ml for fortified plant drinks, which puts a 200 ml glass at 240 to 380 mg, level with or above cows' milk. CoFID has no oat drink entry, so that range is the BDA's. The NHS counts unsweetened calcium-fortified drinks made from soya, coconut or oats as dairy alternatives.

Labels vary. The BDA says many organic products are not fortified and contain little calcium. Check the ingredients for added calcium and the nutrition panel for a calcium figure per 100 ml. A 2007 review in Nutrition in Clinical Practice also noted that absorption from fortified drinks varies and in general isn't equal to that of milk.

What are the symptoms of calcium deficiency?

Calcium deficiency can mean two different things, and neither is easy to spot from symptoms.

The first is eating too little calcium over years. It usually causes nothing you'd notice, because bone holds a large reserve that the body draws on to keep blood calcium steady, as the Linus Pauling Institute at Oregon State University explains. The cost shows later in the bones: the NHS says a lack of calcium could lead to rickets in children, and osteomalacia or osteoporosis in later life.

The second is low calcium in the blood (hypocalcaemia), which is a medical problem. A hospital laboratory guideline from the York and Scarborough NHS trust says mild to moderate low calcium is usually without symptoms. Severe low calcium can cause tingling around the mouth, fingers and toes, muscle twitching and spasm, seizures and changes in heart rhythm. Call 999 if someone has a seizure for the first time or one lasting more than 5 minutes.

Those symptoms have many other causes, so they can't tell you that your calcium is low. The Royal Osteoporosis Society also points out that a calcium blood test doesn't show whether you're getting enough from your diet.

What is the most common cause of low calcium?

There isn't one answer, and diet is rarely it. A 2010 review in Therapeutic Advances in Endocrinology and Metabolism says the most common cause of low blood calcium in the general population is vitamin D deficiency, while the cause most often met in acute cases is underactive parathyroid glands after neck surgery. The York and Scarborough guideline also lists low magnesium, kidney disease and medicines such as bisphosphonates, glucocorticoids and anticonvulsants. It puts low dietary intake and poor absorption under other causes, usually alongside other deficiencies.

A low total calcium can also just reflect a low level of albumin, the protein that carries calcium, which is why laboratories report an adjusted figure.

Is calcium carbonate bad for you?

No. At normal doses it's one of the two standard forms of calcium supplement, and the Royal Osteoporosis Society says carbonate and citrate are both good for your bones. According to Straub's 2007 review and the Linus Pauling Institute, carbonate is usually the cheaper and is best taken with a meal, while citrate can be taken at any time and is preferred if you take a medicine that reduces stomach acid, such as a proton pump inhibitor.

The usual complaints are digestive. The Royal Osteoporosis Society says calcium supplements can cause constipation, diarrhoea or nausea, and suggests asking a healthcare professional about a different form if they do. The prescribing information for a calcium carbonate chewable tablet lists constipation, indigestion, wind, nausea, stomach pain and diarrhoea as rare side effects.

On heart risk, the BDA says the Department of Health reviewed the question and didn't change its advice, and the Royal Osteoporosis Society says there isn't enough evidence to prove a link. A 2016 systematic review in Annals of Internal Medicine found no statistically significant difference in cardiovascular events between calcium supplements and placebo in trials, though heart outcomes were secondary end points.

With supplements, too much is the main risk. The NHS says more than 1,500 mg a day could cause stomach pain and diarrhoea, and that 1,500 mg or less a day is unlikely to cause harm. The Royal Osteoporosis Society adds kidney stones. Count every product, because multivitamins, antacids and electrolyte drinks can contain calcium too.

Who should check before taking calcium supplements?

Ask a pharmacist or GP first if any of these apply:

• You've had kidney stones. The prescribing information for a calcium carbonate tablet lists them as a contraindication and urges caution if you've ever had them. That's about supplements: the Linus Pauling Institute notes that lower calcium from food has been linked with more stones.
• You take levothyroxine. The NHS says calcium and iron supplements may not mix well with it, and the calcium tablet's prescribing information says to separate them by at least 4 hours.
• You take iron. Calcium reduces iron absorption, and the same prescribing information says to take iron 2 hours before or after calcium carbonate. Our guide to supplements you can take together covers the spacing for other medicines, including some antibiotics and bisphosphonates.
• You think you need more than 500 mg of extra calcium. The BDA advises talking to a pharmacist, doctor or dietitian first, as some supplements are not easy to absorb. Straub's review and the Linus Pauling Institute suggest no more than 500 mg at one time.

Should you take calcium and vitamin D tablets together?

Vitamin D helps your body use calcium, which is why the two are often sold together, but whether a combination tablet suits you depends on your age and bone health. In Great Britain vitamin D can be said to contribute to normal absorption and utilisation of calcium and phosphorus, and the NHS says 10 micrograms a day is enough for most people. The Royal Osteoporosis Society says calcium supplements are sometimes prescribed with vitamin D.

Research on fractures is mixed. A 2019 meta-analysis of 6 trials (49,282 people) using 400 to 800 IU (10 to 20 µg) of vitamin D with 1,000 to 1,200 mg of calcium found 6% fewer fractures of any type than without them. A 2017 meta-analysis of 33 trials in 51,145 community-dwelling adults over 50 found no significant effect on hip fracture and concluded that routine use wasn't supported. Ask your GP or pharmacist before starting a combination tablet. Our guide to vitamin D in a UK winter covers who needs vitamin D.

Where Natura fits

Natura's Daily Calcium (coming soon) is one tablet giving 700 mg of calcium as citrate and carbonate, listed with the daily bottles; calcium is needed for the maintenance of normal bones and teeth. The same 700 mg appears as Daily Men Calcium in the Men's Daily Pack and as Daily Calcium in the Core Pack. Don't combine them: two 700 mg tablets make 1,400 mg from supplements, close to the NHS 1,500 mg figure before counting the 50 mg of calcium in each Daily Electrolytes sachet. The Core Pack also contains Daily Iron (14 mg), so take the iron and calcium at least 2 hours apart. Because the tablet is 700 mg, the BDA's advice to talk to a pharmacist about more than 500 mg of extra calcium applies.