Which foods are high in calcium, and how much is in each?

Foods high in calcium include sesame seeds, tofu set with calcium sulfate, small fish and canned fish eaten with the bones, dark leafy greens such as amaranth leaves, Chinese kale and mustard greens, and milk and yoghurt. Per 100 g, whole sesame seeds have 975 mg of calcium and firm tofu made with calcium sulfate 683 mg, while whole milk has 113 mg. The Thai Reference Daily Intake (Thai RDI) for calcium is 1,000 mg a day, and Thai studies have measured everyday intakes of roughly 130 to 380 mg.

In short:

• Highest per 100 g: sesame seeds, calcium-set tofu, canned sardines with bones, soybeans, kale, canned fish
• Highest per usual serving (in the table below): yoghurt, canned sardines with bones, milk, calcium-fortified soy milk, calcium-set tofu
• Thai vegetables measured in studies: ivy gourd leaves, young winged bean pods and cassia leaves
• Daily amount: Thai RDI 1,000 mg

This article is a table-based guide to how much calcium is in foods. For what calcium does in the body, see What is calcium, and how much do you need?, and for meal ideas without milk, see Don't like milk? How can you get enough calcium from food?

Which foods are high in calcium?

The NIH Office of Dietary Supplements (ODS), part of the US National Institutes of Health, says milk, yoghurt and cheese are rich natural sources of calcium, and that non-dairy sources include canned sardines and salmon with bones and vegetables such as kale, broccoli and Chinese cabbage. The UK's NHS adds fish where you eat the bones, green leafy vegetables such as curly kale and okra, and soya drinks with added calcium. Calcium is needed for the maintenance of normal bones and teeth.

Calcium per 100 g of food

The figures below come from the US Department of Agriculture's FoodData Central database (SR Legacy), per 100 g of the food as described. Thai varieties and recipes may give somewhat different amounts.

Seeds and dried beans are listed dry, and the sesame figure is for whole seeds. They are eaten in much smaller amounts than vegetables or milk, so the next section looks at usual servings.

Why does the type of tofu matter?

Tofu is made by setting soy milk with a salt, and the salt used changes the calcium. In the table, firm tofu made with calcium sulfate has 683 mg per 100 g, more than three times the 201 mg in firm tofu made with calcium sulfate and magnesium chloride (nigari). Soy milk itself, without added calcium, has 25 mg per 100 g. The ODS says tofu made with calcium salts is a good source of calcium.

Fish eaten with the bones

Canned fish eaten with the bones has much more calcium than shellfish eaten without the shell. Canned sardines with the bones have 382 mg per 100 g in the table, while raw shrimp, eaten without the shell, has 64 mg. The NHS lists fish where you eat the bones, such as sardines and pilchards, as a source of calcium.

How much calcium is in a usual serving?

Per 100 g figures are useful for comparing foods, but people eat a spoonful of sesame and a whole glass of milk. The ODS table lists calcium per typical serving, based on FoodData Central. The last column compares each serving with the Thai RDI of 1,000 mg.

Calcium per serving

Source: ODS calcium fact sheet, Table 2 (US servings). The share of 1,000 mg is our comparison with the Thai RDI.

Why do raw and cooked figures differ?

The same vegetable can look very different in the two tables. One cup of raw chopped kale has 24 mg of calcium, while one cup of cooked kale has 94 mg, because cooked leaves shrink and more of them fit in a cup. Dried beans work the other way: in FoodData Central, 100 g of raw dried soybeans has 277 mg, and 100 g of boiled soybeans 102 mg, because boiling adds water. When you compare foods, check whether the figure is for raw or cooked food and for 100 g or a serving.

Which Thai vegetables provide calcium, and how much does the body take in?

Two studies from the Institute of Nutrition, Mahidol University, measured the share of calcium absorbed from vegetables that Thai people eat often, with milk alongside for comparison. For context, the ODS says about 30% of the calcium in dairy products and fortified foods is absorbed, and that some plants contain oxalic acid and phytic acid, which bind calcium.

Ivy gourd leaves and young winged bean pods

A 2008 study from the Institute of Nutrition, Mahidol University, gave 19 healthy women aged 20 to 45 test breakfasts of rice with ivy gourd leaves (tamlueng), young winged bean pods (thua phu) or milk, each providing about 100 mg of calcium labelled with a stable isotope. The share of calcium absorbed was 47.6% from ivy gourd, 39.1% from winged beans and 55.2% from milk. The researchers say the difference was partly due to the phytate, oxalate and fibre in the vegetables, and that the two vegetables still gave 71% to 86% of the value for milk. The study measured single meals in a small group of women.

Cassia leaves (khi lek)

A 2015 study from the same institute and Cornell University measured calcium absorption from cassia leaves and from milk in 19 Thai women aged 52 to 63 whose usual calcium intake was low (350 ± 207 mg a day). The share absorbed was 42.6% from cassia and 47.8% from milk. Like the first study, it was small and measured test meals.

Spinach is a different case

Spinach contains a lot of calcium, but it is high in oxalic acid. The ODS says the body absorbs only about 5% of the calcium in spinach, compared with 27% from milk, and the NHS likewise says the body cannot digest all of it. The ODS adds that vegetables without these compounds, such as broccoli, kale and cabbage, give calcium that is absorbed about as well as milk, although they contain less per serving.

How much calcium do Thai meals provide?

Several Thai studies have measured calcium intake directly. They used different methods and groups, so the figures are best read side by side rather than as one national number.

Adults in rural northeastern Thailand

A 2008 study from Khon Kaen University recruited 436 healthy adults aged 20 to 85 (181 men and 255 women) and used 3-day food records and a food frequency questionnaire. Average calcium intake was 378.6 mg a day in men and 265.6 mg in women. The main sources were glutinous rice (32% of calcium intake), small animals eaten with their bones (31%) and fresh and fermented fish (20%), while dairy products gave 8% and vegetables 5%.

Schoolchildren in Ubon Ratchathani

A 2006 study led by the University of Otago with Thai researchers collected a duplicate of everything 40 children aged 6 to 13 ate in one day, and analysed it in the laboratory. The median calcium content was 130 mg a day. The researchers also found that the phytate in these glutinous rice-based diets was below the detection limit, which they partly attribute to soaking the rice overnight before cooking.

Ready-cooked dishes in southern Thailand

A 2007 study from Prince of Songkla University bought four samples each of 14 ready-cooked dishes from shops in Hat Yai and analysed them. Ark shell curry stood out for calcium, at 0.23 g (230 mg) per 100 g of the edible part. The author notes that the main ingredients and the cooking process determined each dish's nutrient values, and that values calculated from single-ingredient tables differed considerably from values calculated using the dishes analysed in the study.

The limits are important. Each study covered one area or a small group, and food records rely on what people report. None of them describes the whole country today. Every figure is below the Thai RDI of 1,000 mg.

How much calcium do you need a day, and how much is too much?

The Thai RDI for calcium is 1,000 mg a day, for the general population aged 3 and over. It counts calcium from all foods. For the Thai reference amounts of other nutrients, see What are the Thai daily reference amounts for each nutrient?

Upper limits

The ODS says the share of calcium absorbed from food is lower when daily intake is higher. The NHS says people should be able to get all the calcium they need from a varied and balanced diet.

Who should talk to a doctor or pharmacist?

People who take regular medication

Calcium can interact with some medicines, and some medicines can affect the body's calcium. If you take medication regularly, ask a doctor or pharmacist before adding calcium.

Pregnant and breastfeeding women

If you are pregnant or breastfeeding, talk to a doctor or pharmacist before taking any dietary supplement, including calcium.

Dietary supplements are not intended to prevent, treat or cure any disease.