Calcium

More than 99% of the calcium in the human body is bound up in the bones and teeth¹. Calcium is an important building block for the skeleton, but it also plays a role in many other bodily functions, such as the regulation of several enzyme reactions, the functioning of the nervous system, as well as muscle contractions. The amounts of calcium required for bodily functions are small, but sufficient blood calcium levels are nevertheless required for the body to function properly². This is why calcium levels in the blood are precisely regulated, and calcium stored in the bones can be released into the bloodstream when needed. Measuring calcium levels with a blood test does not therefore give accurate information about calcium intake or skeletal health. If you suspect your calcium intake may be insufficient or you are concerned about your skeletal health, you should see a doctor or dietitian. A food diary can be used to determine whether your calcium intake is in line with recommendations. Fineli’s food diary function is one good tool for this. 

Calcium from plants – adequate calcium intake on a vegan diet 

The vegan diet includes many sources of calcium. According to studies, however, vegans who do not use calcium-fortified food products often get less calcium from their diet than omnivores, which underlines the importance of keeping an eye on sufficient calcium intake when following a vegan diet.^{3, 4} A study examining the calcium intake of Finnish vegans found that their average daily intake was 1004 mg ⁵. 

The best plant-based sources of calcium include fortified plant milks, yogurts and quarks, as well as sesame seeds (especially as a paste), tofu, white beans, soy, almonds, vegetables of the Brassica family, and dark-green leafy vegetables.^{6, 7} Calcium can therefore be obtained from many different sources, and adequate intake could be reached in different ways. Nevertheless, using fortified food products is recommended as it is the easiest way of meeting nutritional recommendations.^{8, 9} When planning your diet with calcium intake in mind, it is important to note that organic plant milks are not fortified with calcium. In addition, some plant milk-based snack products, for example, may not always be fortified regardless of whether they are organic or not. You should therefore always check the calcium content of products from the packaging. 

Around 20% to 45% of consumed calcium is absorbed by the body¹⁰. The bioavailability of calcium varies between different plant-based products. Some compounds found in plants, such as phytates and oxalic acid, impact absorption. Spinach, for instance, contains high amounts of oxalic acid, which binds to calcium and impairs absorption. Contrastingly, calcium is absorbed very effectively from foods such as broccoli, kale, and soy milk¹. 

Table 1. Recommended intake of calcium for different age groups⁸ 

Age	Recommended daily intake, mg
≤ 6 m	120
7-11 m	310*
1-3 y	450
4-10 y	800
11-17 y	1150
18-24 y	1000
≥25 y	950
Pregnant people	950
Breastfeeding people	950

*Sufficient intake, based on exclusively breastfed infants between the ages of 0 and 6 months. 

So how can you make sure you are getting the recommended amount of calcium from your diet? Below is a table outlining good sources of calcium, as well as two different examples for ensuring adequate calcium intake. Both examples contain approximately 950 mg of calcium, which is the recommended daily intake for adults. 

Table 2. Plant-based sources of calcium, with calcium content per 100 grams and per portion⁶ 

Source of calcium	mg per 100 g	Typical portion size	mg per portion
Sesame seeds, unhulled	960	1 tablespoon	82
Tofu, firm	683	100 g	683
Tahini (sesame seed paste)	680	1 tablespoon	102
Chia seeds	624	1 tablespoon	62
Nettles	430	20 g	86
Almonds	276	1 tablespoon	28
Falafel (chickpea balls), fried	246	150 g	369
Textured soy protein, dry	244	1 deciliter (35 g)	85
Kale	240	50 g	120
Flax seeds, whole or ground	234	1 tablespoon	23
Figs, dried	162	20 g	32
Fortified plant milk (soy, oat, almond, etc.)	120	2 deciliters	240
Fortified oat or soy yogurt	120	2 deciliters	240
Tempeh	111	50 g	56
Spinach	89	50 g	45
White beans, cooked	82	1 deciliter (70 g)	57
Soybeans, cooked	75	1 deciliter (75 g)	57
Blackcurrants	72	1 deciliter (50 g)	36
Orange, peeled	54	215 g	116
Broccoli	30	1 deciliter (55 g)	17

The following two tables show examples of how to easily reach the recommended daily calcium intake⁶: 

Food product	Amount	Calcium content, mg
Plant milk**, fortified with calcium*	2 deciliters	240
Soy or oat yogurt or soy quark, fortified with calcium*	2 deciliters	240
Blackcurrants	1 deciliter	36
Almonds	3 tablespoons	83
Chia seeds	1 tablespoon	62
Orange, peeled	one medium fruit, 215 g	116
Kale, cooked	60 g	101
Tempeh	80 g	89
Total calcium		967 mg

The table includes only good vegan sources of calcium. A day of eating should include considerably more food. 

*Check from the packaging that calcium has been added to the product 

**Made from e.g. soy, oats, rice or almonds 

Food product	Amount	Calcium content, mg
White beans, cooked	100 g	82
Tahini, dark (sesame seed paste)	1 tablespoon	102
Tofu, firm	100 g	683
Sesame seeds	1 tablespoon	82
Broccoli, cooked	80 g	24
Total calcium		973 mg

The table includes only good vegan sources of calcium. A day of eating should include considerably more food. 

You can find out more about the calcium contents of different foods from the Fineli database. 

It is recommended that vegans who do not consume fortified food products use a regular calcium supplement to secure adequate intake⁷. 500 mg per day is usually sufficient for vegans. Calcium supplements should be taken with a meal, as eating increases secretion of lactic acid and thereby enhances calcium absorption¹. 

Good bone health depends on more than just calcium 

Calcium is known for its significant effects on skeletal health, but it is important to remember that there are many other factors that affect bone health, too¹. Vitamin D plays an important role in calcium absorption and bone mineralization¹¹. In addition to calcium and vitamin D, nutrients that affect bone health include protein, phosphorous, magnesium, zinc, copper, manganese, vitamin C, vitamin B12, vitamin K, and potassium. Most of these nutrients are abundant in a well-planned and varied vegan diet, but sufficient intake of calcium, vitamin D, vitamin B12 and protein should be paid close attention to. You can find more information about these nutrients by clicking on the links above. 

Good bone health is the sum of many factors, and nutrition is not the only contributor. Genetics influence peak bone mass in several ways¹. Physical exercise that strengthens the skeleton also plays a large role. Heavy intake of salt and caffeine should be avoided as it increases secretion of calcium into the urine and can thus impair bone health.^{1, 12, 13}