Dietary calcium: why it’s important and which foods contain it

Calcium is vital for healthy teeth and bones – everyone knows that! 😉 However, in this article, we’ll learn that this mineral benefits your body in many other ways. And we’ll also reveal how much you need to live a healthy life, and how to make sure you’re getting enough of it.

The number one mineral by…

abundance! Of all the minerals in our bodies, calcium is the most abundant, amounting to about one kilogram. As much as 99% of it is contained in the skeleton and teeth, while the rest is in the blood, muscles, and other tissues. But calcium is not only an important building block of teeth and bones – it’s also vital for muscle function, heart and vascular health, communication between the brain and other parts of the body, and much more.

It should be noted that calcium is supplied to the body through food, and that it requires vitamin D to be absorbed. Between 20% and 40% of all the calcium we consume actually gets absorbed by our bodies.

Why is dietary calcium so important?

Calcium is essential for the growth, health and repair of bones. That’s why it plays a key role in early childhood and puberty, when the skeleton is developing fastest and the body is growing. This is when bone mass increases the most, so sufficient intake of this mineral is crucial.

A sufficient intake of calcium is also important in older adults, when bone density starts to decrease, increasing the risk of fractures. This risk is highest in post-menopausal women, as the drop in oestrogen levels speeds up the rate of bone breakdown and slows down calcium absorption. In turn, this can lead to osteoporosis – a disease of the bone tissue which leaves bones fragile and brittle.

But as we’ve already pointed out, calcium is not only linked to bones. Let’s find out what other benefits it has for us!

Muscle function

While magnesium is in charge of relaxing muscles, calcium plays the opposite role – it regulates their contraction. When nerves stimulate a muscle, calcium binds to proteins in that muscle, which causes it to contract. When the calcium is drawn back into intracellular stores, the muscle relaxes again.

Cardiovascular health

Calcium supports normal heart function and coagulation of the blood, and is also thought to help lower blood pressure.

A beautiful, healthy smile

Calcium helps our teeth and jawbones stay in their place. This is because calcium, together with phosphorus, keeps teeth strong. It also forms part of the tooth enamel, which protects teeth from bacteria and tartar. Excess tartar causes tooth decay and can lead to diseases such as periodontitis.

For digestive problems

An interesting fact for those interested in biology and chemistry: calcium is not found in nature in its pure form, as it’s a highly reactive metal and always forms compounds with other elements. One such compound is calcium carbonate, which is also a component of antacids – a class of drugs that reduce the acidity of gastric juice. This helps relieve heartburn and other digestive problems.

The National Portal on Food and Nutrition (Prehrana.si) states that calcium helps the normal release of energy required for a healthy metabolism and the functioning of digestive enzymes.

Transmission of nerve signals

What do experts have in mind when they talk about the importance of calcium for neurotransmission? To put it in simple terms: the mineral helps transmit signals from the brain through the nervous system to other parts of the body.

How much calcium do we need each day?

The recommended daily calcium intake depends on your age and sex. Most expert sources recommend a minimum of between 800 and 1,000 mg of calcium per day for adults. Since the body can absorb about 500 mg of this mineral at a time, it’s a good idea to space your calcium intake throughout the day. The maximum recommended daily intake is no more than 2,000 mg.

But how to put these recommendations into a menu? The Slovenian National Portal on Food and Nutrition, and the German Institute for Quality and Efficiency in Health Care (IQWiG) provide some examples. To achieve a daily calcium intake of around 1,000 mg, consider one of the following options.

Calcium intake suggestion 1:

• 250 g of plain liquid yoghurt,
• 1 egg,
• 150 g of cooked spinach, and
• 30 g of cheese.

Calcium intake suggestion 2:

• 2 slices of rye or wholegrain bread,
• 2 slices of cheese,
• 150 g of broccoli,
• 200 ml of mineral water, and
• 200 g of yoghurt.

Calcium intake suggestion 3:

• 200 ml of milk,
• 2 slices of rye or wholegrain bread,
• 2 slices of cheese, and
• 150 g of cooked spinach.

Recommended daily calcium intake

To ensure that we meet our daily calcium requirements, we should also remember to include the vitamin that is essential for calcium absorption – vitamin D. We can get vitamin D from exposure to sunlight, an appropriate diet, or supplements. Research shows that only about 20% of this vitamin is obtained from food, which means that we need sunlight to get the rest. In summer, about half an hour’s walk (with exposed, unprotected skin) is enough to meet your daily vitamin D needs, but in winter most people don’t get enough, so it’s worth considering taking a good-quality supplement.

You can read more about vitamin D and other vitamins in the article The Best Vitamins for a Strong Immune System. But let’s focus on calcium and consult an even more detailed table that summarises the most common guidelines for recommended calcium intakes by sex and age. These take into account the recommendations of the Slovenian National Food and Nutrition Portal, as well as those of the US National Institutes of Health, the German Nutrition Society, and Harvard University.

Who needs to pay special attention to getting enough calcium?

We already mentioned the role of calcium in puberty. During this stage of growth, as much as 90% of a person’s maximum bone density develops. After the age of 20, skeletal development is completed, and after the age of 40, bone density begins to decline. As such, getting enough calcium is also very important from this age on, because the body starts to draw it from the bones if it’s not supplied with enough for normal functioning.

Furthermore, calcium absorption decreases with age, increasing the risk of bone fractures. Post-menopausal women are particularly at risk. In addition to calcium and vitamin D intake, regular exercise is also very important in slowing the decline in bone density. Experts recommend taking calcium before bedtime, as this slows down the breakdown of bone overnight.

Pregnant and lactating women should also ensure that they are getting enough calcium in their diet. Experts have found that not only does the need for calcium increase during pregnancy, but also the body’s ability to obtain more of the mineral from one’s diet. So while there’s no need for a huge increase in intake, expectant and new mothers should still make sure they consume enough of it.

You should also make sure you have an adequate intake of calcium if:

• you’re menopausal,
• you have irregular periods due to anorexia or stress,
• you don’t consume dairy products (e.g. due to lactose intolerance),
• you eat a vegan diet,
• you consume large amounts of magnesium,
• you have been using laxatives for a longer period of time,
• you’re undergoing chemotherapy,
• you’re taking corticosteroids,
• you have parathyroid or hormone problems,
• you suffer from digestive diseases (coeliac disease, Crohn’s disease, irritable bowel syndrome, etc.),
• your kidneys or pancreas are not working properly,
• you’re vitamin D deficient,
• you receive frequent blood transfusions,
• you eat a lot of protein or salt,
• you drink a lot of coffee, sugary drinks or alcohol.

Also remember that the body excretes calcium in sweat, urine, and faeces. If you sweat more or urinate frequently, your body’s calcium levels may be slightly lower.

Adequate calcium intake:

• enables children to grow and develop normally,
• lowers the risk of high blood pressure during pregnancy or young age,
• lowers cholesterol levels,
• helps prevent the development of adenomas (benign intestinal tumours),
• lowers the risk of pre-eclampsia (a complication of pregnancy characterised by high blood pressure and protein in the urine), and
• relieves symptoms of premenstrual syndrome (PMS).

What happens if we don’t get enough calcium?

Calcium is one of the few nutrients that we don’t get enough of, even in the developed countries. This is especially true for pre-school children (girls in particular) and the elderly. We refer to calcium deficiency when the level of calcium in the blood drops below 8.5 mg per decilitre – a condition also called hypocalcaemia.

When calcium levels are too low, the parathyroid hormone is triggered into action. This hormone signals to the bones to lend some calcium to the rest of the body, and so release it into the blood. It can also activate vitamin D to accelerate the absorption of calcium into the intestines and send a message to the kidneys to release less of this important mineral into the urine.

When calcium levels increase sufficiently, the hormone calcitonin, which has the exact reverse function, comes into play. It stops calcium from being released from the bones and speeds up its removal through the urine. The calcium that the bones have given to blood can be replaced, but unfortunately this doesn’t always happen – even if you consume extra calcium later on!

In children and adolescents, calcium deficiency slows down bone growth and mineralisation, while in adults it leads to loss of bone density or osteopenia, which can progress to osteoporosis. People with calcium deficiency are also at higher risk of high blood pressure and bowel cancer.

While a mild calcium deficiency is rarely felt, a serious deficiency can be life-threatening. Its common symptoms include:

• muscle twitching or cramps,
• disturbances in heart rhythm,
• lack of appetite,
• confusion or even hallucinations,
• depression,
• brittle nails,
• problems with teeth,
• tingling sensations in the legs and arms,
• more severe PMS in women.

Calcium deficiency is usually treated mainly by adjusting the diet – by introducing suitable foods rich in calcium. In some cases, people also use supplements, which should be discussed with a doctor or pharmacist.

What happens if we have too much calcium?

Yes, there can be too much of a good thing, so it’s important to strike a healthy balance when it comes to nutrient intake. Excessive calcium levels can have negative effects such as flatulence, bloating or constipation. Too much calcium can also increase the risk of developing kidney stones and prostate cancer. Calcium can start to build up in the arteries, which is called hypercalcaemia. Some of its symptoms include:

• nausea,
• lack of energy,
• shortness of breath and chest pain, and even
• heart problems.

Recently, there has been a growing suspicion among health professionals that calcium supplements may increase the risk of heart disease. Not everyone agrees with this, and more research is needed on the effects of such supplements on the heart and blood vessels.

Calcium can also interfere with the absorption of other minerals, such as iron and zinc.

How to get enough calcium?

Our bodies can get calcium from food or supplements. The easiest way to obtain it – as you’ve probably guessed by now – is through a healthy, balanced diet. While milk, cheese and yoghurt are the main sources of calcium, they’re not the only ones. If you cannot or prefer not to consume dairy products, you can substitute them with plant-based alternatives (soya milk, oat milk, rice milk, almond milk, etc.). Many of these have added calcium, so even those who avoid milk can get enough of this important mineral.

Calcium can also be found in many plant foods, such as:

• cereals,
• curly kale,
• cabbage,
• broccoli,
• soya (and soya milk and tofu),
• beans,
• dried figs (as well as plums and dates),
• spinach,
• chard,
• watercress,
• turnip leaves,
• eggs,
• nuts and seeds (especially chia and sesame seeds and almonds).

Carnivores may be disappointed to learn that meat is not a major source of calcium. The same applies to fish, but with one important exception: fish that can be eaten with their bones (such as sardines) can contain higher amounts of this mineral. But only if you eat the bones too!

What about drinks? One answer can be found in the sparkling bubbles of natural mineral waters such as Donat. Its incredible mineral wealth includes calcium, in addition to magnesium, hydrogen carbonates, and sulphates. This combination is clinically proven to help improve digestion, as well as relieve conditions ranging from heartburn to headaches.

In Europe, most of our calcium needs are still covered by milk and other dairy products. These also have the highest absorption rate, between 50 and 75%, although this also depends on the amount of vitamin D. If we consume a large amount of dairy products, nutritionists advise us to choose those with a lower fat content. The absorption of calcium from good quality food supplements is comparable to that from dairy products.

And another tip, which we’ve already highlighted, but is worth repeating: it’s more effective to introduce calcium into your body a little at a time. If you take in too much at once, the body will not be able to absorb it all.

Calcium in food: table of calcium levels

To help you plan your menu, we’ve included a table with the calcium contents of some of your favourite foods.

And last but not least: some simple ideas to get more calcium in your diet

Breakfast/brunch:

• Drink a glass of milk, yoghurt or kefir with breakfast.
• Mix yoghurt, cottage cheese or ricotta with fruit.
• Add feta cheese or parmesan to salads.
• Add cottage cheese or chopped nuts to apple strudel.
• Add a slice of cheese to the omelette.

Lunch:

• Make a delicious spinach and cheese pie like a quiche.
• Add spinach, beans or chickpeas and broccoli to your salads. Edamame (immature soya beans) are also excellent.
• Dress pasta with a sauce of sautéed spinach, ricotta and a little Parmesan cheese.

Dinner:

Make a cottage cheese-based spread with sardines, tuna or a little pumpkin seed oil.

Sources:

1. Cormick, Gabriela, and Jose M Belizán. “Calcium Intake and Health.” Nutrients vol. 11,7 1606. 15. jul. 2019, doi:10.3390/nu11071606.
2. Harvard T.H. Chan School of Public Health. “Calcium.” The Nutrition Source, Harvard University, www.nutritionsource.hsph.harvard.edu/calcium/. Dostopano 20. mar. 2025.
3. MedlinePlus. “Calcium.” MedlinePlus, U.S. National Library of Medicine, 14. maj 2024, medlineplus.gov/calcium.html. Dostopano 20. mar. 2025.
4. Morales-Brown, P. “Calcium-rich foods” Medical News Today, 27. jun. 2023, www.medicalnewstoday.com/articles/248958#dietary-sources. Dostopano 20. mar. 2025.
5. National Institutes of Health (NIH), Office of Dietary Supplements. Calcium – Consumer. NIH, www.ods.od.nih.gov/factsheets/Calcium-Consumer/. Dostopano 20. mar. 2025.
6. National Institutes of Health (NIH), Office of Dietary Supplements. Calcium – Health Professional. NIH, www.ods.od.nih.gov/factsheets/Calcium-HealthProfessional/. Dostopano 20. mar. 2025.
7. The Royal Osteoporosis Society. “Calcium-Rich Food Chooser.” The Royal Osteoporosis Society, www.theros.org.uk/information-and-support/bone-health/nutrition-for-bones/calcium/calcium-rich-food-chooser/. Dostopano 20. mar. 2025.
8. University of California, San Francisco. “Calcium Content of Selected Foods.” UCSF Health, www.ucsfhealth.org/education/calcium_content_of_selected_foods/. Dostopano 20. mar. 2025.