Calcium: Function and Daily Requirement

Why does the body need calcium, and how high is the daily requirement? The mineral is crucial for strong bones and teeth, muscle function and blood clotting — here is an overview.

Calcium is an essential nutrient that is crucial for maintaining strong bones and teeth, as well as for enabling proper blood clotting. Since the body cannot produce calcium itself, it must be ingested in sufficient quantities with food. Long-term calcium deficiency can significantly impair the stability of bones and teeth and increase the risk of osteoporosis and dental caries. In some situations, it may be useful to take an additional calcium supplement.

Calcium at a glance

• Calcium is an essential mineral, of which the human body can store up to two kilograms.
• According to the reference values of the DGE, adults have a calcium requirement of 1,000 mg per day.
• Milk and dairy products as well as green leafy vegetables and nuts are suitable as calcium suppliers.
• Calcium deficiency can be caused by diet or a health problem.
• An excess of calcium can lead to digestive disorders as well as the formation of kidney stones or kidney calcification.

What is calcium?

Calcium is a vital mineral. In terms of quantity, it is the most important mineral in the organism. Depending on body size and gender, there are between one and two kilograms of it in a person’s body. Most of it is stored in the bones.

Why is calcium important in the body?

Calcium is primarily known for its essential role in the mineralization of bones and teeth. However, the mineral also serves several other important functions.

Calcium also plays an essential role for:

• normal signal transmission between nerve cells,
• a normal energy metabolism,
• normal blood clotting and
• normal muscle function.

How high is the calcium requirement?

The body cannot produce calcium itself. That’s why you have to consume it regularly through your diet. How high the daily requirement is depends on age.

• According to the DGE (German Nutrition Society), adults aged 19 and older need 1,000 milligrams of calcium per day.
• Unlike with many other nutrients, women’s calcium requirements do not increase during pregnancy or breastfeeding.
• Infants and children up to the age of 10 have a daily requirement of 220 to 900 milligrams, depending on their age.
• Children aged 10 to 13 and adolescents aged 14 to 18 have a particularly high calcium requirement of 1,100 and 1,200 milligrams, respectively, due to growth.

What foods are rich in calcium?

Calcium is found in numerous foods. Good sources of calcium are primarily milk and dairy products. In addition, the mineral is found in plant-based foods such as nuts and green leafy vegetables. Although the body can absorb calcium from animal sources more efficiently, a purely plant-based diet can also meet the daily requirement, provided it is well-balanced.

Which foods contain the most calcium?

Cheese is one of the foods richest in calcium. Some varieties such as Emmental and Parmesan have a content of over 1,000 milligrams of calcium per 100 grams. In comparison, calcium-rich plant foods like soybeans and kale contain about 200 milligrams — not even one fifth of the amount found in cheese.

Foods containing calcium (mg per 100 g)

Is mineral water a good source of calcium?

Mineral water can also help to meet calcium requirements. However, the content varies greatly depending on the variety. If mineral water contains more than 150 milligrams per liter, it can be described as calcium-rich.

How does a calcium deficiency develop?

Permanently insufficient calcium intake can lead to a deficiency, which is medically referred to as hypocalcemia. According to the National Consumption Study II from Germany, female adolescents between the ages of 14 and 18 are particularly affected. In this group of people, 74 percent do not succeed in meeting their daily needs. Among older men and women, the figures are 61% and 65%, respectively.

Other causes of a deficiency

In addition to an insufficient intake, a calcium deficiency can also be caused by other factors that significantly impair the absorption of nutrients in the intestine. These include:

• Chronic intestinal diseases such as Crohn’s disease can lead to a deficiency by impairing nutrient absorption in the intestine.
• Taking diuretic medication causes the body to excrete more calcium in the urine.
• Since vitamin D is required for calcium absorption, a vitamin D deficiency can promote a lack of calcium.

What are the consequences of a persistent calcium deficiency?

The body works to maintain a constant calcium level in the blood. Therefore, it releases calcium from the bones if there is no adequate supply in the diet. In the long term, this damages tooth and bone stability. This increases the risk of diseases such as tooth decay and osteoporosis. If the deficiency already exists in childhood, it may lead to growth disorders and rickets.

How does a calcium surplus develop?

Hypercalcemia — an excessive concentration of calcium in the blood — usually results from excessive intake of dietary supplements containing calcium or vitamin D. If calcium intake is limited to dietary sources, harmful excess is virtually impossible.

What are the consequences of an excess of calcium?

Just like a deficiency, an excess can also cause various symptoms and seriously harm your health in the long term.

The possible consequences of an elevated calcium level include:

• problems with digestion,
• calcified kidneys and kidney stones and
• coronary artery disease.

How can calcium excess be avoided?

To prevent an oversupply of calcium, you should follow the recommendations for the maximum daily dose.

• According to the European Food Safety Authority (EFSA), a daily intake of up to 2,500 milligrams of calcium is considered safe for healthy adults.
• The German Federal Institute for Risk Assessment (BfR) recommends a maximum of 500 milligrams of calcium per day from dietary supplements.

When are calcium supplements useful?

Healthy adults can usually easily cover their calcium needs through a balanced diet. In certain situations, a calcium supplement can still be useful. The additional intake as a dietary supplement helps to counteract a nutritional or disease-related deficiency. However, to ensure an appropriate intake and avoid side effects, you should always follow an individualized dosage.

Important to know

If you are not a healthcare professional and experience symptoms, have existing health conditions, or suspect a deficiency, consult a physician.