We constantly hear how important calcium is to keep our bones and teeth strong, especially in such important stages as growth, menopause, pregnancy and lactation, for physical exercise...
But do we know what calcium is? What it is for? What problems might we have with a lack or an excess of calcium? Which are the calcium-rich foods?
Calcium is the mineral that is found in greatest abundance in our bodies.
The greater proportion of calcium (99%) forms part of the structures of the bones and teeth, the rest is found in the blood and extra-celular fluids.
The most important functions of calcium
We can summarise them with the following four points:
The first is its structural function, since it is vital for the formation and regeneration of bone tissue.
Calcium is also very important for the correct transmission of nerve signals (nerve excitability) and for the regulation of the heartbeat.
Calcium also has a regulatory function, since it is involved in the proper membrane permeability.
And other than that, calcium is also essential for good muscle tone and the correct functioning of digestive enzymes.
Vitamin D is essential for helping the body to assimilate calcium
It is one of the most common chemical elements in nature and is present in the body in large quantities. Without calcium the formation and maintenance of healthy bones and teeth would be impossible.
It is absorbed through the intestine, where its supply is controlled by endogenous hormones in the parathyroid gland as well as by vitamin D.
A shortgae can cause deficiencies in bones, loss of teeth and osteoporosis.
In adults 99% of calcium (between 1 and 1.5 kg) is linked to the bones and teeth. The rest is distributed among cells, tissue and blood.
Calcium is abundant especially in milk and milk products, as well as mineral water, various types of cabbage, and walnuts.
Calcium, effects and properties
It is essential for maintaining strong bones and healthy teeth
Helps improve bone density, along with vitamin D3 and K2
It is essential for maintaining good bone density
It is important for the normal functioning of digestive enzymes
It is important for energy metabolism
It plays an important role in the normal functioning of the muscles
It is essential for the transmission of signals between nerve cells
It promotes normal blood coagulation
Calcium has a key role in cell division
Calcium is essential for activating the enzymes that cause muscle contraction.
Calcium is recommended for:
Osteoporosis, also proactively
In pregnancy and lactation
Long term cortisone treatments
For growth stages with children and adolescents
In cases of diabetes mellitus
To combat allergies
For those suffering from lactose intolerance
For those following a high fat or high protein diet
What foods contain calcium?
Animal origin: milk and derivatives, blue fish (tuna, sardines, anchovies, shrimp, clams, mussels, octopus...)
Plant origin: nuts (better when they are toasted) hazelnuts, walnuts or sunflower seeds. Dried fruit, such as figs, plums and dates are good sources of calcium. Seeds such as soybean, sesame, flax, xia and legumes such as lentils, chickpeas and beans.
Mineral water is also a source of calcium. There are other foods that also contain calcium, but not in great quantities, cabbage, broccoli, leeks or onions for example.
The calcium-rich foods are summarised as follows: legumes, nuts, dairy and blue fish. Other good sources of calcium are cereals, milk, cheese, yoghurt (dairy products in general) and juices. Choose low-fat cheese or fat-free dairy products to limit the intake of saturated fats, which whole milk contains. A 2,000 calorie diet should include three servings of dairy products per day.
However vegetable calcium is not absorbed by the body as well as it is from milk or calcium supplements.
People with some kind of milk allergy or a lactose intolerance can easily have a calcium deficiency. And as we have already seen, calcium is an essential mineral for promoting healthy bones and muscles, nervous system health and the secretion of certain hormones. Calcium supplements are the best option in this case, as even though it can be obtained from whole foods, calcium from this source is not absorbed very well.
Even so, many non-dairy products are rich in calcium and can be easily added to the diet. Some examples are: calcium enriched soy milk, fortified orange juice, canned fish (85g pink salmon provide 180mg of calcium and 85g of sardines provides 300mg of calcium), vegetables (broccoli or leafy green vegetables are good sources of calcium), tofu (provides 138mg per 1/2 cup), rhubarb, etc...
What can a lack of calcium cause?
Pain, fractures or deformity and bone diseases
Tetany (hyper excitability)
Heart and blood pressure problems/diseases
Blood clotting disorders
Dry skin, eczema, hair loss, brittle nails
Tingling or tickling
Caries and periodontitis
An excess of calcium in the diet can also be dangerous, as it can cause kidney stones (accumulation of calcium in the kidney), hypertension, vomiting, gastrointestinal disorders, etc.
The assimilation of calcium occurs in the intestine, mainly into the duodenum. It can also be partly assimilated in the colon.
There are nutritional factors that improve or or reduce the assimilation of this mineral. It is therefore essential to take them into account if there is may be a calcium deficiency.
Factors that reduce the assimilation of calcium: lack of vitamin D, fibre, high fat diets, medications (diuretics, anti-acid...), ageing (with age intestinal absorption is reduced), diarrhoea, use of caffeine, etc.
Doses and ingestion of calcium
Depending on the health authorities of each country, the recommended daily calcium levels range from 450-1200 mg. This causes a degree of uncertainty, to which we can also add that the amount of calcium absorbed by the body may vary depending on diet, age and the simultaneous intake of vitamin D.
Children, adolescents, pregnant women and infants tend to absorb 60 to 75 percent of their calcium through food. In adults, absorption is usually around 30 to 40% and decreases with age.
In order to prevent the removal of calcium from the body's reserves and the consequent danger of bone decalcification, taking a dietary calcium supplement is recommended.
Who is calcium especially important for?
Pregnant and lactating women
Children and adolescents
Those permanently taking cortisone
Women over the age of 45 and men over the age of 60
People with lactose intolerance
Those suffering from osteoporosis
People suffering from sun allergy
What the experts say about calcium:
1. Calcium ensures a perfect smile
A clinical study has shown that a reduction in the daily dose of calcium, from 800 to 1000 mg, carries the risk of gum disease, the leading cause of tooth loss. This is probably due to the fact that high calcium levels better resist attacks from the bacteria responsible for periodontitis.
2. Calcium prevents bone loss
A sufficient calcium intake is essential, especially in the elderly, since it helps prevent bone loss. Taking calcium supplements is also useful for preventing the onset of osteoporosis. This calcium should be preferably taken along with a meal, to better facilitate its absorption.