Minerals can be divided into two categories depending on their daily intake: macromineral substances, which must be ingested at high concentrations (calcium, phosphorus, magnesium, sodium, potassium, chlorine, sulfur) and minerals ingested in small quantities (iron, manganese, copper, iod, zinc, fluorine, selenium).
The mechanism of action of many enzymes includes not only vitamins, but also mineral salts, thus acquiring a very important role in metabolic processes. Calcium is the most common mineral in the human body (about 1-2% of our body weight). On a daily basis, we must take 1 g of calcium with a diet, of which only 200 mg are absorbed.
What is the importance of calcium?
Calcium is very important in enzyme regulation processes, nervous system function, cell proliferation, blood clotting and muscle contractions. It also regulates the blood pressure control mechanism. Calcium deficiency can contribute to very serious health problems, such as the development of rickets, the control of muscle activity and a decrease in bone mass. On the contrary, excessive intake of calcium, although very rare, can contribute to the calcification of soft tissues.
As we mentioned earlier, calcium ions make up about 1% of our body weight. About 99% of these calcium ions are deposited in the bone mass, with the remaining percent in the body as free calcium.
A healthy adult should take as much calcium as is excreted in the urine to ensure its balance. Calcium is very important in bone regeneration processes.
How is calcium absorbed?
The intestinal absorption of calcium can occur in two ways: non-specific (paracellular) or specific (transcellular). Calcinin is a hormone produced by thyroid C-cells. When calcium levels are very high, C-cells release calcinin, which acts on bone tissue to increase calcium reserves.
Paratheiditis hormone is released from the paratheiditis gland when calcium levels in the body are low. The action of this hormone affects the kidneys, where calcium excretion decreases as well as in the bone tissue, as the activity of osteoblasts increases. In addition, paratheiditis hormone stimulates the synthesis of vitamin D, which plays a very important role in ensuring calcium balance.
- Increases the absorption of calcium in the intestine
- Increases reabsorption of calcium in the kidneys
- Increases the release of calcium into the bone tissue
Calcium during pregnancy and menopause
During pregnancy, calcium reserves accumulate in the body, which are released during breastfeeding. Therefore, it is not recommended to take high doses of calcium in pregnant women. During menopause, in turn, the level of calcium in the body decreases with a decrease in its absorption from the diet, as well as reduced physical activity contributes to a physiological decrease in bone mass.
Calcium and physical activity
The decrease in calcium levels in the body due to insufficient intake of food is one of the main reasons for the significant loss of bone mass among female athletes. Diets that ingest low calories and fats like many other diets contribute to the triad of female athletes: eating disorders, amenorrhea, as well as early osteoporosis.
Let's look at the last two components of the triad. An excessively low percentage of body fat, usually below 10% in women, interferes with the body's production of the hormone estrogen.
It can cause disorders or even discontinuation of the menstrual cycle (amenorrhoea). With the end of the menstrual cycle, for example during menopause, the level of estrogen in the body decreases, thus losing bone density and endurance to the body (early osteoporosis).
Amenorrhoea can also cause bone stress fractures (fractures without associated trauma) caused by excessive constant body skeletal stress, especially in cases where the skeleton is already osteoporotic due to menstrual dysfunction. Pubic, femur and shin fractures are the most common.
A normal menstrual cycle is necessary for a woman to become pregnant. Unfortunately, a calcium dietary supplement is not the answer to the problem, since bones are able to absorb calcium only when balanced with the consumption of other vitamins and minerals, especially magnesium.
Excessive calcium intake can contribute to magnesium deficiency. Most nutrition scientists recommend taking a calcium/magnesium ratio of 2:1. Nowadays, for most quality dietary supplements, this combination is not alien and is included in the dietary supplements in the recommended relationship. It is also desirable for women to pay attention to other vitamins necessary in the process of bone formation (C, D, K), as well as minerals (boron, magnesium and zinc).