Calcium in the human body - why is it so important?

Calcium is an extremely important mineral in the human body, found mainly in bones and teeth. It performs many important physiological functions . Its low dietary intake is particularly problematic for children and adolescents, as there is a high demand for this element during this period, which is associated with the intensive development of the skeletal system.

• Calcium - what functions does it have in the body?
• Calcium - what are the standards?
• Products rich in calcium
• Calcium bioavailability
• Excess calcium in the body
• Calcium - deficiency symptoms

Calcium - what functions does it have in the body?

Calcium is a mineral that has an important effect on the osteoarticular system due to the fact that it is the main building block of bones and teeth. In addition, in the human body it is involved in blood clotting, regulation of hormones, activation of certain enzymes and conduction of nerve impulses, as well as contraction of skeletal muscles and the heart. To top it off, it reduces the permeability of cell membranes and helps reduce blood pressure values. It has also been suggested that adequate dietary calcium intake may play an important role in both the prevention and treatment of such chronic conditions as obesity, type 2 diabetes and cancer (especially breast, colon and prostate).

Calcium - what are the standards?

The human body's requirement for calcium varies depending on the period of life and physiological state. Among the most important factors that have a significant impact on determining the recommended norms of calcium intake are: intensive development of the skeletal system during childhood and adolescence, maintenance of proper bone mass in adulthood, reduction of bone resorption in the elderly, and maintenance of normal calcium levels in bones and blood serum. According to current standards for the Polish population, the human body's calcium requirements at the level of the recommended daily allowance (RDA) are as follows:

• Children from 1 to 3 years of age - 700 mg,
• Children from 4 to 9 years of age - 1000 mg,
• Boys and girls from 10 to 18 years of age - 1300 mg,
• Men from 19 to 65 years of age - 1000 mg,
• Women from 19 to 50 years of age - 1000 mg,
• Women aged 51 and over - 1200 mg,
• Men aged 66 and over - 1200 mg,
• Pregnant and breastfeeding women up to 19 years of age - 1300 mg,
• Pregnant and breastfeeding women over 19 years of age - 1000 mg.

Products rich in calcium

Milk and dairy products such as yogurt, kefir, buttermilk, and soft and hard cheeses are the main source of well-absorbed calcium in the diets of people in economically developed countries. Other examples of dietary sources include sardines, sprats, pulses (e.g. white beans, soybeans), green vegetables (e.g. broccoli, Chinese cabbage, parsley, spinach and kale), dried fruits (e.g. figs, apricots), nuts (e.g., hazelnuts, walnuts, pistachios), almonds, seeds (e.g., sesame, poppy and sunflower seeds), pumpkin seeds, amaranth, calcium-fortified foods (e.g., tofu, sugar-free vegetable drinks) and highly mineralized waters.

Calcium bioavailability

The bioavailability of calcium from foods is estimated to range from 10 to 40%, and is highly dependent on the composition of the diet. Factors that increase the absorption of this mineral from the gastrointestinal tract include vitamin D, certain amino acids, lactose and casein phosphopeptides derived from milk. And nutrients that reduce calcium absorption in the terminal gastrointestinal tract include oxalic acid, phytic acid, insoluble dietary fiber fractions and high fat and phosphorus content.

Excess calcium in the body

Excess calcium in the human body can occur primarily when there is long-term intake of medications and/or dietary supplements containing high doses of calcium (e.g., more than 3,000 mg per day). Chronic excessive intake of calcium from pharmaceutical preparations can lead to calcification of blood vessels and an increased risk of kidney diseases (e.g., kidney failure, kidney stones, lactic-alkaline syndrome), cardiovascular diseases, prostate cancer, as well as impaired absorption of minerals such as iron, zinc and magnesium.

Calcium - deficiency symptoms

The results of previous studies suggest that calcium intake in the Polish population is low, averaging about 600 mg per day (girls and women average 539 mg per day, while men average 666 mg per day), which is less than 60% of the recommended daily intake. Among the most common health effects of long-term dietary calcium deficiencies are:

• Osteomalacia - as a result of low calcium saturation, bones are characterized by>their poor strength and resistance to stress.
• Osteoporosis - there is a decrease in bone mineral density and a
  weakening of the structure and strength of bone tissue, and consequently
  increase the risk of fractures and injuries.
• Rickets - a disruption in the differentiation of bone and cartilage tissue and the
  mineralization of the long bone growth plate and ossein (i.e.
  the organic intercellular substance of bone tissue responsible
  responsible for the elasticity and strength of the bone) in children.
• Tetany - a syndrome of symptoms characterized by the occurrence of
  painful muscle spasms and/or tremors and unpleasant
  tingling sensations (parasthesias - well known to enthusiasts of supplementation with
  beta-alanine).
• Neurological disorders,
• Excessive excitability of the body,
• Increased blood pressure.

Sources:

• Harvey NC, Biver E, Kaufman JM, et al: The role of calcium
  supplementation in healthy musculoskeletal aging : An expert
  consensus meeting of the European Society for Clinical and Economic
  Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases
  (ESCEO) and the International Foundation for Osteoporosis (IOF).
  Osteoporos Int. 2017 Feb;28(2):447-462.
• Li K, Wang XF, Li DY, et al: The good, the bad, and the ugly of
  calcium supplementation: a review of calcium intake on human health.
  Clin Interv Aging. 2018 Nov 28;13:2443-2452.
• Cormick G, Belizán JM: Calcium Intake and Health. Nutrients. 2019
  Jul 15;11(7):1606.
• Jarosz M., Rychlik E., Stoś K. et al: Nutrition standards for the population of
  Poland and their application. National Institute of Public Health - National Institute of Hygiene, 2020.
• Hadjimbei E, Botsaris G, Chrysostomou S.: Beneficial Effects of
  Yoghurts and Probiotic Fermented Milks and Their Functional Food
  Potential. Foods. 2022 Sep 3;11(17):2691.