Minerals for active people: Calcium
July 24th, 2013 by André Gagnon, ND
Calcium is one of the most important minerals for health. It is the most abundant mineral found throughout the human body. On top of actions significant in the functions of the thyroid and in coagulation, calcium is of capital importance for healthy muscles and bones in athletes.
Calcium plays an essential role in muscle contraction. Calcium works in patterns: the increase of intracellular calcium concentrations provides neurotransmission to the muscle and therefore the contraction. The contracted muscles then produce calcium ions which complete the pattern by easing muscle cell contraction. Finally, calcium promotes the production of energy.
Physical exercise and the high levels of protein in an athlete’s diet increase acidity. Lactic acid is produced when muscle cells break down glucose in oxygen (anaerobic metabolism) provoking the acidification of muscles and blood and eventually the entire body. Calcium is used to decrease this acidity. In cases where calcium intake is insufficient, the skeleton gives tissues the calcium that the body has not sufficiently received through nutrition or supplements, causing partial demineralisation and the weakening of bone structure. A heavy workload and intense training may expose the body to fatigue fractures, or in the worst case scenario, to important decalcification that may lead to real fractures.
How to properly assimilate calcium
Certain factors promote, or on the contrary, reduce calcium assimilation. Calcium absorption may be significantly reduced when present with oxalic acid (found in spinach, cocoa and tea among others). Phosphorus and sugar contained is soda pops are also considerable calcium enemies. Certain medications like corticosteroids, diuretics and antacids may hinder bioavailability. Consuming coffee or salt will raise calcium loss. Age is also a factor. As of 50 years old, the intestinal absorption of calcium decreases. Even though this phenomenon generally affects women, men are also affected.
To improve calcium availability and its absorption, it is a wise choice to spread out calcium intake throughout the day. Pairing calcium with foods rich in lactose, proteins or acids will promote assimilation because the acid will help in the ionisation of calcium. It is also primordial that the intake of vitamin D be sufficient to metabolise the calcium.
Choosing a supplement
Many types of calcium like carbonate, citrate, gluconate and lactate are available in diverse forms; solid (pills, capsules) or liquid. Calcium carbonate should specifically be taken exclusively in liquid form.
Liquid supplements have a 98% assimilation rate versus solid forms.(pills, capsules) which are rarely higher than 20%. As a liquid form, vitamins and minerals are already dissolved and are therefore immediately bioavailable.
Certain non-medicinal ingredients present in liquid supplements such as citric acid, ascorbic acid, vegetal gum, peptides and emulsifying agents increase the bioavailability of minerals. Solid formulas often contain inert excipients that decrease the acidity in the stomach to avoid gastric discomfort during digestion which in turn decreases bioavailability.
It is preferable to choose a supplement like CALCIUM ACTION which contains many sources of combined calcium. An ideal supplement will also include essential elements such as vitamin D, magnesium, bore and silica which promote calcium binding in tissues.
Guide nutritionnel des sports d’endurance, 2e ed. Denis Riché, Vigot 2002
Médecine du sport, Jean-Marcel Ferret md, Henri Kaleckar md, Éditions Boiron 2000
Physician’s Desk Reference (page 1542, #49).