Digestive Enzymes — Calcium
as a subject of research

What Are Digestive Enzymes?

Digestive enzymes are specialized proteins that break down food components into their basic building blocks in the gastrointestinal tract. Without these enzymes, the body would not be able to absorb and use nutrients from food. They start working in the mouth, continue their work in the stomach, and reach their full activity in the small intestine.

The best-known digestive enzymes include amylases (which break down carbohydrates), proteases (which break down proteins), and lipases (which break down fats). Each of these enzymes needs specific conditions — the right pH, sufficient water, and specific cofactors — to carry out its catalytic function.

One such cofactor is calcium. The European Food Safety Authority (EFSA) issued a scientific opinion on the basis of which the European Commission published an authorized health claim for calcium in relation to digestive enzymes.

How Digestive Enzymes Affect Nutrient Balance

The human digestive tract has a finely tuned system of enzymes, acids, and secretions. The job of this system is to split complex food macromolecules into smaller units that can be absorbed through the intestinal wall into the bloodstream:

• Amylases begin breaking down starch into simple sugars in the saliva of the mouth.
• Pepsin is activated in the stomach and splits dietary proteins into shorter peptide chains.
• Trypsin and chymotrypsin continue protein breakdown in the small intestine.
• Lipases break down dietary fats into fatty acids and glycerol, with calcium acting as a cofactor.
• Lactase splits the milk sugar lactose into its two components, glucose and galactose.

Each section of the digestive tract offers specific conditions — such as the strongly acidic pH in the stomach or the alkaline environment in the small intestine — that are optimal for the respective enzymes. Cofactors such as calcium are released by the pancreas into the duodenum together with the pancreatic enzymes.

The Role of Calcium as a Cofactor

Calcium ions (Ca²⁺) are involved in the activation and stabilization of several digestive enzymes. Enzymes synthesized in the pancreas are first secreted as inactive precursors (zymogens) and are only activated in the small intestine through proteolytic cleavage. Calcium influences this activation process and contributes to the structural integrity of the active enzyme forms.

“Calcium contributes to the normal function of digestive enzymes” — Under Regulation (EU) No 432/2012

In addition, calcium forms so-called calcium soaps with fatty acids in the small intestine, which influence lipid metabolism during digestion. This mechanism is the subject of ongoing research and illustrates that calcium has a multifaceted function in the digestive process.

Calcium in the Daily Diet

The EU reference value for daily calcium intake is 800 mg. Different food groups provide calcium in varying concentrations. Milk and dairy products such as cheese and yogurt are considered classic sources of calcium. But plant sources — including sesame, kale, and figs — also contain notable amounts of this mineral.

The bioavailability of calcium is influenced by factors such as the oxalic acid and phytic acid content of food. Spinach, for example, does contain calcium, but the oxalic acid it also contains binds part of it and thus reduces actual absorption in the gut.