Lecithins are a group of chemical compounds and an important component of the cell membrane. Lecithins are vital to the human body.
What are lecithins?
Lecithins are chemical compounds that belong to the group of phosphatidylcholines. They are so-called phospholipids. They are composed of fatty acids, phosphoric acid, glycerol and choline. The name lecithin comes from the Greek lekithos, meaning egg yolk. This name was chosen because lecithin was first isolated from egg yolks in 1846. Only later was it discovered that the phospholipids are found in all animal organisms and also in many plants.
Function, effects, and roles
Lecithins perform numerous functional tasks in the body. Their most important task is the formation of structure in the body. The living cells in the human body are surrounded by a cell membrane. This protects the cell organelles and maintains the internal environment of the cell. The cell membrane consists of a lipid bilayer. Lecithins are an important component of this lipid bilayer. Together with other phospholipids, lecithins form so-called hydrophilic windows in the impermeable membrane. Ions, water molecules and water-soluble substances enter the cell through these windows. The higher the lecithin content of the cell, the more active the cell membrane can act. In nerves and brain, lecithin can be converted to acetylcholine in various chemical processes. Acetylcholine is one of the most important neurotransmitters in the human body. It is responsible, for example, for the transmission of nerve impulses to the heart. It is also the most important transmitter in the parasympathetic and sympathetic nervous systems. Lecithin stimulates enzymes that can neutralize and eliminate free radicals. Free radicals are molecules produced during many metabolic processes in the body. From a chemical point of view, they are incomplete. They lack an electron in their chemical structure. To compensate for this lack, they try to steal this electron from other structures in the body. In doing so, they damage the cell membranes and also the complete cells of the body. Free radicals are believed to play a crucial role in the development of cancer and other serious diseases. Lecithins also play an important role in fat digestion. They act as emulsifiers of lipids in the blood. Only in emulsified form can fats be utilized by the body. Cholesterol is also emulsified by lecithins. In this way, cholesterol remains soluble in the gallbladder. Without this emulsification, gallstones could form from the cholesterol. But lecithins can not only bind cholesterol, they can also activate enzymes that break down excess cholesterol. Thus, lecithins have a vasoprotective effect.
Formation, occurrence, properties, and optimal values
In the body, lecithins are found to a large extent in cell membranes. In particular, high concentrations of lecithin are found in the liver, brain, lungs, heart and muscle tissue. Lecithin is also found in blood plasma. Some of the lecithins, phosphatidylethanolamines and phosphatidylcholines, are produced in the Kennedy metabolic pathway. This is a biochemical process that takes place in nerve cells. However, lecithins can also be ingested through food. The main source of lecithins is soy. But lecithins are also found in rapeseed, sunflower oil and, of course, egg yolks. Lecithin values in blood plasma are not determined. Therefore, there are no reference values.
Diseases and disorders
A deficiency of lecithins can lead to a wide variety of symptoms in the body. Lecithins play an important role in fat metabolism. In one study, men and women were given normal amounts of methionine and folic acid intravenously. In the course of the study, the subjects developed fatty liver as a result, and initial signs of liver damage also became apparent. Regular administration of lecithins could reverse these changes. Lecithins bind portions of so-called VLDL particles. These are responsible for transporting fats from the liver to the tissues. Without lecithins, the VLDL particles can no longer be produced. The fat accumulates in the liver and damages the tissues there. When lecithins are deficient, cell death rates within the liver appear to increase.Studies show that liver cells initiate programmed cell death, known as apoptosis, when they lack lecithins. In rats, a dietary deficiency of lecithins resulted in an increased incidence of liver cancer. Sensitivity to carcinogenic chemicals also increased with lecithin deficiency. Lecithins also appear to play an important role in Alzheimer’s disease. Alzheimer’s disease (Morbus Alzheimer) is a disease of the nervous system. It occurs predominantly in persons older than 65 years. Characteristic of the disease is a deterioration in cognitive performance. Memory is impaired, spatial orientation decreases, the experience of time is disturbed and practical skills are limited. In addition, there are disturbances of speech, a restriction of spatial-constructive abilities, a disturbance of the inner drive and a fluctuating emotional state. The exact causes of Alzheimer’s disease are not yet clear. In the course of the disease, however, there is a deficiency of acetylcholine. The messenger substance is no longer produced in sufficient quantities. As a result, the brain‘s performance is reduced. In several studies, the administration of lecithins to Alzheimer’s patients showed a slight improvement in memory performance. However, lecithins cannot halt or even cure the disease. Nevertheless, in view of the multiple effects of lecithin, care should be taken to ensure an adequate supply of the phospholipids.
