Phospholipids
Special fats that form the basic structure of the membranes of every cell, with a "water-loving" head and "water-fleeing" tails, of which lecithin is the common example.
Phospholipids are fats with a double personality: one hydrophilic end (water-loving) and two hydrophobic tails (water-fleeing). This duality allows them to organise themselves spontaneously into a bilayer, the fundamental structure of all cell membranes.
The original angle (the architecture of life): every cell in the body is surrounded by a phospholipid membrane. Without them, there would be no cell and no life. This membrane is not a mere barrier: it is a dynamic structure that controls exchanges, cell communication and signalling.
The fatty acid composition of membrane phospholipids depends on our diet. A membrane rich in omega-3 is more fluid and functional; a membrane rich in saturated/trans fats is more rigid. This is a concrete mechanism by which “you are what you eat”: quite literally, our cell membranes reflect our fat intake.
Lecithin, the star phospholipid: lecithin (rich in phosphatidylcholine) is a common dietary phospholipid (egg yolk, soya, sunflower). It is used as a natural emulsifier (E322): it is what binds water and oil in mayonnaise, chocolate and sauces. Unlike the controversial synthetic emulsifiers, lecithin is benign, even beneficial.
Health role:
- Phosphatidylcholine is a source of choline, the precursor of acetylcholine (the memory neurotransmitter), and is important for the liver
- Phospholipids are crucial for the brain (rich in fat, notably phospholipid DHA)
- They take part in the transport of fats in the blood (lipoproteins)
Sources: egg yolk, soya, liver, wheat germ, peanuts, oily fish (phospholipid DHA from krill in particular).