Phosphatidylcholine is the main component of lecithin, and acts as a source of choline. Choline is an essential substance related to the B vitamins, and to the amino acid, methionine. Until recently, it was thought that we made sufficient choline to meet our needs. In 1998, however, it was recognised that this is often not the case, especially in later life.
If choline is in short supply, cells cannot function properly and enter a process known as apoptosis or programmed cell death. Conditions that have been linked with choline deficiency include fatty liver degeneration, hardening of the arteries, Alzheimer’s disease, high blood pressure, nervousness, learning difficulties, depression and stomach ulcers.
Most dietary choline is derived from the phosphatidylcholine found in egg yolk, liver, meat, fish, wheatgerm, peanuts, Brazil nuts, beans and green leafy vegetables. The lecithin in phosphatidylcholine or lecithin supplements is usually extracted from soybeans.
What is phosphatidylcholine?
Phosphatidylcholine is a phospholipid which is vital for the structural integrity of cell membranes. It has a peg-like structure in which the head attracts water, while their tails repel water. The molecules therefore naturally form a double layer with the tails on the inside, rather like a cheese sandwich. This property creates the basic skeleton of the double membrane that surrounds every cell in the body.
Phosphatidylcholine also provides choline, which acts as a building block for the production of important neurotransmitters in the brain, including acetylcholine, noradrenaline and dopamine to aid concentration and alertness.
In the liver, phosphatidylcholine is involved in cholesterol metabolism. Phosphatidylcholine also has an emulsifying action and is found in bile, where it helps to dissolve cholesterol and break down dietary fats.
Phosphatidylcholine and cholesterol
Phosphatidylcholine is involved in cholesterol processing in the liver and can improve cholesterol balance by lowering ‘bad’ LDL-cholesterol and increasing ‘good’ HDL-cholesterol. It is also involved in the transportation of cholesterol in the circulation and the removal of excess cholesterol from the tissues. These activities depend on an enzyme called lecithin cholesterol acyltransferase (LCAT) which appears to protect against hardening and furring up of the arteries (atherosclerosis).
In people with type 2 diabetes, taking a phosphatidylcholine and soy protein supplement for 12 weeks significantly reduced total cholesterol by 12%, LDL-cholesterol by 16% and increased HDL-cholesterol by 11%. In addition, blood triglyceride levels fell by 22%.
Phosphatidylcholine and memory
Phosphatidylcholine supplements increase brain levels of acetylcholine and are used to improve memory storage and retrieval. Preclinical research has identified phosphatidylcholine as a promising enhancer of learning, memory and improved cognitive function. This was tested in 80 college students who took phosphatidylcholine supplements or placebo, on two separate occasions. After taking the phosphatidylcholine, significant improvements in explicit memory during a serial learning task were observed 90 minutes after taking the phosphatidylcholine, but not after the placebo. Choline ‘donors’ such as phosphatidylcholine are a component of many nootropic supplements that aim to enhance cognitive function and memory.
Phosphatidylcholine and fatty liver
If phosphatidylcholine is in short supply, liver cells are unable to process and export dietary fats, which build up inside them to produce fatty liver disease. Abnormal regeneration of liver tissues then results in a build-up of collagen (fibrosis), cirrhosis and has been associated with liver cancer. Choline also helps to eliminate toxins from the liver and gall bladder and may be recommended for people with gallstones.
Adequate intakes of phosphatidylcholine are believed to be in the region of 425mg to 550mg per day for adults.
Therapeutic doses of phosphatidylcholine are in the range of 2g – 4g daily. Higher doses may be taken under medical supervision.
One tablespoon of lecithin granules provides 1725 mg phosphatidylcholine and 250 mg choline – a little less than the amount present in a hen’s egg.
Supplements are best taken with meals to boost absorption.
Do not take phosphatidylcholine, lecithin or choline supplements if you have manic depression (except under medical supervision) in case they worsen your symptoms.
High doses of phosphatidylcholine may cause indigestion, loss of appetite, sweating and, fishy body odour. Lecithin supplements are therefore generally preferred as a source of phosphatidylcholine and choline.