agosto 7, 2020
a cracked egg on a table

Choline: the multipurpose tool for metabolism

Choline (vitamin B4) is a component of lecithin and, among other things, is important for the construction of cell walls. It used to be considered a vitamin. Today the term “vitamin-like substance” is sometimes used.

With a good supply of amino acids, the body can produce enough choline on its own. Only in phases of special stress, for example, or during strong growth or effort we have to add additional choline through food.

From choline, nerve cells produce the messenger substance acetylcholine, which regulates, among other things, the function of memory in the brain.

Without acetylcholine, the brain cells in question can no longer exchange signals, and there is memory loss, as in Alzheimer’s disease, in which brain cells containing acetylcholine gradually die.

Therefore, some scientists suspect that an increased intake of choline or foods containing lecithin could improve memory function.

What is choline?

From a chemical point of view, choline is monohydric alcohol since it has a hydroxyl group (-OH), the most important characteristic of alcohol. At the same time, the substance with its three methyl groups (-CH3) and the hydroxyl group, which surround a nitrogen atom, can also be called a quaternary ammonium compound.

One of its most important properties is its versatility and its participation in a variety of metabolic processes. Our metabolism can convert choline into other substances as needed by adding or exchanging groups through catalytic processes, greatly expanding its properties and mechanisms of action.

Although choline can be synthesized in smaller amounts from the amino acids methionine and lysine, it is not sufficient for the total requirement. Therefore, part of the supply must come from food or dietary supplements.

One of the most important and best-known functions is that performed by the quaternary ammonium compound as a messenger or neurotransmitter in the form of acetylcholine.

As called a phospholipid, the hill is an indispensable component of all biomembranes surrounding the cells of our body and is part of the myelin sheaths surrounding nerve fibers certain to avoid electrically shorting.

As a biocatalyst, it also takes on important tasks in the transfer of methyl groups. In addition, the substance participates in the metabolism of fats in the liver and in the synthesis of creatine.

It’s also worth mentioning its interactions with hormones from the catecholamine group like dopamine, norepinephrine, and melatonin.

Choline rich foods

Eggs have the highest choline content of all foods. But meat (especially liver), fish, or vegetables like soy, beans, and cabbage also contain significant amounts of nutrients.

Choline is generally not found in these foods in a free form, but binds as lecithin , a mixture of choline-containing compounds.

Memory impact not tested

But is it true that eating a daily egg at breakfast significantly strengthens brain performance and increases memory?

In one study, the memory of elder people who had eaten more high-choline foods for three years improved slightly compared to people with lower choline intake. However, the study did not provide clear evidence that choline is the cause of better memory performance. Observed improvements could also have other causes.

The effect of high-doses of choline-containing lecithin was summarized in a systematic review of twelve studies on the treatment of dementia and Alzheimer’s and other age-related memory problems.

The daily intake of lecithin for a period of up to three months had no influence in the vast majority of cases on the memory ability of patients with dementia.

Poor study quality

Two other studies looked at how consuming pure choline in the form of food additives affects brain performance. Here, too, no memory-enhancing effect was found. However, the importance of the two studies is limited. Only a few test subjects participated in methodologically inappropriate research.

Another study in just eleven people fed with an infusion showed that adding choline to the nutrient solution led to an improvement in memory compared to the control group that had not received choline. However, this result cannot be transferred to people with a normal diet because, with daily food, most of us ingest at least moderate amounts of choline.

Furthermore, the number of observers in this study was too small to make a general statement.

The special lecithin compound helps a little

However, the compound cytidine-diphosphocholine (CDP-choline) appears to improve memory performance, at least in older people with dementia. CDP choline is not found in food, but the body can convert the choline consumed with food into CDP choline.

In a study in which CDP-choline was added through dietary supplements, regular ingestion for up to three months improved memory ability in people with Alzheimer’s or other memory disorders. How this effect occurs and how long it lasts is unknown.

The substance also cannot cure or even stop Alzheimer’s disease. Also, the memory-enhancing effect is very low. No undesirable side effects have been reported.

Acetylcholine: the messenger that makes your muscles contract

The acetylcholine (ACh ACO) has made a name for itself as one of the most important neurotransmitters. Our metabolism is capable of producing acetylcholine from choline and acetic acid.

Chemically, it is an ester of acetic acid and choline. Acetylcholine esterification is carried out using a specific enzyme as a biocatalyst.

One of the most important functions of acetylcholine is the transmission of nerve impulses in the synaptic cleft, the so-called motor plate of motor neurons in the posterior muscle fibers so that they contract and the desired movement occurs.

Once the work is done, the enzyme acetylcholinesterase breaks the neurotransmitter back into choline and acetate, neutralizing it. The resulting acetate escapes from the synaptic cleft and is metabolized.

Choline is again recovered by the nerve cell in the synaptic cleft and reused. In addition to signal transmission at the motor endplate of neurons, ACh also plays a decisive role in the long-term storage of complex movements.

Acetylcholine: the messenger that guarantees your mental performance

In our brain (Central Nervous System or CNS) and in the two sympathetic and parasympathetic vegetative nervous systems, acetylcholine also plays the role of signal transmission in the synaptic cleft.

Fortunately, the acetylcholine you ingested through food or supplements can easily cross the blood-brain barrier and work on the Central Nervous System.

The blood-brain barrier protects our brain from pathogens and other harmful substances. The brain is somewhat comparable to a high-security wing that only allows access with special identifications.

If there is a lack of acetylcholine in the nerves of the Nervous System, the change between the stress phases to the relaxation and recovery phases does not work correctly and the synthesis of certain stress hormones is interrupted.

The stress phases are controlled by sympathetic nerves that prepare us with stress hormones for maximum physical performance in the short term. The parasympathetic nerves pick up the stress hormones again as soon as “the danger is over” and program our body and mind for relaxation, regeneration, and growth.

Limited sympathetic and parasympathetic function due to a lack of choline has an unfavorable effect on basic unconscious vital functions, such as control of breathing, heart rate, and blood pressure.

In the Central Nervous System, acetylcholine forms in the medullary sheaths of certain nerves. They are neurons that communicate through electrical impulses and are protected from an electrical short circuit by their marrow or myelin sheaths.

If a neurodegenerative disease like Alzheimer’s causes myelin sheaths to break, the reduced level of acetylcholine is the first to damage memory and ability to concentrate.

Damage can be counteracted by administering supplements that inhibit the enzyme acetylcholinesterase. By inhibiting the breakdown enzyme, the concentration of acetylcholine can be artificially maintained, which has a beneficial effect on brain performance in Alzheimer’s and other dementias and improves symptoms.

a basket of eggs, high in choline

Choline protects your liver from obesity and your vessels from arteriosclerosis

Choline is capable of displaying its lipotropic properties, especially in the liver. Excess fat stores in the liver are broken down and lipid metabolism is normalized.

Even the European Food Safety Authority (EFSA) recognizes the effect on the normalization of lipid metabolism and allows manufacturers of food and appropriate food supplements to advertise in this regard.

An oxidation conversion to betaine converts choline into a methyl group donor, which as a biocatalyst can transfer CH3 groups to other substances. This is an enormously important function if, for example, homocysteine is converted to the amino acid methionine by transfer of a methyl group and can, therefore, become harmless.

Homocysteine ​​arises as an intermediary in protein metabolism and is suspected to be one of the triggers for the development of arteriosclerosis if the concentration in the blood is high.

A slightly increased homocysteine ​​level has been shown to increase the risk of cardiovascular disease disproportionately.

There is another important effect on the liver that is caused by a breakdown product of choline. When the metabolism breaks down choline, the intermediate product betaine is produced, which incidentally also occurs in remarkable concentrations in beets.

Betaine activates the enzyme homocysteine ​​methyltransferase, which can partially compensate for the reduced lack of methionine synthase by regular alcohol consumption, and therefore counteracts liver damage caused by excessive alcohol consumption.

There is no biomembrane without lecithin

The phosphatidylcholine or polyenylphosphatidylcholine is a phospholipid, also known as lecithin. Lecithin is a so-called emulsifier, which means that water-insoluble fats and oils can be mixed with water using lecithin.

Lecithin is approved by EU regulations as a food additive, even for organic products. It is also a necessary and important component of almost all biomembranes, in almost all living things, except in many types of bacteria, which have a different structure than their biomembranes.

Biomembranes containing lecithin not only enclose cells, but also separate the cell nucleus, organelles, and vesicles within cells from the cytosol, the fluid that fills the interior of the cell. Even ribosomes, in which each individual cell synthesizes its required proteins, cannot function without a lecithin-containing membrane.

Lecithin is the most common membrane lipid in plant and animal cells. Above all, it is the fatty and water-soluble properties of lecithin that allow the selective exchange of substances between both parts of the membrane.

Choline participates in the synthesis of creatine that improves performance

Creatine has attracted the attention of the fitness and bodybuilding industry for the past ten years. Our metabolism can produce the substance in sufficient quantities. A prerequisite for this is a sufficient amount of the amino acids glycine, arginine, and methionine.

All that is needed now is the tool to assemble creatine from all three amino acids. The substance appears as phosphatidylcholine or lecithin as a donor of the methyl group and participates in the creatine synthesis process by supplying the necessary methyl groups.

The main sites of creatine synthesis are the liver, kidneys, and pancreas. Word has spread in the fitness and bodybuilding scene that creatine has performance-enhancing properties that you can safely benefit from since creatine is synthesized by your own body and therefore cannot be classified as a prohibited anti-doping agent.

A muscle performance increase may occur if phosphatidylcholine supports the energy supply of individual muscle cells by intervening in the cellular respiration process and furthermore acts as a phosphate group transporter in the regeneration of ADP (adenosine diphosphate) to ATP (adenosine triphosphate).

This can speed up the supply of energy to muscle cells and the muscle-building process. Accelerating phosphate group transfers has the greatest effect when training with loads at maximum range and slightly below. However, this does not apply to all people.

The addition of creatine in the form of dietary supplements shows a performance-enhancing effect in approximately 30 percent of people.

Conclusion: great uncertainty

Overall, a memory-enhancing effect of choline or lecithin from food cannot be reliably demonstrated. In elderly patients with Alzheimer’s or other memory problems, the dietary supplement CDP-choline appears to produce a slight improvement in memory, at least in the short term. Nothing can be said about the long-term effectiveness of this substance.

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