PEMT
Protein:
Phosphatidylethanolamine N-Methyltransferase
SNP ID:
Phosphatidylethanolamine N-Methyltransferase (PEMT) is an enzyme encoded for by the gene PEMT, which is responsible for the conversion of phosphatidylethanolamine (PE) into phosphatidylcholine (PC) in the liver 1. PC is a key component of the flexible cell membranes which surround every cell in our body 2. While the majority of choline in the body is derived from dietary sources, PEMT is able to synthesise PC directly meaning it is thought to play an important role in providing PC during times of starvation 3. As part of its activity PEMT produces homocysteine, which plays an important role in MTHFR SNP related health issues 4.
PEMT activity is especially important in the liver and brain which require large amounts of PC, and choline which is derived from PC breakdown, to maintain normal function. Although important for brain function there is only one SNP in PEMT associated with poor health outcomes which is the G523A which is associated with an increased risk of developing fatty liver disease.
| rsID Number | Major Allele | Minor Allele | Minor Allele Frequency (%) | Major Amino Acid | Minor Amino Acid |
|---|---|---|---|---|---|
| rs7946 | g | a | 36 | Val | Met |
Risk Description
The ‘A’ allele of G523A in PEMT gene is associated with an increased risk of developing non-alcoholic fatty liver disease (NAFLD) in Caucasians. In an assay conducted outside of the human body the ‘A’ allele of G523A resulted in approximately a 30% reduction in activity which led to a deficiency in the production of phosphatidylcholine (PC), although no experiments to assess its effect in the body have yet been performed.
PC forms an important part of the flexible cell membrane which surrounds all our cells and also plays an important role in shuttling fats out of cells in the liver, to be trafficked around the body or excreted. The reduction in PEMT activity associated with the ‘A’ allele of G523A is thought to lead to an accumulation of fats within cells of the liver, which then gives rise to NAFLD 5.
Interestingly, this effect was not observed in other populations, with some hypothesising that a poor outcome is only observed when individuals are consuming too many calories and dietary fats, which is often associated with Western diets 6.
Direct Nutrients:*
| Ingredient | Active Ingredient | Effect |
|---|---|---|
| S-Adenosylmethionine |
S-Adenosylmethionine (SAM) provides methyl groups required by PEMT to convert phosphatidylethanolamine (PE) into phosphatidylcholine (PC). The ‘A’ allele of G523A in PEMT is associated with reduced function and a decrease in PC levels. Supplementing with S-Adenosylmethionine may help ensure that this factor is not limiting, ensuring maximum PEMT activity 7. |
|
Indirect Nutrients:*
| Ingredient | Active Ingredient | Effect |
|---|---|---|
| Choline |
Choline is required for numerous important functions throughout the body, it forms phosphatidylcholine (PC) which is a key component of cell membranes but is also required in order to synthesise neurotransmitters such as acetylcholine, which is fundamental in controlling muscle movements. In those carrying the ‘A’ allele of G523A, where PEMT activity is reduced supplementing with additional dietary choline may ensure that choline and PC levels remain normal 8. PC formed by PEMT is readily broken down into choline 9. It is hypothesised that in those carrying the ‘A’ allele of G523A the reduction in PC, may lead to a reduction in choline and thus neurotransmtitter availability. |
|
| Green tea leaf extract |
Green tea leaf extract is rich in polyphenols which have strong anti-oxidant, hypolipidemic, and anti-inflammatory effects, countering the damaging effects of lipid accumulation in the liver associated with the ‘A’ allele of G523A. Green tea has been shown to significantly reduce both the occurrence of NAFLD and its progression 10. |
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Discuss this information with your doctor before taking any course of action.
Citations:
- https://www.ncbi.nlm.nih.gov/pubmed/17881348
- https://www.ncbi.nlm.nih.gov/pubmed/1883207
- https://www.ncbi.nlm.nih.gov/pubmed/24184426
- https://www.ncbi.nlm.nih.gov/pubmed/9509248
- https://www.ncbi.nlm.nih.gov/pubmed/16051693
- https://www.ncbi.nlm.nih.gov/pubmed/17012264
- https://www.ncbi.nlm.nih.gov/pubmed/3057511
- https://www.ncbi.nlm.nih.gov/pubmed/24251710
- https://www.ncbi.nlm.nih.gov/pubmed/22877991
- https://www.ncbi.nlm.nih.gov/pubmed/22221215