What is choline?
Choline is an essential nutrient that doesn't always get the attention it deserves. We hear a lot about folate and vitamin B12, particularly when we talk about methylation, but choline also plays an important role in brain function, liver health and the way our cells work.
You may have come across choline under its old name, vitamin B4. However, choline is not officially classified as a B vitamin. Although our bodies can make some choline, we cannot reliably produce enough to meet all our needs, which is why we also need to obtain it from our diet.
So, what exactly does choline do?
Quite a lot, actually!
Choline is used to make several important compounds in the body, including:
Acetylcholine: A neurotransmitter involved in memory, learning, attention, muscle contraction and other nervous system functions.
Phosphatidylcholine: A major component of cell membranes that helps maintain their structure and function.
Betaine: A compound that donates methyl groups and helps convert homocysteine back into methionine.
This last point is particularly interesting if we are looking at methylation, as choline connects several important metabolic pathways.
Choline, methylation and homocysteine
Methylation is a biochemical process involved in numerous functions throughout the body, including DNA regulation, neurotransmitter metabolism and the production of important cellular compounds.
Choline has an important role here, but it is worth understanding how the pathways connect.
Choline can be converted into betaine, which donates a methyl group to help convert homocysteine back into methionine. Methionine can then be used to produce SAMe (S-adenosylmethionine), an important methyl donor involved in many biochemical reactions.
This pathway works alongside the folate-dependent pathway, which also helps recycle homocysteine back into methionine.
Why does this matter?
Because our methylation pathways do not operate in isolation. They depend on a network of nutrients and enzymes working together, including folate, vitamin B12, choline and betaine.
If homocysteine is elevated, it may be worth looking at the bigger picture rather than focusing on one nutrient alone. Folate and B12 status, vitamin B6, kidney function, diet and other factors can all influence homocysteine levels.
Choline is one part of that picture, but high homocysteine on its own does not tell us that someone is deficient in choline.
Choline and liver health
One of choline's most important roles is helping the liver transport fat.
The liver processes fats, but it also needs to package and export them so they can be transported around the body. Phosphatidylcholine is essential for this process because it helps the liver produce very-low-density lipoproteins (VLDL), which carry triglycerides out of the liver.
When choline availability is inadequate, this process can be disrupted, allowing fat to accumulate in liver cells.
Research has shown that significant choline deficiency can contribute to fatty liver and, in some cases, liver or muscle damage.
This is one reason choline deserves consideration when we talk about liver health. However, fatty liver has many possible causes, including insulin resistance, metabolic dysfunction, alcohol and certain medications. It should never automatically be attributed to a choline deficiency.
As always, we need to look at the whole picture.
Choline, genetics and individual requirements
This is where things become particularly interesting from a nutrigenomics perspective.
We know that genetics can influence how efficiently our bodies use and produce certain nutrients. Choline metabolism is no exception.
Two genes worth understanding are PEMT and MTHFR, although they affect different parts of the picture.
The PEMT gene
The PEMT gene provides instructions for making an enzyme that helps produce phosphatidylcholine in the body.
This is important because we don't obtain all our phosphatidylcholine directly from food; we can also make it ourselves.
Oestrogen influences the activity of the PEMT pathway. This means that hormonal changes, including the decline in oestrogen after menopause, may affect how much phosphatidylcholine the body can produce.
Some variants of the PEMT gene have also been associated with increased susceptibility to choline deficiency, particularly when dietary intake is low.
So, if you are post-menopausal, have a PEMT variant and are not consistently eating choline-rich foods, it may be worth reviewing your intake.
However, having a genetic variant does not automatically mean you are deficient or that you need a high-dose supplement. Genetics is one piece of the puzzle, not the whole story.
The MTHFR gene
The MTHFR gene is involved in the folate-dependent pathway that helps recycle homocysteine back into methionine.
Certain MTHFR variants can affect the activity of the enzyme, but the impact varies between individuals and depends on factors such as nutrient status and the wider metabolic picture.
Because choline and folate participate in interconnected methylation pathways, adequate choline intake may be particularly relevant when we are assessing someone's overall nutritional status.
However, we cannot assume that everyone with an MTHFR variant requires substantially more choline. The more useful approach is to consider dietary intake, relevant laboratory results, symptoms and other contributing factors together.
What about CBS?
The CBS gene is involved in the transsulfuration pathway, which helps convert homocysteine into other compounds, including cysteine.
This is a different pathway from the betaine-dependent recycling of homocysteine. A CBS variant does not automatically mean someone has impaired choline metabolism or needs additional choline.
When interpreting genetic results, it is important to understand what each gene actually does rather than grouping all methylation-related variants together.
Choline, the brain and nervous system
Choline is essential for producing acetylcholine, a neurotransmitter involved in memory, learning, attention and muscle control.
Acetylcholine also plays a role in communication between nerve cells and muscles, making it important for normal nervous system function.
Cholinergic dysfunction is recognised in Alzheimer's disease, and this has contributed to interest in the relationship between choline and cognitive health.
However, we need to distinguish between the importance of a nutrient in normal physiology and evidence that taking more of that nutrient will prevent or treat a disease.
Although choline is essential for brain function, we do not currently have sufficient evidence to conclude that choline supplementation prevents Alzheimer's disease or reliably improves memory in everyone.
The goal is to ensure adequate nutritional intake rather than assume that more is always better.
Choline during pregnancy and infancy
Choline is particularly important during pregnancy and early development, when the brain and nervous system are developing rapidly.
It contributes to cell membrane formation, acetylcholine production and methylation processes involved in normal development.
Maternal choline requirements increase during pregnancy and breastfeeding, and adequate intake is important for both mother and baby.
Choline also works alongside other nutrients, including folate and DHA, in supporting normal development.
For this reason, choline deserves a place in discussions about maternal nutrition. However, individual requirements and supplementation should be considered in the context of the overall diet and pregnancy care.
How much choline do we need?
Choline is essential, but the evidence is still limited when it comes to determining precise requirements for every individual. This is why Australian nutrient reference values use an Adequate Intake (AI) rather than a formal Recommended Dietary Intake.
The Australian reference values are:
Adult women: 425 mg per day
Adult men: 550 mg per day
Pregnancy: 440 mg per day
Breastfeeding: 550 mg per day
These figures provide a useful guide, but individual requirements can be influenced by factors such as life stage, diet and the body's ability to synthesise choline.
It is also worth remembering that an AI is a population-level guide, not a diagnostic test or a guarantee that every individual has the same requirement.
Where do we get choline from?
The good news is that choline is found in a variety of everyday foods.
Some useful sources include:
Egg yolks: One of the more concentrated and practical dietary sources.
Liver: Particularly rich in choline.
Meat and poultry: Contribute to daily intake.
Fish, including salmon: Provides choline alongside other valuable nutrients.
Soybeans and some legumes: Useful options for plant-based diets.
Cruciferous vegetables: Broccoli, Brussels sprouts and cauliflower contribute smaller amounts.
Nuts and seeds: Can contribute to overall intake, although amounts vary.
If you eat eggs, fish or meat regularly, you may already be obtaining a meaningful amount of choline from your diet. If you follow a more plant-based diet, it is worth paying attention to your food choices to help ensure adequate intake.
Before considering a supplement, I would start by reviewing what you are actually eating and how consistently you are meeting your nutritional needs.
Could your choline intake be worth reviewing?
Choline deficiency is uncommon in the general population, and its signs are not always obvious. There is also no single symptom or routine blood test that reliably establishes someone's overall choline status.
However, reviewing choline intake may be worthwhile if you:
Rarely eat choline-rich foods.
Have concerns about liver health or fatty liver disease.
Are pregnant or breastfeeding.
Are post-menopausal and interested in how hormonal changes affect nutrient metabolism.
Have genetic results involving pathways relevant to choline metabolism.
Are investigating elevated homocysteine as part of a broader nutritional assessment.
These are reasons to consider the bigger picture, not proof of a deficiency.
The takeaway
Choline is one of those nutrients that can easily be overlooked when we focus on individual vitamins and minerals.
It plays important roles in liver health, cell membranes, neurotransmitter production and methylation. It also connects with other nutrients and metabolic pathways, which is why I find it particularly interesting from a naturopathic and nutrigenomics perspective.
But the answer is not automatically to take another supplement.
It is about understanding your diet, your individual circumstances and how the different pieces fit together.
If you would like to explore whether your choline intake, methylation pathways or wider nutritional status deserve closer attention, book an appointment with Magnolia Apothecary and we can discuss your individual needs.