Choline Deficiency and Your Genes: What To Know
Article at a Glance
- Choline is an essential nutrient for human health
- Getting adequate choline helps protect brain and liver function
- Certain individuals with variants in the PEMT genes may need more dietary choline and could be at greater risk for choline deficiency
Contents
Choline, also known as vitamin B4, is probably one of the most underrated nutrients in terms of its necessity for the proper functioning of several biological processes. It’s required for the synthesis of phospholipids which form part of every membrane in every cell within your body. It’s also a precursor for the neurotransmitter acetylcholine in your brain and is an important donor of methyl groups 1. It’s clear from medical research that choline deficiencies can have numerous effects on overall health.
Available data strongly suggest that choline is “conditionally essential”, meaning that in conditions such as cirrhosis, pregnancy, jejunoileal bypass for obesity, and methotrexate therapy, choline is required.
Can we make choline?
Humans can synthesize choline in small amounts in the liver, but this is not enough to support metabolic processes, especially during growth cycles.
Note: choline, in both dietary and supplement form, has been shown to increase levels of a gut metabolite called TMAO. High levels of TMAO may increase the risk for heart disease in some people.
Health benefits of Choline
Because choline plays a role in so many physiological systems, its benefits are seen in the functioning of several organs and processes:
- Supports brain function and activity
- Essential component of cell structures
- Protects liver from fatty deposits
- Helps with exercise performance and muscle function
- Maintains heart health
- Ensure normal growth of a fetus and infant
How much are we choline are we ingesting?
It is estimated that the average daily choline intake of adults is approximately 0.6g to 1g. In the United States, adults consume at least 6g phosphatidylcholine per day, of which at least 100 mg is derived from the consumption of processed foods3. So, although the average adult typically consumes enough choline daily, deficiencies still occur.
How does this happen? Sometimes choline is not actually absorbed in the intestines. Therefore, even though most people regularly eat foods that provide high enough levels of choline, certain factors reduce the absorption of choline. Studies show that the average person’s blood levels are lower than they should be4. Reasons for these deficiencies have been linked to changes in genes involved with choline metabolism.
Dietary manipulation of plasma choline
An interesting study in healthy men showed that by ingesting food that was rich in choline, plasma(blood) levels were easily increased7.
This study showed that plasma free-choline levels were doubled by providing a diet high in choline (5.9 g lecithin per day) through ordinary table foods. What was striking was that the diet was not unusual and is essentially much like the average, daily diet of the US population.
Choline intake of persons is affected by factors such as religion, ethnic background, economic status, marital status, geographic location, diet considerations, and personal food preferences, which is where deficiencies may become a factor.
Diets high in choline are likely consumed by many normal healthy persons every day. Based on food choices and preferences, a person could easily consume a diet with greater than 2g choline per day. This is probably the case for people whose diets routinely include foods such as pâté, egg custard, and other foods containing high amounts of choline/lecithin.
Choline deficiency symptoms
Choline is in great demand as a methyl donor in the body, and it has been proposed that choline availability as a methyl donor is a major factor in determining how quickly a choline-deficient diet leads to a pathologic or disease condition.
A choline deficiency may also play a part in age-related cognitive decline, including memory loss and Alzheimer’s disease. This is because choline plays a role in neurotransmitter maintenance as mentioned before, and, as someone ages, nerve signaling can decrease and signs of dementia can occur.
One study that looked at 1400 middle-aged and older adults showed that adults who supplemented with choline did better on memory tests. In brain scans, this group also showed less “white-matter hyperintensity” in their brains, areas which are associated with greater risk of stroke and dementia8. Choline supplements may therefore help in the prevention and/or treatment of Alzheimer’s disease, dementia, certain types of seizures, and Schizophrenia.
Symptoms of a choline deficiency may include:
- cognitive decline
- low energy levels of fatigue
- nerve damage
- muscle aches
- memory loss
- mood changes or disorders
- learning disabilities
As mentioned earlier, genetic factors can be the reason for choline deficiencies which causes these individuals to have a higher need for choline. Research suggests that approximately 50% of the population may have genes that increase dietary methyl requirements, and since choline is a major source of methyl processes, this can result in a choline deficiency.
The PEMT gene and choline deficiency
The high prevalence of common PEMT variants in the population should get the attention of dietitians and nutrition professionals.
A study that looked at women with the PEMT AA genotype found that these individuals had higher concentrations of plasma homocysteine (choline reduces homocysteine) during folate restriction, and women with the PEMT CC genotype did not exhibit a decrease in circulating plasma choline as expected. They found that loss-of-function SNPs in PEMT (meaning genetic variations that inhibit PEMT function) lead to compensatory activation of another choline pathway5.
So, depending on the type of PEMT genetic variation you have, it may have no physiological or physical effect.
On the other hand, PEMT plays a critical role in taking lipids from the liver to the bloodstream and generates a choline molecule that is enriched in long-chain omega 3 fatty acids. Certain variations of PEMT have been associated with non-alcoholic fatty liver disease (NAFLD), hepatic and peripheral insulin sensitivity, and atherosclerosis5.
Choline deficiency and non-alcoholic fatty liver disease
NAFLD is the most common reason for abnormal liver function and may occur in as much as 25% of the population. Humans ingesting diets deficient in the nutrient choline develop fatty liver which is worsened if genetic variations in the PEMT gene are observed.
PEMT knockout mice do not express any PEMT activity in their livers and depend completely on dietary choline intake to meet daily choline requirements. When fed a diet deficient in choline, they developed severe fatty liver which was reversed through a choline-supplemented diet, if it was introduced early enough6.
If you decide to take a choline supplement, always be sure to read the instructions carefully, and talk with a healthcare professional, especially if you’re taking any other medications.
