The world of nutrition research was buzzing recently with a rather remarkable study published in the American Journal of Clinical Nutrition, one of the nation’s top journals for nutrition research. The title of the article was “Choline and betaine concentrations in plasma discriminate levels of dietary choline intake in healthy adults: analysis of a double-blind randomized crossover controlled feeding study”, and it investigated whether or not choline-related metabolites (byproducts your body makes after eating something) could determine if a person was consuming enough of the nutrient choline.(1)

Here’s your user-friendly breakdown for an explanation of the experiment, what it discovered, and its significance.

Let’s begin!

What is choline?

Choline is a lesser-known, but still essential nutrient in the B vitamin family. It also goes by the alias of B4, smack dab in between niacin (B3) and pantothenic acid (B5). Choline is largely a precursor nutrient, meaning it is needed to build several other important nutrients.

At the top of the list, it is used to create phosphatidylcholine (even harder to say three times fast!) which is a primary building block for cell membranes. Choline is also needed to produce acetylcholine, a neurotransmitter in the central nervous system. There are several other jobs where choline plays an important position, as is the case with liver function, methylation, and pregnancy, but more on that later.

People have an enzyme called phosphatidylethanolamine-N-methyltransferase (which is somehow even harder to say three times fast…) which can make small amounts of choline, but most must be acquired through the diet. Scientists estimate that an adequate amount of choline for men and women is 550 mg/day and 425 mg/day, respectively.(2)

Food wise, you get fairly good servings from animal products, such as hard-boiled eggs (147 mg/each), chicken breast (70 mg/3 oz), and milk (45 mg/cup). Plant-based sources include soybeans (107 mg/½ cup), red potatoes with skin (57 mg/potato), and peanuts (24 mg/¼ cup). While there are plenty of food sources for choline, there is general concern in the nutrition science community that on a population level, we’re not getting enough of this underdog nutrient.

Why is getting enough choline important?

In addition to fulfilling some of those important precursor functions, we see some health implications arising when insufficient choline is consumed, notably occurring in the liver, muscle tissue, and during pregnancy. As a specific instance, one study reported restricting participants to only 10% of the recommended amount of choline for 42 days, and most of those people developed fatty liver or some form of muscle damage during that time.(3) Excess fat in the liver is a problem because the liver is not designed to store excess fat. Perhaps more concerning is reports that persistently low choline intake during a woman’s pregnancy is a risk factor for neural tube defects in the baby.(4)

Enter research team, stage right! Since there is a purported risk for under-consumption of choline in parts of the population, having additional ways to assess choline intake and determine who may be at risk is a worthwhile research question. So, are there metabolites (byproducts) of dietary choline intake which appear in the blood that let us determine if people are hitting the recommendations?

To the research design!

How did the researchers investigate plasma choline as a biomarker of dietary choline intake?

For this complex study, researchers used a randomized crossover dietary intervention where every participant was assigned to complete three separate treatment periods in randomized order.

This was a controlled feeding study, meaning all food and drink was prepared for the research participants. Each treatment period for each participant lasted 15 days, where the participants would consume a diet providing the full adequate intake (AI), in this case, 531 mg of choline each day (which is nearly 100% the AI), 255 mg/day (50% the AI), and then about 135 mg/day (25% the AI). Menus worked on a cycle and everyone was required to eat all of the meals. After the period ended, the participants had 2 weeks of washout (back to their normal diet and normal life), and then returned for the next study period.

Now, let’s all take a minute to admire how the researchers controlled the choline intake. Specially baked bread rolls! Yes, the lab team prepared the amount of necessary choline for each period with bread rolls. Everything on the menu was identical for each participant, except for the 3 bread rolls provided each day.

Bread rolls… is there anything they can’t do?

Ahem… to roll out the rest of the study (ba-dum tsk), blood samples were collected from each participant at four points in each study period. These blood samples would be used to measure the specific metabolites of interest and see if they could accurately predict what the participant had been consuming choline-wise.

Is plasma choline a biomarker dietary choline intake?

It really is a thing of wonder to read about how painstakingly detailed the researchers were with analysis of the blood samples, the additional data points collected to help verify that people ate their choline rolls, and so on. So, what did the team find?

Plasma choline, our main metabolite of interest, could successfully predict dietary intake of choline! Why is that so astounding? Because in critical circumstances, it removes the guesswork for whether or not insufficient choline is the root of someone’s health concern. It’s one thing to estimate intake or rely on memory, but it’s another to physically identify something changing in the human body that reliably tells the story.

The measured choline levels were statistically different among the participants, according to the amount of choline they were consuming. However, there was some variation to these findings since the study population was made up of men and women, the latter group in the menopausal transition. For the men and premenopausal women, the researchers could clearly see differences between all three periods (25%, 50%, and 100% of the recommended intake), but for the menopausal women, the difference was only clear between 25% and 100%.

That’s not a problem for the validity of the results, but taken together, it means that the metabolites gave you the most accurate picture of dietary choline intake when forced to choose between low intake and 100% adequate intake.

But there’s more to the picture here. Researchers also looked at whether or not any metabolites from your liver could also predict dietary choline (since chronically low choline is associated with a fatty liver), but alas, nothing on this front. They saw no differences in liver enzymes or fat between the three treatments. Still, that’s good news in the sense that if you’re getting at least 25% of your choline needs, your liver won’t be at risk with additional fat.

And there is one more hero to this story. Betaine!

Why betaine matters in all of this

Betaine happens to be another one of those important products that can be synthesized from choline. Its primary job is assisting with methylation, which means it helps transfer methyl (a kind a chemical signal) to carry out conversion reactions. But as part of their investigation, researchers discovered that serum betaine, similar to serum choline, can also accurately predict dietary choline intake.

When choline levels are high, this triggers the reaction for choline’s conversion to betaine, and this conversion occurs with good predictability.(5) So much so that together, serum betaine and choline together work even better to provide a more robust and accurate distinction between high and low choline intake. As a helpful analogy, consider the crimefighting skills of Batman and Robin. Everyone knows both Batman and Robin are independently excellent crimefighters, but what paired together, they are a dynamic duo more capable of taking down crime. Such it is with plasma choline and betaine, albeit, they’re not fighting crime (unless you count ignorance of dietary choline a crime). Alone they are both good predictors, but together they are stronger.

Perhaps the most important question to close out with is, what does this mean for you?

Consider how choline is a critical precursor for acetylcholine, the neural signal responsible for muscle movement and cognition, including learning, memory, and attention. Those are important functions that can decline with aging made worse by poor dietary choline intake. Unfortunately, most evidence suggests as adults age, fewer achieve recommended choline intake, with less than 15% of pregnant women, or adults 51 and older, meeting the AI. (6)

And now, we have evidence that sufficient choline intake can be assessed through laboratory testing. While a nutritious and varied diet can meet dietary choline needs, should there ever be concern that enough is consumed, we may soon have a way to objectively test this without relying on memory or record. Physicians who suspect inadequate choline as a problem for their patients may have a tool that provides a more objective estimate. While that estimate is strongest when comparing low choline intake (25% of the recommendation) with high choline intake (100% of the recommendation), it’s a major step forward in human health management.

Hats off to the research team!

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. 

Dustin Moore is a nutrition scientist, dietitian, and public health professional dedicated to advancing evidence-based practice. He holds a PhD in Public Health and is deeply invested in enhancing scientific communication to bridge the gap between the health science and the public.

Sources 

1. Trujillo-Gonzalez I, Horita DA, Stegall J, Coble R, Paules EM, Lulla AA, et al. Choline and betaine concentrations in plasma discriminate levels of dietary choline intake in healthy adults: analysis of a double-blind randomized crossover controlled feeding study. Am J Clin Nutr. 2026 Apr 1;123(4). doi:10.1016/j.ajcnut.2026.101236 PubMed PMID: 41687879.
2. Wallace TC, Blusztajn JK, Caudill MA, Klatt KC, Natker E, Zeisel SH, et al. Choline: The Underconsumed and Underappreciated Essential Nutrient. Nutr Today. 2018 Dec;53(6):240. doi:10.1097/NT.0000000000000302
3. Fischer LM, daCosta KA, Kwock L, Stewart PW, Lu TS, Stabler SP, et al. Sex and menopausal status influence human dietary requirements for the nutrient choline2. Am J Clin Nutr. 2007 May 1;85(5):1275–85. doi:10.1093/ajcn/85.5.1275
4. Obeid R, Derbyshire E, Schön C. Association between Maternal Choline, Fetal Brain Development, and Child Neurocognition: Systematic Review and Meta-Analysis of Human Studies. Adv Nutr. 2022 Nov 1;13(6):2445–57. doi:10.1093/advances/nmac082
5. Zeisel SH, Story DL, Wurtman RJ, Brunengraber H. Uptake of free choline by isolated perfused rat liver. Proc Natl Acad Sci. 1980 Aug 1;77(8):4417–9. doi:10.1073/pnas.77.8.4417
6. Wallace, T. C., & Fulgoni, V. L. Usual Choline Intakes Are Associated with Egg and Protein Food Consumption in the United States. Nutrients. 2017; 9(8), 839. doi.org/10.3390/nu9080839