Researchers discovered that two substances in your blood—choline and betaine—can accurately tell doctors whether you’re eating enough of an important nutrient called choline. In a carefully controlled study, people ate different amounts of choline while scientists measured these blood markers. The findings suggest doctors could use simple blood tests instead of asking people to remember everything they eat. This matters because many Americans don’t get enough choline, which is needed for a healthy liver, brain, and muscles. The study also found that some people’s livers showed more fat when eating very low-choline diets, though this varied from person to person.

The Quick Take

  • What they studied: Can doctors use blood tests to figure out if someone is eating enough choline, an important nutrient most Americans don’t get enough of?
  • Who participated: Healthy adults who followed three different eating plans for two weeks each, eating high, medium, and low amounts of choline. The exact number of participants wasn’t specified in the available information.
  • Key finding: Blood levels of choline and betaine were very good at showing how much choline people were eating. When combined, these two blood markers correctly identified dietary choline intake about 83% of the time.
  • What it means for you: If you’re concerned about choline intake, doctors may soon be able to use a simple blood test instead of asking you to track everything you eat. However, this research is still new and needs to be confirmed in larger groups of people before it becomes standard medical practice.

The Research Details

This was a carefully controlled feeding study where researchers gave participants all their food for specific periods. The study used a crossover design, meaning each person went through all three diet conditions (high, medium, and low choline) at different times. Participants didn’t know which diet they were on (double-blind), and neither did the researchers giving them food. On day 12 of each diet period, participants also consumed a special labeled form of choline so researchers could track exactly how their bodies processed it. Scientists then measured choline and related substances in blood samples using advanced laboratory techniques called mass spectrometry.

The researchers also used a special ultrasound machine called Fibroscan to check if low-choline diets caused fat to build up in people’s livers. This non-invasive test bounces sound waves off the liver to measure its stiffness and fat content, similar to how regular ultrasounds work but more specialized.

This approach is stronger than typical nutrition studies because researchers controlled exactly what people ate, eliminating the problem of people forgetting or misreporting their food intake. The crossover design also meant each person served as their own comparison, which reduces the effect of individual differences.

Most nutrition studies rely on people remembering what they ate, which is often inaccurate. This study matters because it tested whether blood markers could objectively measure choline intake without relying on memory or food diaries. If these blood tests work reliably, doctors could identify people at risk for choline deficiency more easily and accurately.

This study has several strengths: it was randomized (reducing bias), double-blind (neither participants nor researchers knew which diet was being tested), and used controlled feeding (eliminating guesswork about what people ate). The researchers used sophisticated laboratory methods to measure blood markers. However, the study appears to have been relatively small, and the exact sample size wasn’t clearly stated. The research was published on a preprint server, meaning it hasn’t yet gone through the full peer-review process that traditional journals use. This means other experts haven’t yet formally reviewed and approved the findings.

What the Results Show

The main finding was that blood levels of choline and betaine changed predictably based on how much choline people ate. When people ate 100% of the recommended amount of choline, their blood levels were highest. When they ate only 25% of the recommended amount, their blood levels dropped significantly. The researchers used a statistical test called ROC analysis to measure accuracy: choline alone correctly identified dietary intake about 81% of the time, betaine alone about 80% of the time, and when combined, they were correct about 83% of the time.

The special labeled choline that participants consumed also showed clear patterns. The ratio of labeled to unlabeled choline in the blood (called isotopic enrichment ratio) varied significantly with dietary intake, suggesting this measurement could also be useful for assessment.

Another blood marker called phosphatidylcholine showed changes related to diet, but it was less reliable for predicting actual choline intake. A marker for homocysteine (another amino acid) didn’t respond clearly to choline intake changes.

The Fibroscan liver fat measurements showed interesting individual differences. Some people developed more liver fat when eating the lowest-choline diet (25% of recommended intake) compared to the highest-choline diet (100% of recommended intake). However, this pattern wasn’t consistent across all participants—some people’s livers didn’t show this change. This suggests that people may respond differently to low choline intake, which is important because it means choline needs might vary from person to person.

Previous research has shown that choline is essential for liver, brain, and muscle health, and that most Americans eat less than recommended amounts. However, doctors have lacked reliable blood tests to measure choline status. This study builds on earlier research by testing whether specific blood markers could serve this purpose. The findings align with smaller previous studies suggesting choline and betaine respond to dietary intake, but this is the first controlled feeding study to systematically test their accuracy across different intake levels.

The study has several important limitations. First, the sample size wasn’t clearly reported, making it hard to know how many people participated and whether results apply broadly. Second, all participants were healthy adults, so findings may not apply to people with liver disease, kidney problems, or other health conditions. Third, the study only lasted two weeks per diet condition—we don’t know if blood markers remain accurate over longer periods. Fourth, the research hasn’t been peer-reviewed yet, meaning other experts haven’t formally evaluated it. Finally, the individual variation in liver fat response suggests that blood markers alone may not tell the complete story about choline status for everyone.

The Bottom Line

Based on this research, blood tests for choline and betaine show promise as tools for assessing choline intake. However, these tests aren’t yet standard medical practice. Current recommendations remain to eat choline-rich foods like eggs, fish, chicken, beef, beans, and leafy greens. Men should aim for 550 mg daily and women for 425 mg daily. If you’re concerned about choline intake, discuss it with your doctor—they can help determine if testing makes sense for your situation. Confidence level: Moderate—this research is promising but needs confirmation in larger, more diverse groups before widespread use.

This research is most relevant to people concerned about liver health, brain health, or muscle function. It may be particularly important for pregnant women (who have higher choline needs), people with liver disease, and those following restrictive diets that might be low in choline. People with genetic variations affecting choline metabolism might especially benefit from better assessment tools. However, if you eat a varied diet including animal products and vegetables, you’re likely getting adequate choline and don’t need special testing.

If blood tests for choline become available, results would be immediate—you’d get results within days like any other blood test. However, if you’re trying to improve choline intake through diet, you might notice benefits to energy, focus, or liver health within weeks to months, though individual responses vary.

Want to Apply This Research?

  • Track daily choline intake in milligrams by logging choline-rich foods (eggs, fish, chicken, beef, beans, broccoli, Brussels sprouts). Set a daily goal of 425-550 mg depending on your sex and aim to hit this target at least 5 days per week.
  • Add one choline-rich food to each meal: eggs at breakfast, fish or chicken at lunch, and beef or beans at dinner. Use the app to log these foods and watch your choline total increase. Start with one meal per day and gradually add to others.
  • Track weekly average choline intake over 4-week periods. If blood tests for choline become available through your doctor, you could compare your dietary tracking with actual blood levels to see how accurately you’re meeting your goals. Monitor energy levels, focus, and overall wellness as indirect indicators of adequate choline intake.

This research is preliminary and hasn’t yet been peer-reviewed by independent experts. Blood tests for choline assessment are not yet standard medical practice. The findings apply to healthy adults and may not apply to people with liver disease, kidney problems, or other medical conditions. Always consult with your healthcare provider before making significant dietary changes or requesting new medical tests. This information is educational and should not replace professional medical advice. If you have concerns about your choline intake or liver health, speak with your doctor or a registered dietitian.