by Sumayyah Elkhouly
The NRI’s fourth annual Virtual Internship Program (VIP) concluded on July 20 with 21 high school students from around the country presenting their research on the nutrients of their choice. Their research papers have been compiled into a journal, which you can view here.
Sumayyah Elkhouly, a rising college freshman set to go to Univeristy of North Carolina at Charlotte, recently graduated from Cato Middle College High School in Charlotte, NC. She concluded the Virtual Internship Program with exceptional results. Her presentation and paper were ranked in the top 3 by NRI faculty and staff. Her chosen nutrient was choline. Here is Sumayyah’s paper.
“Choline until the 1990s was not known as a required nutrient for humans. In fact, all of the textbooks said we could make our own and therefore we didn’t have to eat it” (Zeisel). As this quote suggests, choline is an essential nutrient that plays many active roles in the human body. It is used to maintain cellular structure in humans and animals, and is vital to the production of acetylcholine. Choline has also been found to contribute to brain development in the fetus (National Institutes of Health). Although it is not known by another name, it is produced in the liver in the form of phosphatidylcholine, and is typically consumed in this form as well. Other forms of consumption include choline bitartrate and lecithin, usually available as a component of dietary supplements (National Institutes of Health).
Choline discovery began in the mid-nineteenth century by a pharmacist known as Theodore Gobely, and his research findings were expanded upon by Adolf Strecker. Both scientists studied lecithin in animals, and Strecker was specifically concerned with the relationship between lecithin and bile. After conducting numerous studies, Strecker named the nitrogenous chemical that he had newly discovered after the Greek word for bile, which is “chole”. It is here that choline was given an official name, and therefore its discovery dates back to over a century (Zeisel).
The significance of choline as an essential nutrient was not yet known at this time, however. Building off of a study that used pancreatectomized dogs (which had developed a condition of fatty liver as a result of their pancreas absence) to examine the effects of insulin, a professor by the name of Charles Best observed that feeding these dogs lecithin cured their subsequent fatty liver. He then proved that choline is an active constituent of lecithin in 1934 (Zeisel). Interestingly, by the mid twentieth century, numerous findings on the effects of choline and choline deficiency of animals had been published, yet for the following five decades scientists did not believe that choline consumption was needed for human health. It was not until 1998 that an Adequate Intake level for choline as an essential nutrient was issued in the United States (Zeisel).
Choline is involved in many body processes, including brain, liver, and muscle function. Firstly, choline is responsible for preserving the structure of cell membranes; it produces two phospholipids, phosphatidylcholine and sphingomyelin, that are necessary for the composition of the plasma membrane of cells. Therefore, both plant and animal cells need choline in order to maintain their specific anatomy (National Institutes of Health). Additionally, choline is required in order to produce the neurotransmitter acetylcholine, which functions in brain and nervous system health, as well as in muscle contraction. Choline has also been proven to aid in the healing of certain liver disorders, such as nonalcoholic fatty liver disease, and it helps to ensure the maintenance of optimal liver functioning as well. Furthermore, this nutrient has been found to contribute to gene expression, cell membrane signaling, lipid transport and digestion, and brain development of the fetus during pregnancy (National Institutes of Health). Researchers have found that infant processing speeds increase with a maternal diet high in choline content.
While there is a recommended dietary guideline for choline intake, satisfactory choline consumption depends on one’s age, gender, and ability of the body to endogenously produce this nutrient. This amount is also dependent upon the presence of other nutrients in the diet, specifically methionine, betaine, and folate (National Institutes of Health). Pregnancy and lactation affect the amount of choline needed as well, in which case choline ingestion should slightly increase. The Adequate Intake (AI) for adult males is 550 milligrams per day, and for adult females who are not pregnant or lactating is 425 milligrams per day. However, most people in the United States do not meet this suggestion, especially pregnant women and those with genetic mutations, as they are more likely to be deficient. Choline deficiency may lead to muscle and liver damage, and in severe cases, nonalcoholic fatty liver disease. Although not common, too much choline consumption can cause a fishy body odor, vomiting, heavy sweating, low blood pressure, and liver damage. Increased choline intake may also increase the risk of heart disease, according to some research findings (National Institutes of Health).
As mentioned previously, choline is an essential nutrient; this means that it is a nutrient that must be consumed in the diet in order to meet the body’s needs. Once consumed, bacteria in the gut converts choline into a byproduct known as trimethylamine, and then the liver converts this byproduct to trimethylamine-N-oxide (The Nutrition Source). Most choline is therefore metabolized in the liver, and this organ then initiates choline’s transformation into phosphatidylcholine. Additionally, choline metabolism is both cell and tissue specific, and therefore results in different metabolic pathways. These pathways include donating a methyl group needed for many steps in human metabolism as a whole, playing a role in signaling phospholipids, synthesizing structural membrane phospholipids, and producing acetylcholine (Degani et al.). Free choline in the body is absorbed in the small intestine and is then stored in the liver, where it is distributed throughout the body as necessary, usually to make more cell membranes (National Institutes of Health).
In the human body, choline is produced endogenously by the liver in the form of phosphatidylcholine. However, the amount manufactured naturally by the body is not sufficient enough to meet the body’s needs, and therefore choline must be consumed in the diet. Choline is present in the highest concentrations in animal products, such as meat, fish, poultry, eggs, and dairy foods. It is also found in cruciferous vegetables, beans, nuts, seeds, and whole grains (National Institutes of Health). Breast milk organically contains choline as well. It is important to note that choline is not used as a food additive, but lecithin is; scientists and nutritionists alike recommend eating a diet high in choline in order to meet daily needs, or to utilize supplementation. However, there is a general consensus that it is usually more beneficial to ingest the nutrient in its raw form rather than to supplement. Yet, choline can be taken as a dietary supplement. Some multivitamins contain choline, and this nutrient is typically available in the form of choline bitartrate, lecithin, or phosphatidylcholine (The Nutrition Source).
The Choline Science Summit held in 2018 was summarized in a research article that expanded upon the benefits of choline consumption and the dangers of choline deficiency. This discussion highlighted the current dietary intake of choline in America, and how this level is severely insufficient. Researchers found that about ninety percent of Americans fall below the recommended Adequate Intake for choline, and this number includes the majority of pregnant and lactating women in the United States. According to this article, a mere ten percent of Americans and 8 percent of pregnant women meet the gender, age, and life specific Adequate Intake level for choline (Wallace et al.). This is significant because countless studies have shown that sufficient choline intake is directly linked to more optimal brain functioning, specifically when this intake begins maternally while a woman is pregnant. Ample choline in a mother’s diet has been found to positively benefit an infant’s neurocognitive development. These benefits continue throughout the lifespan if one persists with including choline in the diet (Wallace et al.).
To further expand upon this point, in this article, a study composed of women in their third trimester of pregnancy were placed into two groups; the difference between the two groups was the amount of choline the women ingested regularly. The purpose of this study was to identify the effects of choline on infant brain development, and researchers found that infants born to the mothers with higher choline intake exhibited faster processing speeds and an increase in memory. These same researchers also studied the continued impact of choline on neurocognitive functions, by
inviting the same cohort to participate in the extended study seven years later. They found that the children of the mothers with a high maternal consumption of choline expressed persistent cognitive benefit. These children had longer attention spans, increased memory, and increased ability to problem solve (Wallace et al.).
These findings are important because they emphasize the significance and benefit of sufficient choline intake throughout life on one’s brain health and development. The brain is arguably one of the most vital organs in the entire body, and therefore appropriate nourishment of the brain is directly linked to maximal functioning. This article also sheds light on the unfortunate discovery that only a small portion of health professionals and physicians are fairly familiar with choline and its effects. It is hence a necessity that healthcare workers must become thoroughly aware of choline as an essential nutrient, as well as the food sources of choline (Wallace et al.). This is a needed first step, and an imperative call to action— for a diet inclusive of brain nourishing foods is a diet that should be promoted largely by the healthcare world.
Degani, Hadassa, et al. “Choline Metabolism: Meaning and Significance.” AFNI, https://afni.nimh.nih.gov/sscc/staff/rwcox/ISMRM_2006. Accessed 27 June 2023.
Leland, Elizabeth. “Dr. Steven Zeisel: A chance I might discover something – UNC Gillings School of Global Public Health.” Gillings School of Public Health, 23 July 2018, https://sph.unc.edu/sph-news/dr-steven-zeisel-a-chance-i-might-discover-something/. Accessed 10 July 2023.
National Institutes of Health. “Choline – Health Professional Fact Sheet.” NIH Office of Dietary Supplements, 2 June 2022, https://ods.od.nih.gov/factsheets/Choline-HealthProfessional/. Accessed 26 June 2023.
The Nutrition Source. “Choline | The Nutrition Source | Harvard T.H. Chan School of Public Health.” Harvard T.H. Chan School of Public Health, March 2023, https://www.hsph.harvard.edu/nutritionsource/choline/. Accessed 27 June 2023.
Wallace, Taylor C., et al. “Choline – PMC.” NCBI, 13 November 2018, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6259877/. Accessed 30 June 2023.
Zeisel, Steven H. “A brief history of choline – PMC.” NCBI, 26 November 2012, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4422379/. Accessed 26 June 2023.
Zeisel, Steven H. “Choline.” Linus Pauling Institute, https://lpi.oregonstate.edu/book/export/html/342. Accessed 10 July 2023.