Choline is a nutrient that supports bodily processes like metabolism and cellular growth. Although the body produces a small amount of choline, it is not enough to meet its requirements, making dietary sources necessary. Recognized as a required nutrient in 1998, it is neither a vitamin nor a mineral but is often grouped with the B vitamin complex due to its similarities.
Biological Functions of Choline
The body needs choline to create two major phospholipids, phosphatidylcholine and sphingomyelin, which are fundamental to the structural integrity of cell membranes. All plant and animal cells require choline to maintain this structure. These phospholipids are also active participants in cell signaling, transmitting messages across the cell membrane to trigger responses.
Choline is a precursor to acetylcholine, a neurotransmitter that influences memory, mood, and muscle control. The nervous system uses acetylcholine to regulate automatic bodily functions like breathing and heart rate. The body converts choline from the bloodstream into this chemical, linking dietary intake to nervous system function.
This nutrient is also involved in the metabolism and transport of fat. In the liver, choline is necessary to produce substances that transport cholesterol and other fats out of the organ. Without sufficient choline, fat can accumulate in the liver. This function is tied to the synthesis of phosphatidylcholine, which is part of the particles that move lipids through the bloodstream.
Choline contributes to the processes that synthesize DNA. It works alongside other nutrients, such as folate and vitamin B12, as a source of methyl groups. These methyl groups are involved in metabolic pathways that can affect gene expression, the process by which information from a gene is used to create a functional product.
Dietary Sources of Choline
A variety of foods contain choline, with animal products being among the richest sources. Significant animal-based sources include:
- Beef liver, which provides about 356 milligrams per 3-ounce serving
- Chicken liver, which offers around 247 mg per 3-ounce serving
- A large egg, particularly the yolk, which contains approximately 147 mg
- Various types of fish like salmon and cod
For those following plant-based diets, several options can contribute to choline intake. Plant-based foods that contain choline include:
- Roasted soybeans, with a half-cup serving containing roughly 107 mg
- Other legumes, such as kidney beans and chickpeas
- Shiitake mushrooms
- Cruciferous vegetables like broccoli and Brussels sprouts
Dairy products and certain grains also add to daily choline consumption. A cup of milk provides around 38 mg of the nutrient. Wheat germ is another significant source with a high concentration of choline.
Recommended Intake and Deficiency
The recommended daily intake for choline is expressed as an Adequate Intake (AI). For adults 19 years and older, the AI is 550 mg per day for men and 425 mg per day for women. These recommendations increase to 450 mg during pregnancy and 550 mg during lactation to support development. For children, the AI ranges from 125 mg per day for infants up to 6 months to 375 mg for children aged 9–13.
A lack of sufficient choline can lead to specific health issues, primarily affecting the liver and muscles. Choline deficiency is a known cause of nonalcoholic fatty liver disease (NAFLD), a condition characterized by the accumulation of fat in the liver. In some individuals, a deficient state can also result in muscle damage.
While true deficiency is rare, many people consume less than the recommended AI. Certain populations are at a higher risk of inadequacy, including pregnant women, individuals on intravenous nutrition, and people with certain genetic variations. Consuming an extremely high amount, typically from supplements, can lead to side effects like low blood pressure and a fishy body odor.
Choline’s Role in Brain and Liver Health
Choline is important during pregnancy and early life for brain development. It is actively transported to the fetus, and maternal intake influences the development of the hippocampus, the brain region for memory and learning. Higher choline intake during pregnancy can have lasting positive effects on a child’s cognitive function. The demand for choline remains high during lactation as it is supplied to the infant through breast milk.
The nutrient’s function in fat metabolism is a significant factor in liver health. By assisting in the transport of fats from the liver, choline helps prevent the fat accumulation that defines nonalcoholic fatty liver disease (NAFLD). While it has not been shown to reverse existing fatty liver disease, maintaining an adequate intake is a preventive measure. The connection is strong enough that NAFLD is considered a consequence of choline deficiency.
For postmenopausal women, adequate choline intake is relevant for liver health. Some studies indicate that postmenopausal women with lower choline intakes had more severe signs of liver damage in the context of NAFLD. This suggests hormonal changes may influence an individual’s dietary requirement for this nutrient.