A familiar name it might not be, but choline does have very important functions in the body.
According to consultant child neurologist Dr Malinee Thambyayah, by strict definition, choline is not a vitamin. Instead, it is an essential nutrient and a vitamin-like compound.
Dr Malinee reveals that choline can be synthesised in small amounts in the body. However, this amount is not sufficient to meet the body’s metabolic needs. Thankfully, it is widely available in various foods such as liver, cauliflower, soyabeans, spinach, lettuce, nuts and eggs and exists in such foods as various forms of choline metabolites.
According to Dr Malinee, choline and compounds derived from choline (metabolites) serve a number of vital biological functions. These include:
· Structural integrity of cell membranes
Choline is used in the synthesis of the phospholipids, phosphotidylcholine and sphingomyelin, structural components of all human cell membranes.
· Nerve impulse transmission
Choline is used by the body to produce acetylcholine (Ach). ACh is a very important neurotransmitter involved in muscle control, memory and many other functions. The body cannot function normally without Ach.
· Lipid (fat) transport and metabolism
Fat and cholesterol are transported to the liver by lipoproteins called chylomicrons. In the liver, these are then packaged into very low-density lipoproteins (VLDL) for transport through the blood to the tissues that require them. Phosphotidylcholine is a required component of VLDL particles. Without adequate phosphotidylcholine, fat and cholesterol accumulate in the liver.
· Cell signalling
The choline-containing phospholipids (phosphotidylcholine and sphingomyelin) are precursors for the intracellular messenger molecules (diacylglycerol and ceramide).
Who needs choline?
Because the body can make choline, scientists had for years debated whether people needed to supplement their diet with this nutrient. However, in 1998, an expert panel convened by the Institute of Medicine (IOM) in Washington concluded that diets low in choline might lead to serious health problems, and it subsequently recommended an “adequate intake” standard of 550 milligrams per day for men and 425 mg/day for women.
This first official recommendation on daily intake was a pivotal step in heightening public awareness of choline and its role in staying healthy. Now, in response to the ruling, manufacturers are beginning to fortify a host of processed foods with choline. Milk products are also being supplemented, with different brands containing different amounts.
A significant deficiency of choline can lead to a fatty liver as well as liver damage because large amounts of fat accumulate in the liver. There could also be nerve degeneration, senile dementia and possible memory loss and poor brain function.
In animal studies, dietary choline deficiency is associated with a risk of liver carcinogenesis (cancer), decreased hematopoeisis (decreased blood cell production), renal dysfunction, infertility, growth impairment, hypertension and memory impairment.
Benefits of supplementation
Dr Malinee says that based on the many biological functions of choline outlined above, choline plays a vital role in keeping the nervous system healthy.
Dr Malinee notes that choline has been used to treat human diseases for more than 50 years. “The major site of its therapeutic action is the nervous system. Choline administered systemically rapidly enters the brain by crossing the blood-brain barrier. Choline may also be used to treat memory loss or impairment. Many nutritionally-orientated doctors consider adding phosphotidylcholine, a valuable nerve-building nutrient that makes the neurotransmitter, acetylcholine (Ach) and that may help to slow or reverse memory loss,” she observes.
In one study involving rats, pregnant rats given extra choline produced offspring with memory and learning skills superior to the offspring of those rats on a regular diet. The offspring of rats whose diet was choline-deficient performed poorly on memory tests. Dr Malinee says that as yet, there have been no human trials to test phosphotidylcholine’s effectiveness for memory problems in humans, however.
Dr Malinee notes that though choline is important for learning and memory, it is only one component in the learning and memory process.
There are many other factors involved, and even glucose and exercise can improve learning and memory.
She also cautions that since choline, lecithin or phosphotidylcholine supplements can increase acetylcholine (Ach) levels, they should not be used by persons suffering from bipolar disorder. High levels of Ach can worsen the “depressive” phase of this condition.