Choline

Choline is a fat-like substance that is important for good health and is found in all cells of the body. Although a small amount of choline can be synthesized in the liver, not all of the body's needs can be met this way. If we take in too little choline with our food, we can only store a small amount of choline and thus imbalance the function of the liver. This is why food is an important source of choline. The most common form of choline in food is phosphatidylcholine. Most of the choline ingested from food is absorbed in the liver, brain and kidneys. The term lecithin is used in two senses. In chemistry, lecithin is another name for phosphatidylcholine (the most common form of choline in food). In nutrition, lecithin is the name for a substance often derived from soybeans that contains a mixture of phosphatidylcholine, inositol and other phospholipids. Lecithin granules are a valuable nutrient supplement because they contain choline and inositol in relatively large quantities

Functions

• Detoxification and elimination of chemicals: Choline supports the liver's enzyme system that detoxifies the blood and eliminates drugs and toxic environmental chemicals.
• Fat metabolism in the liver: Choline is necessary for the transport of triglycerides and other fats from the liver into the tissues. A low choline status is synonymous with the accumulation of fat in the liver cells and impaired liver function.
• Synthesis of acetylcholine: Choline is converted to acetylcholine in the nerves and brain. Acetylcholine is one of the main neurotransmitters that controls emotions and behavior in the brain.
• Cell structure: Choline is required for the production of lipids that support the structural integrity of cell membranes (3).
• DNA synthesis: Choline and vitamins such as vitamin B12 and folate support a process that is important for DNA synthesis.

Choline deficiency is unhealthy but rare

A choline deficiency can cause damage, particularly to the liver. A small study of 57 adults found that 77% of men, 80% of postmenopausal women and 44% of premenopausal women suffered liver and/or muscle damage after switching to a choline-deficient diet (4). Another study found that 73% of postmenopausal women who consumed a diet with inadequate amounts of choline developed liver or muscle damage (5). However, these symptoms disappeared when sufficient choline was consumed. However, even though most people in the Western world do not consume adequate amounts of choline, a true deficiency is rare.

Causes of deficiencies

Lack of B vitamins: Low folic acid or vitamin B12 intake significantly increases the need for choline. Chronic diseases: Diseases, such as AIDS, inflammatory bowel disease or arthritis, increase the risk of choline deficiency High alcohol consumption: Regular alcohol consumption lowers choline levels in the body Digestive disorders: People who have pancreatic or other fat digestive disorders absorb choline poorly and can develop deficiency symptoms because of this. Growth: The need for choline is increased during pregnancy and breastfeeding. Choline is found in many foods. Nevertheless, the daily intake of choline in Western Europe and the USA is low at 0.2-1.0 g per day. Lecithin supplements are a particularly good source of choline. They usually contain about 20% phosphatidylcholine. Consequently, 5 g of lecithin contains about 1 g of phosphatidylcholine.

Consequences of a choline deficiency

Most people do not consume enough choline in their diet. Possible symptoms of a deficiency include (1):

• Liver problems including fatty liver
• Mood swings
• Muscle fatigue
• Reduced endurance in athletes
• Increased risk of liver cancer
• Fat storage in the liver, leading to liver damage
• Impaired kidney function
• Impaired carnitine metabolism
• Impaired growth
• High blood pressure
• Learning and memory disorders
• Infertility
• Reduced production of red blood cells

Who is at increased risk of a deficiency

Certain people have an increased risk of choline deficiency (6):

• Endurance athletes: during prolonged endurance activities such as a marathon, choline levels drop. However, the extent to which choline supplementation increases performance is still unclear (7, 8).
• Postmenopausal women: Estrogen helps with choline production in the body. Since estrogen levels tend to decrease in postmenopausal women, these women may be at increased risk for choline deficiency (9, 12).
• High alcohol consumption: Alcohol consumption lowers choline levels in the blood and liver (10, 11). Severe alcohol abuse can lead to fatty liver and liver disorders. Choline supplements can reduce the damage caused by alcohol consumption and speed up recovery.
• Pregnancy: Choline requirements are significantly increased during pregnancy (13). In the latter stages of pregnancy, pregnant women may develop low blood choline levels and increased fat deposits in the liver. Low choline intake can increase the risk of pregnancy complications such as premature birth and low birth weight (2). Supplements can replenish depleted choline stores and protect the liver.

Potential health benefits of choline

Choline may promote and improve cardiovascular health High choline consumption is associated with a reduced risk of heart disease (14). Folate and choline help to convert the amino acid homocysteine into methionine. A lack of choline or folate can therefore result in an accumulation of homocysteine in the blood. Elevated homocysteine levels in the blood are associated with an increased risk of heart disease and stroke (15). However, even though choline can lower homocysteine levels, the links between choline intake and heart disease risk are unclear (16, 17, 18). This may also be related to the fact that increased consumption of choline-rich foods can increase levels of the toxic metabolite trimethylamine-N-oxide (TMAO). High TMAO blood levels are associated with a higher risk of stroke and heart attack, although this is more pronounced in people with other risk factors such as diabetes, kidney disease or high blood pressure (19, 20). Studies that have investigated the relationship between increased choline intake and stroke risk have produced contradictory results. According to data from over 120,000 adults, increased choline intake was associated with a 26% higher risk of dying from heart disease or stroke (21). In contrast, another study with almost 4,000 participants concluded that a higher choline intake could reduce the risk of stroke (22). It is quite possible that there is a dose-dependent correlation here. A moderate intake of choline could reduce the risk of cardiovascular disease, while an excessive intake could reverse this effect. In addition, choline-containing lecithin supplements can lower triglycerides and total and LDL cholesterol and increase HDL cholesterol in the blood, which can reduce the risk of arteriosclerosis. Overall, the data on the effects of choline on cardiovascular health are inconsistent and more research is needed to better understand this relationship.

Choline may have positive effects on brain health and function

Choline is required for the production of acetylcholine, a neurotransmitter that plays an important role in memory, mood regulation and intelligence. (23). In addition, choline is required for the production of DNA, which is important for brain function and development (24). With this in mind, it should come as no surprise that choline is associated with improved brain function. This includes, but is not limited to, the following areas:

Choline may improve memory and brain function

Large observational studies have linked choline intake and blood levels to improved brain function, including better memory and information processing (25, 26). Supplementation with 1000 mg of choline per day led to improved verbal memory in adults between 50 and 85 years of age with poor memory (27). In another study, supplementation with phosphatidylcholine slightly improved memory performance in patients in the early stages of Alzheimer's disease (28). However, other studies with healthy or demented subjects were unable to observe any effects of choline supplementation on memory (39, 40).

Choline could promote brain development

Several animal studies suggest that choline supplementation during pregnancy may promote brain development in the fetus (31, 32). However, there are few human studies on this issue. An observational study of 1,210 pregnant women found that choline supplementation had no association with mental performance in children at 3 years of age (44). However, the same study showed that higher choline intake during the second trimester was associated with better scores on visual memory tests in the same children at 7 years of age (34).

Choline could improve mental health

Some studies suggest that choline may play a role in the development and treatment of certain mental disorders.

One large observational study linked lower choline levels to a higher risk of anxiety disorders but not necessarily depression (35). These levels are used as an indicator of certain mood disorders and choline supplements are sometimes used to treat bipolar disorder (36). One study found that choline therapy can improve symptoms of mania in patients with bipolar disorder (37).

Choline could promote weight loss

In a clinical study of 22 female athletes, choline supplementation (2 grams per day, 7 days before a competition) reduced body mass index (BMI) by 12% with no negative effects on performance (38).

According to an observational study of over 3,200 subjects, low choline intake was associated with the following (39):

• More body fat
• Increased weight
• Higher BMI
• A larger waist-to-hip ratio

In other words, people who consumed more choline had a lower risk of obesity.

A study in obese mice confirmed the potential of choline to stimulate weight loss by increasing mitochondrial function and fat burning (40). However, a review of 50 clinical trials reported inconsistent effects of choline on body composition (41).

Choline may be helpful for liver disease

Choline builds phosphatidylcholine, which helps break down fat in the liver. For this reason, low choline levels can lead to fat accumulation in the liver (42). In a large Chinese observational study of over 56,000 people, choline intake reduced the risk of non-alcoholic fatty liver disease - but only in women of normal weight (43). In 54 healthy adults, a low-choline diet increased the risk of fatty liver disease and other liver problems. Increasing dietary choline intake reversed these effects (44). Another study of 57 adults confirmed that low-choline diets could cause fatty liver disease, particularly in postmenopausal women (45). People who are exclusively fed intravenously have a higher risk of fatty liver disease due to choline deficiency. Doctors have successfully prevented this by adding intravenous choline (46, 47).

In many animal studies, higher choline intake has been shown to do the following (48, 49, 50, 51):

• Prevention and reversal of fatty liver disease
• Stimulation of cholesterol metabolism
• Prevention of oxidative damage and scarring in liver tissue
• Prevention of cell mutations and liver cancer

Choline could alleviate asthma

In a study with 74 asthma patients, choline supplementation with 1,500 mg choline twice a day for six months was able to alleviate asthma symptoms and reduce inflammation. Two further studies came to similar conclusions (52, 53, 54). In animal models of asthma, choline reduced inflammation and oxidative stress while improving lung function (41, 42).

Other potential areas of application

• Movement disorders: Irregularities in the acetylcholine system in the brain can lead to movement disorders. Therefore, people with Parkinson's disease, Huntington's disease and other nerve disorders that manifest in abnormal movements can be helped by administering a choline and lecithin supplement.
• Liver detoxification and elimination of drugs and chemicals: Choline stimulates the liver's enzyme system, which detoxifies the blood and eliminates drugs, alcohol and toxic environmental chemicals such as pesticides, food conditions and heavy metals.
• Inflammation of the liver: Choline and lecithin supplements can alleviate symptoms of viral liver inflammation (hepatitis), reduce its duration and prevent relapses.
• Gallstones: Lecithin can prevent the deposition of cholesterol in the form of gallstones. Choline and lecithin supplements can reduce the risk of such a disorder.

Food sources of choline

Food sources generally contain choline in the form of phosphatidylcholine from lecithin - a type of fat.

The best sources of choline include (57):

• Beef liver 100 g 520 mg
• Chicken egg 1 medium 270 mg
• Peanuts 100 g 95 mg
• Beef, fillet 100 g 66 mg
• Cauliflower 100 g 42 mg
• Iceberg lettuce 100 g 31 mg
• Wholemeal bread 100 g 13 mg
• Potatoes 100 g 8 mg
• Whole milk 1 dl 3 mg

Food additives and supplements

Soy lecithin is often used as a food additive containing choline. For this reason, it is likely that additional choline is consumed via food supplements. Lecithin can also be purchased as a supplement. However, lecithin contains only 10 to 20% phosphatidylcholine. Phosphatidylcholine can be consumed as a supplement in capsule or powder form, but choline only makes up 13% of the weight of phosphatidylcholine (58). Other forms of choline include choline chloride, CDP-choline, alpha-GPC and betaine. CDP-choline and alpha-GPC tend to contain more choline than other choline dosage forms. They are also better absorbed by the body than other forms of choline.

Safety and side effects

Choline is likely safe and harmless for most adults and children when used appropriately.

High doses of choline may not be safe for adults and children. Doses above the maximum tolerated dosage may cause side effects such as sweating, fishy body odors, stomach and intestinal problems, diarrhea and vomiting. No toxic reactions have been observed at low doses. In some individuals, high doses of choline can cause depression.

The maximum tolerated daily dosage of choline (the highest dosage at which there is a high probability of no harmful side effects) is as follows:

• Children from 1 - 8 years: 1 gram
• Children from 9 - 13 years: 2 grams
• Adolescents from 14 to 18 years: 3 grams
• Adults over the age of 18: 3.5 grams

There are concerns that increasing choline intake may increase the risk of colon and rectal cancer. One study found that women whose diets contained a lot of choline had an increased risk of bowel cancer. However, more research is needed to determine the effects of diet on colorectal cancer

Precautions and warnings

Pregnancy and lactation: Choline is probably safe and harmless during pregnancy and lactation when taken orally in adequate amounts. Doses of up to 3 grams in pregnant and breastfeeding women up to 18 years of age and doses of up to 3.5 grams in pregnant and breastfeeding women 19 years of age and older are unlikely to cause adverse side effects. However, not enough is known about the safety and harmlessness of higher doses during pregnancy and breastfeeding, so it is best to stick to the maximum doses indicated.

How much choline does the body need?

Due to a lack of data, no officially recommended daily intake for choline has been established. However, the American Institute of Medicine has determined values for an adequate intake (59). These values are sufficient for most people and should help to prevent negative consequences of a choline deficiency, such as liver damage. Nevertheless, requirements vary depending on genetic predisposition and gender (60, 61, 62). In addition, it is difficult to determine the actual choline intake as the presence of choline in different foods is relatively unknown.

Here are the recommended amounts of choline for different age groups (63):

• 0-6 months: 125 mg per day
• 7-12 months: 150 mg per day
• 1-3 years: 200 mg per day
• 4-8 years: 250 mg per day
• 9-13 years: 375 mg per day
• 14-19 years: 400 mg per day
• Adult women: 425 mg per day
• Adult men: 550 mg per day
• Breastfeeding women: 550 mg per day
• Pregnant women: 450 mg per day

It is important to remember that individual choline requirements vary. Many people can cope with less choline, while others need more (64). In one study, 6 out of 26 men developed symptoms of choline deficiency despite consuming the recommended amount (65).

Conclusion

Choline is an essential nutrient that supports and protects the liver, brain, nerves and more. Despite its importance, many people do not consume enough choline. Athletes, people who consume alcohol, postmenopausal women and pregnant women have an increased need for choline. The best food sources of choline include beef liver, eggs, poultry, whole grains and beans.

Choline may help prevent fatty liver, relieve symptoms of asthma, and promote both cognitive function and fetal development.

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