Eggs are a fantastic food – nutritious, tasty and very versatile. But many people are unaware that eggs contain an essential nutrient called Choline. Choline is often overlooked, but it is crucial for brain health, including for mood and memory, and essential for liver function. A diet lacking in choline can lead to fatty liver disease. It is a little known fact that if you’re not eating eggs regularly it is difficult to get enough choline. Here we outline why choline is so essential for health, and how to make sure you avoid deficiency to keep your brain and liver healthy!
What Is choline and why do we need it?
Choline is a B-vitamin like substance which is an essential component of all cell membranes. It is considered an essential nutrient for human health - the body can only make a little of it, so we have to consume it in our food. In this way it is similar to omega 3 fatty acids – as they are both vital for health and have to be included in the diet.
The name choline comes from the Greek term for bile - 'chole' because it was first isolated from ox bile in 1862. Its nutritional importance was not understood until the 1930s, when deficiency was shown to cause fatty liver disease in dogs and rats, which resolved when choline was reintroduced to the diet.
Unfortunately, few people have heard of choline and may not be aware of the risks of choline deficiency. However, many people are likely to be deficient, particularly if they don’t eat eggs regularly. And unlike the US and Europe, the UK government has not set a recommended daily intake level for this essential nutrient as they do for most vitamins and minerals. This is despite the fact that deficiency can cause non-alcoholic fatty liver disease and affect brain health, including the development of a baby’s brain before birth.
Why we need choline
Choline is essential for health, not least because choline is needed to make the membranes of all the cells in our bodies. It is also needed for the metabolism of fats, and for methylation, which if faulty, can raise homocysteine, a risk for heart disease. But there are two organs in our bodies for which choline is particularly important – the brain and the liver- as detailed below.
Choline for the brain and nervous system
Choline is essential for brain health and is protective against neurodegenerative diseases. It is needed to make the neurotransmitter acetylcholine, which is crucial for effective neural communication and cognitive processes. Acetylcholine is involved in many important functions including memory, mood, muscle control, and other brain and nervous system activities. Choline is needed to maintain the health and integrity of the neuronal membranes, which help protect us against age-related cognitive decline.
Adequate choline intake is linked to improved cognitive function and may help in the prevention of neurodegenerative conditions such as Alzheimer's disease. Studies have shown improvements in cognitive function with higher levels of choline:
The Framingham Heart study Offspring cohort study, involving 1391 volunteers, found that dietary choline was positively associated with specific cognitive functions - verbal and visual memory.
A study, involving 2,393 adults over the age of 60, choline intakes between 187 and 400 mg/day were associated with improved cognitive performance in three separate measures (assessing learning, processing speed, sustained attention, and working memory) compared to intakes of less than 187 mg/day.
In a study of 2195 older adults (aged 70-74), high versus low blood levels of choline were significantly associated with greater performance at cognitive tests assessing sensory motor speed, perceptual speed, executive function and global cognition.
Traumatic brain injury – Citicoline (choline combined with cytidine) appears to limit memory deficits and the duration and severity of other post-traumatic symptoms (e.g., headache, dizziness, attention disorder) in patients with mild-to-moderate injuries
Brain development in babies
Choline is essential for women during pregnancy as it supports the healthy development of the baby’s brain and spinal cord.
“New and emerging evidence suggests that maternal choline intake during pregnancy, and possibly lactation, has lasting beneficial neurocognitive effects on the offspring”
Taylor C Wallace, 2018* |
Whilst this is not well known in the UK, adequate choline intake by pregnant women is needed for early brain development of the foetus, and supports the development of the baby’s nervous system, reducing the risk of neural tube defects. Choline supplementation during late pregnancy has been shown to bring cognitive benefits to the child. Choline requirements are therefore higher for pregnant and breast feeding mothers than for other adults.
Choline for the avoidance of Fatty Liver Disease
Non-alcoholic fatty liver disease (NAFLD) is a condition in which there is a build-up of fat in the liver. NAFLD is associated with a range of metabolic health conditions and it can lead to more serious liver disease, including cancer.
It has been known for many years that a lack of choline results in damage to the liver and the development of NAFLD. This NAFLD can be reversed with the addition of choline. This was reported in the British Medical Journal more than 70 years ago, as shown below.
One of choline’s many important roles is to make the molecules which transport fat out of the liver. Fat and cholesterol from the diet are transported to the liver where they are packaged into lipoproteins, called very-low-density lipoproteins – VLDL, for transport in the bloodstream to other tissues in the body. Choline helps make the VLDL cholesterol molecules that are used to export fat from the liver. Without choline, fat will accumulate in the liver causing NAFLD and other liver damage.
Studies have shown that higher intakes of choline are associated with lower risk of NAFLD:
An analysis of two large prospective studies conducted in China involving over 56,000 people, aged 40-75 people looked at the association between dietary choline intakes and fatty liver disease. Those with the highest intakes of choline (412mg/day) had a 28% lower risk of fatty liver disease compared to those with the lowest intakes of choline intake (179 mg/day) in normal-weight women. No similar association was found in overweight or obese women or in men.
A study of 664 people with NAFLD or NASH (non-alcoholic steatohepatitis) found that choline intake in post-menopausal women was inversely related to NAFLD – that is, the lower the level of choline, the greater the risk of NAFLD.
A US national survey of over 20,000 adults found that higher dietary intakes of choline were associated with a more favourable profile of liver enzymes and with a lower risk of developing NAFLD.
How much Choline do we need?
Health bodies in both the United States and Europe make recommendations on minimum requirements for choline for all ages. These were introduced in 1998 in the US, and, following an evaluation of the evidence, introduced in Europe in 2016. The requirements set in US and Europe for adults and both pregnant and breastfeeding women are set out below.
No minimum requirements have been set for choline to date in the UK. It has been suggested that we could be facing a potential choline crisis in the UK and the Scientific Advisory Committee on Nutrition (SACN) should consider the inclusion of choline as part of the UK Dietary Guidelines.
Choline deficiency
Whilst data on estimated choline intakes are not currently measured in the UK, in the US, research suggests that most people fall below the recommended intake levels set for this nutrient, with only around 8% of adults meeting the recommended intake levels.
Genetics may play a part in our susceptibility to choline deficiency, and it is likely that some people may require more choline than others because of their genetics.
The risk of liver damage due to choline deficiency increases in women after the menopause. as oestrogen assists the body to make choline and 44% of premenopausal women will have liver damage when deficient in choline, compared to 56% of post-menopausal women.
Choline-rich foods
By far the easiest way to get enough choline in your diet is to eat plenty of eggs! One large egg contains nearly 200g of choline. People who regularly eat eggs have choline intakes which are nearly double the intakes of those who don’t consume eggs, according to one US study. Choline is found in the yolks of eggs, and not in egg white, so make sure you eat the whole egg to get your choline.
In general, animal foods contain more choline than plant foods. Some of the best sources of choline include beef, eggs, fish, chicken and milk. However, choline is also found in plant foods - some of the best sources are cruciferous vegetables like cauliflower and broccoli, and nuts. Dried shiitake mushrooms and sundried tomatoes are also very good sources of choline. Details of some of the best sources of choline are shown below.
Table 1: Choline per 100g of food
Source: USDA Food Data Central via MyFoodData
Vegetarians and Vegans
Vegetarians who eat dairy and eggs may be able to meet their choline requirements from diet alone, however this would probably require high egg consumption. Vegans are more likely to find it difficult to consume enough choline through food alone, as even with a high consumption of vegetables such as cauliflower and broccoli, given that adults need at least 400mg/day of choline each day, it would be difficult to reach this target.
Vegans in particular, and vegetarians who don’t eat eggs, are therefore advised to use supplementary choline to meet their daily requirements.
In summary
Choline is an essential nutrient that we need for our health, and particularly for the health of our brains and livers.
Choline deficiency leads to the build up of fat in the liver and causing fatty liver disease.
Choline is important for cognitive function and may reduce risk for neurodegenerative diseases, such as Alzheimer's Disease.
Unlike the US and Europe, the UK government have not yet set recommended daily intake levels for this vitamin, even though the potential impact of deficiency are serious.
Pregnant and breastfeeding women are advised to ensure sufficient choline in their diets to support healthy brain and spine development of their babies
Vegans, vegetarians and those who don't eat eggs are advised to consider taking choline as a supplement.
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