Choline is considered an essential nutrient by the USDA and EU because though humans can make some of it, they can not make enough of it to be healthy without dietary supplementation.
Choline has 3 main functions in the body: one is making acetylcholine the neurotransmitter that among other things make all our muscles move (nerve gases work by inhibiting the breakdown of acetylcholine in the nerve to muscle synapses causing muscles all over the body to lock up preventing breathing and it also causes saliva secretion which is why victims foam at the mouth), acetylcholine is also one of the most important neurotransmitters in the formation of memories in the brain.
Second choline is used to make structural components called phospholipids found in every cell membrane in our bodies.
And finally during human growth and development choline is essential to proper formation of the nervous system. Neural tube defects are highly correlated to inadequate choline intake.
The US and EU governments recommend that everyone get at least 400 mg of choline every day. If you look at the USDA Nutrition Survey Data you will see that there are only 3 plant products in the top 50 choline containing foods. Two of these are purified soy products, the first being soy lecithin oil (lecithin is a choline contain structural component of cell membranes also found in human cells) and soy based protein powder. The other is surprisingly Cocoa Powder. None of the plant sources are near the top. Eggs are the second highest source of choline after chicken liver another reason I consider them a “Super Food”.
If you look at this table whose data comes from the site www.nutritiondata.com :
you will see that it is much easier to get your choline from a meat based diet than from a plant based diet. Choline is one of the many reasons I think a meat based diet is so much more nutritious than a plant based diet.