Role: A methyl donor. A component of bile, and of the neurotransmitter acetylcholine. As part of the phospholipid lecithin, it is an emulsifier and functions in cell membranes.
Deficiency: Fatty liver and liver damage.
Sources: Egg yolk, liver, milk and dairy products, soybeans, peanuts.
Toxicity: Fishy body odor, vomiting, excess sweating and salivation, liver damage, digestive disturbance, low blood pressure.