Choline is an essential nutrient that must be included in your diet for a strong immune system. Choline is one of the latest nutrients to be added to the list of essential nutrients by the National Academy of Sciences (NAS) in 1998. Though your liver can produce small amounts of choline, you must obtain the majority through your choline-rich diet. It enhances liver function, healthy brain development, and metabolism. Eggs are the richest source of choline. But even if you don’t do prefer eggs, you may go for other good choline-rich sources such as brussels sprouts, broccoli, swiss chard, cauliflower, etc.