It belongs to a group of compounds known as phospholipids or phosphatides. Humans need choline, too, but our cells manufacture it. But the evidence that it can counteract any of these is weak or nonexistent. No large well-controlled studies of humans have been done.
Vegetable oils supply an abundance.
Even if lecithin supplements were known to be beneficial, those sold in health-food stores contain variable amounts of lecithin and choline. In any case, high doses of lecithin can produce side effects such as nausea, nerve disorders, or depression.