The specifications for engine oils receive input from a combination of the government (Congress + EPA), the automotive manufacturers, the oil companies. I'm not sure how much role the SAE (Society of Automotive Engineers), and the lubrication engineering groups have on the front end. I know the lubrication engineers were not pleased when the automotive manufacturers starting specifying SAE 20 weight engine oils to improve EPA mileage test results. The SAE motor oil performance tests are extensive. Even a no-name third world brand that meets the SAE standards is very good.
The anti-wear additive is ZDDP, or Zinc dialkyldithiophosphate. Referring to "zinc" as the additive is little too short, as the "zinc" is really not the most active anti-wear part. Though "zinc" is great for sacrificial corrosion protection.
The government/EPA's aim is to extended the life of catalytic converters by lowering zinc and phosphorus in the exhaust.
Good anti-wear protect from ZDDP results in oil phosphorus concentrations of around 0.12%. New oils are typically 0.06% or less. Too much ZDDP can also cause problems, around 0.20%, so don't overfortify the oil if using a ZDDP additive.
There's plenty of information on ZDDP if you 'Google'.
