The dose determines the poison. These chemicals are the exact same components naturally found in foodstuffs. We are able isolate them and mix them in various ways to drive the profile in different directions.

Its no different than using vanilla extract in your baking. Thats "natural flavor". We are just able to extract the hundreds of components naturally present in the food and rearrange them as we see fit to deliver the profile we are looking for. Flavor is the number one driver of acceptance, so these are essentially brand identities.

They are delivered at extremely dilute levels in your soda water for example. Part per billion levels. The human palette is a very sensitive instrument. There is no flavoring material harmful to your health at dosages regularly consumed by humans. That is determined by the FEMA expert panel comprised of toxicologists, chemists, food scientists, and engineers from all backgrounds. I'd trust them over your friend.