People used to consume much more raw foods which brought higher content of vitamin C, thermal processing destroys it. For comparison, gorillas, whose biology is similar to humans, consume 5, 6 grams daily of vitamin C from their food. That’s because like humans they lack an enzyme needed to organically synthesise vitamin C. A goat will synthesise 13 grams daily, and up to 100 grams daily during an infection. So that should give you an idea of the amounts needed for humans. Linus Pauling, who I mentioned earlier, consumed 18 grams daily until the day he died. He lived 93 years, had prostate cancer for the last 20, and was still scientifically engaged in his last years of life. In a conversation with the president of the Food and Drug Administration, Linus Pauling plainly said it is a crime not to inform the population about the advantages of taking daily doses of vitamin C. (Linus Pauling didn’t know he had prorate cancer they didn’t check back then) https://www.amazon.com/dp/B00028PH2Q/ref=as_glm?linkCode=ml2&tag=markkahl-20