One of the most succinct and strong arguments justifying a higher standard  intake of vitamin C can be found in nature.  The argument is this, nearly all other animals in nature manufacture their own vitamin C.  These animals synthesize their own vitamin C in much larger quantities than we are advised to consume for ourselves.  Why is this?  Somewhere along the way, due to a genetic mutation,  humans lost the ability to make one of the four enzymes necessary to turn the simple sugar glucose into vitamin C.

With few exceptions, humans have virtually the exact dietary needs of other mammals in nature.  There are very few animals in nature that do not synthesize their own vitamin C. We are one of those animals, along with gorillas and guinea pigs to name a few.

Animals that do make their own vitamin C, do so at a level of about 30-300 mg per kilogram per day. According to this scale if a 70kg(154lb) human could still manufacture its own vitamin C, it would do so in the range of 2,100 or 21,000 mg per day.  This is equivalent to 2.1 to 21 grams per day. This wide range of vitamin c synthesis is due to the similarly wide range of diets found in these animals. Some eat large amounts of fresh vegetation and need to manufacture less of their own vitamin C. Other animals are strictly carnivorous, thereby receiving  little vitamin C from their diets and as such required to manufacture more vitamin C per kilogram body weight than that produced by herbivores with vitamin C rich diets. This production in nature of 2,100 to 21,000 grams per 70kg vertebrate is still 35-350 times the recommended 60mg USRDA daily intake.

It is difficult to believe that all other vertebrates in nature(literally thousands of animals) would produce these comparatively large amounts of vitamin c if it were not necessary for them in some way. It is also a struggle to conceive  that humans are so much different from other animals in nature that they could  maintain optimal health on a comparatively minuscule dose of vitamin C that other vertebrates  in nature seem to find essential. The Food and Nutrition Board may not think you need much vitamin C, but the physiology of all other vertebrates in nature would seem to disagree.

Dr. Linus Pauling had this to say, ” Other animals, including the goat, cow, sheep, mouse, gerbil, rabbit, cat and dog, also manufacture vitamin C at a high rate, averaging about 10,000 mg per day for 70kg(154 lbs) body weight… I conclude that the optimum daily intake of vitamin C for most adult human beings lies in the range of 2.3 to 10 grams per day. The amount of biochemical variability is such that for large populations the range for this dosage may be as much as 250 mg to 20 grams per day.” This large range is due to the fact that animals under stress or that have succumbed to infection can produce 4-5 times the amount of vitamin C that they would under normal conditions.”

It would seem from the evidence found in animals that we vertabrate, creatures of nature known as  humans  need far more than 60 mg  of vitamin c daily to compensate for our inability to make it in our own bodies.