Have you ever thought about what your diet would be like if you had to fend for yourself? Have you found a solution to the problems of vitamin insufficiency in restricted diets? Most of our modern, processed foods have been vitamin-enriched to prevent scurvy, rickets, and folate deficiency. If you were trying to supply your whole diet from what you can grow or forage, would you be safe?
Interestingly, capybaras and guinea pigs (cuys) also lack the ability to synthesize ascorbic acid just like humans, bats, and some other apes. If cuys are one of your survival protein sources or urban farming animal, this is a problem you will have to address.
Although I have no real proof, I suspect that the leaves of many of our edible plants that produce high-vitamin crops probably have a higher than average concentration of those vitamins, particularly before flowering and fruiting. I suspect strawberry, rose, and hibiscus leaves to be higher in vitamin C, banana leaves to be higher in potassium, citrus leaves high in both. With our soils naturally being magnesium-deficient, I suspect that to be lacking in a person living on a native Floridian diet (in the absence of shellfish and other seafoods). The more research I have done to prove or disprove this hypothesis, the more I notice there is a lack of study in this area, though I did find here that purslane and plantain are very high in vitamin A precursor. This study finds that ascorbic acid is higher in lemon leaves than in the bark, roots, and juice, partially confirming my hypothesis.