Micronutrient intakes of wild primates: are humans different? - PubMed - NCBI
Low micronutrient intake is implicated in a diversity of human health problems, ranging from problems associated with food insufficiency to those associated with food over-consumption. Humans are members of the order primates, suborder anthropoidea, and are most closely related to the great apes. Humans and apes are remarkably similar biologically. In the wild, apes and monkeys consume diets composed largely of plant foods, primarily the fruits and leaves of tropical forest trees and vines. Considerable evidence indicates that the ancestral line giving rise to humans (Homo spp.) was likewise strongly herbivorous (plant-eating). The wild plant parts consumed by apes and monkeys show moderate to high levels of many minerals and vitamins. The estimated daily intake of specific minerals, vitamin C and some other vitamins by wild primates is often quite high in comparison to intake levels of these same micronutrients recommended for humans. Are the high micronutrient intakes of wild primates simply a non-functional, unavoidable by-product of their strongly plant-based diets or might they actually be serving important as yet undetermined immunological or other beneficial functions? A better understanding of the basis for this apparent difference between humans and wild primates could help to clarify the range and proportions of micronutrients best suited for optimal human development, health and longevity.
Full text: http://nature.berkeley.edu/miltonlab/pdfs/kmilton_micronutrient.pdf
It's an interesting question. Denise Minger posted a diagram comparing human intestines to other primates. What's clear is humans are quite different. Loooong small intestines, and short colons, whereas the primates listed were just the opposite. We're likely designed to get a lot of our nutrition through highly digestible foods, not through bacterial fermentation in the colon. I assume howler monkeys are more like other primates than humans, in that most of their food will pass into the colon undigested (hence they're not absorbing most of those micronutrients in the small intestine). They may gain access to those nutrients after bacteria breaks down the fiber in the colon. There's some debate over whether or not humans can make use of the vitamins synthesized in the colon.
Looking at the estimated intakes, it seems unrealistic for humans to reach those levels of micronutrients. By their estimates, a 150 lb. howler monkey would consume over 50k mg of potassium in a day. Even the fruitarians eating ungodly amounts of fruit are only getting half that. Larger primates likely consume far lower amounts of micronutrients per kg, however.
The primate gut chart is posted on this page:
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