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Unformatted text preview: Back to Basics: Why Foods of Wild Primates Have Relevance for Modern Human Health Katharine Milton, PhD From the Department of Environmental Science, Policy and Management, Division of Insect Biology, University of California, Berkeley, California, USA Many current health problems are attributed to diet, and numerous views exist as to which types of foods contribute to such prob~ Items},2 This issue is not one of purely academic hrterestmrather, it has important ramifications for human health and well~behrg in the new millennium. It is difficult to cement on “the best diet” for humans because there have been and are so many different yet successful diets in our species. Humans can thrive on diets con- sisting almost exclusively of the raw fat and protein of marine mammals (Arctic Eskimo)3 and on diets composed largely of a few wild plant species (Australian aborigines of the Western Desert)4; and there is an almost infinite number of successful dietary per- mutations between these two extremes. Because of the dietary diversity modern humans display, it is reasonable to conclude that human ancestors exhibited similar flexibility. Like extant wild primates, our ancestors were probably opportunistic foragers and took advantage of the most nutritious foods in their environment at any given time, so long as these could be secured without undue cost or hazard. Present fossil evidence places the earliest human beings at approximately 2 million y ago.5 In contrast, evidence for agricul- _ one has been dated to only some 12 000 y ago. This means for most of human existence, members of our genus (Homo) and species (Homo sapiens) have lived as hunter-gatherers, that is, people using only wild plants and animals as foods. Various attempts have been made to reconstruct the average daily macro— nutrient intake for paleolithic hunter-gatherers.“ The logic behind such attempts seems to be the belief that modern hm‘uan biology is somehow adapted to paleolithic foodways and that, by following such a diet, we might be able to prevent many of the so«called diseases of civilization (cg, cardiovascular disease, obesity, type II diabetes). However, data from ethnographic studies of recent (largely 20th century) huntermgatherers and evidence from historical ac— counts and archaeologic sites indicate that past hunter-gatherer Correspondence to: Katharine Milton, PhD, Department of Environmental Science, Policy and Management, Division of Insect Biology, 210 Well- man Hall, University of California. Berkeley, CA 94720-3112, USA. Email: lenilton®socratesberlreleyedu societies enjoyed a rich variety of different diets, depending on locale and season of the yearns-1° Thus, nutrient estimates for “the average paleoh'thic diet” probably do not reflect actual daily in- takes for many huntetmgatherers.6 In fact, we do not know much about the range of foods our paleolithic ancestors ate each day or season in almost any environment, although it seems likely that periods of relative food abundance may have alternated with periods of low food availability in many environments. Regardless of what paleolithic hunter-gatherers were eating, there is little evidence to suggest that human nutrient needs or digestive physiology were significantly affected by such diets at any point in human evolution. To date, we know of few adapta~ tions to diet in the human species that differentiate us from our closest living relatives, the great apes.1H3 Those identified are largely (although not exclusively) regulatory mutations such as Iactase synthesis in adulthood, and unique selective pressures favoring such dietmassociated mutations seem fairly well understood}1 . Food has played a major role in human evolution but in a somewhat different way than seems generally appreciated. Hu- mans are not creations sui generis. Rather, they have an evolution- ary history as anthropoid primates that stretches back more than 25 million y, a history that shaped human nutrient requirements and digestive physiology long before there were humans or even protohumans. Hunter-gatherers were not free to determine their dies—quite the opposite; it was their predetermined need for particular nutrients that constrained their evolution. At the same time these dietary needs apparently allowed for natural selection to favor increased brain size in the human lineage and the concomitant development of technologic, social, and other abilities directed at securing these nutrients; in this sense, it can be said that diet influenced, indeed drove, human evolution. In turn, expansion of the human brain and increasing dependence on cultural behaviors to obtain and prepare foods buffered human biology from many selective pressures related to diet‘that other animal species. must resolve largely through genetic adapta~ tionsfil'l2 The difference in gut proportions between modern hu- mans and great apes, for example, seems to reflect the fact that most foods humans consume are “predigested” by technology in one way or another before they ever reach the gut of the t‘eeder.12v13 This “predigestion” minimizes dietary bulk relative to the diets of Nutrition Volume 16, Numbers 7/8, 2000 wild apes and generally enhances dietary quality.12-13 Comparative data suggest that human nutrient requirements and most features of human digestive morphology and physiology are conservative in nature and probably were little affected by the hunter-gatherer phase of human existence.12«13 For this reason, if humans deviate too far from these ancestral foodways and simultaneously consume foods at variance with their pattern of digestive kinetics, a pattern shared with the great apes and one predicated on a slow turnover of ingeslutfzr13 they will likely suffer the consequences, some of which appear to be reflected in the diseases of civilization now affecting many individuals. ' Humans come from a fairly generalized line of higher primates, a lineage able to use a wide range of plant and animal foods. Data from various lines of evidence—«anatomic, physiologic, and paleontologicmsupport the view that the ancestral line (Homi— noidea) giving rise to humans was strongly herbivorous (i.e., plant eating).““15 The daily diet probably consisted largely of wild fruits, supplemented with young tree leaves and other highuquality plant parts in addition to some animal matter (insects, vertebrates) when this could be secured.13-15 It seems unlikely that the ancestral line leading to humans consumed a high foliage diet because of its low content of digestible energy and high content of indigestibIe built.13 Humans also lack the rapid passage rate of ingesta and specialized metabolic and other adaptations to flesh diets that characterize obligate carnivores.” Given the dietary characteristics of the primate lineage leading to humans and the lack of evidence supporting any notable diet» related changes in human nutrient requirements, metabolism, or digestive physiology relative to those of great apes,13 a better understanding of the nutritional composition of plant foods in the daily diets of wild primates should enhance our understanding of human dietary requirements. Although the necessary nutrients for human beings have been fairly well established since the 19305 and 1940s, the quantities needed are constantly under revision as new facts become available,15 suggesting that there is more to learn in this area. As most primates are arboreal, the plant foods they eat in the natural environment consist largely of the leaves, fruits, and flow— ers of tropical forest trees and vines.l3“15 A number of analyses have been made of the nutritional and other chemical constituents of such plant foods from both the Old and New World tropics}?-E9 When this information is compared with data on similar features in cultivated plant foods, some interesting differences emerge. Most primates include considerable fruit in the diet. These wild fruits typically are more nutritious than cultivated fruits; they have a slightly higher protein content and a higher content of certain essential vitamins and minerals.15 Of interest is the fact that, as a rule, sugar in the pulp of wild fruits is dominated by hexose (considerable glucose andJor some fructose, and very little sun arose), whereas that of cultivated fruits is high in sucrose, :1 disaccharidefli20 Cultivated fruits are therefore very tasty to bun mans because sucrose tastes sweeter than glucose. The sugar composition of cultivated fruits is one example of the way in which a strong sweet taste may be used to enhance the appeal and consumption of many foods humans now consume, foods that often consist largely of calories. Because sucrose must be broken down into glucose and fine” rose before it can be absorbed, the difference in sugar content between wild and cultivated fruits may seem trivial. However, Western diets rich in sucrose have been suggested to relate to various health problems. The difference in sugar composition between wild and cultivated fruits could affect features of molec- ular transport and absorption and perhaps insulin production. Fur- ther, many wild fruits contain fibrous pulp and multiple seeds, which provide a high ratio of indigestible to digestible components and may slow sugar digestion and absorption.21 In terms of micronutrient levels, considerable comparative data indicate that wild plant foods, regardless of geographic locale, often show higher values and more interspecific variation in their Primate Foods Have Relevance for Human Health 481 content of particular minerals than cultivated plant foods.” Study of the vitamin-C content of wild plant foods consumed by primates in Panama has shown that most such foods, both leaves and fruits, contain notable vitamin C.15 Kuhnlein and ’l‘urner22 compared the nutrient composition of wild plant foods of Canadian indigenous peoples with that of commercial plant foods reported in the United States Department of Agriculture Handbook 8 Series and the National Canadian Nutrient Table. in particular, the list of com- mercial vegetable foods with a nutrient composition similar to that of wild vegetable foods was quite short (21 entries in total and many obscure species), suggesting that few commercial vegetables compared nutritionally to the wild species analyzed. Because primates tend to fill up each day largely on plant foods, they generally ingest much higher amounts of some vitamins and minerals on a body~weight basis than modern humans. These differences are not trivial. For example, a 7-kg wild howler mon- key (Alumna palliata) in Panama takes in some 600 mg of vitamin C per day and more than 6000 mg of potassium and some 38 mg of iron.is Examination of the micronutrient intakes of captive primates fed commercial monkey chow has shown that these primates ingest markedly higher amounts of many micronuttients than are currently recommended for humans, on a body~weight basis.23 The reason for including such high micronutrients levels in the commercial monkey chows was not known, even by the rnamifacturers.23 Estimates for the level of certain micronutrients in the average paleolithic diet likewise are often higher than current reconunended daily allowancesft'7 probably because, like wild primates, paleolithic hunter-gatherers were eating wild plant (and animal) foods. Do nonhuman primates require much higher levels of certain micronuuients than humans on a body~weight basis or is their apparent high daily intake in the wild an unavoidable byproduct of their largely plant~based diet that actually serves no important physiologic functions? If these micronutrient levels do serve im- portant functions, why don’t humans likewise benefit from similar high levels of vitamins and minerals? Wild plant foods also con- tain a host of other biologically active compounds besides nutriu ents.i The physiologic effects of these other compounds in relation to plant nutrients are little studied or understood and could affect nutrient use and other functions. These topics seem of relevance for future research in terms of better understanding human nutri- tional physiology and nutrient requirements. The diets of most wild primates contain saturated and unsatur- ated fats in fairly equal proportions (ratio of polyunsaturated to saturated fat in the howler monkey diet m 0.85) and close to the 1.9 ratio recommended for modern humans.24 Fat intake is low. For example, dietary fat is estimated to contribute only around 17% of daily calories to the bowler monkey diet,24 and the largely plant~based diets of most other wild primates, including apes, are also estimated to be low in fat-derived calories.25 The ratio of (0-3 to (9—6 in wild plant foods eaten by Panamanian howler monkeys averaged 0.724 and similar ratios likely are typical of the diets of other wild primates. In contrast, the Western diet is often low in a-linolenic acid, high in calories from fat, and high in sauuated fatl5‘24 In the wild, many primates take in more grams of vegetable protein per day than seem necessary based on body weight.15 This probably reflects the fact that vegetable protein, even high-quality protein, shows a lower digestibility than animal proteirt?‘s Assim— ilation studies have indicated that 20% or more of the total nitro- gen concentration in wild plant parts is not available to the primate feeder.is In contrast to wild primates, most Western humans obtain considerable daily protein from the meat (muscle) of domesticated livestock. This meat is marbled with fat, a condition not seen in the muscle tissue of wild prey, which is always lean, irrespective of the season, and does not marble.8 Because a high proportion of the fat of wild animals is structural fat, it is also relatively rich in long-chain polyunsaturated fatty acids.8 As far as is known, monkeys and apes can digest both animal and vegetable protein. Although wild primates typically eat only Nutrition Volume 16, Numbers 7/8, 2000 wild apes and generally enhances dietary qualityfl'13 Comparative data suggest that human nutrient requirements and most features of human digestive morphology and physiology are conservative in nature and probably were little affected by the huntermgatherer phase of human existence.”13 For this reason, if humans deviate too far from these ancestral foodways and simultaneously consume foods at variance with their pattern of digestive ldnetlcs, a pattern ,, shared with the great apes and one predicated on a slow turnover of ingestafl'b’v13 they will likely suffer the consequences, some of which appear to be reflected in the diseases of civilization-now affecting many individuals. Humans come from a fairly generalized line of higher primates, a lineage able to use a wide range of plant and animal foods. Data from various lines of evidencemanatomic, physiologic, and paleontologic~support the view that the ancestral line (Homi— noidea) giving rise to humans was strongly herbivorous (i.e., plant eating).“‘15 The daily diet probably consisted largely of wild fruits, supplemented with young trite leaves and other high«quality plant parts in addition to some animal matter (insects, vertebrates) when this could be secured.“‘15 It seems unlikely that the ancestral line leading to-humans consumed a high foliage diet because of its low content of digestible energy and high content of indigestibie ' bulk.13 Humans also lack the rapid passage rate of ingesta and specialized metabolic and other adaptations to flesh diets that characterize obligate carnivores.13 Given the dietary characteristics of the primate lineage leading to humans and the lack of evidence supporting any notable diet— related changes in human nutrient requirements, metabolism, or digestive physiology relative to those of great apes,13 a better understanding of the nutritional composition of plant foods in the daily diets of wild primates should enhance our understanding of human dietary requirements. Although the necessary nutrients for human beings have been fairly well established since the 19303 and 1940s, the quantifies needed are constantly under revision as new facts become available,16 suggesting that there is more to learn in this area. As most primates are arboreal, the plant foods they eat in the natural environment consist largely of the leaves, fruits, and flow- ers of tropical forest trees and vinesJHS A number of analyses have been made of the nutritional and other chemical constituents of such plant foods from both the 01d and New World tropics.”-19 When this ‘mformation is compared with data on similar features in cultivated plant foods, some interesting differences emerge. Most primates include considerable fruit in the diet. These wild fruits typically are more nutritious than cultivated fruits; they have a slightly higher protein content and a higher content of certain essential vitamins and minerals.” Of interest is the fact that, as a rule, sugar in the pulp of wild fruits is dominated by hexose (considerable glucose and/or some fructose, and very little su- crose), whereas that of cultivated fruits is high in sucrose, a disaccharideds'20 Cultivated fruits are therefore very tasty to hu— mans because sucrose tastes sweeter than glucose. The sugar composition of cultivated fruits is one example of the way in which a strong sweet taste may be used to enhance the appeal and consumption of many foods humans now consume, foods that often consist largely of calories. Because Sucrose must be broken down into glucose and fruc~ tose before it can be absorbed, the difference in sugar content between wild and cultivated fruits may seem trivial. However, Western diets rich in sucrose have been suggested to relate to various health problems. The difference in sugar composition between wild and cultivated fruits could affect features of molec- ular transport and absorption and perhaps insulin production. Furm (her, many wild fruits contain fibrous pulp and multiple seeds, which provide a high ratio of indigestible to digestible components and may slow sugar digestion and absorption.21 In terms of micronuu'ient levels, considerable comparative data indicate that wild plant foods, regardless of geographic locale, often show higher values and more interspccific variation in their i’n‘mate Foods Have Relevance for Human Health 481 content of particular minerals than cultivated plant foods.15 Study of the vitamin-C content of wild plant foods consumed by primates in Panama has shown that most such foods, both leaves and fruits, contain notable vitamin (3.15 Kuhnlein and Turner22 compared the nutrient composition of wild plant foods of Canadian indigenous peoples with that of commercial plant foods reported in the United States Department of Agriculture Handbook 8 ,Series and the National Canadian Nutrient Table. In particular, the list of com- mercial vegetable foods with a nutrient composition similar to that of wild vegetable foods was quite short (21 entries in total and many obscure species), suggesting that few commercial vegetables compared nutritionally to the wild species analyzed. Because primates tend to fill up each day largely on plant foods, they generally ingest much higher amounts of some vitamins and minerals on a body-weight basis than modern humans. These differences are not trivial. For example, a 7-kg wild bowler mon- key (Alouatta palliuta) in Panama takes in some 600 mg of vitamin C per day and more than 6000 mg of potassium and some 38 mg of iron.15 Examination of the micronutrient intakes of captive primates fed commercial monkey chow has shown that these primates ingest markedly higher amounts of many micronutrients than are currently recommended for humans, on a body-weight basis.23 The reason for including such high micronuttients levels in the commercial monkey chews was not known, even by the _ mtunufacturers.23 Estimates for the level of certain micronuuients 5'in the average paleolitbic diet likewise are often higher than current recommended daily allowancesfifl probably because, like wild primates, paleolithic hunter-gatherers were eating wild plant (and animal) foods. Do non-human primates require much higher levels of certain micronulrients than humans on a body—weight basis or is their apparent high daily intake in the wild an unavoidable byproduct of their largely plant-based diet that actually serves no important physiologic functions? If these ndcronutrient levels do serve in portant functions, why don’t humans likewise benefit from similar high levels of vitamins and minerals? Wild plant foods also con tain a host of other biologically active compounds besides nutri- ents.ll The physiologic effects of these other compounds in relation to plant nutrients are little studied or understood and could affect nutrient use and other functions. These topics seem of relevance for future research in terms of better understanding human nutri~ tional physiology and nutrient requirements. The diets of most wild primates contain saturated and unsatur- ated fats in fairly equal proportions (ratio of polyunsaturated to saturated fat in the bowler monkey diet = 0.85) and close to the 1.0 ratio recommended for modern humans.” Fat intake is low. For example, dietary fat is estimated to contribute only around 17% of daily calories to the bowler monkey diet,24 and the largely plant-based diets of most other wild primates, including apes, are also estimated to be low in fat—derived calories.25 The ratio of (9-3 to (0-6 in wild plant foods eaten by Panamanian howler monkeys averaged 057,94 and similar ratios likely are typical of the diets of other wild primates. In contrast, the Western diet is often low in oc—linolenic acid, high in calories from fat, and high in saturated fat‘zsm In the wild, many primates take in more grams of vegetable protein per day than seem necessary based on body weight.” This probably reflects the fact that vegetable protein, even high—quality protein, shows a lower digestibility than animal protein.26 Assim- ilation studies have indicated that 20% or more of the total nitro- gen concentration in wild plant parts is not available to the primate feeder.15 In contrast to wild primates, most Western humans obtain considerable daily protein from the meat (muscle) of domesticated livestock. This meat is marbled with fat, a condition not seen in the muscle tissue of wild prey, which is always lean, irrespective of the season, and does not marble.8 Because a high proportion of the fat of wild animals is structural fat, it is also relatively rich in long-chain polyunsaturated fatty acids}3 As far as is known, monkeys and apes can digest both animal and vegetable protein. Although wild primates typically eat only 482 Milton small amounts of animal matter, most primates relish meat and will eagerly consume it when available in the wild or offered in captivitydlz-l3 The barrier to greater meat consumption by wild primates appears to be its patchy distribution and high cost of procurement in the natural environment rather than any physio- logic or gustatory barrier to animal moduli-13 Archaeologic evidence indicates that even the earliest humans began to incorporate bone marrow, meat, and other animal prod- ucts from vertebrates into the diet?»28 Such animal foods may have been scavenged for a considerable period of time, but even» tually social innovations such as cooperative hunting and techno- logic innovations permitted humans to capture wild prey.2mg Using animal matter to satisfy daily requirements for protein, essential fatty acids, some energy, and many micronuuients would free up space in the gut for carbohydrate-rich plant foods (the principal energy scurce for most wild primates) and allow for their use as fuel (glucose) for the increasingly large human brain.11 The strongly plant-based diet of most higher primates tends to be high in dietary fiber. Approximately 44% of the daily dry-mass consumption of a 7-kg bowler monkey, for example, is made up of fiber (some 88 g of fiber per day).M In contrast, a 70-kg American human probably takes in no more than 10—20 g of dietary fiber per day. Evidence from reconstituted human goprolites suggests that 10 000 y ago some human populations may have taken in as much as 130 g of fiber per day,29 and even today some humans are reported to take in 70 —90 g per day.30 Fatty acids produced in fiber fermentation may provide more than 10% of the required daily energy for some human populations, and data suggest various important health benefits may be conferred by particular fermen— tation products.“ These comparative data indicate that the daily diets of monkeys and apes differ in a number of ways from the modern human diet. Higher primates eat a variety of fresh plant foods each day. Most of these foods come from dicotylednous canopy tree species. In contrast, much of the plant food modern humans consume is cooked cereal grain from monocotylednous grasses. Most culti— vated cereals are nutritionally inferior to plant foods consumed by wild primates, and cereal grains, such as wheat, rye, and barley, contain highly insoluble fiber.21 Cultivated fruits and vegetables generally differ nutritionally from their wild counterparts. Further— more, modern humans typically do not eat large quantities of fresh plant foods each day and thus take in lower amounts of many nutrients on a body~weight basis relative to wild primates and less dietary fiber and non-nutrient phytochemicals. As noted above, there is considerable interest in better under— standing causal factors related to “diseases of civilization.” As appealing as the notion of the paleolithic diet is as a panacea for these health problems, data suggest that one does not have to be a paleolithic hunter-gatherer to escape them. Information on the diets and health of recent and contemporary traditional peoples, both hunter-gatherers and small~scale agriculturalists who also hunt and gather, show that all such societies are largely free of diseases of civilization whether the daily diet is made up primarily of wild animal foods, of wild plant foods, or of a single cultivated starchy carbohydrate supplemented with wild plant and animal foods.3v1°-31~33 Thus, it is not some special paleolitbic diet or macronutrient profile particular to hunter~gatherers that signals relief from diseases of civilization but rather shared features of the diets (and of lifestyle?) of many different traditional societies that spell the difference between their health and ours in this respect.11 I suggest that it is the relatively low calorie density of most wild foods, both plant and animal, in combination with certain features of panhuman gut physiology that have played the critical role in the lack of diseases of civilization in hunter«gatherer societies, both past and present.11 Similarly, indigenous hunter— gatherer agriculturalists of the Amazon Basin (cg, Yanomamo, Parakana, Arawete), societies dependent for hundreds of years on a single staple cultivar to meet most caloric requirements, also appear constrained in daily calorie intake because such cultivars typically lack many essential nutrients, forcing the intake of other Nutrition Volume 16, Numbers 7/8, 2000 foods, generally wild, and many staple cultivars also contain considerable fiber. Because the human gut Can hold only a limited amount of food at any one time and because transit time of food through the human gut is protracted (averaging 52 h with low-fiber diets and 40 h with high-fiber diets),34 there is a clear upper threshold to the amount of such foods the human gut can process each day/ALI?" Recent technology has circumvented this natural caloric barrier by processing, condensing, refining, and otherwise altering both plant and animal foods such that many more calories can be ingested per unit of time than used to be possible. In addition, as many have noted, most Westerners lead sedentary lifestyles in comparison with more traditional peoples, who typically perform physical activities, often strenuous, for 8 h or more each day. Getting back to basics in terms of diet would appear to involve turning more to foods similar to those of wild primates and human ancestors, that is, unprocessed foods, in particular more fresh fruits and vegetables, grass-fed rather than grain-fed livestock, and do veloping a more physically active lifestyle. A few cultivated cereal grains and domesticated livestock spe— cies cannot begin to compensate humanity for its loss of traditional foods or for the loss of genetic diversity of the myriad plant and animal species that have nourished humans and their ancestors for millions of years and that are rapidly being exterminated in the name of progress. As we enter a new millennium, we need to pause and reevaluate our dietary situation. Such reflection could lead to important changes in the types of foods we choose to eat and result in better human health. REFERENCES 1. Iampe JW. Health effects of vegetables and fruit: accessing mechanisms of action in human experimental studies. Am J Clin Nutr 1999;70:4758 2. Bray GA, Popldn BM. Dietary fut does affectobesity. Am J Clin Nut): 1998;68:l157' 3. Ho Kl, Mikkelson B, Lewis LA, et a1. Alaskan arctic esklmos: response to a customary high fat diet. Am J Clin Nutr 1972;25:737 4. Gould RA. Living archaeology. Cambridge: Cambridge University Press, 1980 . Groves C. Australopirhecus garhz': a new-found link. Rep Nat Center Sci Ed 1999;19:10 6. Eaton SB, Konner M. Paleolithic nutrition: a consideration of its nature and current implicatiom. N Engl J Med 1985;312:283 7. Eaton SB, Eaton SB 111, Konner Ml. Paleolithic nutrition revisited. In: Trevathan WR, Smith 130, McKenna JJ, eds. Evolurionary medicine. New York: Oxford University Press, 1999:313 8. O'Dea K Traditiorral diet and food preferences of Australian aboriginal hunterw gatherers. Phil Trans R Soc Lond B 1991;334:233 9. Hayden B. Subsistence and ecological adaptations of modem hunterlgathcregs. In: Harding R50, Telekl G, eds. Omnivorous primates: gathering and Farming in lawman evolution. New York: Columbia University Press, 1981:344 10. Lee RB. What hunters do for a living or how to make out on scarce resources. In: bee RB, DeVore I, eds. Man the hunter. Chicago: Aldine l’ublishiug, 1968:30 11. Milton K. Hunter-gatherer diets: a different perspective. Am .l Cl.th Nutt 2000; 71:665 12. Milton K, Demment M. Digestive and passage kinetics of chhnpannees fed high and low fiber diets and comparison with human data. 3 Nuu1938;118:l 13. Milton K A hypothesis to explain the role of ruminating in human evolution. Evol Anthropol l999;8:11 14. Milton FL Diversity of plant foods in tropical {crests as a stimulus to mental development in primates. Am Anthropol 1981;83:534 15. Milton K. Nutritional characteristics of wild primate foods: do the capital diets of our closest living relatives have lessons for us? Nutrition 1999;15:488 16. Lieberman LS. Biological conSequences of animals versus plants as sources of fats, protein and other nutrients. In: Harris M, Ross EB, eds. Food and evolution. Philadelphia: Temple University Press, 19875225 17. Milton K. Factors influencing leaf choice by bowler monkeys: a test of some hypothesis of food selection by generalist herbivores. Am Nat 1979;114:362 18. Dasilva GL. Diet of Colobus polykomos on Tiwai Island: selection of food in relation to seasonal abundance and dietary quality. Int J Primate! 1994351655 19. Heiduck 5. Food choice in masked till monkeys (Callicebus personams mela- uocbir): selectivity or opportunism? Int J Primate] l997;18:487 20. Baker BH, Baker 1. Sugar composition of nectars and Ends consumed by birds and bats in the tropics and subtropics. Biotmpica 1998;30:559 2i. Vandemoof 3A. lmmunonuttition: the role of carbohydrates. Nutrition 1998;l4:595 U'I -<- Nutrition Volume 16, Numbers 7/8, 2000 22. Kuhnlein HV, Tamer N5. Traditional“ plantfoods of Canadian indigenous peo— 23. 2.4. 25. 26. 27. 28. 29. pies. Phiiadelphia: Gordon and Breach Science Pubiishers, 1991 Kallman B. Micronulrient intakes in iaboratory animals and humans. J App: Nut: E939;4i:23 ' Chamberlain J, Nelson G, Milan; K Fatty acid gnomes of major food games of bowler monkeys (Momma palliara) in the neotropics. Experientia 1993;49:820 King GK. Comparative feeding and intuition in captive, non~human primates. Br I Nutr 1978;40:55 Carpenter K}. Protein and energy: a study of changing ideas in nutrition. Cambridge: Cambridge University Press, 1994 Blumenshine RJ, Cavallo IA. Scavenging and human evoimion. Sci Am 1992;276:90 Maxean CW, Assefa A. Zooarcheological eviiience for the fauna! exploitation behavior of Neanderthals and eaziy madam humans. Evol Amhropol 1999:8522 Kliks M. Paleodietefics: a review of the role of dietary fiber in preagxicuitwai 30. 31. 32. 33. 34. Influences on the Evolution of the Human Diet 483 human diets. In: Spilier GA, Amen R3, eds. Topics in dietary fiber research. New York: Plenum Press, 1978:181 Bingham A. Patterns of dietary fiber consumpzien in humans. in: Spiller GA, ed. CRC handbook of dietary fiber in human nutrition, 2nd ed. Boca Raton: CRC Press, 1993509 Tmswell AS. Diet and nutrition of hunterugameters. In: Health and disease in tribal societies. Ciba Fem)! Symposizm 49. New Yodc Eisevier Science, 19771213 Neel IV. Health and disease in unaocnitmated Amerindian popiflafions. In: Health and disease in tribal socieiies. Ciba Foundation Symposium 49. New York: Elsevier Science, E977:155 Saizano W, Caflegafi—Jaques SM. South American indium: a case study in evolution. Oxford: Glazeudon PIBSS, 1988 Wrick KL, Robertson JB. Van Sees: PJ, et ai. The influence of diam fiber some on human intestinal msit and 3:001 auteur. I Nun: 1983;113:1464 ...
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Why foods of primates - Back to Basics: Why Foods of Wild...

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