Library of Excerpts

The Influence of Diet on Heterochronic Change (Development and Maturation)

"The possible effect of dietary fat content and the ratio of polyunsaturated to saturated fatty acids (P/S-ratio) on serum sex hormones was studied in 30 healthy male volunteers. The customary diet of the subjects, which supplied 40% of energy as fat (mainly from animal sources, P/S-ratio 0.15) was replaced for a 6 weeks period by a practically isocaloric experimental diet containing significantly less fat (25% of energy) with a higher P/S-ratio (1.22) and other environmental factors were stabilized. Serum testosterone and 4-androstenedione decreased from 22.7 +/- 1.1 nmol/l to 19.3 +/- 1.2 nmol/l, (SEM, P less than 0.001) and from 4.6 +/- 0.2 nmol/l to 4.3 +/- 0.2 nmol/l (SEM, P less than 0.01), respectively. These changes were paralleled by a reduction in serum free (non-protein bound) testosterone (P less than 0.01) suggesting a possible change in biological activity. During the low fat period a significant negative correlation between serum prolactin and androgens was observed. All the changes in androgen levels were reversible. With the exception of a small but non-significant decrease in serum estradiol-17 beta, the other hormone parameters were practically unaffected by the dietary manipulation. Our results indicate that in men a decrease in dietary fat content and an increase in the degree of unsaturation of fatty acids reduces the serum concentrations of androstenedione, testosterone and free testosterone. The mechanism and importance of this phenomenon is discussed in the light of epidemiological and experimental data." (Hamalainen E, Adlercreutz H, Puska P, Pietinen P (1984) Diet and serum sex hormones in healthy men. J Steroid Biochem 20(1):459)

Links to diet and its influence on human evolution are available at http://www.panix.com/~paleodiet/

"Historically, the first genetic condition to be reported to be associated with autism was phenylketonuria. Phenylketonuria (PKU) is an inborn error of metabolism, inherited as an autosomal recessive disorder (Folling, 1934, and usually, but not universally, associated with mental retardation. Most newborns in the United States are now screened for PKU, and a phenylalaline-free diet is instituted within the first weeks of life. The diet substantially diminishes the cognitive behavioral handicap, although Stevenson and colleagues (Stevenson et al., 1979) found a high rate of behavioral deviance in an unselected school-aged sample with PKU that had been treated from infancy. None were autistic or had other behaviors common to autistic children. ... It is of interest that not all socially unresponsive children with PKU were mentally retarded by IQ testing. (Sutherland et al., 1960; Blainy & Gulliford, 1956; Crowie, 1951; Bjornson, 1964), and reports from the 1950's and 1960's suggest that when dietary treatment was instituted after infancy, IQ showed no improvement, but that autistic symptoms frequently disappeared (Lewis, 1959; Bickel et al., 1954; Berry, Sutherland, Guest, & Umbarger, 1958; Armstrong & Tyler, 1955; Armstrong, Low, & Bosma, 1957; Blainy & Guillford, 1956; Woolf, Griffiths, & Moncrieff, 1955). [note: all citations after Lewis not in bibliography, find in some other way] In his review, Friedman concluded that autism and mental retardation were separate manifestations of PKU, as evidenced by the presence of autistic symptoms in normally intelligent children with PKU and by the improvement of autistic symptoms, but not mental retardation, when a phenylalanine-free diet was begun after infancy." (Folstein SE, Rutter ML (1988) Austism: Familial aggregation and genetic implications. J Autism and Developmental Disorders 18: pp. 14-15)

"...Hill et al. found a decline in testosterone concentration among men who were briefly switched from a western higher fat diets to vegetarian diets." (Field AE, Colditz GA, Willett WC, Longcope C, McKinlay JB (1994) The relation of smoking, age, relative weight, and dietary intake to serum adrenal steroids, sex hormones, and sex hormone-binding globulin in middle-aged men. J Clinical Endocrinological Metabolism 79: 1314)

"We propose, and have assembled a variety of epidemiological and biochemical evidence to support this hypothesis that an increase in red cell oxidant sensitivity form fava bean consumption could lower rates of infection from malarial parasites and, therefore, be highly advantageous in the diet. If this hypothesis is fully substantiated, it would provide the first evidence that biological and cultural evolution of diesease resistence are linked through dietary practices." (Katz, Solomon H. (1979) Fava bean consumption and biocultural evolution. Medical anthropology 3(4): pp. 473)

"Brain tissue is metabolically expensive, but there is no signiticant correlation between relative basal metabolic rate and relative brain size in humans and other encephalized mammals. ...No matter what is selecting for relatively large brains in humans and other primates, they cannot be achieved without a shift to a high-quality diet unless there is a rise in the metabolic rate. Therefore the incorporation of increasingly greater amounts of animal products into the diet was essential in the evolution of the large human brain." (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 199)

"This means that the average human has a brain that is 4.6 times the size expected for the average mammal and the average non-human primate anthropoid has a brain almost twice as large as that of the average mammal. The second factor is the metabolic cost of the brain. On the basis of in vivo determinations, the mass-specific metabolic rate of the brain is approximately 11.2 W.Kg-1 (watts per kilogram) (table 1, Aschoff, Gunther, and Kramer 1971). This is nine times higher than the average mass-specific metabolic rate of the human body as a whole (1.25 W.Kg-1)." (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 200)

"In fact, the mean BMR's of mature men and women straddle the values predicted by both primate and eutherian equations for mammals of comparable body mass (fig. 2). Consequently, there is no evidence of an increase in basal metabolism sufficient to account for the additional metaboic expenditure of the enlarged brain. Where does the energy come from to fuel the encephalized brain?" (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 201)

"Although the human heart and kidney's are both close to the size expected for a 65-kg primate, the mass of the splanchnic organs is approximately 900 g less than expected. Almost all of this shortfall is due to a reduction in the gastro-intestinal tract, the total mass of which is only about 60% of that expected for a similar-sized primate. Therefore, the increase in mass of the human brain appears to be balanced by an almost identical reduction in the size of the gastro-intestinal tract." (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 204

"Obviously, it is impossible to determine the total daily energy expenditure--the field metabolic rate (FMR) --- of earlier hominids, but interferences about the likely levels of energy utilization can be made from measurements of modern humans and other living mammals." (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 205

"This analysis implies that there has been a coevolution between brain size and gut size in humans and other primates. The logical conclusion is that no matter what is selecting for brain-size increase, one would expect a corresponding selection for reduction in the relative size of the gut. This would be essential in order to keep the total body BMR at the typical level. If it was necessary for a primate to have a large gut, that primate would also be expected to have a relatively small brain." (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 205)

"If the hypothesis of coevolution is correct, what is essential for understanding how encephalized primates can afford large brains is identifying the factors that allow then to have relatively small guts. The gut is the only one of the expensive metabolic tissues that could vary in size sufficiently to offset the metabolic cost of the encephalized brain. The reason for this is that, although gut size is related to body size, its size and proportions are also strongly determined by diet...Gut size is associated with both bulk and the digestibility of food. ... There is also a close relationship between relative gut size and relative brain size (fig. 4). Animals with relatively large guts also have relatively small brains, while animals with relatively small guts have relatively large brains." (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 206)

"Although all hominids are more encephalized than the majority of living primate genera, the australopithecines show an overall lower encephalization than members of the genus Homo. They are similar in degree of encephalization to Pan, Hylobates, and Saimiri, which suggests that they had a diet a least equal in quality to that of these primates." (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 208)

"H. ergaster is the first known hominid to approximate modern human body proportions (Ruff and Walker1993). The inference is that it most probably also had a relatively smaller gut. ... For the second increase, the introduction of cooking may have been an important factor. Cooking is a technological way of externalising part of the digestive process. It not only reduces toxins in food but also increased its digestibility (Stahl 1984, Sussman 1987). This would be expected to make digestion a metabolically less expensive activity for modern humans than for non-human primates or earlier hominids. Cooking could also explain why modern humans are a bit more encephalized for their relative gut sizes than the non-human primates (see fig. 4)." (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 210)

"The threefold increase in hominid brain size since the Pliocene is paralleled by a 3.2 times increase in brain size in equids (from 270 g in Pliohippus to 870 g in modern horse (Jerison 1973)) and does not seem exceptional. The uniqueness of hominid evolution rests in the lack of expected increase in body size." (Henneberg, M.(1995) response to ...Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 213)

"During sleep, metabolic rate falls to about 10% (Blaxter 1989). It also falls in other contexts, such as during starvation. It can differ between human populations by as much as 17% (Blaxter 1989: 144)." (Wrangham RW, Jones JH, Leighton M (1995) response to ...Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 216)

"As Falk has clearly stated, we view these factors [diet, gut size & encephalization], for the most part, as "prime releasers' which make available the not inconsiderable energy resources that are a necessary concomitant of encephalizaition." (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 217)

"We suggest that the change in body proportions in H. ergaster in relation to the autralopithecines may have marked a major shift to a higher-quality food and correspondingly smaller guts." (Aiello, Leslie C. (1995) Expensive-tissue hypothesis: the brain and digestive system in human and primate evolution. Current Anthroplogy 36(2): pp. 219)


[citations removed] "Five dietitians supervised the subjects to follow the experimental diet. The reduction in fat was realized by replacing the regular milk, butter, fatty meat, cheese and suasages by skimmed milk, vegetable oil, margarine (high P/S-ratio) fish, vegetables and fruit as described in detail previously. ... Indeed, the diet influenced the degree of protein binding of testosterone resulting in a small but uniform rise in the percentage of free testosterone fraction as measured utilizing the precipitation method of Bergink et al. Therefore, the calculated concentrations of free (non-protein bound) testosterone decreased less than that of total unconjugated hormone (P < 0.01). ... With regard to testosterone and androstenedione, which decreased 15 and 11% respectively our results show the same tendency as those in the study of Hill el al. However, they reported a more remarkable fall in testosterone in white subjects and the change of androstenedione in black subjects, was not statistically significant. ... Interestingly, there was a negative correlation between serum prolactin and androgens during the whole study. The hypogonadic effect of hyperprolactinemia in man is well-documented. There is evidence that prolactin may interfere with the gonadal steroidogenesis in rats and man and low levels of testosterone can occur without a gonadotrophin response." (Hamalainen E, Adlercreutz H, Puska P, Pietinen P (1984) Diet and serum sex hormones in healthy men. J Steroid Biochem 20(1):459-462)

"Patients with severe and frequent migraine and their parents were encouraged to participate in a study of dietary treatment, and their informed consent was obtained. Headache due to middle-ear disease, sinusitis, refractive errors, dental disease, raised blood pressure, or intracranial hypertension were excluded. ... Almost all patients had behavior disturbance at the time of an attack, but 41 also had behavior disturbance (mostly hyperkinetic) at other times. In those whose headaches responded on the oliogoantigenic diet most of the associated symptoms (table 1), except the permanent neurological abnormalities, also responded. Antiepileptic drugs were withdrawn in those who became fit-free, without recurrence of fits unless the diet was broken. Many of these symptoms recurred on reintroduction of foods. In 18 patients open provocation on 27 occasions with several foods caused behavior disorder without headache, whereas other foods caused migraine. This pattern was reproducible in patients given the foods repeatedly. ... Patients were usually very fond of the provoking foods, sometimes craving them, and often ate very large amounts. Cows' milk caused symptoms in most children. All but 1 of those reacting to milk also reacted to cheese, whereas 13 reacted to cheese but not to cows' milk. Sheep-milk and goats' milk cheese, given to those who reacted to cows' milk cheese, caused no symptoms." ( Egger J, Carter CM, Wilson J, Turner MW, Soothill JF (1983) Is migraine food allergy? Lancet 2: 865-6)

Chart describing incidents of migraine in 38 patients: Exercise 13, Trauma 11, Emotional 10, Perfumes and Cigarette smoke 10, Travel 9, Bright light 5, Heat 2, Noise 2. ( Egger J, Carter CM, Wilson J, Turner MW, Soothill JF (1983) Is migraine food allergy? Lancet 2: 867

"This trial indicates that the suggestion that diet may contribute to behavior disorders in children must be taken seriously. .. It is interesting that the psychologist's overall assessment of the patients indicated a statistically significant difference between those on active substance and placebo. The sequential reintroduction of foods enabled us to identify the foods that adversely affected a child's behavior. The hypothesis that combinations of any foods can alter behavior (based on allergy theory) has been supported in double-blind, controlled trials, not only in hyperkinetic syndrome but also in migraine. By contrast, thials bsed on the idiosyncracy hypothesis (tyramine in migraine and salicylates, colorants, and preservatives in behavioral disorders) have produced largely negative results. All the same, colorants (tartrazine) and preservatives (benzoate) were the commonest substances that provoked abnormal behavior in our patients, although no patient in this series reacted to them alone. ... We have found that patients with migraine no longer responded to such non-specific stimuli as exercise, heat, or trauma to the head if they avoided the foods to which they responded adversely. ... The children in our study were selected for severe overactivity and so were not representative of hyperkinetic children in the general population. Also, a surprisingly high proportion had associated symptoms such as headache, fits, and allergic disorders. ... In several children the initial improvement produced by the diet was preceded by a deterioration in behavior. This is difficult for the family to accept, but means it is necessary to persist for 2-3 weeks to guage the effects. Giving full helpings of possibly provoking food for as long as a week in the reintroduction period is important to exclude a reaction." (Egger J, Carter CM, Graham PJ, Gumley D, Soothill JF (1985) Controlled trial of oligoantigenic treatment in the hyperkinetic syndrome. Lancet 1: 544-5)

"The strontium:calcium ratio of the human samples is about 60% of the strontium:calcium ratio of the herbivorous mamal samples at the three sites (see Fig. 6). Based on the results of this analysis, nothing other than a constant proportion of meat versus vegetable material can be shown in the diets of humans throughout the time represented by these sites (70,000-35,000 years BP). It is possible that different foods were being collected even though there was no net change in the meat:vegetable proportions. The composition of the fauna, recovered from the three sites, however, suggests that there was no change in the kinds of fauna being exploited other than changing from one genus of large bodied herbivore to another (Garrod and Bate, 1937, Bouchud, 1974)." (Schoeninger, Margaret (1982) Diet and evolution of modern human form in the middle east. American Journal of Physical Anthropology 58(1): pp. 47)

"Between the time represented at Skhul and Qafzeh (30,000 - 35,000 BP) and the time represented at Kebara C (around 15,000 BP) there was a decrease in robustness but no change can be demonstrated in the average human diet." (Schoeninger, Margaret (1982) Diet and evolution of modern human form in the middle east. American Journal of Physical Anthropology 58(1): pp. 48)

"The distributions of strontium and stronum:calcium ratios from the two late phase pipaleolithic sites (Kebara B and el-Wad which date to around 10,000 years BP), compared with all the earlier sites, however, sugget that a major dietary change occurred between early and late phases of the Epipaleolithic. The strontium:calcium ratios of the human samples are over 90% that of the strontium:calcium ratios in their respective faunal samples (Fig. 6). The large increase in this ratio between the early Epipaleolithic level site (Kebara C) and the two late Epipaleolithic level sites (Kebara B and el-Wad) suggests that the major dietary shift occurred some 15,000 years after the major morphological shift had been completed. ... Both the results of the trace element analysis and the archeological record, therefore, indicate that the change in subsistence activities related to dietary components occurred long after the change in skeletal robustness from archaic to modern Homo sapiens. In fact, the shift toward greater dependence on plant products, occurred some 15,000 years after the first appearance of fully modern Homo sapiens." (Schoeninger, Margaret (1982) Diet and evolution of modern human form in the middle east. American Journal of Physical Anthropology 58(1): pp. 49)

"Dawson (1972, 1974) has pointed out that hunting and fishing cultures, such as Eskimo and Australian Aborigine peoples, tend to show higher rates of left-handedness than agricultural communities, such as the Temne and the Chinese Hakka, and he suggested that this may be accounted for by the emphasis on independent values and the relatively low degree of conformity found in nomadic groups." (Bishop, D.V.M. (1990) Handedness and Developmental Disorder. MacKeith, Manchester pp. 13)

"The relationships of cigarette smoking, age, relative weight, and dietary intake to serum dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androstenedione, cortisol, 3-alpha-androstanediol, 3-alpha-androstanediol-glucuronide, testosterone, albumin-bound testosterone, free testosterone, dihydrotestosterone (DHT), and sex hormone-binding globulin (SHBG) were examined cross-sectionally in 1241 randomly sampled middle-aged U.S. men. Compared with nonsmokers and independent of relative weight (body mass index) and age, cigarette smokers had increased serum levels of DHEA (18% higher, P = 0.0002), DHEAS (13% higher, P = 0.0007), cortisol (5% higher, P = 0.01), androstenedione (33% higher, P = 0.0001), testosterone (9% higher, P = 0.009), DHT (14% higher, P = 0.004), and SHBG (8% higher, P = 0.004). Androstenedione, total plasma testosterone, albumin-bound testosterone, DHT, and SHBG decreased with increasing relative weight. Age was positively associated with serum SHBG and negatively associated with albumin-bound testosterone, DHEA, and DHEAS. An association was found between alcohol intake and DHEA (r = 0.15; P = 0.0001), cortisol (r = 0.10; P = 0.0007), and 3-alpha-androstanediol-glucuronide (r = 0.08; P = 0.0004). Cortisol was the only hormone that was associated with carbohydrate intake (r = -0.09; P = 0.002). The only hormones associated with dietary lipids were DHT (for vegetable fat, r = 0.07; P = 0.02), cortisol (for total fat, r = 0.08; P = 0.007), and SHBG (for animal fat, r = -0.06; P = 0.05). In addition, SHBG was positively associated with dietary (r = 0.07; P = 0.008) and crude (r = 0.08; P = 0.007) fiber. These data suggest that serum adrenal steroid and sex hormone concentrations in middle-aged men are more influenced by cigarette smoking, age, and obesity than by dietary intake; however, serum adrenal steroids were influenced by alcohol intake." (Field AE, Colditz GA, Willett WC, Longcope C, McKinlay JB (1994) The relation of smoking, age, relative weight, and dietary intake to serum adrenal steroids, sex hormones, and sex hormone-binding globulin in middle-aged men. J Clinical Endocrinological Metabolism 79: 1310)

[abstract] "The concentrations of serum total and free testosterone were studied in 30 healthy, middle-aged men during a dietary intervention program. When men were transferred from their customary diet to an experimental diet, which contained less fat with a higher polyunsaturated/saturated ratio (P/S-ratio) and more fibre, there was a significant decrease in serum total testosterone concentrations (22.7 +/- 1.2 vs 19.3 +/- 1.1 nmol/l SEM, P less than 0.001). Furthermore, serum free, unbound testosterone fell from 0.23 +/- 0.01 to 0.20 +/- 0.01 nmol/l SEM (P less than 0.01). The hormonal changes were reversible. This observation suggests that testosterone activity in plasma can at least partly be modified by changing the composition of the diet." (Hamalainen EK, Adlercreutz H, Puska P, Pietinen P (1983) Decrease of serum total and free testosterone during a low-fat high-fibre diet. J Steroid Biochem18(3):369-70)

[abstract] "Seventy-eight children, referred to a diet clinic because of hyperactive behaviour, were placed on a 'few foods' elimination diet. Fifty nine improved in behaviour during this open trial. For 19 of these children it was possible to disguise foods or additives, or both, that reliably provoked behavioural problems by mixing them with other tolerated foods and to test their effect in a placebo controlled double blind challenge protocol. The results of a crossover trial on these 19 children showed a significant effect for the provoking foods to worsen ratings of behaviour and to impair psychological test performance. This study shows that observations of change in behaviour associated with diet made by parents and other people with a role in the child's care can be reproduced using double blind methodology and objective assessments. Clinicians should give weight to the accounts of parents and consider this treatment in selected children with a suggestive medical history." (Carter CM, Urbanowicz M, Hemsley R, Mantilla L, Strobel S, Graham PJ, Taylor E (1993) Effects of a few food diet in attention deficit disorder. Arch Dis Child 69(5):564-8)

"76 selected overactive children were treated with an oligoantigenic diet, 62 improved, and a normal range of behaviour was achieved in 21 of these. Other symptoms, such as headaches, abdominal pain, and fits, also often improved. 28 of the children who improved completed a double-blind, crossover, placebo-controlled trial in whichfoods thought to provoke symptoms were reintroduced. Symptoms returned or were exacerbated much more often when patients were on active material than on placebo. 48 foods were incriminated. Artificial colorants and preservatives were the commonest provoking substances, but no child was sensitive to these alone." (Egger J, Carter CM, Graham PJ, Gumley D, Soothill JF (1985) Controlled trial of oligoantigenic treatment in the hyperkinetic syndrome. Lancet 1: 540)

[abstract) "The etiopathogenesis of infantile autism is still unknown. Recently some authors have suggested that food peptides might be able to determine toxic effects at the level of the central nervous system by interacting with neurotransmitters. In fact a worsening of neurological symptoms has been reported in autistic patients after the consumption of milk and wheat. The aim of the present study has been to verify the efficacy of a cow's milk free diet (or other foods which gave a positive result after a skin test) in 36 autistic patients. We also looked for immunological signs of food allergy in autistic patients on a free choice diet. We noticed a marked improvement in the behavioural symptoms of patients after a period of 8 weeks on an elimination diet and we found high levels of IgA antigen specific antibodies for casein, lactalbumin and beta-lactoglobulin and IgG and IgM for casein. The levels of these antibodies were significantly higher than those of a control group which consisted of 20 healthy children. Our results lead us to hypothesise a relationship between food allergy and infantile autism as has already been suggested for other disturbances of the central nervous system." (Lucarelli S, Frediani T, Zingoni AM, Ferruzzi F, Giardini O, Quintieri F, Barbato M, D'Eufemia P, Cardi E (1995) Food allergy and infantile autism. Panminerva Med 37(3):137-41)

"Fully modern human form more gracile than the antecedent archaic modern form was evident by 30,000 years ago. One hypothesis to explain this decrease in skeletal robustness is that change occurred in human diet and that this change was associated with a decrease in activity levels required in both individual and group behavior. It is possible to study dietary change directly using trace element analysis of strontium levels in bone. The amount of strontium in bone reflects the amount of strontium in diet. Since plants contain higher levels of strontium than do animal soft tissues, the level of bone strontium will differ between individuals according to the proportion of plant and animal products in their diets. In this study the ratio of strontium:calcium in human bone to strontium:calcium in faunal bone is compared for samples of archaic modern humans (from Mugharet et Tabun, Mugharet es-Skhul, and Jebel Qafzeh) and fully modrn humans from Mugharet el-Kebara and Mugharet el-Wad) from Israel. The use of a ratio controls for potentially unequal strontium levels in soils at different sites and for different diagenetic histories between sites. The results of the analysis are internally reliable, reflecting bone strontium levels rather than technique error; therefore, they reflect diet. It appears that a change occurred in the amount of animal protein in the diet of humans but that this change occurred almost 20,000 years after the first appearance of skeletally modern humans. These results refute the hypothesis that the morphological transformation to modern human form occurred as a result of behavioral changes involved in obtaining previously unused foods. If any decrease in human activity level occurred between archaic modern and fully modern humans, this decrease probably was due to alterations in the means of procuring or processing the same kinds of foods that had been utilized earlier in time." (Schoeninger, Margaret (1982) Diet and evolution of modern human form in the middle east. American Journal of Physical Anthropology 58(1): pp. 37)

"93% of 88 children with severe frequent migraine recovered on oligoantigenic diets; the causative foods were identified by sequential reintroduction, and the role of the foods provoking migraine was established by a double-blind controlled trial in 40 of the children. Most patients responded to several foods. Many foods were involved, suggesting an allergic rather than an idiosyncratic (metabolic) pathogenesis. Associated symptoms which improved in addition to headache included abdominal pain, behaviour disorder, fits, asthma, and eczema. In most of the patients in whom migraine was provoked by non-specific factors, such as blows to the head, exercise, and flashing lights, this provocation no longer occurred while they were on the diet." (Egger J, Carter CM, Wilson J, Turner MW, Soothill JF (1983) Is migraine food allergy? Lancet 2: 865)

"If it is assumed that the last common ancestor of apes and humans had a diet similar to that of a modern ape, and that the earliest members of our species (Homo sapiens sapiens) consumed a diet whose composition fell within the range encompassed by modern hunter-gatherers, then it appears that hominid evolution was characterized by increasing diet quality. The distinctiveness of the human diet relative to other primates is likely associated with important metabolic differences. One possiblity is that the high caloric density of our diet is reflective of elevated resting metabolic requirements." (Leonard, William R. (1994) Evolutionary perspectives on human nutrition: the influence of brain and body size on diet and metabolism. American Journal of Human Biology 6(1): pp. 79)

"Dietary patterns strongly influence metabolic requirements in mammalian species (McNab, 1978, 1986; Kurland and Pearson, 1986; Nagy, 1987). McNab (1986) found that mammals consuming high quality food items, such as, vertebrates, seeds, or nuts, tended to have high resting metabolic rates (RMR), while those consuming poor quality foods, e.g., leaves and woody plants, tended to be hypometabolic. If such a pattern holds for primates, it should be expected tht metabolic rates will vary according to relative diet quality." (Leonard, William R. (1994) Evolutionary perspectives on human nutrition: the influence of brain and body size on diet and metabolism. American Journal of Human Biology 6(1): pp. 80)

"These results imply that changes in diet quality during hominid evolution were linked with the evolution of brain size. The shift to a more calorically dense diet was probably needed in order to substantially increase the amount of metabolic energy being used by the hominid brain. Thus, while nutritional factors alone are not sufficient to explain the evolution of our large brains, it seems clear that certain dietary changes were necessary for substantial brain evolution to take place. ... It is intriguing that the clear departure from the general primate brain-metabolism regression occurs with the emergence of species of our own genus, H. habilis and H. erectus, since this is a time when other important anatomical and behavioral changes appear. Specifically, both archeological and morphological evidence indicate that these early members of the genus Homo incorporated greater amounts of animal material in their diet than the australopithecines (Bunn, 1981; Wolpoff, 1980). With early Homo there is the first clear evidence of home bases, implying that resources were collected and brought back to a central location where they were shared. (Potts, 1988). Hence, it is likely that what supported the rapid expansion of brain size in Homo habilis and Homo erectus were both the higher quality and greater stability of the diet." (Leonard, William R. (1994) Evolutionary perspectives on human nutrition: the influence of brain and body size on diet and metabolism. American Journal of Human Biology 6(1): pp. 83-4)

"Contemporary human foraging groups obtain at least 30% of their dietary energy from animals foods, compared to 5-7% in chimpanzees. Adaptation to this calorically dense, easy to digest diet is evident in our gut morphology, as humans have a relatively reduced digestive tract in comparison to most other primates (Sussman, 1987; Chivers and Hladik, 1980; Milton, 1987). This distinct diet appears to be linked to the high metabolic costs of the human brain. In general, primate brain size varies as a direct (linear) function of body metabolism. This means that the proportion of metabolic energy spent on the brain is relatively constant across primates of all size (about 8-9% of RMR). Species spending a larger proportion of RMR on their brain have a higher quality diet than expected for their body size. Conversely, small brains relative to metabolic turnover are associated with poor quality diets. Humans represent the positive extreme, having both a very high quality diet and a brain that accounts for 20-25% of resting metabolic energy. Other researchers have previously noted the apparent link between metabolic rate and brain size. (Armstrong, 2985; Mink et al., 1981; Martin, 1989, 1990). In particular, Martin (1989) has argued tht this relationship reflects the association between brain growth and maternal metabolism. Theis hypothesis posits that since the majority of brain growth in humans and other primates occurs prenatally and early in the postnatal period, it is maternal metabolic output (through pregnancy and lactation) that largely determines achieved adult brain size. If this hypothesis is correct, the results of the present study would imply that improvement in the stability and quality of maternal nutrition (to support the high metabolic demands of pregnancy and lactation) was a consequence of the selection for larger brain size in hominid evolution." (Leonard, William R. (1994) Evolutionary perspectives on human nutrition: the influence of brain and body size on diet and metabolism. American Journal of Human Biology 6(1): pp. 85)

"McGrew (1979) reports that a female chimpanzee may obtain as much as 20 grams of ants in a typical session of ant dipping. From preliminary observations, females engage in these insect collecting activities with tools for longer periods and more often than do males (Nishida, 1973; McGrew, 1979)." (Tanner, Nancy M. (1981) On Becoming Human: Cambridge University Press, Cambridge p. 73)

"A variety of insects are eaten, and they provide an important protein source. For example, at Kosage near the Mahali Mountains in Tanzania, Nishida (1973) noted chimpanzees eating eight species of insects --- four species of arboreal ants, one species of termite, one species of sand cricket, one species of cicada, an done species of moth --- with ants and termites eaten most frequently. Over a 10 year period, chimpanzees at Gombe also were observed killing an average of 9 to 10 mammals per year (Teleki, 1973a). Meat has been estimated to form from 1 percent to 5 percent of the diet at Gombe (Teleki, 1975)." (Tanner, Nancy M. (1981) On Becoming Human: Cambridge University Press, Cambridge p. 78)

"Apes and humans share relatively complex Pb proteins and the PPb protein. All the apes are predominantly frugivorous-folivorous, whereas humans are omnivorous. What this means is that certain aspects of the diet did not change sufficiently in the process of becoming human for there to be strong selection for a change in salivary proteins from that of the apelike ancestors. Early humans shared with the apes saliva proteins useful in a diet having a great deal of plant carbohydrate and/or texture. This model suggests that the foods gathered by the early hominids had both." (Tanner, Nancy M. (1981) On Becoming Human: Cambridge University Press, Cambridge p. 188)

"However, other environmental factors can produce dramatic phenotypic effects. Bernays (1986) demostrated how differences n diet in the grass-feeding caterpillar Pseudoaletia unipuncta can have a pronounced effect on head size, changes in diet inducing changes in head allometry. Individuals reared on hard grass developed heads with twice the mass of those fed on soft, artificial diet, even though body masses were the same. Individuals fed on an intermediate diet (soft wheat seedlings) had intermediate head masses (Fig. 4-2). Bernays attributed these allometric differences to an increase in muscular development, which resulted in a significant morphogenetic effect on head size. Size differences, with correlated differences in mandibular strength, directly affect the insect's abiltity to cope with foods of different hardnesses; those with large heads are adaptively more suited to dealing with hard grasses. " (McKinney, M.L. & McNamara, K.J (1990) Heterochrony: The Evolution of Ontegeny: Plenum Press, New York p. 105)

"Clutton-Brock and Harvey (1980) showed that primate relative brain size decreases as the proportion of leaves in the diet increases. They suggested that a larger memory is needed to exploit fruits, which are relatively more scattered and patchy in occurence than leaves. A similar pattern has recently been found in myomorph rodents (Mann et al., 1988). Folivorous groups average only about two-thirds the brain size of granivorous, insectivorous, or generalist groups of the same body weight. Hence, we may infer that nonfolivory played a role in our ancestors reaching the threshold. An important additional factor has been extensively discussed by Gibson (1986 and references therein) who has shown that primates regularly eating foods that need to be extracted from the environment have relatively larger brains. Such "extractive foods" include such diverse diets as nut-meat, pod seeds, termites, snails, and many others. While they are more trouble to extract, they are generally higher in nutrition and more available throughout the year compared to more readily eaten foods such as berries or leaves. Omnivorous diets of extractive foods lead to the largest relative brain sizes of all, as opposed to those primates which specialize on just one of a few types. Hence, it may be that dietary habits of extractive omnivory and nonfolivory played a major role in the development of brains large enough to reach the threshold." (McKinney, M.L. & McNamara, K.J (1990) Heterochrony: The Evolution of Ontegeny: Plenum Press, New York p. 324)

"In sum, there appears to be compelling evidence that increased energy demands of large brain size are associated with high diet quality among extent primates. It is unfortunate that more is not known about total energy expenditure among living primate species and its association with diet and brain size." (Leonard WR & Robertson ML (1996) On diet, energy metabolism, and brain size in human evolution. Current Anthropology 37(1): pp. 128)

"If it is assumed that the last common ancestor of apes and humans had a diet similar to that of a modern ape, and that the earliest members of our species (Homo sapiens sapiens) consumed a diet whose composition fell within the range encompassed by modern hunter-gatherers, then it appears that hominid evolution was characterized by increasing diet quality. The distinctiveness of the human diet relative to other primates is likely associated with important metabolic differences. One possiblity is that the high caloric density of our diet is reflective of elevated resting metabolic requirements. Indeed, the work of McNab (1986) and Nagy (1987) indicates that greater diet quality is associated with higher resting and total metabolic rates among mammalian species. An alternative hypothesis is that the high metabolic costs of our large brain necessitate an energy-rich diet (Martin, 1989; Leonard and Robertson, 1992). Each of these possibilities is examined subsequently. ... Dietary patterns strongly influence metabolic requirements in mammalian species (McNab, 1978, 1986; Kurland and Pearson, 1986; Nagy, 1987). McNab (1986) found that mammals consuming high quality food items, such as, vertebrates, seeds, or nuts, tended to have high resting metabolic rates (RMR), while those consuming poor quality foods, e.g., leaves and woody plants, tended to be hypometabolic. If such a pattern holds for primates, it should be expected that metabolic rates will vary according to relative diet quality. " (Jolly, Clifford J. (1963) A suggested case of evolution by sexual selection in primates. Man (London) 63: 79-80)

"These results imply that changes in diet quality during hominid evolution were linked with the evolution of brain size. The shift to a more calorically dense diet was probably needed in order to substantially increase the amount of metabolic energy being used by the hominid brain. Thus, while nutritional factors alone are not sufficient to explain the evolution of our large brains, it seems clear that certain dietary changes were necessary for substantial brain evolution to take place. ... It is intriging that the clear departure from the general primate brain-metabolism regression occurs with the emergence of species of our own genus, H. habilis and H. erectus, since this is a time when other important anatomical and behavioral changes appear. Specifically, both the archaelogical and morphological evidence indicate that these early members of the genus Homo incorporated greater amounts of animal material in their diet than the australopithecines (Bunn, 1981; Wolpoff, 1980). With early Homo there is the first clear evidence of home bases, implying that resources were collected and brought back to a central location where they were shared (Potts, 1988). Hence, it is likely that what supported the rapid expansion of brain size in Homo habilis and Homo erectus were both the higher quality and greater stability of the diet. (Jolly, Clifford J. (1963) A suggested case of evolution by sexual selection in primates. Man (London) 63: 83-84)

"Contemporary human foraging groups obtain at least 30% of their dietary energy from animals foods, compared to 5-7% in chimpanzees. Adaptation to this calorically dense, easy to digest diet is evident in our gut morphology, as humans have a relatively reduced digestive tract in comparison to most other primates (Sussman, 1987; Chivers and Hladik, 1980; Milton, 1987). This distinct diet appears to be linked to the high metabolic costs of the human brain. In general, primate brain size varies as a direct (linear) function of body metabolism. This means that the proportion of metabolic energy spent on the brain is relatively constant across primates of all size (about 8-9% of RMR). Species spending a larger proportion of RMR on their brain have a higher quality diet than expected for their body size. Conversely, small brains relative to metabolic turnover are associated with poor quality diets. Humans represent the positive extreme, having both a very high quality diet and a brain that accounts for 20-25% of resting metabolic energy. Other researchers have previously noted the apparent link between metabolic rate and brain size. (Armstrong, 1985; Mink et al., 1981; Martin, 1989, 1990). In particular, Martin (1989) has argued that this relationship reflects the association between brain growth and maternal metabolism. This hypothesis posits that since the majority of brain growth in humans and other primates occurs prenatally and early in the postnatal period, it is maternal metabolic output (through pregnancy and lactation) that largely determines achieved adult brain size. If this hypothesis is correct, the results of the present study would imply that improvement in the stablity and quality of maternal nutrition (to support the high metabolic demands of pregnancy and lactation) was a consequence of the selection for larger brain size in hominid evolution." (Jolly, Clifford J. (1963) A suggested case of evolution by sexual selection in primates. Man (London) 63: 84-5)