Authors
Leonard WR. Robertson ML. Snodgrass JJ. Kuzawa CW.
Title
Metabolic correlates of hominid brain evolution [Review]
Source
Comparative Biochemistry & Physiology. Part A, Molecular & Integrative
Physiology. 136(1):5-15, 2003 Sep.
Abstract
Large brain sizes in humans have important metabolic consequences as
humans expend a relatively larger proportion of their resting energy
budget on brain metabolism than other primates or non-primate mammals. The
high costs of large human brains are supported, in part, by diets that are
relatively rich in energy and other nutrients. Among living primates, the
relative proportion of metabolic energy allocated to the brain is
positively correlated with dietary quality. Humans fall at the positive
end of this relationship, having both a very high quality diet and a large
brain size. Greater encephalization also appears to have consequences for
aspects of body composition. Comparative primate data indicate that humans
are 'under-muscled', having relatively lower levels of skeletal muscle
than other primate species of similar size. Conversely, levels of body
fatness are relatively high in humans, particularly in infancy. These
greater levels of body fatness and reduced levels of muscle mass allow
human infants to accommodate the growth of their large brains in two
important ways: (1) by having a ready supply of stored energy to 'feed the
brain', when intake is limited and (2) by reducing the total energy costs
of the rest of the body. Paleontological evidence indicates that the rapid
brain evolution observed with the emergence of Homo erectus at
approximately 1.8 million years ago was likely associated with important
changes in diet and body composition. (C) 2003 Elsevier Science Inc. All
rights reserved. [References: 53]
Institution
Reprint available from:
Leonard WR
Northwestern Univ, Dept Anthropol, Lab Human Biol Res
1810 Hinman Ave
Evanston, IL 60208
USA
Authors
Sponheimer M. Lee-Thorp JA.
Title
Differential resource utilization by extant great apes and
australopithecines: towards solving the C-4 conundrum [Review]
Source
Comparative Biochemistry & Physiology. Part A, Molecular & Integrative
Physiology. 136(1):27-34, 2003 Sep.
Abstract
Morphological and biogeochemical evidence suggest that australopithecines
had diets markedly different from those of extant great apes. Stable
carbon isotope analysis, for example, has shown that significant amounts
of the carbon consumed by australopithecines were derived from C,
photosynthesis in plants. This means that australopithecines were eating
large quantities of C-4 plants such as tropical grasses and sedges, or
were eating animals that were themselves eating C-4 plants. In contrast,
there is no evidence that modern apes consume appreciable amounts of any
of these foods, even,in the most and extents of their ranges where these
foods are most prevalent. Environmental reconstructions of early
australopithecine environments overlap with modem chimpanzee habitats.
This, in conjunction with the stable isotope evidence, suggests that
australopithecines and great apes, even in similar environments, would
utilize available resources differently. Thus, the desire or capacity to
use C-4 foods may be a basal character of our lineage. We do not know,
however, which of the nutritionally disparate C-4 foods were utilized by
hominids. Here we discuss which C-4 resources were most likely consumed by
australopithecines, as well as the potential nutritional, physiological,
and social consequences of eating these foods. (C) 2003 Elsevier Science
Inc. All rights reserved. [References: 66]
Institution
Reprint available from:
Sponheimer M
Univ Utah, Dept Biol
Salt Lake City, UT 84112
USA
Authors
Benzie IFF.
Title
Evolution of dietary antioxidants [Review]
Source
Comparative Biochemistry & Physiology. Part A, Molecular & Integrative
Physiology. 136(1):113-126, 2003 Sep.
Abstract
Oxygen is vital for most organisms but, paradoxically, damages key
biological sites. Oxygenic threat is met by antioxidants that evolved in
parallel with our oxygenic atmosphere. Plants employ antioxidants to
defend their structures against reactive oxygen species (ROS; oxidants)
produced during photosynthesis. The human body is exposed to these same
oxidants, and we have also evolved an effective antioxidant system.
However, this is not infallible. ROS breach defences, oxidative damage
ensues, accumulates with age, and causes a variety of pathological
changes. Plant-based, antioxidant-rich foods traditionally formed the
major part of the human diet, and plant-based dietary antioxidants are
hypothesized to have an important role in maintaining human health. This
hypothesis is logical in evolutionary terms, especially when we consider
the relatively hypoxic environment in which humans may have evolved. In
this paper, the human diet is discussed briefly in terms of its
evolutionary development, different strategies of antioxidant defence are
outlined, and evolution of dietary antioxidants is discussed from the
perspectives of plant need and our current dietary requirements. Finally,
possibilities in regard to dietary antioxidants, evolution, and human
health are presented, and an evolutionary cost-benefit analysis is
presented in relation to why we lost the ability to make ascorbic acid
(vitamin C) although we retained an absolute requirement for it. (C) 2002
Elsevier Science Inc. All rights reserved. [References: 68]
Institution
Reprint available from:
Benzie IFF
Hong Kong Polytech Univ, Ageing & Hlth Sect, Fac Hlth & Social Sci
Kowloon
Hong Kong
Peoples R China
Authors
Eaton SB.
Title
An evolutionary perspective on human physical activity: implications for
health [Review]
Source
Comparative Biochemistry & Physiology. Part A, Molecular & Integrative
Physiology. 136(1):153-159, 2003 Sep.
Abstract
At present, human genes and human lives are incongruent, especially in
affluent Western nations. When our current genome was originally selected,
daily physical exertion was obligatory; our biochemistry and physiology
are designed to function optimally in such circumstances. However, today's
mechanized, technologically oriented conditions allow and even promote an
unprecedentedly sedentary lifestyle. Many important health problems are
affected by this imbalance, including atherosclerosis, obesity,
age-related fractures and diabetes, among others. Most physicians
recognize that regular exercise is a critical component of effective
health promotion regimens, but there is substantial disagreement about
details, most importantly volume: how much daily caloric expenditure, as
physical activity, is desirable. Because epidemiology-based
recommendations vary, often confusing and alienating the health-conscious
public, an independent estimate, arising from a separate scientific
discipline, is desirable, at least for purposes of triangulation. The
retrojected level of ancestral physical activity might meet this need. The
best available such reconstruction suggests that the World Health
Organization's recommendation, a physical activity level of 1.75 (similar
to2.1 MJ (490 kcal)/d), most closely approximates the Paleolithic
standard, that for which our genetic makeup was originally selected. (C)
2003 Elsevier Science Inc. All rights reserved. [References: 56]
Institution
Reprint available from:
Eaton SB
Emory Univ, Dept Anthropol
2887 Howell Mill Rd NW
Atlanta, GA 30327
USA
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