The nature of nutrition Simpson, Stephen J; Simpson, Stephen J; Raubenheimer, David
2012., 20120722, 2012, 2012-07-22
eBook
Nutrition has long been considered more the domain of medicine and agriculture than of the biological sciences, yet it touches and shapes all aspects of the natural world. The need for nutrients ...determines whether wild animals thrive, how populations evolve and decline, and how ecological communities are structured.The Nature of Nutritionis the first book to address nutrition's enormously complex role in biology, both at the level of individual organisms and in their broader ecological interactions.
Stephen Simpson and David Raubenheimer provide a comprehensive theoretical approach to the analysis of nutrition--the Geometric Framework. They show how it can help us to understand the links between nutrition and the biology of individual animals, including the physiological mechanisms that determine the nutritional interactions of the animal with its environment, and the consequences of these interactions in terms of health, immune responses, and lifespan. Simpson and Raubenheimer explain how these effects translate into the collective behavior of groups and societies, and in turn influence food webs and the structure of ecosystems. Then they demonstrate how the Geometric Framework can be used to tackle issues in applied nutrition, such as the problem of optimizing diets for livestock and endangered species, and how it can also help to address the epidemic of human obesity and metabolic disease
Drawing on a wealth of examples from slime molds to humans,The Nature of Nutritionhas important applications in ecology, evolution, and physiology, and offers promising solutions for human health, conservation, and agriculture.
Polyphenism in Insects Simpson, Stephen J.; Sword, Gregory A.; Lo, Nathan
CB/Current biology,
09/2011, Letnik:
21, Številka:
18
Journal Article
Recenzirano
Odprti dostop
Polyphenism is the phenomenon where two or more distinct phenotypes are produced by the same genotype. Examples of polyphenism provide some of the most compelling systems for the study of ...epigenetics. Polyphenisms are a major reason for the success of the insects, allowing them to partition life history stages (with larvae dedicated to feeding and growth, and adults dedicated to reproduction and dispersal), to adopt different phenotypes that best suit predictable environmental changes (seasonal morphs), to cope with temporally heterogeneous environments (dispersal morphs), and to partition labour within social groups (the castes of eusocial insects). We survey the status of research on some of the best known examples of insect polyphenism, in each case considering the environmental cues that trigger shifts in phenotype, the neurochemical and hormonal pathways that mediate the transformation, the molecular genetic and epigenetic mechanisms involved in initiating and maintaining the polyphenism, and the adaptive and life-history significance of the phenomenon. We conclude by highlighting some of the common features of these examples and consider future avenues for research on polyphenism.
Much attention has been focused on fats and carbohydrates as the nutritional causes of energy overconsumption and obesity. In 2003, a model of intake regulation was proposed in which the third ...macronutrient, protein, is not only involved but is a primary driver of calorie intake via its interactions with carbohydrates and fats. This model, called protein leverage, posits that the strong regulation of protein intake causes the overconsumption of fats and carbohydrates (hence total energy) on diets with a low proportion of energy from protein and their underconsumption on diets with a high proportion of protein. Protein leverage has since been demonstrated in a range of animal studies and in several studies of human macronutrient regulation, and its potential role in contributing to the obesity epidemic is increasingly attracting discussion. Over recent years, however, several misconceptions about protein leverage have arisen. Our aim in this paper is to briefly outline some key aspects of the underlying theory and clarify 10 points of misunderstanding that have the potential to divert attention from the substantive issues.
Nutritional Ecology and Human Health Raubenheimer, David; Simpson, Stephen J
Annual review of nutrition,
07/2016, Letnik:
36, Številka:
1
Journal Article
Recenzirano
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In contrast to the spectacular advances in the first half of the twentieth century with micronutrient-related diseases, human nutrition science has failed to stem the more recent rise of obesity and ...associated cardiometabolic disease (OACD). This failure has triggered debate on the problems and limitations of the field and what change is needed to address these. We briefly review the two broad historical phases of human nutrition science and then provide an overview of the main problems that have been implicated in the poor progress of the field with solving OACD. We next introduce the field of nutritional ecology and show how its ecological-evolutionary foundations can enrich human nutrition science by providing the theory to help address its limitations. We end by introducing a modeling approach from nutritional ecology, termed nutritional geometry, and demonstrate how it can help to implement ecological and evolutionary theory in human nutrition to provide new direction and to better understand and manage OACD.
•Branched chain amino acids influence aging, sarcopenia and cardiometabolic disease.•Branched chain amino acids regulate food intake, protein synthesis and insulin release.•Therapeutic effects of ...branched chain amino acids depend upon background diet.
Branched chain amino acids (BCAA: leucine, valine, isoleucine) have key physiological roles in the regulation of protein synthesis, metabolism, food intake and aging. Many studies report apparently inconsistent conclusions about the relationships between blood levels of BCAAs or dietary manipulation of BCAAs with age-related changes in body composition, sarcopenia, obesity, insulin and glucose metabolism, and aging biology itself. These divergent results can be resolved by consideration of the role of BCAAs as signalling molecules and the bidirectional mechanistic relationship between BCAAs and some aging phenotypes. The effects of BCAAs are also influenced by the background nutritional composition such as macronutrient ratios and imbalance with other amino acids. Understanding the interaction between BCAAs and other components of the diet may provide new opportunities for influencing age-related outcomes through manipulation of dietary BCAAs together with titration of macronutrient ratios and other amino acids.
The fundamental questions of what represents a macronutritionally balanced diet and how this maintains health and longevity remain unanswered. Here, the Geometric Framework, a state-space nutritional ...modeling method, was used to measure interactive effects of dietary energy, protein, fat, and carbohydrate on food intake, cardiometabolic phenotype, and longevity in mice fed one of 25 diets ad libitum. Food intake was regulated primarily by protein and carbohydrate content. Longevity and health were optimized when protein was replaced with carbohydrate to limit compensatory feeding for protein and suppress protein intake. These consequences are associated with hepatic mammalian target of rapamycin (mTOR) activation and mitochondrial function and, in turn, related to circulating branched-chain amino acids and glucose. Calorie restriction achieved by high-protein diets or dietary dilution had no beneficial effects on lifespan. The results suggest that longevity can be extended in ad libitum-fed animals by manipulating the ratio of macronutrients to inhibit mTOR activation.
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•Food intake is regulated primarily by dietary protein and carbohydrate•Low-protein, high-carbohydrate diets are associated with the longest lifespans•Energy reduction from high-protein diets or dietary dilution does not extend life•Diet influences hepatic mTOR via branched-chain amino acids and glucose
Solon-Biet et al. look at whether health and aging are influenced by macronutrient balance or calorie intake in mice by investigating the effects of diets differing in protein, carbohydrate, and fat content. Diets low in protein and high in carbohydrates increase lifespan, while calorie restriction through high-protein diets does not extend life.
•Defining the dynamics of behavioural phase change has unified the study of desert locust swarming,•Leading to discovery of key crowding stimuli and neurochemical mechanisms,•Uncovering the ...importance of local resource distribution and quality,•Explaining the emergence of collective mass movement,•And yielding landscape-scale predictive models for control and management of outbreaks.
Behavioural phase change initiates and functionally couples the suite of traits that comprise density-dependent polyphenism in locusts. Here I provide a semi-expurgated account of my 25-year research journey studying behavioural phase transition in the desert locust. The journey spans continents, involves a cast of extraordinary colleagues, and travels across levels of biological organisation from deep within the nervous system of individual locusts to mass migration and the evolution and population dynamics of swarming.
Fibroblast growth factor 21 (FGF21) is the first known endocrine signal activated by protein restriction. Although FGF21 is robustly elevated in low-protein environments, increased FGF21 is also seen ...in various other contexts such as fasting, overfeeding, ketogenic diets, and high-carbohydrate diets, leaving its nutritional context and physiological role unresolved and controversial. Here, we use the Geometric Framework, a nutritional modeling platform, to help reconcile these apparently conflicting findings in mice confined to one of 25 diets that varied in protein, carbohydrate, and fat content. We show that FGF21 was elevated under low protein intakes and maximally when low protein was coupled with high carbohydrate intakes. Our results explain how elevation of FGF21 occurs both under starvation and hyperphagia, and show that the metabolic outcomes associated with elevated FGF21 depend on the nutritional context, differing according to whether the animal is in a state of under- or overfeeding.
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•FGF21 is maximally elevated under low protein, high carbohydrate intakes•The Geometric Framework reconciles conflicting findings on FGF21 elevation•Metabolic effects of FGF21 are dependent on nutrient context
FGF21 is elevated in seemingly opposite nutrient contexts such as starvation, overfeeding, protein restriction, and ketogenic and high-carbohydrate diets. Using the Geometric Framework and 25 different types of diets, Solon-Biet et al. reconcile these findings and demonstrate that maximal FGF21 elevation occurs on low protein, high carbohydrate intakes.
Putting the Balance Back in Diet Simpson, Stephen J.; Le Couteur, David G.; Raubenheimer, David
Cell,
03/2015, Letnik:
161, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The notion of dietary balance is fundamental to health yet is not captured by focusing on the intake of energy or single nutrients. Advances in nutritional geometry have begun to unravel and ...integrate the interactive effects of multiple nutrients on health, lifespan, aging, and reproduction.
The notion of dietary balance is fundamental to health, yet is not captured by focusing on the intake of energy or single nutrients. Advances in nutritional geometry have begun to unravel and integrate the interactive effects of multiple nutrients on health, lifespan, aging, and reproduction.
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