Effects of body size and lifestyle on evolution of mammal life histories

It has recently been proposed that life-history evolution is subject to a fundamental size-dependent constraint. This constraint limits the rate at which biomass can be produced so that production per unit of body mass is inevitably slower in larger organisms than in smaller ones. Here we derive predictions for how changes in body size and production rates evolve in different lifestyles subject to this constraint. Predictions are tested by using data on the mass of neonate tissue produced per adult per year in 637 placental mammal species and are generally supported. Compared with terrestrial insectivores with generalized primitive traits, mammals that have evolved more specialized lifestyles have divergent massspecific production rates: (i) increased in groups that specialize on abundant and reliable foods: grazing and browsing herbivores (artiodactyls, lagomorphs, perissoclactyls, and folivorous rodents) and flesh-eating marine mammals (pinnipeds, cetaceans); and (ii) decreased in groups that have lifestyles with reduced death rates: bats, primates, arboreal, fossorial, and desert rodents, bears, elephants, and rhinos. Convergent evolution of groups with similar lifestyles is common, so patterns of productivity across mammalian taxa reflect both ecology and phylogeny. The overall result is that groups with different lifestyles have parallel but offset relationships between production rate and body size. These results shed light on the evolution of the fast-slow life-history continuum, suggesting that variation occurs along two axes corresponding to body size and lifestyle.

Ingestion of onion soup high in quercetin inhibits platelet aggregation and essential components of the collagen-stimulated platelet activation pathway in man: a pilot study

Epidemiological data suggest that those who consume a diet rich in quercetin-containing foods may have a reduced risk of CVD. Furthermore, in vitro and ex vivo studies have observed the inhibition of collagen-induced platelet activation by quercetin. The aim of the present study was to investigate the possible inhibitory effects of quercetin ingestion from a dietary source on collagen-stimulated platelet aggregation and signalling. A double-blind randomised cross-over pilot study was undertaken. Subjects ingested a soup containing either a high or a low amount of quercetin. Plasma quercetin concentrations and platelet aggregation and signalling were assessed after soup ingestion. The high-quercetin soup contained 69 mg total quercetin compared with the low-quercetin soup containing 5 mg total quercetin. Plasma quercetin concentrations were significantly higher after high-quercetin soup ingestion than after low-quercetin soup ingestion and peaked at 2.59 (SEM 0.42) mu mol/l. Collagen-stimulated (0.5 mu g/ml) platelet aggregation was inhibited after ingestion of the high-quercetin soup in a time-dependent manner. Collagen-stimulated tyrosine phosphorylation of a key component of the collagen-signalling pathway via glycoprotein VI, Syk, was significantly inhibited by ingestion of the high-quercetin soup. The inhibition of Syk tyrosine phosphorylation was correlated with the area under the curve for the high-quercetin plasma profile. In conclusion, the ingestion of quercetin from a dietary source of onion soup could inhibit some aspects of collagen-stimulated platelet aggregation and signalling ex vivo. This further substantiates the epidemiological data suggesting that those who preferentially consume high amounts of quercetin-containing foods have a reduced risk of thrombosis and potential CVD risk.

Flavonoid supplement improves leg health and reduces fluid retention in pre-menopausal women in a double-blind, placebo-controlled study

Flavonoid extracts derived from plant foods have been shown to benefit certain types of fluid retention. However, no studies have investigated these compounds for use in premenstrual fluid retention, a complaint common among women with otherwise normal menstrual cycles. Therefore, we conducted a double-blind, placebo-controlled, pilot study into the effect of a daily flavonoid extract (Colladeen(R), 320 mg oligomeric procyanidins) on premenstrual fluid retention. Fluid retention was assessed at baseline and throughout 4 menstrual cycles of the intervention using validated questionnaires. Leg girth was also measured at baseline and at the end of the study. Thirty subjects completed the study (n = 18 active treatment; n = 12 placebo). Although no significant changes in leg girth measurements were noted, there was a significant improvement in subjective "leg health" scores after flavonoid treatment compared to placebo (p = 0.013). Furthermore, this was accompanied by an improvement in reported premenstrual fluid retention nearing significance (p = 0.066). We conclude that flavonoids supplements may provide a new therapeutic direction to counter premenstrual fluid retention and improve leg health. A larger study is now warranted.

Acquiring, managing and applying knowledge for environmental conservation

We are experiencing an explosion of knowledge with relevance to conserving biodiversity and protecting the environment necessary to sustain life on earth. Many science disciplines are involved in generating this ne, knowledge and real progress can be made when scientists collaborate across disciplines to generate both macro- and micro-environmental knowledge and then communicate and interact with specialists in sociology, economics and public policy. An important requirement is that the often complex scientific concepts and their voluminous supporting data are managed in such ways as to make them accessible across the many specializations involved. Horticultural science has much to contribute to the knowledge base for environmental conservation. While it seems that production horticulture has been slow to embrace knowledge and concepts that would reduce the heavy reliance on agricultural chemicals, the use of peat as a growing medium, and lead to more sustainable use of water and other resources, environmental horticulture is providing valuable opportunities to rescue or protect endangered species, educate the public about plants and plant science, and demonstrate environmental stewardship and sustainable production practices. Likewise, social horticulture is drawing, attention to the many contributions of horticultural foods and parks and gardens to human health and welfare. Overall, horticulture has a vital role to play in integrating, knowledge from other scientific, social, economic and political disciplines.

Optimal foraging when regulating intake of multiple nutrients

There is growing evidence that, rather than maximizing energy intake subject to constraints, many animals attempt to regulate intake of multiple nutrients independently. In the complex diets of animals such as herbivores, the consumption of nutritionally imbalanced foods is sometimes inevitable, forcing trade-offs between eating too much of nutrients present in the foods in relative excess against too little of those in deficit. Such situations are not adequately represented in existing formulations of foraging theory. Here we provide the necessary theory to fit this case, using an approach that combines state-space models of nutrition with Tilman's models of resource exploitation (Tilman 1982, Resource Competition and Community Structure, Princeton: Princeton University Press). Our approach was to construct a smooth fitness landscape over nutrient space, centred on a 'target' intake at which no fitness cost is incurred, and this leads to a natural classification of the simple possible fitness landscapes based on Taylor series approximations of landscape shape. We next examined how needs for multiple nutrients can be assessed experimentally using direct measures of animal performance as the common currency, so that the nutritional strategies of animals can be mapped on to the performance surface, including the position of regulated points of intake and points of nutrient balance when fed suboptimal foods. We surveyed published data and conducted an experiment to map out the performance landscape of a generalist leaf-feeding caterpillar, Spodoptera littoralis. (C) 2004 Tire Association for the Study of Animal Behaviour. Poblished by Elsevier Ltd. All rights reserved.

Weaning preterm infants: a randomised controlled trial

Objective: To assess the effect on growth and iron status in preterm infants of a specially devised weaning strategy compared with current best practices in infant feeding. The preterm weaning strategy recommended the early onset of weaning and the use of foods with a higher energy and protein content than standard milk formula, and foods that are rich sources of iron and zinc. Subjects and design: In a blinded, controlled study, 68 preterm infants (mean (SD) birth weight 1470 (430) g and mean (SD) gestational age 31.3 (2.9) weeks) were randomised to either the preterm weaning strategy group (n = 37) or a current best practice control group (n = 31), from hospital discharge until 1 year gestation corrected age (GCA). Main outcome measures: Weight, supine length, occipitofrontal head circumference, and intakes of energy, protein, and minerals were determined at 0, 6, and 12 months GCA. Levels of haemoglobin, serum iron, and serum ferritin were assayed at 0 and 6 months GCA. Results: Significant positive effects of treatment included: greater increase in standard deviation length scores and length growth velocity; increased intake of energy, protein, and carbohydrate at 6 months GCA and iron at 12 months GCA; increased haemoglobin and serum iron levels at 6 months GCA. Conclusions: The preterm weaning strategy significantly influenced dietary intakes with consequent beneficial effects on growth in length and iron status. This strategy should be adopted as the basis of feeding guidelines for preterm infants after hospital discharge. School of Applied Statistics Faculty of Life Sciences

On the yield stress of frozen sucrose solutions

Measurement or prediction of the mechanical and fracture properties of foods is very important in the design, operation and optimization of processes, as well as for the control of quality of food products. This paper describes the measurement of yield stress of frozen sucrose solutions under indentation tests using a spherical indenter. Effects of composition, temperature and strain rate on yield stress of frozen sucrose solutions have also been investigated.

Kinetic models as a route to control acrylamide formation in food

Reports that heat processing of foods induces the formation of acrylamide heightened interest in the chemistry, biochemistry, and safety of this compound. Acrylamide-induced neurotoxicity, reproductive toxicity, genotoxicity, and carcinogenicity are potential human health risks based on animal studies. Because exposure of humans to acrylamide can come from both external sources and the diet, there exists a need to develop a better understanding of its formation and distribution in food and its role in human health. To contribute to this effort, experts from eight countries have presented data on the chemistry, analysis, metabolism, pharmacology, and toxicology of acrylamide. Specifically covered are the following aspects: exposure from the environment and the diet; biomarkers of exposure; risk assessment; epidemiology; mechanism of formation in food; biological alkylation of amino acids, peptides, proteins, and DNA by acrylamide and its epoxide metabolite glycidamide; neurotoxicity, reproductive toxicity, and carcinogenicity; protection against adverse effects; and possible approaches to reducing levels in food. Cross-fertilization of ideas among several disciplines in which an interest in acrylamide has developed, including food science, pharmacology, toxicology, and medicine, will provide a better understanding of the chemistry and biology of acrylamide in food, and can lead to the development of food processes to decrease the acrylamide content of the diet.

Prebiotics and bowel cancer

Bowel cancer is a growing malignancy, with more than a million annual cases reported worldwide. It has been suggested that there is microbial involvement in onset of the disease and that an altered composition has previously been observed in those suffering from the malignancy, compared to healthy counterparts. The use of prebiotic functional foods to modify the colonic microflora may provide a method of reducing genotoxic potential within the colon, whilst offering-Protective strategies in the form of metabolites such as butyrate. The following review highlights some of the studies that demonstrate the potentia role for prebiotics as protective factors against bowel cancer.

The neuroprotective potential of flavonoids: a multiplicity of effects

Flavonoids exert a multiplicity of neuroprotective actions within the brain, including a potential to protect neurons against injury induced by neurotoxins, an ability to suppress neuroinflammation, and the potential to promote memory, learning and cognitive function. These effects appear to be underpinned by two common processes. Firstly, they interact with critical protein and lipid kinase signalling cascades in the brain leading to an inhibition of apoptosis triggered by neurotoxic species and to a promotion of neuronal survival and synaptic plasticity. Secondly, they induce beneficial effects on the vascular system leading to changes in cerebrovascular blood flow capable of causing angiogenesis, neurogenesis and changes in neuronal morphology. Through these mechanisms, the consumption of flavonoid-rich foods throughout life holds the potential to limit neurodegeneration and to prevent or reverse age-dependent loses in cognitive performance. The intense interest in the development of drugs capable of enhancing brain function means that flavonoids may represent important precursor molecules in the quest to develop of a new generation of brain enhancing drugs.

Flavanol monomer-induced changes to the human faecal microflora

We have investigated the bacterial-dependent metabolism of (-)-epicatechin and (+)-catechin using a pH-controlled, stirred, batch-culture fermentation system reflective of the distal region of the human large intestine. Incubation of (-)-epicatechin or (+)-catechin (150mg/l or 1000mg/l) with faecal bacteria, led to the generation of 5-(3,4'-dihydroxyphenyl)-gamma-valerolactone, 5-phenyl-gamma-valerolactone and phenylpropionic acid. However, the formation of these metabolites from (+)-catechin required its initial conversion to (+)-epicatechin. The metabolism of both flavanols occurred in the presence of favourable carbon sources, notably sucrose and the prebiotic fructo-oligosaccharides, indicating that bacterial utilisation of flavanols also occurs when preferential energy sources are available. (+)-Catechin incubation affected the growth of select microflora, resulting in a statistically significant increase in the growth of the Clostridium coccoides-Eubacterium rectale group, Bifidobacterium spp. and Escherichia coli, as well as a significant inhibitory effect on the growth of the C. histolyticum group. In contrast, the effect of (-)-epicatechin was less profound, only significantly increasing the growth of the C. coccoides-Eubacterium rectale group. These potential prebiotic effects for both (+)-catechin and (-)-epicatechin were most notable at the lower concentration of 150 mg/l. As both (-)-epicatechin and (+)-catechin were converted to the same metabolites, the more dramatic change in the growth of distinct microfloral populations produced by (+)-catechin incubation may be linked to the bacterial conversion of (+)-catechin to (+)-epicatechin. Together these data suggest that the consumption of flavanol-rich foods may support gut health through their ability to exert prebiotic actions.

The gut microbiota in obesity and metabolic disease - a novel therapeutic target

Obesity is sweeping the westernized world at a rate which far outstrips human genomic evolution, highlighting the importance of the obesogenic environment. Diet is an important component of this obesogenic environment, with certain diets (high fat, high refined carbohydrates and sugar) predisposing to overweight. On the other hand, there are also foods shown to protect against obesity and the diseases of obesity, including whole plant foods, dairy products, dietary fibre and functional foods like probiotics, prebiotics and phytochemicals. Interestingly, many of these foods mediate their health-promoting activities through the gut microbiota. The human gut microbiota itself has recently been identified as a contributory factor in this obesogenic environment, with differences observed between lean and obese. Evidence from human studies indicates that important groups of fermentative bacteria differ in abundance between lean and obese. Recently it has been suggested that anomalous microbiota composition in infancy can predispose to overweight in later life, highlighting the important role of optimal microbiota successional development, and that – as observed in laboratory animals – the gut microbiota may contribute to the aetiology of obesity. In this review we will introduce the gut microbiota, describe its interactions with major dietary components and the host, and then go on to discuss evidence indicating that the gut microbiota may contribute to the obesogenic environment. Finally, we will explore possible strategies for modulating the composition and activity of the human gut microbiota which may impact on obesity or the metabolic diseases associated with obesity. (Nutritional Therapy & Metabolism 2009; 27: 113-33)

Post-genomics approaches towards monitoring changes within the microbial ecology of the gut

The human gut microbiota, comprising many hundreds of different microbial species, has closely co-evolved with its human host over the millennia. Diet has been a major driver of this co-evolution, in particular dietary non-digestible carbohydrates. This dietary fraction reaches the colon and becomes available for microbial fermentation, and it is in the colon that the great diversity of gut microorganisms resides. For the vast majority of our evolutionary history humans followed hunter-gatherer life-styles and consumed diets with many times more non-digestible carbohydrates, fiber and whole plant polyphenol rich foods than typical Western style diets today.

Flavonoids and brain health: multiple effects underpinned by common mechanisms

The neuroprotective actions of dietary flavonoids involve a number of effects within the brain, including a potential to protect neurons against injury induced by neurotoxins, an ability to suppress neuroinflammation, and the potential to promote memory, learning and cognitive function. This multiplicity of effects appears to be underpinned by two processes. Firstly, they interact with important neuronal signalling cascades leading to an inhibition of apoptosis triggered by neurotoxic species and to a promotion of neuronal survival and differentiation. These interactions include selective actions on a number of protein kinase and lipid kinase signalling cascades, most notably the PI3K/Akt and MAP kinase pathways which regulate pro-survival transcription factors and gene expression. Secondly, they induce peripheral and cerebral vascular blood flow in a manner which may lead to the induction of angiogenesis, and new nerve cell growth in the hippocampus. Therefore, the consumption of flavonoid-rich foods, such as berries and cocoa, throughout life holds a potential to limit the neurodegeneration associated with a variety of neurological disorders and to prevent or reverse normal or abnormal deteriorations in cognitive performance.