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PubMed2004

The nutrition transition: worldwide obesity dynamics and their determinants.

OBJECTIVE: This paper explores the major changes in diet and physical activity patterns around the world and focuses on shifts in obesity. DESIGN: Review of results focusing on large-scale surveys and nationally representative studies of diet, activity, and obesity among adults and children. SUBJECTS: Youth and adults from a range of countries around the world. MEASUREMENTS: The International Obesity Task Force guidelines for defining overweight and obesity are used for youth and the body mass index > or =25 kg/m(2) and 30 cutoffs are used, respectively, for adults. RESULTS: The nutrition transition patterns are examined from the time period termed the receding famine pattern to one dominated by nutrition-related noncommunicable diseases (NR-NCDs). The speed of dietary and activity pattern shifts is great, particularly in the developing world, resulting in major shifts in obesity on a worldwide basis. Data limitations force us to examine data on obesity trends in adults to provide a broader sense of changes in obesity over time, and then to examine the relatively fewer studies on youth. Specifically, this work provides a sense of change both in the United States, Europe, and the lower- and middle-income countries of Asia, Africa, the Middle East, and Latin America. CONCLUSION: The paper shows that changes are occurring at great speed and at earlier stages of the economic and social development of each country. The burden of obesity is shifting towards the poor.

Adolescent↗
PubMed2006

The thrifty 'catch-up fat' phenotype: its impact on insulin sensitivity during growth trajectories to obesity and metabolic syndrome.

The analyses of large epidemiological databases have suggested that infants and children who show catch-up growth, or adiposity rebound at a younger age, are predisposed to the development of obesity, type 2 diabetes and cardiovascular diseases later in life. The pathophysiological mechanisms by which these growth trajectories confer increased risks for these diseases are obscure, but there is compelling evidence that the dynamic process of catch-up growth per se, which often overlaps with adiposity rebound at a younger age, is characterized by hyperinsulinemia and by a disproportionately higher rate in the recovery of body fat than lean tissue (i.e. preferential 'catch-up fat'). This paper first focuses upon the almost ubiquitous nature of this preferential 'catch-up fat' phenotype across the life cycle as a risk factor for obesity and insulin-related complications - not only in infants and children who experienced catch-up growth after earlier fetal or neonatal growth retardation, or after preterm birth, but also in adults who show weight recovery after substantial weight loss owing to famine, disease-cachexia or periodic dieting. It subsequently reviews the evidence indicating that such preferential catch-up fat is primarily driven by energy conservation (thrifty) mechanisms operating via suppressed thermogenesis, with glucose thus spared from oxidation in skeletal muscle being directed towards de novo lipogenesis and storage in white adipose tissue. A molecular-physiological framework is presented which integrates emerging insights into the mechanisms by which this thrifty 'catch-up fat' phenotype crosslinks with early development of insulin and leptin resistance. In the complex interactions between genetic constitution of the individual, programming earlier in life, and a subsequent lifestyle of energy dense foods and low physical activity, this thrifty 'catch-up fat' phenotype--which probably evolved to increase survival capacity in a hunter-gatherer lifestyle of periodic food shortages--is a central event in growth trajectories to obesity and to diseases that cluster into the insulin resistance (metabolic) syndrome.

Adiposity↗
PubMed2006

Obesity: a problem of darwinian proportions?

Obesity has been described as an abnormality arising from the evolution of man, who becomes fat during the time of perpetual plenty. From the perspective of "Darwinian Medicine," if famine is avoided, obesity will prevail. Problems regarding obesity arise within many disciplines, including socioeconomic environments, the educational system, science, law, and government. This article will discuss various ethical aspects of several disciplines regarding obesity, with a focus on scientific inquiry. We will discuss this within the categories: (1) chronic kidney disease predialysis, (2) dialysis, and (3) renal transplantation. This article aims to help nephrologists and their patients navigate through the ethical aspects of obesity and chronic kidney disease.

Bariatrics↗
PubMed2000

Shattered: Medawar's test tubes and their enduring legacy of chaos.

Medawar's 1952 paper 'An Unsolved Problem of Biology' underlies most subsequent theoretical work regarding the evolution of aging; it concludes that aging is accidental and could not have evolved; this prevents reconciling the growing body of evidence suggesting the existence of multiple, evolved, aging systems. The paper features a well-known thought experiment using test tubes to show why aging could not evolve. Medawar assumes that constant, random, breakage sufficiently represents lethal forces of nature; however, famine, drought, predation, disease, and accidents each uniquely affect populations. Predation is the only evolving force that continually invents new ways to kill members of the prey populations; thus all prey defenses to predation will eventually be defeated. Defenses to non-evolving or non-obligate lethal forces, however, should quickly evolve. Thus unevolving, identical test tubes cannot adequately represent biological populations. The example also ignores population booms and busts which often occur in nature. By ignoring these issues, Medawar examines only one population age distribution skewed towards younger individuals in predator-dominated environments while ignoring predator-free populations skewed towards older individuals after population crashes. Further, Medawar's test tubes lack meaningful competition for finite resources, and ignore declining fertility which occurs in all aging species. Medawar concludes that older individuals are too few in number to influence the population's gene pool for or against aging. This conclusion is found to be incorrect when variations in the age of reproductive senescence are introduced into a predator-free population.A new thought experiment with competing strains of algae corrects for these issues and shows that aging evolved and is retained so that groups retain enough genetic variability to allow for rapid evolution of a defense to novel predation. The example shows reasons why the rate of aging is directly linked to the reproductive rate, litter size, metabolic rate, reproductive senescence, and fixed body size. It also suggests that in the absence of predation, immortality would quickly evolve if not for the evolution of highly-conserved aging systems. Prior analysis of aging evolution is incorrect due to theorists' rejection of the idea of group selection. It is believed to be 'impossible' to select for mutations that are bad for the individual but good for the group. However, mutations that are neutral to young individuals which are only deleterious if expressed at older ages can accumulate in early-mortality, predator-dominated environments. Removing the predator allows deleterious mutation expression. Positive group selection then occurs amongst traits that are negative to the individual. Further, group selection is a universal force that occurs between local, non-breeding groups and not, as theorists propose, between distant groups of potentially interbreeding species. Local survivors migrate to replace extinct, related species. The antagonistic pleiotropy theory, which was created to salvage the idea of accidental aging, is examined and shown to be untenable. The hypothetical antagonistic pleiotropy genes that are beneficial to young while detrimental to old individuals, predicted to exist in the 1950s, are unlikely to exist, have not, and likely will not be found in sufficient quantity to participate in the aging process.

Aging↗
PubMed2000

Sex, kings and serial killers and other group-selected human traits.

(Note: This unorthodox paper contains the first argument for heart disease being a programmed age change and promoted by the dramatic, post age-40 increases in the hormones FSH and hCG seen in some individuals.) A recent issue of Science suggests that the evolutionary purpose of sex is unknown. PARADOX: Surviving to adulthood implies a valuable gene combination which is destroyed by sexual recombination. This should be detrimental to offspring. PROPOSED: Sex is group-selected in prey to allow coalescence of beneficial, and disposal of detrimental, mutations in single individuals enabling rapid adaptation to novel predation. Group selection is a universal force driven by local inter-species (not intra-species) competition. Aging, metabolism, litter size, and fixed body size are directly linked. Sexual recombination and chromosomes destroy gene linkage and exist because mutations are usually detrimental, rarely positive, and occur in linked groups. In unevolving environments, sex is selected against and asexuality emerges. Periodic evolution of novel predators, like man, can explain the 'punctuated equilibria' fossil record. Genes inhibited by methylation or chromatin condensation, expressed at older ages in predation-minimized environments, allow for group selection. Stress increases mutation rates and beneficial mutation likelihood. Females select bigger, brighter, louder, or stronger males that can survive predator attention. Size approximates age and thus predator encounters; male traits represent predation-survival potential. Human male traits include, balding, acne, beard-length, wrinkling, graying, nose/ear growth. Progeria accelerates development of most male traits. Domination of groups by single males allows rapid predation-defense evolution: adolescent males are expelled, brave the wild, and expel another group's male to mate. If expelled and dominant males are culled by predation, males reaching puberty first will reproduce. Hormonal acceleration of puberty accelerates aging/population turnover, induces smaller bodies, larger litters. With a fixed group biomass, more, smaller, stressed individuals with faster aging/turnover, increase beneficial mutation likelihood. 'Kin selection', where dominant families are supported by celibate relatives, allow the best group genes to survive famine. Dominant families gorge while others starve. Equal food sharing results in group extinction leading to group-evolved human traits of social hierarchy, greed, king/queen/God worship. Menstrual hormone cycling parallels aging. FSH and DHT promote ovarian, hair, acne, dental, and arterial follicle development causing ovulation, hair growth, pimples, dental caries, and atherosclerotic soft plaques. Soft plaques contain macrophages and LDL plug; upper plaque layers thin and rupture, releasing LDL plug, causing thrombosis. FSH withdrawal or LH/hCG increases trigger ovulation and thrombosis. Artery narrowing atherosclerotic hard plaques are stress-induced through cortisol-promoted necrotic calcification. LH/hCG-induced apoptosis promotes ovulation and aging-related somatic atrophy. Long-term estradiol stimulates, while progesterone suppresses, gonadotropin levels. Estradiol protects by inhibiting gonadotropin bioactivity and has extracellular antioxidant, but intranuclear free radical, effects. Female X-linked gene mosaicism conserves evolved aging systems. Maternal age factors for chromosomal trisomy suggest menopause prevents human parthenogenesis. Homosexuality and serial killing inhibit genetic contribution by individuals evolutionarily perceived as stressed. Smoking during pregnancy may induce homosexual offspring. Nitric oxide, a free radical, stimulates cGMP, but not cAMP. cGMP likely first evolved as an antioxidant defense to free radicals. Human aging syndromes might reflect human evolution progression. AS#4 affects tissues evolved from plant ancestors, AS#5a - from predators, AS#5b-immune system, and AS#6-sex tissues. (ABSTRACT TRUNCA

Aging↗
PubMed2005

An ancestral oomycete locus contains late blight avirulence gene Avr3a, encoding a protein that is recognized in the host cytoplasm.

The oomycete Phytophthora infestans causes late blight, the potato disease that precipitated the Irish famines in 1846 and 1847. It represents a reemerging threat to potato production and is one of >70 species that are arguably the most devastating pathogens of dicotyledonous plants. Nevertheless, little is known about the molecular bases of pathogenicity in these algae-like organisms or of avirulence molecules that are perceived by host defenses. Disease resistance alleles, products of which recognize corresponding avirulence molecules in the pathogen, have been introgressed into the cultivated potato from a wild species, Solanum demissum, and R1 and R3a have been identified. We used association genetics to identify Avr3a and show that it encodes a protein that is recognized in the host cytoplasm, where it triggers R3a-dependent cell death. Avr3a resides in a region of the P. infestans genome that is colinear with the locus containing avirulence gene ATR1(NdWsB) in Hyaloperonospora parasitica, an oomycete pathogen of Arabidopsis. Remarkably, distances between conserved genes in these avirulence loci were often similar, despite intervening genomic variation. We suggest that Avr3a has undergone gene duplication and that an allele evading recognition by R3a arose under positive selection.

Agrobacterium tumefaciens↗
PubMed1996

Induced intensification: agricultural change in Bangladesh with implications for Malthus and Boserup.

Bangladesh is dominated by a small-holder agrarian economy under extreme stress. Production shortfalls, increasing economic polarization, and chronic malnutrition are persistent, but major famine has been diverted in part by significant growth in agriculture. This recent history is open to both Malthusian and Boserupian interpretations-a history we explore here through a test of the induced intensification thesis of agricultural change. This thesis, framed by variations in the behavior of small-holders, has grown from a simple demand-production relationship to a consideration of the mediating influences on that relationship. The induced intensification thesis is reviewed and tested for 265 households in 6 villages in Bangladesh from 1950-1986. A time-series analysis of an induced intensification model provides relatively high levels of explained variance in cropping intensity (frequency and land productivity) and also indicates the relative impacts of household class, environment, and cropping strategies. On average, the small-holders in question kept pace with the demands on production, although important class and village variations were evident and the proportion of landless households increased. These results, coupled with evidence that agricultural growth involved intensification thresholds, provide clues about Malthusian and Boserupian interpretations of Bangladesh, and suggest that small-holder agriculture there is likely to continue on a "muted" path of growth.

Agriculture↗
PubMed1998

Plant genomics: more than food for thought.

In all but the poorest countries of South Asia and Africa, the supply and quality of food will rise to meet the demand. Biotechnology, accelerated by genomics, will create wealth for both producers and consumers by reducing the cost and increasing the quality of food. Famine and malnutrition in the poorest countries may be alleviated by applying genomics or other tools of biotechnology to improving subsistence crops. The role of the public sector and the impact of patent law both could be great, but government policies on these issues are still unclear.

Journal Article↗
PubMed1996

Adult malnutrition: simple assessment techniques for use in emergencies.

The recent recognition of the problem of adult malnutrition requires methods for specifying the severity of undernutrition. The measurement of mid upper arm circumference (MUAC) can now be used as a screening method for underweight (normally assessed from the BMI) or as an additional criterion with the BMI to identify the preferential loss of peripheral tissue stores of fat and protein. By analysing and extrapolating anthropometric data from nine detailed adult surveys from Asia, Africa and the Pacific a series of MUAC cut-off points have now been identified to allow the screening of individual adults under extreme conditions, e.g. during famine. Grade 4 malnutrition is now specified for those with a MUAC < 200 mm for men and < 190 mm for women since these MUAC values correspond to the loss of fat stores at BMI of < 13. Food supplementation is clearly needed in these individuals. Extreme wasting (grade 5 malnutrition) corresponds to MUAC values of < 170 and < 160 mm for men and women respectively. These adults have extremely low BMI, i.e. about 10, have lost most, if not all, of their protein stores and are at a high risk of imminent death. These individuals will need immediate special feeding regimens to ensure their survival. The sex-specific MUAC values corresponding to BMI of 16, 13 and 10 can now therefore be used for rapid screening and the choice of remedial action.

Adult↗
PubMed2001

Obesity and undernutrition in a very-low-income population in the city of Maceió, northeastern Brazil.

Obesity is the nutritional disorder which has shown the greatest increase in prevalence, even in those countries in which deficiency diseases represent a severe public health problem. The goal of the present study was to analyse the anthropometric profile of a community living in the outskirts of Maceió, capital of Alagoas (northeastern Brazil), and to investigate the hypothesis of a coexistence of undernutrition and obesity in a very low-income population. The survey was conducted on 315 families (1247 individuals). Among the children (aged < or =10 years), the prevalence of wasting, stunting and wasting plus stunting was 3.8, 8.3 and 8.7 % respectively. Wasting (10.2 %) was the most prevalent form of undernutrition among adolescents; nonetheless, a higher frequency of stunting (11 %) and overweight-obesity (5.5 %) was seen specifically in girls, in agreement with trends found in other studies. Adults exhibited a high prevalence of overweight-obesity (25 %), but stunting was also present (22 %). Of the stunted individuals, 30 % were overweight-obese and 16.3 % were underweight. There were eighty-six families with at least one parent who was underweight (27 %) and 104 families with at least one parent who was overweight (33 %). Underweight and overweight-obesity were both present in ninety-six households (30 %). These results may indicate that better living conditions in urban areas in a population 'adapted' to chronic famine might increase the susceptibility to obesity. Considering the harm caused by the cumulative effect of these two conditions (undernutrition in childhood and obesity in adult life) there is a clear need for new studies to uncover the determinant factors so that preventive measures can be implemented.

Adolescent↗
PubMed2001

Food transitions in the 20th-21st century.

Food transitions in history have been fast, violent processes in some cases, while on other occasions they have taken place slowly, overlapping the traditional food culture as food items are replaced by new ones. Despite the contribution of potato and maize to avoiding famine in Europe, the exclusive crop system caused serious problems. Main food transitions are currently taking place in Asia. Emerging economies face the dilemma of improving the health and well-being of the population while avoiding excess and surplus. The challenge is twofold: on the one hand, to counteract the negative effects of food transitions and, on the other, to fight against hunger and malnutrition.

Diet↗
PubMed2002

The shift in stages of the nutrition transition in the developing world differs from past experiences!

OBJECTIVE: This paper explores the unique nutrition transition shifts in diet and activity patterns from the period termed the receding famine pattern to the one dominated by nutrition-related non-communicable diseases (NR-NCDs). The paper examines the speed and timing of these changes; unique components, such as the issue of finding both under- and overnutrition in the same household; potential exacerbating biological relationships that contribute to differences in the rates of change; and political issues. SETTING: The focus is on lower- and middle-income countries of Asia, Africa, the Middle East and Latin America. RESULTS: These changes are occurring at great speed and at earlier stages of these countries' economic and social development. There are some unique issues that relate to body composition and potential genetic factors. The significance of the high number of persons exposed to heavy insults during pregnancy and infancy (foetal origins hypothesis) and the subsequent rapid shifts in energy imbalance remains to be understood. Countries that are still addressing major concerns of undernutrition are not ready to address these NR-NCDs. CONCLUSIONS: The developing world needs to give far greater emphasis to addressing the prevention of the adverse health consequences of this shift to the nutrition transition stage of degenerative diseases.

Africa↗
PubMed2006

Evaluation of health, nutrition and food security programmes in a complex emergency: the case of Congo as an example of a chronic post-conflict situation.

OBJECTIVE: To describe the case of Congo as an example of the assessment and appropriateness of donor operational and sectoral strategies in a complex emergency. DESIGN AND SETTING: The paper reports the findings of an external evaluation of operations financed by the European Commission Humanitarian Office in the Democratic Republic of Congo (DRC). RESULTS: The Congolese health system is suffering from severe deterioration. What is functioning in the public health context is donor-dependent with high costs and limited coverage. Despite a relatively favourable agro-climatic situation, food shortage and famine severely affect the nutritional status of large population groups. In this context, humanitarian programmes have generally improved access to health care and the nutritional status of beneficiaries. The reduction of malnutrition in project areas is often demonstrated even though the context did not permit consolidation of these results. Malnutrition continues to claim a massive cost of lives owing to the effect of widespread food insecurity that follows a circular cause-and-effect pattern of very low food production and extreme poverty. CONCLUSIONS: The current context in DRC does not correspond yet to 'post-crisis': neither at population level with regard to indicators of poverty, malnutrition, disease and death, nor at institutional level, with regard to state support to institutions. In these situations, the international community is often called upon to replace the state as service provider. Integrated humanitarian actions should be the future of relief projects in DRC. Health, nutrition and food security components should be considered a standard public health intervention strategy representing the most sensible approach to address the needs of the affected population.

Delivery of Health Care↗
PubMed2002

Nutrient insult in early pregnancy.

Nutrient insults in early pregnancy, such as nutrient deprivation during famines, are often associated with an unfavourable outcome. Suboptimal nutrition in the early stage of gestation has been linked to a number of adverse effects on fetal growth and development. Historically, nausea and vomiting in pregnancy (NVP) was an important contributor to pregnancy-related mortality; indeed, Charlotte Bronte died from starvation and dehydration after suffering very severe NVP 4 months into her first pregnancy (Gaskell, 1858). Although NVP seldom now progresses to be life-threatening, it affects the majority of pregnant women, and potentially presents a challenge to nutrient intake in the most vulnerable period of development. Symptoms range from mild (nausea only) to severe (a level of vomiting that restricts nutrient intake and ultimately threatens metabolic and electrolyte balance). Although NVP has been documented for thousands of years, its cause has not yet been satisfactorily elucidated, but seems to be related to endocrinological changes. Pregnant women also frequently report dietary cravings and aversions during pregnancy which can be linked to both the incidence and severity of NVP. Paradoxically, NVP appears to be positively associated with a favourable outcome of pregnancy, including increased birth weight and gestational age. The mechanisms by which NVP favours the outcome of pregnancy are not known. They may be related to women increasing their nutrient intake to alleviate symptoms, improving the quality of their diet or reducing energy expenditure. Alternatively, adaptation to a reduced nutrient intake might stimulate the expression of growth factors and affect placentation or metabolism, thus favouring fetal growth when NVP resolves.

Embryonic and Fetal Development↗
PubMed2005

Insights from the developing world: thrifty genotypes and thrifty phenotypes.

Few researchers would dispute that the pandemic of obesity is caused by a profound mismatch between humanity's present environmental circumstances and those that have moulded evolutionary selection. This concept was first articulated when gestational diabetes was described as being the result of a 'thrifty genotype rendered detrimental by progress'. More recently, this hypothesis has been extended to the concept of a 'thrifty phenotype' to describe the metabolic adaptations adopted as a survival strategy by a malnourished fetus; changes that may also be inappropriate to deal with a later life of affluence. Both the thrifty genotype and the thrifty phenotype hypotheses would predict that populations in some areas of the developing world would be at greater risk of obesity and its co-morbidities; a proposition to be explored in the present paper. To date thrifty genes remain little more than a nebulous concept propagated by the intuitive logic that man has been selected to survive episodic famine and seasonal hungry periods. Under such conditions those individuals who could lay down extra energy stores and use them most efficiently would have a survival advantage. The search for candidate thrifty genes needs to cover every aspect of human energy balance from food-seeking behaviour to the coupling efficiency of oxidative phosphorylation. The present paper will describe examples of attempts to find thrifty genes in three selected candidate areas: maternally-transmitted mitochondrial genes; the uncoupling proteins; apoE4, whose geographical distribution has been linked to a possible thrifty role in lipoprotein and cholesterol metabolism.

Adaptation, Physiological↗
PubMed2001

Cross-national changes in time-use: some sociological (hi)stories re-examined.

The paper addresses some macro-sociological questions about changes in broad categories of time-use. The focus is on large-scale cross-national time trends from developed countries in paid and unpaid work, and leisure. Reference is made to some well-known sociological and historical accounts of such change, and to the fact that time-use diary data has only relatively recently become available for analysing trends over time. The data used are drawn from a comparative cross-time data archive held by the Institute for Social and Economic Research at Essex University, comprising successive time-use diary surveys from a range of industrialized countries collected from the 1960s to the 1990s. The time use evidence suggests relative stability in the balance between work and leisure time over the period covered by the analyses. Some alternative explanations are advanced for why there seems to be a gap between this evidence and, on the one hand, the burgeoning literature in both academic and popular media addressing the 'time famine' and, on the other, people's professed experience of what is happening to their time.

Adult↗
PubMed2002

A new estimate of Ukrainian population losses during the crises of the 1930s and 1940s.

Ukraine experienced two very acute demographic crises during the Soviet era: the 1933 famine and the Second World War. While different estimates of total losses have been produced previously, we have tried here to distinguish the specific impact of the crises on mortality from their impact on fertility and migration. Taking into account all existing sources of registered data and estimates, a painstaking reconstruction of annual demographic changes has been produced and complete annual life tables have been computed for the years 1926-59. Life expectancy at birth fell to a level as low as 10 years for females and 7 for males in 1933 and plateaued around 25 for females and 15 for males in the period 1941-44.

History, 20th Century↗
PubMedDate not supplied

Age at menarche in a Chuvashian rural population.

OBJECTIVES: The secular trend and familial influences on age at menarche among a rural Chuvashian population was examined in a cross-sectional community-based study. SUBJECTS AND METHODS: The cohort included 617 females aged 18-80 years, with age at menarche ranging from 10 to 24 years (mean 15.4 +/- 2.1). Statistical analyses included simple linear regression, maximum likelihood estimation and a whiskers plot. RESULTS: Women born during the second through the fourth decade of the 20th century showed increasing mean values of age at menarche from 15.4 (second decade) up to 16.5 (fourth decade). Women born after the fourth decade showed a decrease in mean values from 15.5 (fifth decade) to 13.0 (ninth decade). The highest peak of age at menarche was in women born in 1932. Significant familial correlations were observed between adjusted to year of birth age at menarche in mothers and daughters r = 0.195, p<0.01 and sisters and sisters r = 0.404, p<0.01. CONCLUSION: Our study demonstrated the certain secular trends of age at menarche in Chuvashian women who matured after World War II. Periods of socio-economic disasters such as war and famine disrupt the secular trend. Our findings also confirm the hypothesis of significant familial influences on menarcheal age.

Adolescent↗