Archives of Public Health

Metabolic syndrome (MetS) predicts type II diabetes mellitus (TIIDM), cardiovascular disease (CVD) and cancer, and their rates have escalated over the last few decades. Obesity related co-morbidities also overlap the concept of the metabolic syndrome (MetS). However, understanding of the syndrome’s underlying causes may have been misapprehended. The current paper follows on from a theory review by McGill, A-T in Archives of Public Health, 72: 30. This accompanying paper utilises research on human evolution and new biochemistry to theorise on why MetS and obesity arise and how they affect the population. The basis of this composite unifying theory is that the proportionately large, energy-demanding human brain may have driven co-adaptive mechanisms to provide, or conserve, energy for the brain. A ‘dual system’ is proposed. 1) The enlarged, complex cortico-limbic-striatal system increases dietary energy by developing strong neural self-reward/motivation pathways for the acquisition of energy dense food, and (2) the nuclear factor-erythroid 2-related factor 2 (NRF2) cellular protection system amplifies antioxidant, antitoxicant and repair activity by employing plant chemicals. In humans who consume a nutritious diet, the NRF2 system has become highly energy efficient. Other relevant human-specific co-adaptations are explored. In order to ‘test’ this composite unifying theory it is important to show that the hypothesis and sub-theories pertain throughout the whole of human evolution and history up till the current era. Corollaries of the composite unifying theory of MetS are examined with respect to past under-nutrition and malnutrition since agriculture began 10,000 years ago. The effects of man-made pollutants on degenerative change are examined. Projections are then made from current to future patterns on the state of ‘insufficient micronutrient and/or unbalanced high energy malnutrition with central obesity and metabolic dysregulation’ or ‘malnubesity’. Forecasts on human health are made on positive, proactive strategies using the composite unifying theory, and are extended to the wider human ecology of food production. A comparison is made with the outlook for humans if current assumptions and the status quo on causes and treatments are maintained. Areas of further research are outlined. A table of suggestions for possible public health action is included. (Continued on next page) Correspondence: [email protected] School of Population Health and Human Nutrition Unit, Faculty of Medicine and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand B-Med Weight Control Consultancy, Auckland, New Zealand © 2014 McGill; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. McGill Archives of Public Health 2014, 72:31 Page 2 of 18 http://www.archpublichealth.com/content/72/1/31 (Continued from previous page) Forward: A composite unifying theory on causes of obesity related-MetS has been formulated and published in an accompanying article (1). In the current article, the historical and recent past, present and future corollaries of this theory are discussed. By presenting this composite theory and corollaries, it is hoped that human evolution and physiology will be viewed and studied from a new vantage point. The politics of management of ecological farming and nutrition will change, a profound reconfiguration of scientific theory generation and advancement in a ‘high-tech’ world can be made, and pathways for solutions recognised. Background The degenerative disorders associated with major health problems such type II diabetes mellitus (TIIDM), atherosclerotic cardiovascular disease (CVD) and cancer have increased markedly over the last 100 years or so. Almost all populations suffer from high rates of these diseases in the 21 Century. In the last five decades obesity rates have accelerated and are associated with the above degenerative conditions. They are linked, and predicted by, a cluster of markers comprising hypertension, dyslipidaemia and hyperglycaemia, denoted the metabolic syndrome (MetS). A change to an individualistic, capitalist, westernised way of life has contributed. High energy, refined, overappetising food has always been a profitable commodity. Science prioritises high-technology oriented commodities that can be mass produced for high financial returns. However, processed food has little overall nutritional value, and its production also involves significant amounts of antinutrient additives. Such high energy refined food is known to influence obesity, but the mechanisms of its contribution to MetS are not understood. Much public health and ecological science has been developed to try to rectify the issues caused by technological production of food. However, some cultures have been pursuing this pattern of increasingly designing and using new technologies since agriculture and animal husbandry arose. The foraging or a hunter/gatherer way of life was effectively that in which humans evolved and for which they were most adapted. Even primitive farming meant a significant change in nutrition, which may need accounting for. As effective methods to deal with human obesity, let alone basic causes of MetS, are unknown, a review of human evolution and history is required in order to form a unifying theory. Any such theory is likely to be a composite of various hypothesises and extant or new sub theories. Once such a composite unifying theory is formulated it needs to be ‘tested’ against what we know of all of the changes humans have made or have occurred to them, since they left their time of maximum fitness and health. The composite unifying theory has been developed [1]. It states that human physiology, in addition to anatomy, changed during the evolution of the proportionately large, energy-demanding human brain. Such co-adaptive mechanisms were required to provide or conserve more energy for the brain. There are a number of human specific mechanisms that may be contributing to human obesity. However, two co-dependent, but unrelated coadaptive systems or a ‘dual system’ is proposed: 1) the enlarged, complex cortico-limbic-striatal system increases dietary energy by developing strong neural self-reward/ motivation pathways for the acquisition of energy dense food, and 2) the nuclear factor-erythroid 2-related factor 2 (NRF2) cellular protection system amplifies antioxidant, antitoxicant and repair activity by employing plant chemicals, becoming highly energy efficient in humans. These two systems may have come to interact in a negative way since technologies advanced. The complex human cortico-limbic-striatal system generates strong behavioural patterns, based on neural rewards, for energy dense food procurement, including motivating the development of agricultural technologies and social systems to augment the process. Once significant amounts of this high energy, refined food are produced for communities, the cortico-limbic-striatal reward system tends to an extreme, ‘overdrive’ setting or addiction in many individuals. Aspects of addiction include lack of control of the behaviour and over-consumption of the salient item, and neglect of healthy behaviours such as eating nutritious but less appetising ‘common or garden’ food. Insufficient consumption of food micronutrients, such as secondary plant food micronutrients, prevents optimal human NRF2 function. In humans, the micronutrient dependant, hyper-functioning NRF2 appears to protect long lived cells, such as cardiomyocytes and neurones, from oxidative stress, thus conferring many decades of excess functional longevity. Additionally, the human NRF2 protects fast turnover immune/endocrine or other epithelial cells from toxins, stabilises and controls replication, which decreases rates of neoplastic change and cancer. If there are insufficient food micronutrients, inefficient oxidation of excess energy forces central and non-adipose cells to store excess toxic lipid. Lack of detoxification of foreign or unnecessary (xenobiotic) chemicals exposes cells to toxins which poison many cell processes, introducing dysfunction or apoptosis. Ensuing oxidative stress and metabolic inflammation (metaflammation) allows susceptibility to infectious, McGill Archives of Public Health 2014, 72:31 Page 3 of 18 http://www.archpublichealth.com/content/72/1/31 degenerative atherosclerotic cardiovascular, autoimmune, neurodegenerative and dysplastic diseases. Corollaries of the composite unifying theory on the