Nutrition and infectious diseases

Human growth is influenced by two elements that are closely related: nutrition and infectious illnesses. Malnutrition puts people at risk for communicable diseases, and these infections can also cause famine, creating a vicious cycle (Semba et al., 2007). A diet that is inadequate due to poor nutrition leads to weight loss, stunted growth and development, weakened immune, and disease invasions. Additionally, malabsorption, nitrogen loss from the urine, diarrhea, and appetite loss can all worsen a patient's nutritional status. All of these elements weaken the immune system, which results in nutritional loss. This is followed by a decrease in nutritional intake. The timing of these factors in influencing human growth is dependent on many factors, most commonly, age. Malnutrition tends to affect children more than adults and so does infectious diseases. Children with these hardships are stricken by problems associated with human growth, although as they grow up, their immune system becomes stronger. The vicious cycle of poor nutrition and infectious diseases is more prevalent third world nations in Africa, Asia, and Latin America.
Secular change is an important aspect of fitting in the natural selection process. Throughout the 20th century, the secular change was taking the same direction in most of the countries in the world (Van, 1978). The uniformity can be attributed to the improvement of social and economic conditions coupled with longitudinal growth indices. Although the various direction of the secular change might be same in different communities, there is a big variation in terms of rate. Developed countries have a clear secular trend in as far as height, and weight increase is concerned. The result of this has been affecting the time of puberty and the right period for the onset of sexual activities. The changes have been so rapid such that they have triggered a genetic modification.
Small body sizes can be considered as a form of adaptation especially for the places where there is a food scarcity. The size reduces the food intake that is required for the small-bodied people to carry out their day to day activities. Besides, several kinds of research done on the field have shown that the laws of physics favor the small-bodied people by making them more agile and faster compared to their bigger counterparts (Blanckenhorn, 2000). Scientifically, a large body requires a greater force to be set in motion as well as changing the direction of the body. The suitability of the small body size is supported by the Bergmann's rule on the resource availability dictating the success and ultimately the survival of organisms (Atkinson & Sibly, 1997). However, it should be noted that the reduction in the body size is only applicable where there is the scarcity of resources such as food. There could be other instances in which other characteristics like height could be favored. The reduction in the size of the body is, however, more standard and fit for evolution where competition for food is at the top of the hierarchy of needs.
Adaptation and adaptability are also addressed by Van Valen's Red Queen Theory. The theory states that organisms have been maintaining an effort to always co-evolve to survive by constancy change in given environmental conditions (Van 1977). Van Valen also aimed at explaining whether adaptation creates a need or whether the reverse is true. The argument was backed up with the concept of preadaptation in which some organisms acquire features or characteristics before they are required in the environment. Her ideas were later supplemented by Gould and Vrba who came up with the concept of exadaptation. The concept entailed evoking those traits in an organism that were developed to perform a different function from the one currently served. Gould and Vrba provided a deeper explanation of the differences that were in organisms in their behavior and appearances (Gould, 1991).
Life history tradeoff is another quality that is necessary for adaptation. Traits can be removed, retaining more practical ones, hence increasing the chances of survival. Human beings are brought out in different bio-cultural environments that expose them to different challenges such as poverty, ethnic oppression and the exposure to infections. Some problems like malnutrition and the exposure to infectious diseases might result in stunted growth, being overweight or even having asymmetrical body proportions. The study of these factors and their impact is referred to as developmental programming (DP) that is guided by the principle of predictive adaptive response (PAR) (Nettle et al., 2013). Under the principle, two possible alterations can be done. One is short-term and guided by the need for guaranteeing the immediate survival while the second aims at securing the postnatal survival. PAR is the concept of trade-off to ensure survival, reproduction, and productivity. It should, however, be noted that adverse conditions do not favor the tradeoffs but rather result in poor growth, reduced survival changes and constraints on the physical activities.
Question 3
Despite having an immense adaptation capability, human beings can be regarded as being maladapted. People have been succumbing to the forces in the environment that are avoidable through using our innate responses that have guaranteed the survival of the human race for millions of years. They, therefore, end up being victims of stress for failing to effectively adapt to the constraints encountered, a technique that is of utmost importance to guarantee survival. Among the typical modern factors causing the stress are the need to meet the demands of urbanization and the media which is dictating what is right and what is not. Stress can, therefore, be said as being primarily triggered by the inabilities and challenges posed by environment as organism fight for their survival.
As humans, there is the need to underscore the importance of adapting to our environment and look for ways to manage stress within ourselves. Failure to find pragmatic solutions to the stress problem will mostly tend trigger health problems. Although adaptation is more of an individual role, it is worth appreciating efforts made in the medical field in coming up with preventive measures and therapies that promote a healthy and a relaxed life. The application of counterbalance measures is sometimes difficult when one is going through the condition. The response to the changes in the environment should be made at a minimal cost because it is a crucial physiological attribute of great adaptive value. Coping mechanisms to unpredictable changes in the environment tend to manifest at various stages in life. Similarly, the level of stress in any given environment act as a selective measure of high degree, driving the life histories evolution.
From another scholastic angle, stress can regard as a process that involves an individual and the milieu in which transactions take place. Individuals here struggle to strike or reestablish an internal balance whenever events call for interpretations that may threaten the integrity of the well-being (Davidson & McEwen, 2012). Whenever the constraints are too persistent, the system of adaptation become exhausted and thus ineffective in its adaptability hence circumstances such as the appearance of diseases like psychosomatic disorders, ulcers, and asthma.
Key findings of the Michael Marmot studies were that health and stress are related to a person's social and economic status. People with high social and economic status were found to have a relatively better health and were less likely to suffer from stress. The situation was different to those occupying low levels of the socioeconomic hierarchy. The inequalities that people find themselves in at birth or in the process of growing up affect their levels of stress and their health conditions. Although the economic factors at birth might be beyond victims of control, choices made after that should be geared towards bettering one's life hence reducing the level of stress at adulthood. Sir Michael Marmot, therefore, made significant contributions in guiding people on their lifestyle and health choices.
The research further underscored those social interactions particularly in the reproduction process increase the reproduction of steroid hormones which respond to stress. The theory of traits guided the study. Michael Marmot further noted that small social order causes a stress response. The people with lower economic and social class are not only vulnerable to stress but also other diseases that are related as documented in the DSM 5. In a landmark study, called Whitehall Study, Marmot used British men serving at various levels of the civil service as the target group. He identified a clear gradient in as far as a risk was concerned between the levels. Deaths decreased as public servant went up the employment ladder, a factor that was necessary for establishing the relationship between wealth and stress (Marmot et al., 1991).
Marmot's input into the relationship between health and stress and the causing agents made him the key proponent behind these studies. People have since then been observant in maintaining a sense of connectedness in the social realm and maintaining an autonomy over their lives as measures to preserve good health. Having a low control over these two key issues makes it hard for a person to live a healthy life. Moreover, this low control is attributed to chronic stress that makes our bodies vulnerable to diseases. It is, therefore, a universal rule that the more people feel insecure, powerless and exploited in their workplace, the higher the chances of them getting sick and maybe dying earlier. Marmot's academic research was therefore well researched and will continue informing the decisions of many generations to come on the matters of health and stress.





















References
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Davidson, R. J., & McEwen, B. S. (2012). Social influences on neuroplasticity: stress and interventions to promote well-being. Nature neuroscience, 15(5), 689-695.
Gould, S. J. (1991). Exaptation: A crucial tool for an evolutionary psychology. Journal of social issues, 47(3), 43-65.
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Semba, R. D., De Pee, S., Berger, S. G., Martini, E., Ricks, M. O., & Bloem, M. W. (2007). Malnutrition and infectious disease morbidity among children missed by the childhood immunization program in Indonesia.
Van Valen, L. (1977). The red queen. The American Naturalist, 111(980), 809-810.
Van Wieringen, J. C. (1978). Secular growth changes. Human growth, 445-473.