According to the World Health Organization, malnutrition refers to the cellular imbalance that occurs between energy and nutrients supply and their demand by the body for growth and maintenance purposes. Protein malnutrition, commonly known as protein-energy malnutrition or undernutrition (PEM), involves pathological conditions that arise from lack of much-needed dietary protein in varying proportions (Vlasova et al., 2017). As seen in the patient in the case, the presence of edema or oedema serves as the primary diagnostic feature in PEM patients. Edema is characterized by the fluid leaking from the body’s tiny blood vessels, capillaries. The fluid buildup then causes surrounding tissues to swell, manifesting in the patient’s generalized edema of the abdomen, as well as extremities. Edema of extremities involves inflammation of the hands, legs, arms, ankles, in addition to feet.
A variety of patient factors often play a central role in PEM. In particular, given the patient’s old age, they are most likely to stay, sit, or sleep in one position for a considerably long time. At the same time, some older adults have difficulty following a healthy diet. In this case, the patient does not have dentures to allow them to eat and absorb food properly. This means that the patient is more likely to rely on fluids, thus lacking protein and energy foods (Guleria et al., 2017). The physical examination explains these patient factors because the disease is inextricably linked to the patient’s history of prolonged protein deficiency and overall inadequate food intake.
The pathophysiology of PEM starts with protein deprivation, causing intestinal dysbiosis, compromised immune system, epithelial breaches, pathobiont invasion, as well as altered metabolism. In malnourished children and adults, these pathological activities cause environmental enteric dysfunction (EED) (Vlasova et al., 2017). As reported in the case of the patient, the PEM’s multifactorial pathobiology and the EED involve a vicious cycle characterized by impaired immunity, malabsorption, and potentially recurrent enteric infections that worsen malnutrition. Worsened malnutrition is clinically manifested by micronutrient deficiencies and edema, which do not only comprise immunity but also impair the intestinal epithelial cell (IEC) barrier.
Apart from the role played by intestinal epithelial cells (IECs), additional genetic, racial, and ethnic factors contribute to the development of PEM. In this respect, nutritionists and other scientists strive to provide information about why people eat, including a wide range of motivational factors that drive food choices. With this understanding, scientists can explain how to manage lifestyle-related diseases or epidemics, such as obesity and malnutrition (Grimm & Steinle, 2011). This means that eating behavior comprises one of the most complex interplays of genetic, physiologic, social, as well as psychological determinants, which influence people’s meal preference, the timing of amount, or intake. Findings from a recent study by Choi (2019) supports previous research that the gene TAS2R38 defines a person’s food habit, determining both lower and higher intake of given foods. The TAS2R38 is a bitterness-sensing protein that helps mediate taste perception and other physiological responses, such as energy-related mechanisms. Regarding ethnicity and gender, Sheean et al. (2019) found that blacks and women have the highest PEM risk scores compared to whites and Hispanics. This is mainly due to health disparities between the majority and minority groups.
Choi, J. (2019). Variation in the TAS2R38 bitterness receptor gene was associated with food consumption and obesity risk in Koreans. Nutrients, 11(9). https://doi.org/10.3390/nu11091973
Grimm, E. & Steinle, N. (2011). Genetics of eating behavior: Established and emerging concepts. Nutrition Review, 69(1), 52-60.
Guleria, P., et al. (2017). Genetic engineering: A possible strategy for protein-energy malnutrition regulation. Molecular Biotechnology, 59, 499-517.
Sheean, P., et al. (2019). Nutrition risk among an ethnically diverse sample of community-dwelling older adults. Public Health Nutrition, 22(5), 894-902.
Vlasova, A. et al. (2017). Protein malnutrition modifies innate immunity and gene expression by intestinal epithelial cells and human rotavirus infection in neonatal gnotobiotic pigs. American Society for Microbiology. DOI: 10.1128/mSphere.00046-17