Food Allergies and Ageing

Abstract

All over the world, there is an increase in the overall survival of the population and the number of elderly people. The incidence of allergic reactions is also rising worldwide. Until recently, allergies, and in particular food allergies (FAs), was regarded as a pediatric problem, since some of them start in early childhood and may spontaneously disappear in adulthood. It is being discovered that, on the contrary, these problems are increasingly affecting even the elderly. Along with other diseases that are considered characteristics of advanced age, such as cardiovascular, dysmetabolic, autoimmune, neurodegenerative, and oncological diseases, even FAs are increasingly frequent in the elderly. An FA is a pleiomorphic and multifactorial disease, characterized by an abnormal immune response and an impaired gut barrier function. The elderly exhibit distinct FA phenotypes, and diagnosis is difficult due to frequent co-morbidities and uncertainty in the interpretation of in vitro and in vivo tests. Several factors render the elderly susceptible to FAs, including the physiological changes of aging, a decline in gut barrier function, the skewing of adaptive immunity to a Th2 response, dysregulation of innate immune cells, and age-related changes of gut microbiota. Aging is accompanied by a progressive remodeling of immune system functions, leading to an increased pro-inflammatory status where type 1 cytokines are quantitatively dominant. However, serum Immunoglobulin E (IgE) levels and T helper type 2 (Th2 cytokine production have also been found to be increased in the elderly, suggesting that the type 2 cytokine pattern is not necessarily defective in older age. Dysfunctional dendritic cells in the gut, defects in secretory IgA, and decreased T regulatory function in the elderly also play important roles in FA development. We address herein the main immunologic aspects of aging according to the presence of FAs.

New Perspectives in Food Allergy

“…However, the current exponential growth of the adult and elderly population, especially in Western countries, and the environmental and lifestyle changes, have profoundly changed the epidemiology of FA with a growing increase even in advanced age. Moreover, FA in aging exhibits peculiar clinical features and immunopathogenetic mechanisms, increasing the diagnostic complexity [14].…”

“…Other cytokines, including thymic stromal lymphopoietin (TSLP) and IL-33, reprogram the APCs, transforming them into cells capable of shifting the differentiation of naive lymphocytes towards IL-4 and IL-13, producing Th2 cells rather than Tregs, with consequent allergic sensitization [94,95]. Inflammation, favored by the age-related gut barrier and digestive function impairment, as well as by the chronic inflammation that characterizes senescence, plays a central role in the breakdown of tolerance to food antigens in the elderly [14,96,97].…”

Sex and Gender Aspects for Patient Stratification in Allergy Prevention and Treatment

“…Sex, age, psychological and socio-economic factors influence the developing and the manifestations of these disorders. IgE-mediated such as oral allergic syndrome and digestive anaphylaxis and non-IgE-mediated such as eosinophilic disorders and food protein induced enterocolitis syndrome food allergies are described and represent an increasing public health concern [68][69][70][71]. It is recognized the association of food allergy with some congenital immunodeficiency syndromes.…”

Persistent Iron Deficiency Anemia in Patients with Celiac Disease Despite a Gluten-Free Diet

“…In their meta-analysis including 16 studies with a total of 956 patients (both adults and children), Yuan et al concluded that H. pylori eradication could resolve IDA [80]. The pathogenesis of IDA related to H. pylori is not fully known [79], and various mechanism have been proposed: chronic gastrointestinal bleeding due to gastric mucosa erosions, the use of iron by bacteria for growth and proliferation, a reduced concentration of ascorbic acid in the gastric juices, and the upregulation of proinflammatory cytokines and hepcidin (a key regulator of iron homeostasis) [69,77,79,[81][82][83][84]. In vitro studies have shown that iron-repressible outer membrane proteins are expressed by H. pylori and could be involved in heme binding and/or uptake [85].…”