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Nutrition & Dietetics
Obesity is a global problem. It affects every age group and is associated with many negative health effects. As an example, there is a relationship between obesity and allergic and immunological diseases, such as asthma, psoriasis, food allergies, allergic rhinitis and atopic dermatitis. Obesity undeniably affects their development.
- obesity
- asthma
- atopic dermatitis
- psoriasis
- allergic rhinitis
- food allergy
1. Introduction
Obesity affects more than 2 billion people worldwide, and if the upward trend continues, 38% of the world’s adult population will be overweight and 20% will have obesity by 2030. The type of diet has a very significant impact on the calories supplied. Highly processed foods are known to contain large amounts of calories of little nutritional value and contribute to increasing rates of obesity. These days, in the Americas, the so-called “Western diet” became popular. It consists of highly processed foods and fast foods. This diet provides a large amount of calories with little nutritional value. High amounts of saturated fatty acids (high-fat diet—HFD) have a pro-inflammatory effect on dendritic cells and macrophages [1]. Obesity is diagnosed with a body mass index (BMI) above 30 and predisposes to many diseases: metabolic, cardiovascular, psychological, neurological, osteoarticular and hepatobiliary. It is also connected to the development of cancer and diseases of an allergic and immunological origin [1,2]. Adipose tissue is one of the main secretory organs. It is estimated that it is responsible for the release of over 600 different adipokines, including the immunomodulating leptin, resistin and ghrelin [3,4]. Adipokines are involved in inflammatory and autoimmune diseases by influencing innate and acquired immune responses.
2. Asthma
Asthma is a heterogeneous, chronic inflammatory disease of the airways with multiple phenotypes [6,7]. Obesity-related asthma is often described on the basis of paediatric patients, because it particularly affects this group of patients [8,9]. Obesity and related hypovitaminosis D (HVD), obstructive sleep apnoea (OSA) and gastro-oesophageal reflux (GER) contribute to its development [10,11,12]. As a result, patients with obesity have an increased risk of developing asthma. In addition, the severity of asthma in this group of patients (especially patients with abdominal obesity) is higher, and exacerbations are more frequent. Moreover, treatment is more difficult and less effective [10,13,14].
3. Atopic Dermatitis
One of the main chronic and recurrent inflammatory skin diseases—atopic dermatitis (AD)—is closely related to obesity [3]. AD is a global problem affecting mainly children and adolescents, although it also affects the older population [30,31]. AD at a young age predisposes to the development of other allergic diseases later in life: allergic rhinitis, asthma and food allergy. This phenomenon is called the atopic march [30]. Atopic dermatitis is manifested by an erythematous rash, dry and cracked skin and intense itching. It significantly affects the quality of life of patients, and predisposes to anxiety, sleep disturbances and depression [30,32].
4. Psoriasis
Psoriasis (PSO) is a chronic, recurrent, papulo-squamous inflammatory skin disease [3]. It can develop at any age—on average, at 33 years of age, and earlier in women. PSO is associated with high physical and mental strain and a shorter lifespan. The most common phenotype is psoriasis vulgaris [35]. PSO classically takes the form of an erythematous plaque covered with silvery scales, the removal of which reveals the Auspitz sign (minor bleeding spots). The size of the plaque can vary. Its edges are the most active area and the lesion expands outwards. The lesions typically occur symmetrically, in the extensor areas of the knees and elbows, on the scalp and in the lumbosacral region [35].
5. Allergic Rhinitis
Obesity is a factor that increases the risk of atopic allergic diseases in children [41]. One example is allergic rhinitis (AR). Studies have confirmed its relationship with excessive body weight in the paediatric population, but no such relationship was found in adults [42]. Allergic rhinitis is an allergic disease that has been increasing in frequency for years [43]. Although it does not affect mortality, it is a disease that reduces the quality of life of patients through poor sleep quality, fatigue and stress [43,44,45].
6. Food Allergy
Food allergy is an inflammatory disease that is associated with a specific allergen. It is common and has a significant impact on the patient’s life [47]. Food allergies affect both children and adults. A new allergy can become active at any age, mainly at early childhood proceeding obesity [48]. The eight most common food allergens are peanuts, eggs, fish, milk, tree nuts, wheat, crustacean shellfish and soy [49]. In some cases, obesity affects the risk and course of new food allergies as a result of, inter alia, the low-grade inflammatory state and the non-specific activation of the immune system [47].
7. Conclusions
Obesity is a global epidemic that is constantly evolving. It shows indisputable influence on the development, course and management of various diseases. Its pathogenesis consists of many complex mechanisms. The process of building up fat is called adipogenesis. It can take the form of hypertrophy, which is an increase in the size of existing adipocytes, and hyperplasia consisting of the formation of new adipocytes [1,3].
Obesity is characterized by low-grade systemic inflammation. Under normal conditions, adipocytes produce hormones and cytokines called adipokines. Those substances take part in the regulation of the body’s homeostasis system. The hypertrophy of white adipose tissue disturbs the activity of adipocytes. They produce higher amounts of pro-inflammatory adipokines, resulting in higher levels of inflammation, also called metainflammation. Hypoxia and intracellular oxidative stress are also important in its pathogenesis [5]. Constant inflammation leads to the increased risk of developing many diseases, including allergic and immunological ones [1]. Reducing the BMI in the population would lead not only to a reduction in the number of people suffering from obesity but also other systemic diseases.
Asthma is an example, in which pathogenesis is influenced by obesity through changes in the microbiome, disturbed hormonal balance, structural changes in the body and continuous low-grade systemic inflammation [22].
In the case of allergic rhinitis, the relationship between the risk of its occurrence and obesity in the elderly population has not been proven but in children such a relationship exists [42]. It can be concluded that obesity most severely affects younger children and causes the greatest changes in their organism. Additional therapy in this group would provide the best results. In the future, research should focus on the ways to improve the quality of life of these patients and introduce effective treatment that is not an excessive burden for the patient and does not bring major side effects. It is also important to promote obesity prevention and a healthy diet as a form of reducing the risk of developing various systemic diseases.
This entry is adapted from the peer-reviewed paper 10.3390/nu15173813
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