**1. Introduction**

Inflammation is a defensive reaction of the immune system to a pathological factor that damages cell structures. It is the natural response of any healthy organism to neutralize pathogens and maintain homeostasis. The normal inflammatory response occurs when the threat is present and resolves when the threat is over [1,2]. However, the action of certain biological, psychological, social, and environmental factors can prevent acute inflammation from subsiding and contribute to the persistent presence of chronic inflammation in the body. Chronic inflammation is characterized by the activation of the immune system components that often differ from those involved in an acute immune response [3]. Shifting the inflammatory response from short-term to long-term leads to severe changes in the functioning of all tissues and organs, which can increase the risk of various diseases in both young and old people. Long-term inflammation in the body is now linked to the development of chronic non-communicable diseases such as obesity, diabetes, and cancer [4,5].

Factors contributing to the development of long-term inflammation include chronic infections, lifestyle-related obesity, intestinal dysbiosis, sleep disturbances, psychological stress, social isolation and environmental and industrial pollution [2]. According to existing data low physical activity and poor diet also contribute to the occurrence of chronic

**Citation:** K ˛eska, A.; Pietrzak, A.; Iwa ´nska, D. Use of the Dietary Inflammatory Index to Assess the Diet of Young Physically Active Men. *IJERPH* **2022**, *19*, 6884. https://doi.org/10.3390/ ijerph19116884

 Academic Editor: Paul B. Tchounwou

Received: 30 April 2022 Accepted: 2 June 2022 Published: 4 June 2022

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inflammation [6]. The link between physical inactivity and an increased risk of diseases associated with long-term inflammation has been well documented [7,8]. It is assumed that lack of physical activity promotes inflammation as it causes the body to store more fat, especially visceral fat [9]. It is also believed that in physically inactive people, the intensification of inflammation is a result of the reduced secretion of anti-inflammatory substances by the skeletal muscles. These substances are cytokines (e.g., IL-6, Il-8) and other small proteins (e.g., brain-derived neurotrophic factor BDNF, irisin) called myokines [10]. It should be emphasized that myokines are produced by skeletal muscles and have systemic anti-inflammatory effects primarily during muscles' contraction [11]. Decreased production of myokines in physically inactive people is associated with increased pathophysiological changes typical of chronic inflammation, including insulin resistance, dyslipidemia and high blood pressure [12]. On the other hand, exercise-induced damage to muscle fibers is known to cause transient inflammation which, if overtrained, can turn into chronic inflammation [13]. Thus, the relationship between exercise and inflammation is more complex and depends on many factors.

The same goes for diet. For example, following a Mediterranean Diet based mainly on fruits, vegetables, fish and other products containing many unsaturated fatty acids is associated with the reduction of inflammation [14]. In turn, the Western Diet, very popular in developed countries, characterized by a high consumption of saturated fatty acids and simple carbohydrates, contributes to a significant increase in the level of inflammatory markers in the blood (e.g., C-reactive protein, CRP). It has been shown that these nutrients negatively affect the intestinal microflora, and by increasing the permeability of the intestinal barrier, they cause inflammation [15].

A growing number of studies confirming diet influence on the occurrence of inflammation have contributed to the creation of an indicator called the Dietary Inflammatory Index (DII) [16,17]. DII was established in 2013 on the basis of numerous publications from 1950 to 2007, which described the influence of 45 food components, then included in the DII, on inflammation development [18]. Each component of DII was given an individual positive or negative point value. Positive values were assigned to ingredients and/or products that exhibit pro-inflammatory properties (e.g., saturated fatty acids), while negative values were assigned to ingredients and/or products with anti-inflammatory properties (e.g., vitamins, minerals) [19]. This relatively new dietary index was validated against inflammatory cytokines [20,21]. The studies conducted so far have also confirmed its relationship with the occurrence of components of the metabolic syndrome, such as high waist circumference, high TG concentration or hypertension [22]. Thus, the development of the Diet Inflammatory Index allowed for a better assessment of the quality of consumed food, mainly in the context of its impact on health.

Previous studies which analyzed DII mainly concerned middle-aged and elderly people, often in the early or advanced stages of the disease (e.g., cancer, diabetes) and characterized by moderate physical activity. For example, a large 2017 United States study looked at ethnically diverse people aged 45–75 participating in the cancer registry program [23]. This study confirmed an association between the pro-inflammatory potential of the diet, described by the DII index, and an increased risk of colorectal cancer. In another study by Visseres et al., the relationship of DII with the development of arterial hypertension was investigated in women aged 51–53 years [24]. Therefore, data on the value of the Diet Inflammatory Index of healthy young people are insufficient. Meanwhile, the few existing studies show that the diet of young people, especially men, often promotes chronic inflammation, thus increasing the risk of diseases related to it [25,26].

Taking into account the above information, as well as the importance of proper nutrition for maintaining high physical performance, it seems advisable to undertake research on the inflammatory potential of the diet, expressed by the DII index, in young, physically active men.

#### **2. Materials and Methods**
