**1. Introduction**

The benefit of dietary patterns has appeared as a complementary and alternative approach to the study of the relation of diet and the risk of diseases. In contrast to a single substance or nutrient approach, an evaluation of whole dietary patterns may provide a more complete picture of a combination of foods and nutrients, such as synergistic and antagonist properties of the foods [1]. People do not eat isolated nutrients and rather consume foods that contain a variety of foods with complex interactive combinations of nutrients. Thus, a single active substance approach might be insufficient for considering complex interactions between food bioactive

components in the human study such as vitamin C improves Fe absorption [2]. Often, the high degree of intercorrelation between nutrients (e.g. magnesium and potassium) can be difficult for the evaluation of their separate effects in particular conditions [3]. Additionally, the cumulative effects of several nutrients are more likely detectable compared to the influence of a single substance. In the clinical trial setting, the dietary patterns approach has shown a positive health outcome in degenerative diseases [4]. Nutritional approach as dietary pattern intervention (e.g. Dietary Approaches to Stop Hypertension and Mediterranean Diet) as an integral part of disease management have been studied extensively on metabolic chronic diseases (cardiovascular diseases and diabetes) with beneficial clinical results [5, 6].

To what extend dietary patterns beneficial as an integral part of management and prevention strategy for communicable disease? The dietary pattern approach is more likely not only effective for non-communicable diseases but also infectious diseases [7]. Perhaps, this is a possible explanation that partial nutritional intervention exhibits lower than expected results in infectious diseases study settings. Partial nutritional interventions (macronutrients or micronutrients supplementation) as adjunctive treatment of standard antituberculosis agents among active tuberculosis patients is one of the examples. These nutritional interventions have shown no beneficial effects for main treatment outcomes. Even though the supplementation improves weight gain of the TB patients in some settings [8]. World Health Organization (WHO) has declared officially coronavirus diseases (COVID 19) as a global pandemic on 11 March 2020. Currently, there have been several attempts to recommend nutritional approaches for mitigation strategy the disease [9–14]. The dietary pattern plays important role in this communicable disease due to its severity is affected by a previous underlying disease. Comorbidities such as respiratory system diseases, chronic obstructive pulmonary diseases (COPD), diabetes, hypertension, cardiovascular/cerebrovascular disease have shown significant evidence of associations with the severity and prognosis of COVID-19 [15].

Intestinal dysbiosis (gut microbiota imbalance) recently has been proposed as a significant factor that is associated with several immune-related human diseases including infectious, inflammatory, neoplastic, metabolic, autoimmune diseases [7, 16, 17]. Within the gut lumen itself, the human gut microbiome will provide antigens and signals with the potential to interact with resident and systemic immune cells. The composition of the gut microbiome changes over the life course, in response to dietary components, infection, antibiotic exposure [18]. All of these may result in dysbiosis. During this condition, nutritional changes have been suggested as a suitable approach to restoring a healthy gut microbiota and host homeostasis [19]. Also, it has been proposed dietary patterns such as Mediterranean diet and low-fat diet possess the ability to restore partially microbiota dysbiosis [20]. Despite commonly studied single nutrient supplementation, this narrative review aimed to provide current perspectives on the association between the major dietary patterns and infectious disease susceptibility through immune response and systemic inflammation. Relevant articles (original articles, literature reviews, systematic reviews and meta-analyses articles) that identified major dietary patterns and related keywords (e.g., "infection", "disease", "immune system", "inflammation", and "gut microbiota") were searched in Google Scholar, PubMed, MEDLINE, and Cochrane databases from the year 2010 to the year 2020 with exception for one article.
