article fr 2021…
Various dietary combinations, bioactive components, nutrients and fortified foods have been reported to modulate inflammation during disease progression. Dietary combinations of dairy-derived products and eggs are gaining an increasing attention given the huge immunomodulatory and anti-inflammatory properties attributed to some of their chemical constituents. Eggs are complex dietary components containing many essential nutrients and bioactive compounds as well as a high-quality proteins. Similarly, yogurts can replenish beneficial bacteria and contains macronutrients capable of stimulating immunity by enhancing cell immunity, reducing oxidative stress, neutralizing inflammation and regulating the intestinal barriers and gut microbiome. Thus, this review highlights the impact of nutritional intervention on COVID-19 management, focusing on the immunomodulatory and inflammatory effects of immune-enhancing nutrients.
Egg as an Immune-Enhancing Food
It has been reported that various dietary combinations, bioactive components, nutrients, and fortified foods modulate inflammation during disease progression (23–25). Eggs represent a complex and controversial dietary component (26) that contains numerous essential nutrients and bioactive compounds, besides being high-quality protein source leading to divergent opinions in dietary recommendation across populations (27, 28).
Egg Structure
Structurally, eggs are composed of albumin (63%), eggshell (9.5%), and yolk (27.5%) (29). Biochemically, they comprise of 75% water, 12% proteins, 12% lipids, various minerals and carbohydrates (30, 31). Though proteins are distributed across the different egg parts, they are mainly contained in the yolk and egg white, while small proportions occur in the eggshell and shell membrane (32, 33). Lipids exclusively occur in the egg yolk mainly as lipoproteins (30, 32), while the bulk of minerals is found in the eggshell. As minor egg components, carbohydrates are found throughout the egg either as free carbohydrates or glycoconjugates (32). The bulk component of egg is the albumen or egg white that constitutes 60% of cumulative egg weight, whereas protein and water add up to other major components (31, 32). The major egg white's proteins are ovalbumin, ovotransferrin, and ovomucoid. Other proteins include ovomacroglobulin (ovostatin), cystatin, lysozyme, avidin, ovoinhibitor andovomucin that gives the albumen its characteristic viscosity (32).
Dietary Benefits of Eggs
Eggs are rich in complete proteins that promote muscle protein synthesis and maintenance of skeletal mass (34, 35). On average, one large egg provides ~6.3 g protein that is rich in essential amino acids (36). Eggs are affordable nutritious dietary components with significant health benefits (37). These nutrients include vitamins, essential proteins, minerals, fats, and various bioactive compounds. Eggs contain high nutrients to energy density ratio per egg, while also providing numerous essential nutrients (38). For instance, a typical boiled egg weighing ~50 g can provide as much as 78 kcal energy, 0.56 g carbohydrate, 6.29 g protein, and 5.3 g total fat. The total fats from an egg contains up to 1.6, 0.7, 2.0, and 186 mg of saturated, polyunsaturated, monounsaturated fats, and cholesterol, respectively. The micronutrients from eggs include iron, calcium, phosphorus, zinc, potassium magnesium, sodium, and most vitamins except vitamin C. These vitamins include riboflavin, niacin, thiamin, folate, and vitamins A, B6, B12, D, E, and K. Besides providing high quality proteins comparable to breast milk, eggs are also a source of antioxidants. Notable antioxidants from eggs include phosvitin rich in phosphoserines, ovotransferrin that chelates Fe3+and ovalbumin that improves the polysaccharide's antioxidant activity through covalent binding (39). These antioxidants act by chelating metal ions and scavenging free radicals thereby inhibit the lipids oxidation. Therefore, eggs are potential sources of natural antioxidants that can be used in both cosmetic and food industries. The eggs' antioxidant activity can ameliorate many degenerative conditions, such as cardiovascular diseases (CVD) in humans (40). However, eggs are not only rich in bioactive components and vital nutrients but also in complete proteins and nutritional cholesterol (28, 41). This controversy has resulted in divergent opinions in dietary recommendation of across populations. Nonetheless, owing to their nutritive quality, eggs, and their derivatives are known to regulate inflammation and modulate immunity.
https://www.frontiersin.org/articles/10.3389/fnut.2021.629440/full