ABSTRACT
The immune system protects the body from infectious agents such as bacteria, viruses, or fungi. Once encountered with pathogens or antigens, the innate and adaptive arms of the immune system trigger a strong immune response to eliminate them from the system and protect the body. Thus, well-balanced immunity is pivotal for maintaining human health, as an insufficient level of immune defense leads to infections and tumors. In contrast, the excessive functioning of the immune system causes the development of autoimmune diseases and allergies. Strong immunity requires adequate nutrition, dietary interventions, and sufficient intake of certain vitamins (vitamin C, vitamin D, and folic acid) and minerals (magnesium, zinc, and selenium). Therefore, nutritional and micronutrient deficiencies lead to compromised immunity. Several natural ingredients have shown potent immunomodulatory properties. The immune-enhancing properties of many plants and fungi are due to containing bioactive phytoconstituents such as polyphenols, terpenoids, ß-glucans, vitamins, etc. Probiotics and prebiotics can be used as innovative tools to reduce intestinal inflammation and downregulate hypersensitivity reactions. Plant sources of melatonin, a multifunctional molecule with proven anti-inflammatory and immunomodulatory properties, have been discovered relatively recently. The bioactive compounds augment the immune response by directly increasing the cytotoxic activity of natural killer cells, macrophages, and neutrophils. Many phytoconstituents prevent cell damage due to their powerful antimicrobial, antioxidant, and anti-inflammatory properties. The present review attempts to understand the molecular mechanisms underlying the immune-enhancing properties of some bioactive compounds from plants, fungi, animals, microorganisms, and other natural sources.
ABSTRACT
Many diseases, including caries, chronic inflammatory diseases, diabetes, and obesity, are associated with uncontrolled sugar consumption. Artificial sweeteners are commonly used in food and pharmaceutical industries as sugar substitutes for the prevention of several dental and body diseases; they also have a favorable impact on body weight as they may help to restrict simple sugar consumption. Xylitol is a sugar alcohol that is commonly used as a sweetener. It can be found naturally or artificially prepared mainly from plant materials chemically or by fermentation of hemicelluloses from agricultural biomass by yeast or bacteria strains. This polyol has a significant antiplaque effect on teeth surface and can reduce the gingival inflammation; it is being used as a preventive agent for dental caries due to decreasing the growth levels of pathogenic Streptococcus mutans and Streptococcus sangui at the very early stages. Xylitol can bind with calcium ion leading to consequent remineralization of teeth enamel; it is also able to prevent osteoporosis. This polyol can treat respiratory tract and middle ear diseases due to its antibacterial and anti-inflammatory potential and prevent some diseases which cannot be cured through antibiotics or surgery. Xylitol can reduce constipation, diabetes, obesity, and other body syndromes or illnesses; it has also revealed its stimulating effect on digestion and immune system. However, it can produce some side effects such as irritable bowel syndrome, diarrhea, nephrolithiasis, etc., when consumed in excessive amounts. Different vehicles are used for delivering the xylitol into the human body, but chewing gums occupy a leading position. The present review is devoted to comprehensive analyses of the positive and negative effects of this polyol on human health.Key Points⢠The health benefits of xylitol are not limited to oral hygiene.⢠Xylitol efficiently stimulates the immune system, digestion, lipid and bone metabolism.⢠Xylitol helps in glycemic and obesity control; reduces ear and respiratory infections.⢠Xylitol treats diseases that cannot be cured through antibiotics or by surgery.
