Some nutrients play key roles in maintaining the integrity and function of the immune system, such as zinc, vitamin C, and vitamin D. These stand out for having immunomodulatory functions and for playing roles in preserving physical tissue barriers.
Zinc is essential for the integrity of the immune system, with an important role in the maintenance, development and activation of cells during innate and adaptive immune responses. Zinc also plays a role in the integrity of epithelial barriers, which are essential for organism defense and prevention of pathogen entry. Another important function of zinc is its direct antiviral activity, which makes it essential for the immune response upon viral infection
Zinc deficiency affects approximately one-third of the population worldwide and is considered a global nutritional problem, affecting population groups in both developed and developing countries. According to a WHO report, zinc deficiency is responsible for 1.4% (0.8 million) of annual deaths and 2.9% of loss of healthy life years around the world
Ascorbic acid is a water-soluble micronutrient with antioxidant properties that plays a crucial role in the immune system, supporting the epithelial barrier against the entry of pathogens and the cellular functions of the innate and adaptive immune systems. As an antioxidant, vitamin C prevents damage to biomolecules (nucleic acids, proteins, lipids and carbohydrates) resulting from exposure to oxidants generated by normal metabolism and exposure to pollutants and toxins.
Vitamin C levels in the body may vary due to environmental conditions, such as air pollution, and the presence of pathologies, such as type 2 diabetes. A meta-analysis of 44 studies that used doses of vitamin C starting at 200 mg per day reported a reduction in the duration of the common cold in adults and children, which has been related to the role of this vitamin in supporting the immune system and in reducing the severity of symptoms.
Despite the traditional name, vitamin D is actually a hormone, given that in addition to being endogenously produced, it acts on the regulation of more than 200 genes in different cell types. Only 10% of the vitamin D required is obtained from food, whose main sources include animals such as tuna and salmon, and plants such as edible mushrooms. The remaining 80 to 90% are endogenously synthesized, a process that begins in the deep layers of the epidermis, following exposure to ultraviolet (UV) solar radiation.
Vitamin D plays an important role in the body’s immune function. This immunomodulating function of vitamin D is considered complex during viral infections and appears to vary according to the nature of the pathogen and the type of immune function responsible for the resolution of the disease.