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. Hence, high level of immunity is very important for maintaining robust health. An insufficient level of immune defence leads to infections diseases and tumours. Strong immunity requires adequate wholesome nutrition of macro as well as micro nutrients. Sufficient intake of vitamin C, vitamin D, folic acid, magnesium, zinc, and selenium is necessary. Intake of imbalanced macronutrients and micronutrients lead to obesity compromised immunity.
Several
natural ingredients have potent immune enhancing, regulating and suppressing
(immune modulatory) properties. The immune-enhancing properties of many plants
and fungi are due to containing bioactive phytoconstituents such as
polyphenols, terpenoids, vitamins, etc. Probiotics rich in fermented foods can
be used as effective tools to reduce intestinal inflammation and reduce
hypersensitivity reactions. Plant sources of melatonin, a multifunctional
molecule with proven anti-inflammatory and immune modulatory properties, have
been discovered recently.
Bioactive
compounds support the immune response by directly increasing the cytotoxic
activity of natural killer cells. Many phytoconstituents prevent cell damage
due to their powerful antimicrobial, antioxidant, and anti-inflammatory
properties
Human
beings are constantly exposed to various external influences, such as
environmental pollutants or harmful pathogens, that affect homeostasis. In
recent decades, the rapid growth of the frequency of various infectious
diseases, inflammatory conditions, allergies, cancers, brought much suffering to human beings.
At
the beginning of the 21st century, medical scientists concluded that an
insufficient level of immune defence leads primarily to the occurrence of
severe infections or/and tumors, while the abnormal functioning of the immune
system causes the development of allergic diseases. So, well-balanced immunity
is pivotal for maintaining good health. The importance of using natural
substances with immune activating properties to prevent or support medical
treatment of the above mentioned ailments is quite obvious.
The
immune system comprises a wide range of immune cells, various cytokinines, and
signaling pathways that protect the skin, intestinal tract, and respiratory
tract from foreign invaders such as bacteria, viruses, and fungi. The host
immune system has two functions: the innate immune system and the adaptive
immune system. While innate immunity lacks immunological memory, it is a
hallmark of adaptive immunity.
Medicinal
plants, beekeeping products, probiotics and prebiotics, melatonin, and other
natural compounds with immune modifying properties could be utilized to enhance
immunity against various diseases. Many vitamins and minerals are also very effective
in supporting the proper functioning of immunity. The high cost of synthetic
drugs, their known toxicity, and various adverse effects are undesirable for
patients.
In
contrast, herbal substances as health promoters have gained increasing attention
of both medical researchers and among consumers. Some medicinal plants do
exhibit immunity normalising effects. In addition to the significant growth of
interest in so-called super foods, berries, nuts, green tea, sea products, and
honey, among many others, in the era of the coronavirus pandemic, COVID-19
prompted a search for new effective natural remedies to prevent or cure it.
Natural
medicinal substances are regarded as effective immunity boosters in the case of
COVID-19 disease. Despite the progressive successes in developing various
vaccines against COVID-19, the importance of natural substances as immunity
enhancing agents cannot be underestimated. Recently, herbal medicines have been
considered the drugs of choice to enhance immunity in pre- and post-COVID-19
patients.
Herbs
promote health and help fight infections by boosting the immunity of the host.
Some herbal substances increase the proportion of beneficial gut bacteria,
which are crucial for maintaining immunity. Recently, Rondanelli et al.
described the pivotal role of vitamins (C, D), zinc, and Echinacea preparations
in self-care for the prevention or treatment of common colds. The natural
biochemicals of garlic (Allium sativum) boost immunity by increasing
the functions of innate immune system cells such as lymphocytes and natural
killer cells, which kill invading pathogens. Some biochemical compounds in
herbs modify innate and adaptive immune responses. The appropriate intake of
some polyphenols, vitamins, and minerals helps boost immune functions and fight
infections, including COVID-19. The immune-boosting properties of flavonoids
help fight cancer, inflammation, and viral infections.
Micronutrients,
such as vitamin C, also improve immune functions. Vitamin D increases the the
cell response and suppresses unhealthy cell activation. Overall, deficiencies
in certain vitamins and minerals can lead to the weakening of the immune
system. Propolis, a famous beekeeping product, is widely used for managing
upper respiratory tract infections, which occur when the level of immunity
decreases. Research in recent years revealed that appropriate administration of
the hormone melatonin plays a significant role in improving immunity.
Botanical
families comprise many plants with proven immune modulating properties. For
example, the immune stimulating properties of Echinacea, ginger,
and fresh citrus juice have been well-known worldwide for several decades. In
recent years, an increasing number of herbs with immune stimulating properties
have been researched and discovered for western medicine based on the study of
plant species from different parts of the globe.
The
molecular pharmacology of herbal drugs is a tremendous challenge, as medicinal
herbs are multi component substances with multi level modes of action compared
to single molecule synthetic pharmaceuticals.
Western
medicine approaches to medicine in the 21st century, as a rule, require the
isolation and purification of one or two active compounds from a given
medicinal plant. However, the isolation of one or two active biochemical
compounds from an herb could lead to the loss of its medicinal properties. For
instance, the effectiveness of multi-component herbal prescriptions in
Traditional Chinese Medicine and Indian Ayurveda are highly appreciated by
modern health care practitioners. It should be noted that individually, many of
the ingredients in these combinations do not possess therapeutic activities but
can assist other herbs in immune modulation.