In addition, it also regenerates endogenous important cellular and membrane antioxidants like vitamin E. Vitamin C could also modulate immune function by regulating redox-sensitive cell signaling pathways.
This is a complex mechanism which we won't be going into. But just bear in mind that vitamin C in conjunction with other micronutrients like, folate, Vitamin E, selenium, zinc, copper, and iron affects synthesis of cytokines, prostaglandins and histamine.
Cytokines - important cell signaling molecules that are secreted by a variety of immune cells, in response to infection and inflammation modulate both humoral and cell-mediated immune responses.
Cytokines can elicit pro-inflammatory or anti-inflammatory responses, and vitamin C modulates their production in a complex manner and also decreases histamine levels.
However studies have shown that the effect of vitamin C on cytokine generation appears to depend on the cell type and/or the inflammatory stimulant.
Did you know Vitamin C influences your white blood cells?
White blood cells are like the soldiers defending the integrity of the body system against invasion by foreign pathogens.
Neutrophils and monocyte-derived macrophages in particular, play a major role during inflammation (to initiate the process of wound healing)/infection and Vitamin C plays a big role in their actions.
During the initial stages of inflammation, phagocytic cells especially neutrophils migrate to the wound site through the process of diapidesis in response to inflammatory mediators (chemotaxis) in order to sterilize it via the release of reactive oxygen species (ROS) - oxidants and antimicrobial proteins.
Hope you now see how some of these oxidants accumulate in the body. Let's continue.
Does it means oxidants doesn't have any role they play in body?
Actually some oxidants like reactive oxygen species in moderate and low concentration have some roles they play in the body especially in the aspect of immuno modulation.
Many infections just like we explained above lead to the activation of phagocytes, with the release of reactive oxygen species assists in the deactivation of bacteria, viruses and other microbes. So they could also in addition to immuno modulation, acts as sterilizing agents.
When you take Vitamin C after an infection, what it does is to stimulate and enhance the migration of phagocytic cells to the site of infection, enhances phagocytosis and microbial killing.
Patients with severe infection exhibit compromised neutrophil chemotactic ability which could in part be attributed to reduced levels of vitamin C which is prevalent during severe infection.
ThIs is why you are always encouraged to take enough vitamin C during infection. In summary some oxidants also have beneficial roles to play in us.
Vitamin C and apoptosis
Following microbial phagocytosis and killing, the phagocytes have to undergo apoptosis (programmed cell death).
This process facilitates their subsequent phagocytosis and clearance from the body by macrophages that consequently engulfs and destroys them together with the pathogens.
There is a key enzyme that must be present before apoptotic cell death is activated and it is known as Caspases.
Their presence on any cell marks the cell for destruction, re-uptake and clearance by macrophages.
Because Caspases are thiol-dependent enzymes, they are highly sensitive to inactivation by reactive oxygen species generated by activated neutrophils.
Thus, vitamin C acts as an antioxidant protecting this oxidant-sensitive enzyme and the apoptotic process which in turn enhances the resolution of inflammation and prevents excessive tissue damage.
Without the protective effect of vitamin C on this enzyme, the apoptosis will continue non-stop. This is another wonderful role of vitamin C in the body.
We will continue next time... keep in touch.
