Commonly we say, ‘nutrient-rich
food boost up the immunity’ and in the crisis of COVID -19, immunity is the
ultimate hope as we don’t find any effective treatment yet. But most of us
don’t know how immune systems are working in our body. Today we are going to
know about the mechanism between diet and immune response in the body.
An
working outline of immune system
Different kinds of
immune cells triggers the immune response in the human body. Two kinds of
immune responses are found in the body. One is the innate immune response and
the other is the adaptive immune response. The Innate response is the first
response to an invading pathogen. This response is rapid, not specialized and
less effective than adaptive immune response. Phagocytic cells like macrophages
and monocytes, neutrophils, mast cells, dendritic cells, eosinophils are the
cells of the innate immune response.
Adaptive
Immune response
The adaptive immune
systems are capable to specifically recognize a pathogen, take necessary
actions accordingly and can memorize this throughout the life to perform
pathogen-specific immune response if encountered again. Two types of
lymphocytes trigger the function of the adaptive immune response. One is T-cells
(thymus cell) and the other one is B-cells (bursa derived cells).
T-
cells are divided into cytotoxic T-cells and T helper
cells (Th).
Cytotoxic
T-cells: Involved in direct killing of infected damaged cells
and tumour cells.
T
helper cells (Th): Important in coordinating the responses
of other immune cells. Two major subtypes of Th cells are
- ·
Th1 cells that produce interferon gamma (
IFN- γ) and interleukin (IL)-2, important in antiviral or cellular and
antiviral immune responses.
- ·
Th2 cells produce IL-4, IL-5, IL-13 and
involve in humoral (antibody) and anti-parasitic responses.
- ·
Other subtypes include Th17 produce
IL-A, IL-17-F, IL-22 and important for fighting against extracellular pathogens
like bacteria and fungi.
- ·
T regulatory cells (Treg), which are
CD4-bearing T cells vital in maintaining immune tolerance to allow the immune
system to ignore non-harmful non-self (such as food, pollen, and environmental
antigens such as latex).
B-cells are responsible for antibody or Immunoglobulin (Ig) production. Igs are pathogen-specific molecules, which help the immune system to recognize and destroy pathogens. Igs can be into plasma cells (short-lived plasma cells and long-lived plasma cells) and which produce one of 5 classes of Igs like IgM, IgD, IgG, IgA, IgE. Each class has a specific role. Sometimes their presence in the blood helps to detect the diseases.
The effective
deployment of the immune system against pathogens or harmful signals and the
swift resolution of the immune response is required for survival. Cytokines
play a role in resolution of immune responses. The activities of immune cells
and an active immune response results in inflammation which indicates the
immune system work properly most of the cases.
How diets affect the immunity
An active immune system
increases the demand of energy and associate nutrients to keep functioning the
immune cells. Nutrition supports the functions of immune cells allowing them to
initiate effective responses against pathogens. The demand for energy and other
nutrients are filled up from exogenous source (through diet) or in case of
inadequacy of diet, from endogenous sources (such as body reserves). Some
micro-nutrients, essential amino acids, and dietary components have very
specific role in an active immune system. Even a mild deficiency in zinc
has been associated with widespread defects in both the adaptive and innate
immune response. Vitamin C is very important for immune function and it's deficiency results in impaired immunity and increase the risk of infections. Vitamin A and Zinc regulate cell division and are essential
for proliferative response within the immune system. Vitamin E works as an
antioxidant and interacting with enzyme and transport protein. Vitamin D
receptor (VDR) plays an important role in the activities of immune cell.
Vitamin A, B-complex, C, D receptor, Vitamin E, Zinc, Iron, selenium, copper,
and amino acids have a specific role in functioning the immune systems (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6212925/).
Malnutrition breakdowns
the immunity functions by repressing the system. About 6 million children die
worldwide each year because of infections caused by malnutrition due to
breakdown of immunity. Sometimes a single micronutrient deficiency (such as vitamin
E) can affect the whole immune systems.
Ageing gradually declines
the immune function which is known as immunosenescence. That is the reason
older people are more sensitive in any bacterial or viral attack especially
COVID-19. Ageing is also associated with increased inflammation without
infection. T-cells are decreasing in case of older people. A number of
micronutrient deficiencies are associated with decline immunity.
Egg, Milk, meat, nuts, fruits
and vegetables provide immune nutritional elements and keep our immune system active.
These ingredients provide energy, micro-nutrients (vitamins and minerals),
essential amino acids required by the immune cells which results in a proper
functioning immune system. In addition, mild exercise every-day, adequate
sleep, no tension and anxiety can make us healthy and cheerful. Hope for your
good health. Stay healthy, stay safe.
Nuronnabi
Sagor
Informative.
উত্তরমুছুনThanks
উত্তরমুছুন