VITAMIN D - The Boosting Hormone For The Immune System

Vitamin D is actually a hormone, not a vitamin, as you may have heard. In reality, the body's end product of Vitamin D conversion is classified as a hormone. 

Vitamin D can be obtained through a variety of foods, including fatty fish, egg yolks, and whole milk, but our bodies produce 90% of the vitamin. 

Vitamin D is synthesised in the liver and kidneys from direct sunlight (especially UV-B radiation) in the skin, and the process continues in the liver and kidneys until the final active form of the hormone is produced.

Many different kinds of cells in the body, including immune cells, have Vitamin D receptors, which means they can respond to Vitamin D molecules and cause various physiological reactions. 

It's no surprise that Vitamin D has a wide range of health effects, including bone health, cardiovascular health, immunity, autoimmune illness, type 1 diabetes, and mental health.

As the cold season is approaching, we're going to look at how Vitamin D affects the immune system and how it can help you avoid catching a cold.

Is vitamin D effective in the treatment of colds and flu?

According to a study, during winters people with low vitamin D levels are more likely to get upper respiratory infections than those with adequate amounts. Furthermore, reduced Vitamin D levels have been linked to an increased risk of illness, particularly influenza, in multiple studies. When compared to a control group, daily Vitamin D supplementation for 15 to 17 weeks over the winter dramatically reduced the prevalence of influenza infections in Japanese children.

Vitamin D supplementation for three months during the winter reduced the occurrence of upper respiratory tract infections in children with Vitamin D deficiency, according to another study.

How much vitamin-D do you need during the winter season? 

Humans are more susceptible to diseases and spend less time outside in the winter. It's debatable how much vitamin D healthy folks need to take. 

Some sources prescribe anywhere from 200 to 2,000 IU per day. The Institutes of Medicine advises 600-800 IU per day for individuals in the United States, whereas the Endocrine Society suggests 1500-2,000 IU per day for optimal vitamin D sufficiency.

What role does Vitamin D play in immune system support?

The innate (responsible for swiftly combating infections) and adaptive (responsible for fighting infections over time) immune systems are both vital in fighting infections (responsible for the production of antibodies). 

Both systems appear to be modulated by vitamin D, which explains why this hormone has such a broad impact on the immune system. Vitamin D is known to play a function in autoimmune as well. 

Patients with autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease, and lupus erythematosus, have a high prevalence of Vitamin D insufficiency.


It is critical to maintain your Vitamin D levels over the winter months. Several studies have shown that maintaining a healthy level of Vitamin D not only strengthens your immune system but also aids your body in fighting infections and illnesses.

It's always a good idea to see your doctor before taking vitamin D supplements to improve your overall immune response.

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