Supplements like vitamin D3 or zinc already support your immune system and should be a part of your daily routine – but eating the right vegetables and fruits will help you to stay healthy and strong additional.
On the surface of your white blood cells, who defend your body against infection and disease there are vitamin d receptors and activating enzymes. By binding to its receptor, it regulates the expression of various genes and affects the behaviour of different cell types within the immune system.
Vitamin D works like a light switch in your body, who turns on or off genes and processes that your body needs to maintain health. Active Vitamin D is sent to many areas of the body, including bones, intestines, brain, and immune cells, which all have receptors for vitamin D. The active vitamin D binds with the receptors and promotes vitamin D responsive genes.
Low levels of vitamin d3 are associated with frequent colds and influenza (https://www.nih.gov/news-events/nih-research-matters/low-vitamin-d-levels-associated-colds-flu).
In 2017 analyses of prospective clinical trials showed that taking vitamin D reduces the chances of developing a respiratory infection by 42% in people with low baseline levels of 25-hydroxyvitamin D (Martineau AR, Jolliffe DA, Hooper RL, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data).