Vitamin D – the ‘sunshine vitamin’ – is best known for its ability to keep bones strong.
But it also plays a key role in keeping the immune system strong. Making it an important micronutrient to benefit for seasonal challenges.
While vitamin D may not help prevent an infection directly, it may be able to assist with reducing severity and duration of a contracted illness.
What is Vitamin D
Vitamin D is a fat-soluble vitamin linked to several important functions of the body. An adequate amount can also provide several benefits throughout the lifespan.
It is also not just one vitamin – vitamin D comes in many forms. The most common forms are D2 and D3, which are derived from different sources. But can both be found in supplement form.
Vitamin D2 is found in plant-based foods. Including mushrooms and fortified foods like dairy, cereals, and juices (1).
Vitamin D3, however is found in animal-sourced foods, fatty fish (i.e., salmon), cheese, and egg yolks (2). However, D3 is also the form of vitamin D found in sunlight and can be produced by the skin (1). This version is also more effective in the body.
Vitamin D – in all its forms – is best known for its ability to keep bones strong. Also, for its ability to regulate mood and assist the brain in functioning properly. However, vitamin D is also essential for keeping the immune system strong and healthy.
3 Ways Vitamin D Strengthens Your Immune System
Vitamin D is involved in many parts of the immune system, protecting the body against a number of viruses, infections, and illnesses.
Most important are – promoting immune response, boosting immune cell function, and protecting the respiratory system from infections.
- Promoting immune response
Vitamin D is one of the most crucial micronutrients involved in regulating immune responses in the body and system adaptation. This is because it has both anti-inflammatory and immunomodulary properties, essential for activating the body’s immune defenses to protect itself from pathogens (3).
Also, vitamin D is a crucial component of immune antibodies and enzymes that breakdown harmful viruses and bacteria (4).
- Immune cell function
Vitamin D assists in the function of immune cells and enhances their functions when needed (4). Including white blood cells – like T cells and macrophages – that protect your body against invading pathogens.
These cells are found all across the body. Even within the body’s first line of defense – the skin.
- Respiratory protection
This vitamin has also been known to have an extra benefit of protecting the lungs from viruses and bacteria associated with respiratory infections (3).
Will Vitamin D Help You During Seasonal Challenges?
There is little evidence that vitamin D can prevent infections like the cold and flu. But because of its proven functions in supporting the immune system, vitamin D may help you through cold and flu season (5).
With the vitamin’s ability to improve immune response and promote immune cell function can assist in fending off harmful pathogens. They may also reduce severity and duration if you happen to contract an illness.
Other Benefits of Vitamin D
Beyond immune system strength, vitamin D provides the body several other benefits –keeping bones strong, boosting brain health, and may improve the symptoms of depression.
These functions also play essential roles in keeping the body healthy during cold and flu season as you age.
- Keeps bones strong
Vitamin D plays a significant role in the mineralization, maintenance, and repair of bone. Not only bones of the body, but also teeth and cartilage.
It is important for regulating the amount of calcium and phosphorous absorbed into the blood stream through the intestines, which are both important minerals for bone building (1). Higher intake of vitamin D is linked to higher bone density.
- Boosts brain health
The brain, and nervous system, also benefits from vitamin D.
It is present in cells, tissues, receptors, and neurons in the brain – allowing efficient sensory, motor, and cognitive messages to be sent (6).
Vitamin D also assists with the delivery of calcium to the brain, which is important for internal messaging and memory.
- Improves mood and combats depression
Low levels of vitamin D increase risk for depression and unstable mood. When deficient in vitamin D3, receptors and neurons are unable to function efficiently. This leads to a declining and unstable mood, and sometimes more serious, chronic mental illness like depression (7).
Daily Requirements of Vitamin D
The recommended daily intake for vitamin D3 is 600 IU (15 mcg) for all male and female adults between the ages of 18 and 70 years old (1).
However, recommendations can vary based on age, geographic location, skin type/color, and even sunscreen usage and sun exposure (1).
Avoid Vitamin D Deficiency During Cold and Flu Season
Low intake or minimal sun exposure can lead to vitamin D deficiency. A deficiency of vitamin D is especially important during cold and flu season.
Being vitamin D deficient can result in several complications. Including (1):
- Bone and muscle pain
- Unstable and depressed mood
- Decreased wound healing
- Hair loss
Low levels of vitamin D is also associated with a poor immune response. Increasing risk of contracting illnesses caused by harmful viruses or bacteria. Especially the respiratory tract, which is the most susceptible bodily system to bacterial infection during a vitamin D deficiency (3).
To avoid deficiency, make sure to access plenty of sunlight, vitamin D-rich foods, or a high-quality supplement.
How to Boost Your Immunity with Vitamin D this Cold and Flu Season
While vitamin D may not directly reduce your risk of coming into contact with a virus, it may help minimize your illness this season (5).
Make sure you are consuming plenty vitamin D-rich foods or are getting enough sunlight to keep your immune system strong. Or consume a high-quality supplement for the most benefit – even beyond immunity.
Author: Allison Lansman, RDN, LD