Vitamin D serves many important functions in the immune system. For example, it acts to stimulate the immune system against various infections, such as tuberculosis, and may help prevent certain types of cancer and even autoimmune diseases such as multiple sclerosis. (but all of this is still being researched).
Additionally, research suggests that vitamin D may play an important role in preventing various allergic diseases.
Allergies and Vitamin D
Almost every type of allergic disease, including asthma, allergic rhinitis, food allergies, eczema, and even anaphylaxis, has become much more common over the past few decades. This can be partly explained by the hygiene hypothesis, but some experts think it is also related to vitamin D deficiency.
In support of this connection, scientific evidence shows that anaphylaxis to a variety of triggers (such as foods, medications, and insect stings) occurs at much higher rates in areas with less sun exposure (northern climates).
Additionally, asthma, eczema, and atopy have been associated with low vitamin D levels, especially in people with mutations in vitamin D receptor genes. (5) Vitamin D supplementation given to pregnant women significantly reduced the occurrence of asthma and other allergic diseases in young children.
Research shows that vitamin D can activate certain regulatory immune system cells that prevent the release of chemicals that cause and worsen allergic diseases. (1) That is, vitamin D deficiency can lead to worsening of allergy diseases, even a trigger for allergic diseases, or inhibit the regulatory mechanism.
Why Does Vitamin D Deficiency Occur?
The causes of vitamin D deficiencies, which are common in various societies, are not fully understood. Many researchers attribute vitamin D deficiency to modern lifestyles that include spending more time indoors with less sunlight exposure, as well as widespread sunscreen use (due to skin cancer concerns). Remember, vitamin D is produced in the skin by exposure to sunlight – so sunscreen and indoor lifestyle will prevent vitamin D synthesis.(8)
Diet may be another explanation for the deficiency. Vitamin D is an essential nutrient but is naturally found in only a few foods (e.g., fatty fish, cod liver oil, egg yolks).(9) However, many foods are fortified with vitamin D, including breakfast cereals, milk, and other dairy products. However, many people still do not get enough vitamin D. (10)
Many studies show that vitamin D deficiency is extremely common, not to the extent that bone health is affected (vitamin D prevents bone diseases such as rickets and osteomalacia) but to the extent that the immune system is affected.(7)
How Much Vitamin D Do You Need?
It is not known exactly how much vitamin D is needed for good immune function, but most people in developed countries get enough vitamin D for healthy bones.
Although there is still debate among experts about what constitutes a deficient vitamin D level, after a review of research on vitamin D, experts reported that the vast majority of people have adequate vitamin D levels when their levels are 25 (OH) D. People most at risk for vitamin D deficiency are those with levels less than 12ng/mL.
However, how much one may need daily to maintain a normal vitamin D level depends on a number of factors. These factors include:
- skin color
- Average sun exposure
- Diet
- Whether a person has any medical problems (for example, liver or kidney disease).
- Additionally, it is possible to overdose on vitamin D, with the main side effect being kidney stones, so it is important to talk to your doctor before taking any vitamin D supplements.(12)To obtain adequate vitamin D, tanning beds and excessive sun exposure are recommended due to the risk of skin cancer. It is not done. 15 minutes of sunbathing a day may be sufficient. (13)
