Can Vitamin D deficiency trigger autoimmune disease? Here's what we know

Vitamin D is a fat-soluble vitamin that helps the body absorb calcium, magnesium, and phosphate, which are important for bone health. Vitamin D also helps with muscle movement, nerve function, and the immune system. Vitamin D deficiency is more prevalent than ever before and is considered a pandemic. About 1 billion people worldwide have vitamin D deficiency, while 50% of the population has vitamin D insufficiency. Vitamin D deficiency has been linked to many health conditions, including cancer, cardiovascular disease, diabetes, autoimmune diseases, and depression. The main cause of vitamin D deficiency is not getting enough sun exposure. Other factors include living at latitudes above or below 37 degrees north or south of the equator, spending most of your time indoors, using sunscreen, and obesity.

Why Vitamin D is essential for the body?

Bone health: Vitamin D helps your body absorb calcium, which is a key component of strong bones. Vitamin D and calcium work together to prevent osteoporosis, a disease that weakens bones and makes them more likely to break. Vitamin D is called the ‘sunshine vitamin’ because of that reason. When skin is exposed to ultraviolet (UVB) light from the sun, the body converts a molecule called 7-dehydrocholesterol into pre-vitamin D3. Pre-vitamin D3 then changes into vitamin D3 within a few hours.

Muscle and nerve function: Vitamin D helps muscles move and nerves carry messages between the brain and body.

Immune system: Vitamin D helps your immune system fight off viruses and bacteria.

Brain health: Vitamin D may play an important role in the health of an aging brain.

Inflammation and pain: Vitamin D affects how the body responds to inflammation and pain.

Blood pressure: Vitamin D deficiency is linked to hypertension or high blood pressure. Vitamin D3 may help lower blood pressure in people with hypertension and vitamin D deficiency.

Sources of vitamin D:

Sunlight: The body can produce vitamin D naturally when exposed to sunlight. However, the amount of vitamin D produced depends on a number of factors, including skin color, time of day, and cloud cover. Exposure to too much sun can also lead to skin cancer, so it's not recommended to spend more than a few minutes in the sun without sunscreen.

Diet: Some foods that contain vitamin D include fish, like salmon or light canned tuna, mackerel, and herring are among the best sources of vitamin D. Cod liver oil contains 400–1,000 IU of vitamin D per teaspoon. Some mushrooms, like portobello and white mushrooms, can contain large amounts of vitamin D if exposed to UV light. Egg yolks contain about 20 IU of vitamin D. Milk, yogurt, cereal, and some 100% juices are vitamin D-fortified products too. Yogurt makers often add vitamin D to their products. An 8-ounce serving typically contains 3 mcg of vitamin D.

Supplements: During the autumn and winter, when the sun isn't strong enough, people may need to take a vitamin D supplement. Vitamin D supplements can be a good way to help ensure you're getting enough vitamin D, which is important for bone health. The two main types of vitamin D supplements are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). You can take vitamin D supplements with or without food, and you can take the full amount at once. However, taking too much vitamin D can be harmful.

What is Vitamin D deficiency?

Vitamin D deficiency can be caused by a number of factors, including limited sun exposure, dark skin, and prolonged breastfeeding without vitamin D supplementation. Vitamin D deficiency can lead to problems like rickets in children and osteoporosis in adults. Too much vitamin D, also known as vitamin D toxicity, can also be harmful. Signs of toxicity include nausea, vomiting, constipation, weakness, and weight loss.

Does Vitamin D deficiency cause autoimmune disease?

Scientists recently have made some notable discoveries about how deficiency early in life can trigger problems with the body's immune system. Researchers from McGill University in Canada used a combination of analysis techniques to take a close look at mice genetically engineered to not produce vitamin D naturally. It was found that the thymus – a small organ that trains our immune system – ages faster in these mice, allowing self-attacking immune cells to run rampant. Thymus is known to have an important role in educating the T cell defense force in our bodies not to attack healthy cells, and we also know vitamin D is closely linked to this process too.

Thymus development: Vitamin D deficiency during childhood can cause the thymus to age faster, which can lead to a less effective immune system. This can increase the risk of autoimmune diseases like Type 1 diabetes.

Immune system regulation: Vitamin D helps regulate the immune system and induce immune tolerance. Low levels of vitamin D have been associated with an increased risk of developing autoimmune diseases like rheumatoid arthritis, lupus, multiple sclerosis, and inflammatory bowel disease.

Gene polymorphisms: Some polymorphisms of the vitamin D receptor (VDR) gene can predispose to autoimmune diseases.

Sunlight exposure: People with lupus may avoid sun exposure to prevent skin rashes and disease flare-ups, which can lead to vitamin D deficiency.

Medications: Some medications used to treat lupus, like corticosteroids, can lead to low vitamin D levels.
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