What deficiency causes lupus?

Lupus is an autoimmune disease that causes inflammation throughout the body. While the exact cause of lupus is unknown, research suggests that genetics, hormones, and environmental factors all play a role in the development of the disease. One theory is that lupus may be triggered by vitamin D deficiency.

What is lupus?

Lupus is a chronic autoimmune disease that causes inflammation and damage to various parts of the body. The most common type is systemic lupus erythematosus (SLE). With SLE, the immune system mistakenly attacks healthy tissue and organs, including the skin, joints, kidneys, brain, and other parts of the body. This leads to a variety of symptoms such as fatigue, joint pain, rash, and fever. Lupus can range from mild to life-threatening. While there is no cure, treatments focus on reducing inflammation and managing symptoms.

What causes lupus?

The exact causes of lupus are not fully understood. Research suggests lupus likely develops from a combination of factors including:

  • Genetics: Lupus tends to run in families. You may be at increased risk if you have a close relative with lupus.
  • Hormones: Lupus is more common in women, especially during childbearing years. Estrogen may influence development of the disease.
  • Environmental factors: Sunlight, stress, infections, and certain medications may trigger lupus flares.
  • Immune system: People with lupus appear to have an overactive immune system that loses ability to differentiate between threats and healthy tissue.

While those factors may increase risk, they do not necessarily cause lupus. Many people with those risk factors never develop the disease. Researchers continue investigating what prompts lupus to develop in some people but not others.

What does vitamin D have to do with lupus?

Vitamin D is emerging as a potentially important factor in lupus. Vitamin D is crucial for immune system function. It interacts with cells throughout the body, including immune cells. Research shows that people with SLE frequently have lower vitamin D levels. There are several theories about how vitamin D deficiencies may contribute to lupus:

  • Increased autoimmunity: Vitamin D interacts with cells that regulate the immune system. Deficiencies may cause the immune system to become hyperactive and produce more autoantibodies.
  • Inflammation: Vitamin D helps regulate inflammatory processes. Lower levels allow inflammation to go unchecked.
  • Flare triggers: Vitamin D levels that are too low may trigger lupus flares and worsen symptoms.
  • Disease activity: Lower vitamin D levels tend to correlate with more active lupus symptoms and higher disease activity scores.

Overall, experts theorize that inadequate vitamin D allows the immune system malfunctions seen in lupus to develop more easily. It reduces the checks and balances that keep autoimmunity in line.

Are lupus patients deficient in vitamin D?

Numerous studies show a strong connection between vitamin D deficiencies and lupus:

  • A meta-analysis of 28 studies found that over 75% of lupus patients had insufficient vitamin D levels.
  • A National Institute of Health study of 405 lupus patients found that >90% had low vitamin D levels.
  • Multiple studies show lupus patients frequently have lower vitamin D levels than healthy controls.

Research consistently shows that the majority of lupus patients are deficient in vitamin D compared to the general population. One study estimated that 16% of lupus cases could potentially be attributed to vitamin D deficiency.

Which lupus patients are most vitamin D deficient?

While vitamin D deficiency is common overall in lupus patients, some groups tend to have even lower levels. These include:

  • African American patients: Up to 70% deficiency rates, likely due to darker skin reducing vitamin D production.
  • Patients with kidney involvement: Kidney damage can reduce activation of vitamin D.
  • Patients with more severe/active lupus: Increased disease activity correlates with lower vitamin D.
  • Patients on corticosteroids: These medications cause vitamin D depletion.
  • Overweight/obese patients: Vitamin D becomes trapped in fat cells.
  • Pregnant patients: Requirements for vitamin D increase during pregnancy.

Doctors should screen for vitamin D deficiency in all lupus patients. But special attention to vitamin D levels may be warranted in these higher risk groups.

How much vitamin D should lupus patients supplement?

There are no official vitamin D guidelines specific to lupus patients. However, many experts recommend the following daily vitamin D supplementation based on vitamin D blood levels:

Vitamin D Level Supplement Recommendation
Under 30 ng/mL (deficiency) 5000 IU per day
30-39 ng/mL (insufficiency) 3000-4000 IU per day
40-60 ng/mL (normal) 1500-2000 IU per day
Over 60 ng/mL Reduce to avoid toxicity

*IU = International Units of vitamin D

These recommendations help optimize vitamin D levels in lupus patients. Monitoring blood levels is important to adjust dosages accordingly.

Does vitamin D supplementation reduce lupus disease activity?

A number of studies have looked at whether vitamin D supplementation improves lupus symptoms and flare-ups:

  • A 2019 meta-analysis found vitamin D supplementation significantly reduced disease activity scores in lupus patients.
  • Multiple studies show vitamin D supplementation reduces fatigue and depression in lupus patients.
  • Patients with higher vitamin D levels tend to have reduced autoantibody production.
  • Some clinical trials found no improvements with vitamin D supplementation. However, many had limitations in their study design.

Overall, evidence generally supports that vitamin D supplementation provides benefits in lupus. It helps regulate the immune system and suppress inflammation. Ongoing research will help clarify optimal dosing strategies.

Are there risks for excessive vitamin D supplementation?

There are some potential side effects and risks with high vitamin D doses:

  • Hypercalcemia: High calcium blood levels that can cause nausea, vomiting, kidney stones.
  • Kidney damage: Excess vitamin D activates calcium deposits that impair kidney function.
  • Nausea, vomiting, poor appetite: Usually mild symptoms that resolve with lower doses.
  • Joint pain: Caused by elevated calcium levels.

These side effects generally only occur with prolonged vitamin D intake exceeding 10,000 IU per day. To avoid adverse effects, doctors monitor vitamin D and calcium blood levels in lupus patients on supplements.

What other nutrients are important in lupus?

In addition to vitamin D, research shows other vitamins and nutrients may help minimize lupus flares and symptoms:

  • Vitamin C: Potent antioxidant that reduces oxidative damage from inflammation.
  • Vitamin E: Helps protect cells from damage caused by lupus autoantibodies.
  • Omega-3 fatty acids: Found in fish oil, helps lower autoantibody production.
  • Magnesium: Important cofactor for cellular enzymes, deficiency worsens inflammation.
  • Zinc: Critical for proper immune cell function, low levels linked to more active lupus.
  • Iron: Prevents anemia that commonly occurs in chronic inflammatory diseases.

A balanced diet high in these vitamins, minerals, and nutrients may help provide additional benefits to lupus patients beyond vitamin D alone.


In summary, a large body of evidence shows vitamin D deficiency is very prevalent among lupus patients. This deficiency may exacerbate immune dysfunction and inflammation characteristic of the disease. Research indicates vitamin D supplementation helps normalize immune cell behavior and reduces disease activity. However, high supplement doses can cause toxicity in some cases. Doctors recommend sufficient daily vitamin D – typically 1500-4000 IU – to achieve normal blood levels around 40-60 ng/mL. Monitoring levels and adjusting dosages is important. Additional vitamins and nutrients like vitamin C, omega-3s, and magnesium may provide added benefits. Further research will continue elucidating the precise role vitamin D deficiency plays in lupus and optimal treatment regimens.

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