Can Vitamin D Deficiency Cause High Body Temperature?

October 16, 2025 •

4 min read

An estimated one billion people worldwide have vitamin D deficiency, a condition predominantly recognized for its impact on bone health. While not a direct cause, there are important indirect connections between low vitamin D levels and an increased risk of developing conditions that cause a high body temperature.

Quick Summary

Vitamin D deficiency does not directly cause high body temperature (fever), but it weakens the immune system and promotes inflammation, increasing susceptibility to infections. These infections are the true cause of fever. The deficiency itself can also impair the body's thermoregulation and exacerbate inflammatory responses.

Key Points

No Direct Causal Link: Vitamin D deficiency does not directly cause high body temperature or fever, but it is indirectly associated through its impact on the immune system.
Weakened Immunity: A deficiency compromises the immune system's ability to fight off infections, which are the real cause of fever.
Exaggerated Inflammation: Low vitamin D impairs the regulation of inflammatory responses, potentially leading to more severe fevers during illness.
Thermoregulation Issues: Beyond fever, a deficiency can disrupt overall body temperature control, increasing vulnerability to heat stress or causing a heightened sensation of cold.
Consult a Doctor: Persistent high body temperature should be evaluated by a healthcare professional to determine the actual cause, which is most likely an underlying infection.

The Indirect Connection: Vitamin D, Immunity, and Fever

While the search for a direct causal link between vitamin D deficiency and fever has been largely inconclusive, the relationship is most accurately described as indirect. A deficiency compromises the immune system's ability to function effectively, making the body more vulnerable to infections from viruses and bacteria. It is these infections, not the deficiency itself, that trigger the physiological response of fever. Vitamin D, often called the "sunshine vitamin," plays a critical, yet complex, role as an immunomodulator, helping the body's defense systems to respond appropriately and resolve infections efficiently.

How Low Vitamin D Affects Immune Function

Compromised Innate Immunity: The innate immune system is the body's first line of defense. Vitamin D helps regulate antimicrobial peptides, such as cathelicidin, which directly combat pathogens. In a deficient state, the production of these protective agents is reduced, leaving the body more exposed to pathogens and increasing the likelihood of infection.
Dysregulated Adaptive Immunity: Vitamin D influences T-cell and B-cell function, which are central to the adaptive immune response. A deficiency can alter the balance of T-cell subsets, potentially leading to a more inflammatory, rather than protective, response to a pathogen.
Reduced Efficiency Against Infections: Studies have repeatedly shown a link between low vitamin D levels and an increased risk of respiratory tract infections, such as pneumonia, the common cold, and flu. One study found that vitamin D supplementation led to a faster resolution of fever and cough in children with tuberculosis. This underscores the vitamin's importance in supporting the body's ability to fight off and recover from infections that cause fever.

Inflammation and Exaggerated Responses

Beyond just preventing infections, vitamin D plays a key role in moderating the body's inflammatory response. During an infection, the immune system releases pro-inflammatory cytokines, which help fight the pathogen but can also cause fever and widespread tissue damage in high concentrations. This is known as a "cytokine storm." Vitamin D helps to down-regulate this excessive inflammatory response, promoting a more balanced and controlled immune reaction.

The Impact of Deficiency on Inflammatory Pathways

When vitamin D levels are insufficient, this regulatory mechanism is impaired, potentially leading to a more severe and prolonged inflammatory state. This can result in a more intense or persistent fever in response to an infection. The phenomenon has been particularly noted in research related to COVID-19, where lower vitamin D levels were associated with a higher likelihood of experiencing severe symptoms and higher inflammatory markers.

Thermoregulation Issues and Heat Stress

It's important to distinguish between a fever caused by infection and other temperature-related issues. While vitamin D deficiency doesn't directly cause fever, it can affect overall thermoregulation. The body's ability to respond to heat stress—such as during a heatwave—can be compromised by low vitamin D levels. This can increase the risk of heat-related illnesses like heatstroke. On the other end of the spectrum, some individuals with low vitamin D report feeling colder than usual, attributed to impaired circulation and a slower metabolism.

Comparing Fever vs. Temperature-Related Symptoms of Deficiency


Feature	Fever Caused by Infection	Temperature Issues from Vitamin D Deficiency
Cause	An immune response to a pathogen (e.g., virus, bacteria).	Indirectly linked via weakened immunity or exaggerated inflammation, or directly related to heat stress.
Temperature Profile	Clinically elevated core body temperature (e.g., above 38°C/100.4°F).	Can include feelings of being either excessively hot (hyperthermia due to heat stress) or cold/chills.
Accompanying Symptoms	May include body aches, chills, fatigue, sore throat, cough, and other signs of illness.	Often accompanied by fatigue, muscle pain or weakness, bone pain, depression, and frequent infections, rather than typical flu-like symptoms.
Primary Treatment	Address the underlying infection (e.g., antiviral or antibiotic), possibly with fever-reducing medication.	Correction of the deficiency through supplementation and lifestyle changes (e.g., sun exposure), which may help resolve associated immune/inflammatory issues.

Conclusion: A Reminder to Consider the Whole Picture

In conclusion, while vitamin D deficiency is not a direct cause of high body temperature, it can increase the risk of contracting infections that do cause fever. The deficiency weakens immune defenses and can lead to a more severe inflammatory response, potentially resulting in a more pronounced fever during illness. Additionally, it may impair the body's ability to regulate temperature under heat stress. If you experience persistent or recurrent high body temperature, it is essential to consult a healthcare provider to identify the correct underlying cause, rather than assuming it is solely due to a vitamin deficiency. Addressing a diagnosed vitamin D deficiency can improve overall immune function and may help to mitigate the severity of future infections. For comprehensive information on Vitamin D, consider resources from reputable health organizations like the National Institutes of Health.

Get More Information

For more detailed information on the benefits and potential risks of Vitamin D supplementation, consult reliable medical sources such as the National Institutes of Health (NIH) Office of Dietary Supplements.

How to Assess Your Vitamin D Levels

Blood Test: The most accurate method is a blood test to measure serum 25-hydroxyvitamin D (25(OH)D) levels, as recommended by healthcare professionals.
Professional Consultation: A doctor can properly interpret your results and determine if supplementation is necessary based on your overall health status.

Risks of Low Vitamin D

Skeletal Issues: Increased risk of rickets in children and osteomalacia in adults.
Frequent Illness: Higher susceptibility to common infections due to impaired immunity.
Inflammatory Conditions: Lower vitamin D has been linked to chronic inflammatory diseases.

How to Address a Deficiency

Sun Exposure: Moderate, safe exposure to sunlight helps the body produce its own vitamin D.
Diet: Include foods rich in vitamin D, such as fatty fish, fortified milk, and egg yolks.
Supplements: A doctor may recommend supplements, especially for those with limited sun exposure or dietary intake.

Frequently Asked Questions

No, low vitamin D does not cause a fever. A persistent low-grade fever can be a symptom of a chronic infection or other medical condition, which may be more likely if your immune system is weakened by low vitamin D.

Feeling feverish or experiencing chills is not a primary symptom of vitamin D deficiency itself. It is a sign of an active infection. Low vitamin D can make you more prone to infections, leading to these sensations.

Vitamin D is an immunomodulator that helps regulate the body's inflammatory response by down-regulating pro-inflammatory cytokines. A deficiency can lead to a dysregulated, excessive inflammatory reaction during infection, which can contribute to fever.

Yes, indirectly. Severe deficiency can weaken the body's response to heat stress, potentially increasing the risk of heat-related illness. Conversely, some people with low vitamin D report feeling colder, likely due to impacts on circulation and metabolism.

While it won't prevent all fevers, correcting a vitamin D deficiency can improve overall immune function and resilience. A healthier immune system may lead to fewer infections and potentially less severe inflammatory reactions that cause fever.

Vitamin D deficiency has been associated with increased susceptibility to various infections, particularly respiratory ones like the flu, cold, and pneumonia, all of which commonly cause fever. Research also links it to outcomes in viral diseases like COVID-19.

Typical symptoms include fatigue, muscle weakness and aches, bone pain, depressed mood, and frequent infections. Severe cases can lead to conditions like rickets in children or osteomalacia in adults.