Researchers studied 96 people who experienced severe trauma to understand how vitamin D might affect stress hormones in those with PTSD. They found that people with PTSD had significantly lower vitamin D levels than those without PTSD. The study also discovered that vitamin D levels were connected to the body’s stress hormone system, which often goes haywire in PTSD patients. While these findings are interesting and suggest vitamin D deficiency might play a role in PTSD, the researchers emphasize that more studies are needed before vitamin D can be recommended as a treatment.

The Quick Take

  • What they studied: Whether vitamin D levels in the blood are connected to stress hormone problems in people with PTSD
  • Who participated: 96 people who came to a hospital in China after experiencing severe trauma between 2022 and 2024. They were divided into two groups: those diagnosed with PTSD and those without PTSD
  • Key finding: People with PTSD had much lower vitamin D levels than those without PTSD. Additionally, lower vitamin D was connected to higher levels of stress hormones that are typically elevated in PTSD
  • What it means for you: This research suggests that vitamin D deficiency might be part of what goes wrong in PTSD, but it’s too early to say whether taking vitamin D supplements would help treat PTSD. Talk to your doctor before making any changes based on this study

The Research Details

This was a straightforward comparison study where researchers looked at two groups of people who had experienced severe trauma. One group had been diagnosed with PTSD, and the other group had not developed PTSD despite their traumatic experiences. The researchers measured vitamin D levels in everyone’s blood and also measured three different stress hormones that are controlled by a part of the brain called the hypothalamic-pituitary-adrenal axis (HPA axis). They used statistical tests to see if vitamin D levels were connected to the stress hormone levels and PTSD symptoms. They also created a diagnostic test to see if vitamin D levels alone could predict who had PTSD.

Understanding the connection between vitamin D and stress hormones is important because PTSD involves problems with the body’s stress response system. If vitamin D plays a role in controlling this system, it could eventually lead to new ways to help PTSD patients. This type of study helps researchers identify potential biological markers and treatment targets

This study has both strengths and limitations. The strength is that it measured actual blood levels of vitamin D and stress hormones rather than just asking people questions. However, the sample size of 96 people is relatively small, and the study only included people from one hospital in China, so the results may not apply to everyone. The study shows correlation (connection) between vitamin D and stress hormones, but cannot prove that low vitamin D causes PTSD

What the Results Show

The main finding was that people with PTSD had significantly lower vitamin D levels compared to people without PTSD. The average vitamin D level in the PTSD group was much lower, and this difference was statistically significant, meaning it’s unlikely to have happened by chance. Additionally, the researchers found that vitamin D levels were connected to the levels of three stress hormones: corticotropin-releasing hormone, adrenocorticotropic hormone, and cortisol. People with lower vitamin D tended to have higher levels of these stress hormones. The connections were strong enough to suggest a real relationship rather than just random variation.

The researchers also tested whether vitamin D levels alone could be used to diagnose PTSD. They found that a vitamin D level below 16.32 ng/mL could identify about 86% of people who actually had PTSD, though it would also incorrectly identify about 49% of people without PTSD as having it. This means vitamin D levels alone aren’t reliable enough to diagnose PTSD, but they might be useful as one piece of information among many

Previous research has shown that vitamin D plays important roles in brain health and protecting nerve cells. Other studies have also found that people with PTSD often have problems with their stress hormone system. This study is one of the first to directly examine the connection between vitamin D deficiency and stress hormone problems in PTSD patients, making it a novel contribution to the field

This study has several important limitations. First, it only included 96 people from one hospital, so the results may not apply to people in other countries or with different backgrounds. Second, the study shows that vitamin D and stress hormones are connected, but it doesn’t prove that low vitamin D causes PTSD or stress hormone problems—it could work the other way around, or both could be caused by something else entirely. Third, the study was done at one point in time, so we don’t know if these relationships stay the same over time. Finally, the study didn’t test whether giving people vitamin D supplements would actually help their PTSD symptoms

The Bottom Line

Based on this research alone, doctors should not yet recommend vitamin D supplements specifically to treat PTSD. However, maintaining adequate vitamin D levels through sunlight exposure, diet, or supplements is generally good for overall health and is already recommended by health organizations. If you have PTSD, work with your healthcare provider on proven treatments like therapy and medication. Vitamin D might eventually play a supporting role, but more research is needed first. Confidence level: Low to Moderate—this is early-stage research suggesting a possible connection

This research is most relevant to people with PTSD and their doctors, as well as researchers studying PTSD. It’s also interesting for people interested in how nutrition affects mental health. However, people without PTSD shouldn’t assume they need vitamin D supplements based on this study. People with PTSD should not replace proven treatments with vitamin D supplementation

If vitamin D does eventually prove helpful for PTSD, it would likely be a long-term support rather than a quick fix. Benefits from any nutritional intervention typically take weeks to months to appear. Proven PTSD treatments like therapy and medication show effects more quickly

Want to Apply This Research?

  • Track daily vitamin D intake (through food, supplements, or sunlight exposure) alongside mood and stress levels using a simple daily log. Record: (1) estimated vitamin D source and amount, (2) stress level on a 1-10 scale, (3) sleep quality, and (4) any PTSD symptoms you’re monitoring with your doctor
  • If you have PTSD and low vitamin D, work with your doctor to gradually increase vitamin D through safe sun exposure (10-30 minutes daily depending on skin tone and location) and vitamin D-rich foods like fatty fish, egg yolks, and fortified milk. Use the app to set reminders for consistent vitamin D intake and track whether you notice any changes in how you feel
  • Create a weekly summary view showing your vitamin D intake, stress levels, and symptom patterns. Share this data with your healthcare provider at regular appointments to see if there are any connections between your vitamin D levels and your PTSD symptoms. This helps your doctor make informed decisions about your overall treatment plan

This research suggests a possible connection between vitamin D and PTSD but does not prove that vitamin D supplements will treat or prevent PTSD. If you have PTSD, continue working with your mental health provider on proven treatments such as therapy and medication. Do not stop or replace prescribed PTSD treatments with vitamin D supplementation. Before starting any new supplements, including vitamin D, consult with your doctor, especially if you take medications or have other health conditions. This article is for educational purposes and should not be considered medical advice. The findings are preliminary and require further research before clinical recommendations can be made.