A Gram Research analysis of 100 Jordanian asthma patients found that people with asthma and low vitamin D showed different activity levels in two genes (SNAIL1 and VDR) compared to those with normal vitamin D. Researchers also identified a rare genetic variation in the SNAIL1 gene in one participant with asthma and low vitamin D, though its biological significance remains unclear. This exploratory study suggests vitamin D status and genetic factors may be connected to asthma, but larger studies are needed to confirm these findings and understand how they affect treatment.
Researchers studied 100 people in Jordan to understand how vitamin D levels, genes, and asthma are connected. They found that people with asthma and low vitamin D had different patterns in two important genes: SNAIL1 and VDR. These genes may affect how airways change and respond to inflammation. While the study is early-stage and exploratory, it suggests that vitamin D status and specific genetic variations might play a role in asthma severity. The findings open doors for future research to better understand why some people with asthma struggle more than others.
Key Statistics
A 2026 case-control study of 100 Jordanian patients found that serum vitamin D levels differed significantly among people with asthma and low vitamin D compared to control groups without asthma.
According to research reviewed by Gram, a rare genetic variant (p.Ala66Val) in the SNAIL1 gene was identified in a single asthmatic participant with low vitamin D status who also showed higher SNAIL1 gene expression.
A 2026 exploratory study of 100 participants found that vitamin D receptor (VDR) gene expression patterns differed among asthma patients with varying vitamin D levels, suggesting a potential connection between vitamin D status and gene activity.
The Quick Take
- What they studied: Whether vitamin D levels and specific genes (SNAIL1 and VDR) are connected to asthma severity in Jordanian patients
- Who participated: 100 people in Jordan divided into four groups based on whether they had asthma and their vitamin D levels (some with asthma and low vitamin D, some with asthma and normal vitamin D, and control groups without asthma)
- Key finding: People with asthma and low vitamin D showed different gene activity patterns compared to other groups. One person with asthma and low vitamin D had a rare genetic variation in the SNAIL1 gene that hasn’t been well studied before.
- What it means for you: This early research suggests vitamin D status might matter for asthma control, but the findings are preliminary. Don’t change your asthma treatment based on this study alone. Talk to your doctor about whether vitamin D testing or supplementation makes sense for your situation.
The Research Details
Researchers recruited 100 people in Jordan and sorted them into four groups based on two factors: whether they had asthma and whether their vitamin D levels were low or normal. They measured vitamin D in the blood and looked at how active two specific genes were in the participants’ cells using a lab technique called quantitative real-time PCR, which measures how much of each gene is being used by the body. They also searched for rare genetic variations in the SNAIL1 gene by copying and sequencing the DNA code.
This type of study, called a case-control study, compares people with a condition (asthma) to people without it to find differences that might explain the disease. By organizing participants into four groups instead of just two, the researchers could see whether vitamin D status made a difference in the gene patterns they observed.
The study was exploratory, meaning it was designed to find patterns and generate ideas for future research rather than prove a cause-and-effect relationship. The researchers used standard lab methods that are reliable and widely accepted in genetic research.
Understanding the connection between genes, vitamin D, and asthma could eventually help doctors predict who will have more severe asthma and how to treat them better. The SNAIL1 gene is involved in a process called epithelial-mesenchymal transition, which affects how airway cells change shape and function during inflammation. If vitamin D influences this process through gene activity, it might explain why some studies have found that low vitamin D is linked to worse asthma. This research approach allows scientists to explore multiple factors at once rather than studying them separately.
This study has both strengths and limitations. The strength is that it used validated lab techniques and measured multiple factors (genes and vitamin D) in the same people. The main limitation is the small sample size of 100 people, which makes it harder to spot real patterns and easier to find results by chance. The study was also limited to one population (Jordanian patients), so results may not apply to other groups. The researchers themselves noted this is exploratory work, meaning the findings need confirmation in larger studies before doctors should use them to guide treatment decisions.
What the Results Show
Vitamin D levels differed significantly among the four groups, with people who had asthma and low vitamin D showing the lowest levels overall. The two genes studied, SNAIL1 and VDR, showed different activity patterns across the groups, suggesting that vitamin D status may influence how these genes work in people with asthma.
One participant with asthma and low vitamin D carried a rare genetic variation in the SNAIL1 gene (a change called p.Ala66Val). This person also showed higher activity of the SNAIL1 gene compared to others. However, the researchers emphasized that this finding is preliminary and its real-world importance is unclear. Computer prediction tools suggested this genetic change is probably harmless, but that assessment needs to be tested in the lab.
The study did not find strong evidence that this rare genetic variation is common in asthmatic patients or that it directly causes asthma. Instead, it represents a starting point for future investigation.
The VDR gene, which helps the body respond to vitamin D, also showed different activity levels among the groups. This suggests that vitamin D status may affect how well cells can use vitamin D, creating a potential feedback loop. The combination of low vitamin D and altered gene activity appeared in people with asthma, but the study could not determine whether low vitamin D causes these gene changes or whether the gene changes affect vitamin D levels.
Previous research has linked low vitamin D to worse asthma outcomes, but the reasons why remain unclear. This study adds a genetic layer to that observation by showing that vitamin D status may be connected to how certain genes are expressed in asthmatic patients. However, the findings are much more exploratory than previous work. Earlier studies in other populations have not identified the specific SNAIL1 variant found here, so it may be unique to Jordanian populations or very rare overall. The research supports the general idea that vitamin D matters for asthma but doesn’t prove it or explain the mechanism.
The study had several important limitations. First, 100 participants is a small sample size, making it difficult to spot real patterns and easy to find false results by chance. Second, the study included only people from Jordan, so the findings may not apply to other ethnic groups or populations. Third, the study was exploratory and cross-sectional, meaning it captured a snapshot in time rather than following people over months or years to see how vitamin D and genes affect asthma over time. Fourth, the researchers could not determine cause and effect: they don’t know whether low vitamin D causes the gene changes, whether the gene changes lead to low vitamin D, or whether both are caused by something else. Finally, the rare genetic variant was found in only one person, making it impossible to draw conclusions about its importance.
The Bottom Line
Based on this exploratory study, there is not yet enough evidence to recommend specific actions. However, if you have asthma, it may be reasonable to ask your doctor about checking your vitamin D level, especially if your asthma is difficult to control. Some research suggests vitamin D supplementation might help some asthma patients, but this study doesn’t prove that. Any decisions about vitamin D testing or supplementation should be made with your healthcare provider based on your individual situation and other research. Do not stop or change your asthma medications based on this study.
People with asthma, especially those with poorly controlled symptoms, may want to discuss vitamin D status with their doctor. Healthcare providers treating asthma in Jordanian or similar populations might find this research interesting as a starting point for future investigation. Genetic researchers studying asthma will want to follow up on the rare SNAIL1 variant identified. People without asthma or those with well-controlled asthma don’t need to change anything based on this study.
This is very early-stage research. It will likely take several years of follow-up studies before any new treatments or recommendations emerge. If vitamin D does help asthma, benefits would probably appear over weeks to months of consistent supplementation, not days. Genetic findings like this one typically require 5 to 10 years of additional research before they influence clinical practice.
Frequently Asked Questions
Does low vitamin D cause asthma to get worse?
Research suggests a connection between low vitamin D and worse asthma, but this study doesn’t prove that low vitamin D directly causes asthma to worsen. The relationship is complex and may involve genes. Talk to your doctor about whether checking your vitamin D level makes sense for your asthma management.
Should I take vitamin D supplements if I have asthma?
This study doesn’t provide enough evidence to recommend vitamin D supplements for all asthma patients. However, if your doctor finds you have low vitamin D, supplementation may help. Discuss your individual situation with your healthcare provider before starting any supplements.
What is the SNAIL1 gene and why does it matter for asthma?
SNAIL1 is a gene that controls how airway cells change shape during inflammation. This study found it may be connected to vitamin D status in asthma patients, but the exact role remains unclear. The rare variant found in one person needs further study to understand its importance.
Can genetic testing predict whether my asthma will be severe?
Not yet based on this research. While the study identified a rare genetic variant, it was found in only one person and its significance is unknown. Genetic testing for asthma severity is not currently recommended in clinical practice. Your doctor can assess asthma severity through symptoms and lung function tests.
Does this research apply to people outside of Jordan?
This study included only Jordanian patients, so results may not apply to other populations. Genetic variations and vitamin D patterns can differ among ethnic groups. More research in diverse populations is needed before generalizing these findings worldwide.
Want to Apply This Research?
- Track your vitamin D supplementation (if recommended by your doctor), asthma symptom frequency (number of days per week with symptoms), and peak flow measurements if you use a meter. Record these weekly to spot patterns over time.
- If your doctor recommends vitamin D supplementation, set a daily reminder in your app to take it at the same time each day. Log your asthma symptoms daily to see whether they improve over weeks or months. Share these logs with your doctor at appointments.
- Over 3 to 6 months, track whether your asthma symptoms improve, worsen, or stay the same while taking vitamin D (if recommended). Compare your symptom patterns before and after starting supplementation. Note any changes in how often you need your rescue inhaler. Share this data with your healthcare provider to guide treatment decisions.
This research is exploratory and preliminary. The findings have not been confirmed in larger studies and should not be used to guide treatment decisions without consulting your healthcare provider. If you have asthma, continue taking your prescribed medications as directed by your doctor. Do not start, stop, or change any asthma medications or supplements based on this study. Discuss any questions about vitamin D, genetics, and your asthma management with your healthcare provider or a genetic counselor. This article is for informational purposes only and is not a substitute for professional medical advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.