According to Gram Research analysis, about 35% of college students have vitamin D deficiency, and students with obesity are 4.3 times more likely to have low vitamin D levels. A specific genetic variation in the VDR BsmI gene independently increases deficiency risk by 4.4 times. This cross-sectional study of 189 students shows that both body weight and genetics significantly influence vitamin D status, suggesting that personalized screening and treatment may be more effective than one-size-fits-all approaches.
A new study of 189 college students found that about one-third don’t have enough vitamin D in their bodies. Researchers discovered that students who were overweight or obese were more likely to have low vitamin D, and certain genetic variations also played a role. The study looked at a specific gene called VDR BsmI that helps control how your body uses vitamin D. Students with a particular genetic pattern and extra body weight had the highest risk of vitamin D deficiency. This research suggests that both your genes and your weight matter when it comes to vitamin D levels.
Key Statistics
A cross-sectional study of 189 undergraduate students found that 34.9% had vitamin D deficiency, with students carrying a specific VDR BsmI genetic variation showing 4.4 times higher odds of deficiency.
According to research reviewed by Gram, obese college students had 4.3 times higher odds of vitamin D deficiency compared to non-obese students in a 2023 study of 189 undergraduates.
A 2023 study of 189 college students found that individuals with vitamin D deficiency had significantly higher body weight, waist circumference, hip circumference, and body fat percentage than those with sufficient vitamin D levels.
Gram Research analysis shows that obesity and a recessive VDR BsmI genetic model were independently associated with vitamin D deficiency in 189 undergraduate students studied in 2023.
The Quick Take
- What they studied: Whether a person’s genes and body weight affect their vitamin D levels in college students
- Who participated: 189 undergraduate students (college students) who hadn’t taken vitamin D supplements in the previous six months, studied in April and May 2023
- Key finding: Students with obesity were 4.3 times more likely to have low vitamin D, and a specific genetic variation also increased the risk by 4.4 times
- What it means for you: If you’re overweight or obese, you may want to check your vitamin D levels with a doctor. Your genes might also influence how much vitamin D your body needs, so one-size-fits-all recommendations may not work for everyone. Talk to a healthcare provider about whether you need vitamin D testing or supplementation.
The Research Details
This was a cross-sectional study, which means researchers collected information from all participants at one point in time (April-May 2023) rather than following them over months or years. The researchers measured three main things: vitamin D levels in the blood using a special lab test, body measurements like weight and waist size following official health guidelines, and genetic information by testing a specific gene variation called VDR BsmI using advanced DNA testing methods. They excluded anyone who had taken vitamin D supplements in the six months before the study to get a clearer picture of natural vitamin D levels.
This approach is important because it lets researchers see patterns and connections between genes, body weight, and vitamin D all at once. By studying college students specifically, the researchers looked at a group that might have similar lifestyles and sun exposure patterns, making it easier to spot the effects of genes and weight. The genetic testing was precise, using modern laboratory methods that can identify exact DNA variations.
The study used reliable, established methods for measuring vitamin D (chemiluminescent immunoassay) and genetic testing (qPCR with TaqMan probes), which are gold-standard techniques in research. The researchers used proper statistical methods to separate the effects of weight from the effects of genes. However, because this was a snapshot study of one group at one time, we can’t be completely sure about cause-and-effect relationships. The study was also limited to college students, so results may not apply to other age groups.
What the Results Show
About 35% of the college students studied had vitamin D deficiency. Students with low vitamin D had noticeably higher body weight, larger waist and hip measurements, and more body fat compared to students with normal vitamin D levels. When researchers used statistical analysis to separate the effects of different factors, they found two main independent risk factors: obesity increased the odds of vitamin D deficiency by 326% (4.3 times higher), and carrying a specific genetic variation in the VDR BsmI gene increased the odds by 336% (4.4 times higher). This means that having either factor alone increased risk, but having both would increase risk even more.
The distribution of different genetic versions of the VDR BsmI gene was significantly different between students with normal vitamin D and those with deficiency. This suggests that genetics play a meaningful role in how the body manages vitamin D, separate from body weight effects. The study also confirmed that body measurements like waist circumference and body fat percentage were directly linked to vitamin D status, not just overall weight.
Previous research has suggested connections between obesity and low vitamin D, and between certain genes and vitamin D levels, but this study is notable for showing that both factors matter independently in young adults. The findings align with earlier research showing that excess body fat may interfere with vitamin D absorption and storage. This study adds new evidence that genetic variations in the VDR gene specifically influence vitamin D status in college-age populations.
The study only included 189 students from one time period, so results may not apply to all college students or other age groups. Because it was a snapshot study, researchers couldn’t prove that obesity or genes directly cause vitamin D deficiency, only that they’re associated. The study didn’t measure sun exposure, diet, or physical activity, which also affect vitamin D levels. Students who had taken supplements were excluded, so the findings don’t apply to people using vitamin D supplements.
The Bottom Line
College students, especially those who are overweight or obese, should consider having their vitamin D levels checked by a doctor (moderate confidence). If you have a family history of vitamin D deficiency or genetic testing shows you carry the VDR BsmI variation, discuss vitamin D screening with your healthcare provider (moderate confidence). General vitamin D recommendations may need to be personalized based on both body weight and genetic factors (low to moderate confidence, pending more research).
College students, particularly those who are overweight or obese, should pay attention to this research. Young adults with limited sun exposure or those living in northern climates should consider vitamin D screening. People with family histories of vitamin D deficiency may benefit from genetic testing and personalized recommendations. Healthcare providers working with young adults should consider both weight and genetic factors when assessing vitamin D risk.
If you start vitamin D supplementation based on your doctor’s recommendation, it typically takes 2-4 weeks to see improvements in blood vitamin D levels. However, you may not notice physical symptoms improving for 4-8 weeks. Regular blood tests every 2-3 months can help track whether supplementation is working for you.
Frequently Asked Questions
Does being overweight cause low vitamin D?
Research shows overweight and obese individuals are 4.3 times more likely to have low vitamin D. Excess body fat may interfere with vitamin D absorption and storage, but genetics and sun exposure also play important roles. A doctor can test your vitamin D levels and recommend personalized treatment.
Can genes affect my vitamin D levels?
Yes. A specific genetic variation in the VDR BsmI gene increases vitamin D deficiency risk by 4.4 times in college students. Your genes influence how your body processes and uses vitamin D, meaning some people naturally need more vitamin D than others regardless of sun exposure.
What percentage of college students have low vitamin D?
About 35% of the college students in this 2023 study had vitamin D deficiency. The actual percentage varies by location, season, and sun exposure, but deficiency is common in young adults, especially those who are overweight or spend limited time outdoors.
Should I get tested for vitamin D deficiency?
If you’re overweight, obese, have limited sun exposure, or experience fatigue and muscle weakness, ask your doctor about vitamin D testing. A simple blood test can measure your levels. If deficient, supplementation is safe and effective, typically improving levels within 2-4 weeks.
Can I change my vitamin D levels through diet and exercise?
Diet and sun exposure help, but if you’re obese or carry certain genetic variations, supplementation may be necessary. Exercise and weight loss can improve vitamin D status, but genetic factors mean some people need higher doses. Work with your doctor to determine the right approach for your situation.
Want to Apply This Research?
- Log your vitamin D supplement intake (if prescribed) daily and track your body weight weekly. Record any symptoms like fatigue or muscle weakness that might improve with adequate vitamin D.
- Set a reminder to take vitamin D supplements at the same time each day if your doctor recommends them. Track your waist circumference monthly as an indicator of body composition changes that may affect vitamin D status.
- Create a health dashboard showing your vitamin D levels (from lab tests), body weight trends, and supplement adherence over 3-6 months. Share this data with your healthcare provider at regular check-ins to adjust recommendations based on your individual response.
This article summarizes research findings and is for educational purposes only. It does not constitute medical advice. Vitamin D deficiency should be diagnosed and treated by a qualified healthcare provider through blood testing. Do not start, stop, or change vitamin D supplementation without consulting your doctor. Individual vitamin D needs vary based on age, genetics, location, sun exposure, and health conditions. People with kidney disease, certain medications, or specific health conditions should discuss vitamin D supplementation with their healthcare provider before beginning. This study was conducted in college students and may not apply to other age groups or populations.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.
