Researchers used genetic data to study whether vitamin A and B12 levels influence the risk of coronary artery atherosclerosis—a condition where fatty deposits build up in heart arteries. They analyzed information from thousands of people’s genetic studies and found that higher vitamin A levels appeared to protect against heart disease, while higher B12 levels seemed to increase risk. These findings suggest that different vitamins may play opposite roles in heart health, and that personalized nutrition approaches based on genetics could help prevent heart disease in the future.

The Quick Take

  • What they studied: Whether vitamin A and vitamin B12 levels in the blood actually cause changes in the risk of getting coronary artery atherosclerosis (buildup in heart arteries)
  • Who participated: The study used genetic information from large databases of thousands of people. Researchers didn’t directly test people but instead analyzed genetic data that shows natural variations in vitamin levels
  • Key finding: Vitamin A appeared to lower heart disease risk by about 98%, while vitamin B12 appeared to raise it by about 27%. These findings came from analyzing genetic patterns rather than from direct vitamin supplementation
  • What it means for you: This research suggests vitamin A may be heart-protective and B12 may increase risk, but these are early genetic findings. Don’t change your vitamin intake based on this alone—talk to your doctor before making any changes, especially since B12 is important for nerve and blood health

The Research Details

This study used a special research method called Mendelian randomization, which is like using genetic clues to figure out cause-and-effect relationships. Instead of giving people vitamins and watching what happens, researchers looked at natural genetic variations that affect vitamin levels in the blood. They used genetic information from large databases (GWAS and FinnGen) that contain DNA information from thousands of people. The researchers then used statistical tools to see if genetic variations linked to higher or lower vitamin levels were also linked to heart disease risk. They used multiple statistical methods to check their answers and make sure the results were reliable.

This approach is valuable because it helps avoid confusion from other factors. When people take vitamins, many other things in their lives also change, making it hard to know if the vitamin caused the effect. By using genetics, researchers can study vitamin effects more cleanly. However, genetic studies show associations and possibilities, not definite proof that vitamins cause changes in heart disease

Strengths: The study used multiple statistical methods to verify findings and performed additional analysis to control for confounding factors. The results were consistent across different analytical approaches. Limitations: The study is based on genetic associations, not direct evidence from people taking vitamins. The sample size wasn’t specified in the abstract. The findings need confirmation in actual clinical trials before changing medical practice

What the Results Show

The research found two opposite effects. Vitamin A showed a strong protective association with heart disease—people with genetically higher vitamin A levels had much lower risk of coronary artery atherosclerosis. The statistical measure (odds ratio) was 0.018, meaning the risk dropped dramatically. This relationship held true even when researchers adjusted for other factors that might affect heart disease. Vitamin B12 showed the opposite pattern—genetically higher B12 levels were associated with increased heart disease risk. The odds ratio was 1.268, meaning risk went up by about 27%. This unexpected finding also remained significant after adjusting for other factors. Both findings were statistically significant, meaning they’re unlikely to be due to chance alone.

When researchers performed additional analysis to control for confounding factors (other things that might affect results), both vitamin A and B12 remained significantly associated with heart disease risk in the same directions. The protective effect of vitamin A and the risk-increasing effect of B12 were robust across different statistical methods used. This consistency across methods suggests the findings aren’t just statistical flukes. The study suggests that trace elements and vitamins may play important roles in heart disease development through multiple biological pathways

Vitamin A’s protective role aligns with previous research suggesting antioxidant vitamins help prevent heart disease. However, the strong protective effect found here is more dramatic than many previous studies reported. The finding that B12 increases risk is surprising and contradicts some previous research showing B12 is protective. This contradiction highlights that genetic associations don’t always match what we see in clinical practice, and more research is needed to understand why. The study suggests that the relationship between vitamins and heart disease may be more complex than previously thought

This study has several important limitations. First, it’s based on genetic associations, not actual vitamin supplementation—genetics can predict vitamin levels but don’t prove that changing vitamin intake will change heart disease risk. Second, the sample size wasn’t clearly reported. Third, genetic studies can only show associations, not definite cause-and-effect. Fourth, the findings need confirmation in actual clinical trials with real people taking vitamins. Fifth, the study doesn’t explain the biological mechanisms explaining why B12 would increase risk, which is counterintuitive. Finally, results from one population may not apply to all ethnic groups

The Bottom Line

Based on this genetic research alone, we cannot recommend changing vitamin A or B12 intake. The findings are interesting but preliminary. If you’re concerned about heart disease risk, focus on proven strategies: exercise regularly, eat a heart-healthy diet rich in vegetables and fruits, maintain a healthy weight, don’t smoke, and manage stress. Talk to your doctor before taking high-dose vitamin supplements, especially B12. Your doctor can test your actual vitamin levels and recommend appropriate intake based on your individual health

This research is most relevant to people with family history of heart disease, those concerned about cardiovascular health, and healthcare providers developing personalized medicine approaches. It’s less immediately relevant to people without heart disease risk factors. People with B12 deficiency should not reduce B12 intake based on this study—B12 is essential for nerve and blood health. Anyone considering major dietary changes should consult their doctor

If these findings are confirmed and lead to actual interventions, benefits would likely take months to years to appear, similar to other heart disease prevention strategies. Genetic changes don’t happen, but vitamin levels can change within weeks of dietary changes. Any real-world benefits would need to be studied in clinical trials lasting months to years

Want to Apply This Research?

  • Track daily vitamin A intake (in micrograms) and B12 intake (in micrograms) from food and supplements, along with monthly heart health markers like blood pressure and resting heart rate. Note any dietary changes and correlate with health measurements over 3-6 months
  • Users could increase vitamin A-rich foods (carrots, sweet potatoes, spinach, kale) while monitoring B12 intake and discussing supplementation with their doctor. Track mood, energy, and cardiovascular markers to see personal patterns. Set reminders to eat more colorful vegetables daily
  • Establish a baseline of current vitamin intake and heart health markers. Track weekly dietary patterns and monthly health measurements. Review trends every 3 months. Share data with healthcare provider to make informed decisions about supplementation. Don’t make major changes without medical guidance

This research presents genetic associations, not definitive proof that vitamins cause changes in heart disease risk. Genetic studies cannot replace clinical trials or medical advice. Do not change your vitamin intake, especially B12 supplementation, based solely on this research. B12 is essential for health and deficiency can cause serious problems. Always consult with your healthcare provider before starting, stopping, or changing vitamin supplements. This information is for educational purposes and should not be considered medical advice. People with existing heart disease, vitamin deficiencies, or those taking medications should discuss any dietary changes with their doctor before implementing them.