Vitamin D has long been linked to good health, especially when it comes to bone strength and immune support. But in recent years, scientists have been looking into how it may also protect the heart.
Some studies have shown that low levels of Vitamin D are connected to a higher risk of heart attacks and strokes. However, results from large trials testing Vitamin D supplements have been mixed.
Now, new research from Intermountain Health in Salt Lake City suggests that the issue may not be whether Vitamin D is helpful, but whether people are taking enough of it to make a real difference—especially when it comes to heart health.
What the Research Found
The Intermountain Health team, including lead author Dr. Heidi May and researcher Dr. Viet T. Le, looked closely at how Vitamin D dosing affects patients with heart problems. They found that the current U.S. Recommended Dietary Allowance—600 to 800 International Units (IU) per day—might be far too low for many people to reach optimal Vitamin D levels.
In fact, some patients needed more than 10,000 IU per day to reach what the researchers considered a healthy blood level of Vitamin D (more than 40 nanograms per milliliter, or ng/mL). This was particularly true for patients who had recently suffered a heart attack or stroke.
The research included the Target-D clinical trial, which followed people who had experienced a cardiovascular event within the previous month. Nearly 90% of participants needed Vitamin D supplements, and most required much higher doses than usual. Even with high-dose supplements, many participants took three to six months or more to reach optimal Vitamin D levels.
Why This Matters
Previous large studies on Vitamin D’s effects on heart disease may have failed to show benefits—not because Vitamin D doesn’t help, but because the doses used were simply too low. If participants in those studies didn’t reach therapeutic levels, it would be hard to see any positive effects on heart health.
That’s why the team at Intermountain Health is calling for a rethink of how Vitamin D is used in both research and clinical practice.
The Case for Personalized Dosing
The studies suggest that a one-size-fits-all approach to Vitamin D may not work—especially for people with existing heart conditions. Some patients may absorb or use Vitamin D differently due to age, weight, genetics, or health issues. This makes a strong case for personalized supplementation, where doctors monitor Vitamin D levels and adjust the dose as needed for each individual.
Dr. Viet T. Le emphasizes that this tailored method is not just about reaching numbers—it’s about getting the dose right to actually support heart health.
What Should You Do?
If you’re taking Vitamin D or thinking about it for your heart, here are a few key points:
- Don’t guess your dose: Talk to your doctor and consider getting your Vitamin D levels tested.
- Avoid over-supplementing: While some people may need high doses, taking too much without supervision can lead to problems like kidney damage or high calcium levels.
- Stick with it: Even when taking higher doses, it may take several months to reach optimal levels, so patience is important.
The Bigger Picture
These findings are part of a larger movement in medicine toward personalized care—treating people as individuals, not statistics. When it comes to supplements like Vitamin D, this means checking blood levels, adjusting doses, and paying attention to the needs of each patient.
The research from Intermountain Health challenges outdated dosing guidelines and urges both the medical community and the public to take a more intentional approach. For patients with heart issues, especially those recovering from heart attacks or strokes, this could be an important step in preventing future problems and improving long-term health.
For now, it’s a good reminder that even something as simple as a vitamin pill might need a more thoughtful, tailored approach to make a real impact.
If you care about health, please read studies about the best time to take vitamins to prevent heart disease, and vitamin D supplements strongly reduce cancer death.
For more health information, please see recent studies about plant nutrient that could help reduce high blood pressure, and these antioxidants could help reduce dementia risk.
Copyright © 2025 Knowridge Science Report. All rights reserved.
