What You Should Know About Vitamin D

• Taking vitamin D2 might reduce levels of vitamin D3, indicating that these two forms could have different effects.
• Vitamin D3 seems to be more effective for maintaining healthy levels of vitamin D.
• Natural food sources of vitamin D are scarce, which means fortified foods or supplements can be essential.

Countless individuals take vitamin D for its benefits related to bone and immune health. However, recent research indicates that the specific type you opt for might significantly influence its effects.

A group of researchers from the U.K. delved into clinical trial data and discovered that vitamin D2, which is often plant-based and found in fortified foods, may actually lower levels of vitamin D3—the kind produced naturally by the body from sunlight.

This vitamin is crucial for your body because it helps absorb calcium, strengthens bones, and supports a healthy immune system. Many people struggle to get adequate vitamin D from sunlight, especially during fall and winter months, which is why supplements are frequently suggested.

New findings published in *Nutrition Reviews* bring up questions about whether vitamin D2 and D3 can be viewed as interchangeable. Let’s take a closer look at what the research revealed.

Study Overview

To understand how vitamin D2 might influence vitamin D3 levels, researchers from institutions like the University of Surrey and John Innes Centre searched through PubMed for studies spanning from January 1975 to February 2023. They found 202 articles but narrowed it down to 20 that fit their criteria, eventually including 11 studies in their analysis.

Each study was a randomized controlled trial where participants were assigned randomly to take vitamin D2 or not. The researchers then compared vitamin D3 levels in the blood before and after supplementation, aiming to determine any noticeable changes across the trials.

Findings from the Study

Participants taking vitamin D2 supplements experienced a significant drop in vitamin D3 levels compared to those not taking them. On average, serum levels of vitamin D3 decreased by approximately 18 nanomoles per liter by the study’s conclusion. When assessing the overall variations during the trials, the average drop was about 9 nanomoles per liter.

This pattern, consistent across several randomized trials, suggests a true cause-and-effect relationship—meaning that vitamin D2 may lower vitamin D3 levels in the body.

Researchers mention that more exploration is necessary to grasp the full implications of these findings, but it supports the idea that vitamin D3 might be more suitable for most individuals when selecting a supplement.

Practical Implications

If you’re considering a vitamin D supplement, this research shows that the type you select does matter. While both D2 and D3 can enhance overall vitamin D levels, D3 appears to be more effective in maintaining those levels and supporting long-term health.

There are also some dietary sources of vitamin D, although natural options are limited. Fatty fish like salmon and mackerel rank among the top choices, along with egg yolks, beef liver, and UV-exposed mushrooms. Many common foods like milk and breakfast cereals are often fortified to help bridge the gap in vitamin D intake, but meeting daily requirements through diet alone can be challenging. If you’re worried about meeting your goals, consider discussing it with a healthcare professional, who might have suggestions for effective supplements available in stores.

If you follow a vegan or plant-based diet, there’s promising news. Vegan vitamin D3 derived from lichen is available and functions similarly to conventional D3.

Expert Perspective

This research reinforces what smaller studies have suggested over the years: vitamin D3 seems to be the more effective form for maintaining healthy levels in the body. The consistent decline in D3 levels after D2 supplementation indicates that these forms don’t work identically and shouldn’t be treated as equivalents. Although D2 can slightly boost total vitamin D levels, this analysis suggests it may also reduce D3. Until more is understood about this effect, D3 may be the safer choice for many. It’s always wise to consult with a healthcare professional when considering starting a vitamin D supplement or if you’re unsure whether your current one meets your needs.