A recent clinical trial from Brigham and Women’s Hospital has highlighted the significant influence of body mass index (BMI) on the effectiveness of vitamin D also known as D3. The findings, published in JAMA Network Open, indicate that individuals with a healthy weight gain the most advantages from vitamin D supplementation. Co-author Deirdre K. Tobias, ScD, from the Division of Preventive Medicine at Brigham, noted that positive health outcomes related to vitamin D were observed primarily in those with a BMI under 25. The research suggests that different mechanisms may exist in D3 metabolism among individuals with higher BMIs, which could account for the reduced effectiveness of supplementation in these cases.
Senior author JoAnn E. Manson, MD, DrPH, who leads the Division of Preventive Medicine at Brigham, pointed out that previous research has largely focused on overall vitamin D blood levels. However, the research team’s exploration of a broader range of vitamin D metabolites and novel biomarkers provided valuable insights into D3 availability and activity, raising questions about potential disruptions in vitamin D metabolism for certain individuals.
The study highlights that there is no universal approach to D3 supplementation, as the effects vary significantly between individuals with different BMI levels. Tobias emphasized that after two years of vitamin D supplementation, notable differences emerged, showing a diminished response in those with higher BMIs. This observation has clinical implications and may help explain the limited effectiveness of vitamin D supplementation in people with obesity.
Manson suggests that the findings clarify why D3 supplementation has been linked to a reduction in cancer deaths, autoimmune diseases, and other health outcomes in individuals with lower BMIs, while showing limited benefits for those with higher BMIs. She advocates for personalized dosing of vitamin D to ensure that benefits are realized across diverse populations. In summary, while D3 remains essential for health, this study accentuates the necessity of considering BMI when determining appropriate supplementation dosages.
1) Vitamin D and Bone Health
D3 is crucial for the body’s absorption of calcium and phosphorus from food. As stated by Pauline M. Camacho, MD, FACE, most people are aware of the benefits of calcium for maintaining bone health and preventing osteoporosis. However, calcium’s potential in building and strengthening bones can only be fully realized if the body has sufficient vitamin D. Both nutrients work together to protect bones – calcium plays a role in building and maintaining bones, while vitamin D ensures efficient absorption of calcium. In cases where there is enough calcium intake but a deficiency in vitamin D, the calcium may go to waste.
Therefore, it is important to maintain adequate levels of both calcium and vitamin D to promote bone health throughout one’s lifetime.
2) D3 and Immune Health
D3 is a crucial nutrient that supports the immune system’s ability to fend off bacteria and viruses. According to Jaclyn Tolentino, a physician at Parsley Health in Los Angeles, while vitamin D is widely recognized for its role in musculoskeletal health, it has other functions in the body, including its impact on immune function and inflammation reduction.
Studies have linked vitamin D deficiency to a higher risk of upper respiratory tract infections, such as influenza, tuberculosis, and viral infections. Low serum levels of calcidiol, a form of vitamin D, have also been associated with greater susceptibility to infections. Vitamin D activates killer T cells, which play a vital role in fighting infections. Therefore, maintaining adequate levels of vitamin D is critical for a healthy immune system that can effectively combat foreign pathogens.
3) Vitamin D and Inflammation
Vitamin D has been found to have a potent anti-inflammatory effect, as demonstrated by research. A study conducted by Purdue University and the National Institutes of Health has revealed that vitamin D may eventually be used to support immune health against viruses like COVID-19.
Majid Kazemian, an assistant professor in the departments of Computer Science and Biochemistry at Purdue University, explains that the research shows a mechanism by which vitamin D reduces inflammation caused by T cells, which are essential cells of the immune system and part of the immune response to COVID-19. However, further research, including clinical trials and testing in patients, is required before vitamin D can be adopted as a treatment option. Kazemian cautions against taking normal vitamin D off the shelf at the pharmacy and warns against taking excessive amounts of vitamin D in an attempt to prevent or combat COVID-19 infections.
Kazemian notes that clinical trials are necessary to understand the potential efficacy of vitamin D as a treatment option. In normal infections, Th1 cells, a subset of T cells, go through a pro-inflammatory phase before transitioning to the anti-inflammatory phase. Vitamin D helps speed up this transition, which can potentially help patients with severe inflammation caused by Th1 cells. Kazemian emphasizes that the vitamin D used in the study was a specialized form, not the type available at drugstores, and that the results of the experiments in the test tube must be validated through clinical trials with actual patients.
In conclusion, while the study’s findings are promising, further research is needed to understand the role of vitamin D in immune health and its potential as a treatment option.
4) D3 and Type 2 Diabetes
Scientific research and clinical trials have demonstrated that D3 can positively influence insulin sensitivity and type 2 diabetes, according to Dr. Sanchari Sinha Dutta, Ph.D. Maintaining a D3 level of 80 nmol/l or above is essential for sustaining normal glucose homeostasis. D3 may affect type 2 diabetes through several mechanisms, including the presence of receptors for the active D3 metabolite in the pancreas, which plays a crucial role in insulin synthesis and secretion by pancreatic beta cells.
Moreover, D3 may also have implications for obesity, as noted by Dr. Dutta. The secondary effects of D3 on diabetes management include weight loss and a reduced risk of obesity, both of which help decrease the likelihood of developing diabetes. Research has shown that D3 can regulate appetite by increasing blood leptin levels, which helps control fat storage and promotes feelings of fullness.
Additionally, D3 can lower the blood level of parathyroid hormone, potentially triggering long-term weight loss mechanisms. In conclusion, the effects of D3 on insulin sensitivity, type 2 diabetes, and obesity may have significant implications for diabetes management and the prevention of complications related to the condition.
5) Sources of D3
Vitamin D3 is produced naturally when the skin is exposed to sunlight and can be found in certain foods. As explained by Tolentino, D3 is naturally occurring in egg yolks, beef liver, fatty fish like salmon, tuna, swordfish, and sardines, as well as in fish liver oils. However, it is not commonly present in most foods, which is why some items have D3 added to them. Cereals, dairy and plant milk, and orange juice are examples of foods fortified with D3. Unfortunately, it can be challenging to consume enough D3 through diet alone, as most people do not eat large quantities of these D3-rich foods.
Exposure to sunlight for about 15 minutes is generally sufficient to produce D3. However, Tolentino notes that factors such as geographic location, sunscreen use and coverage, and skin color can all affect D3 absorption, making it difficult to establish universal guidelines for appropriate sun exposure. What may be a healthy amount of time in the sun for one person without protection might not be advisable for another individual. In conclusion, while D3 can be obtained through sunlight and certain foods, getting enough from food alone can be difficult, and the ideal amount of sun exposure varies based on individual circumstances.
Here is a list of foods that are rich in vitamin D or D3. https://www.healthline.com/nutrition/9-foods-high-in-vitamin-d