Latest Vitamin D Recommendations US (Jan 2025)

The latest recommendations for vitamin D supplementation in the US, updated for January 2025, emphasize personalized approaches based on individual needs, dietary intake, sun exposure, and specific health conditions, moving beyond a one-size-fits-all dosage.

Understanding the most current guidelines for vitamin D intake is crucial given its pivotal role in overall health. So, What are the Latest Recommendations for Vitamin D Supplementation in the US? (Updated January 2025) reflects a dynamic scientific landscape, where nuanced advice is replacing generalized directives. This article delves into the evolving consensus, offering clarity on optimal dosages, factors influencing absorption, and specific considerations for various population groups, grounding its insights in the most recent research and expert opinions available as of early 2025.

The Evolving Landscape of Vitamin D Guidelines

Vitamin D, often dubbed the “sunshine vitamin,” continues to be a subject of intense scientific scrutiny, with new research constantly refining our understanding of its complex role in human health. In the US, the recommendations for supplementation are not static; they evolve as more data emerges on optimal levels, absorption rates, and the long-term impacts of both deficiency and excessive intake. As of January 2025, health authorities and medical professionals are increasingly emphasizing a more personalized approach to vitamin D supplementation, moving away from universal mandates.

This shift acknowledges that individual needs vary significantly based on a multitude of factors, including age, geographic location, skin pigmentation, lifestyle, existing health conditions, and even genetic predispositions. The focus is now on ensuring adequacy rather than merely avoiding overt deficiency, recognizing the broader implications of vitamin D for bone health, immune function, and potentially reducing the risk of chronic diseases. Navigating these updated guidelines requires a clear understanding of what constitutes an effective and safe supplementation strategy tailored to one’s unique circumstances.

Beyond Bone Health: Vitamin D’s Broader Roles

While vitamin D’s indispensable role in calcium absorption and bone mineralization is well-established, contemporary research highlights its broader systemic functions. It is now understood to be critical for immune system modulation, cardiovascular health, and even mood regulation. These expanded insights underscore why maintaining optimal vitamin D levels is more important than ever. The body’s intricate network of cells and organs rely on adequate vitamin D for various enzymatic processes and gene expression, making it a foundational nutrient for overall well-being.

• Regulates calcium and phosphate levels for strong bones and teeth.
• Supports immune system function, helping fight off infections.
• Plays a role in cell growth, reducing inflammation, and glucose metabolism.

Key Influencers on Vitamin D Status

Several variables impact an individual’s vitamin D status, making a one-size-fits-all recommendation ineffective. Sun exposure remains a primary natural source, but its effectiveness is contingent on latitude, season, time of day, and skin type. Dietary sources, though fewer, contribute to overall intake. Fortified foods, such as milk, cereals, and orange juice, along with fatty fish like salmon and mackerel, offer beneficial amounts. Supplemental intake then bridges any existing gaps, addressing the reality that many Americans struggle to achieve adequate levels through sunlight and diet alone.

It’s important to remember that lifestyle choices, such as spending most of the day indoors or having certain medical conditions that impair fat absorption, can also significantly affect one’s vitamin D levels. The updated recommendations encourage a holistic view, integrating dietary intake, sun exposure habits, and supplementation decisions into a comprehensive health plan.

The evolving understanding of vitamin D’s wide-ranging health benefits means that personalized assessment and precise supplementation strategies are paramount. This section merely scratches the surface of the complexity involved, setting the stage for a deeper dive into the specific updated recommendations for adults, children, and specific populations in the US.

Updated Daily Recommended Allowances for Adults

For adults in the US, the recommendations for vitamin D supplementation have seen a slight refinement, moving towards a more nuanced understanding of individual needs rather than a rigid, universal daily dose. While the broad guidelines from institutions like the Institute of Medicine (IOM), now part of the National Academies of Sciences, Engineering, and Medicine (NASEM), still serve as a foundational reference, the emphasis in 2025 is on achieving optimal blood levels of 25-hydroxyvitamin D [25(OH)D], which is the best indicator of vitamin D status.

The established Recommended Dietary Allowance (RDA) for most healthy adults remains 600 international units (IU) per day, increasing to 800 IU for adults over 70 years old. However, emerging perspectives suggest that many individuals may benefit from higher doses to reach and maintain optimal serum levels, particularly those with limited sun exposure or conditions affecting absorption. This doesn’t mean exceeding the Tolerable Upper Intake Level (UL) of 4,000 IU/day, but rather carefully considering individual factors.

Optimizing Levels: Beyond the Minimum

The goal is to move past merely preventing overt deficiency symptoms like rickets in children or osteomalacia in adults. Instead, the focus is on achieving serum 25(OH)D levels generally considered optimal for broader health benefits, which typically fall between 20 ng/mL and 40 ng/mL (50 to 100 nmol/L). Some experts advocate for levels towards the higher end of this range, citing potential benefits for immune function and chronic disease prevention.

Healthcare providers are now more frequently recommending blood tests to assess vitamin D levels, especially for individuals at higher risk of deficiency. This allows for a much more precise and personalized supplementation strategy. The “test, don’t guess” approach is gaining traction, ensuring that supplementation is tailored to bring an individual’s levels into the optimal range, rather than relying solely on generalized dietary allowances. This personalized method reduces the risk of both deficiency, which can have long-term health consequences, and excessive intake, which can lead to toxicity.

Considerations for personalized dosing:

• Individual baseline vitamin D levels as measured by blood tests.
• Daily sunlight exposure and geographic location.
• Dietary intake of vitamin D-rich and fortified foods.
• Presence of conditions affecting vitamin D absorption or metabolism.

Key Takeaways for Adult Supplementation in 2025

For most healthy adults, 600-800 IU/day continues to be the baseline recommendation. However, if there are risk factors for deficiency or specific health considerations, consulting a healthcare professional for a blood test and personalized dosing plan is highly advised. This proactive approach ensures that individuals meet their unique vitamin D needs effectively and safely. The emphasis is on informed choices, prioritizing clinical assessment over generalized advice, particularly as individuals age or develop health conditions that might alter their vitamin D requirements.

Special Considerations for Specific Populations

While general guidelines for vitamin D supplementation provide a starting point, certain populations have unique needs that necessitate special consideration. These groups are often at a higher risk of vitamin D inadequacy due to various physiological, environmental, or lifestyle factors. Understanding these specific recommendations is crucial for healthcare providers and individuals alike to ensure optimal health outcomes.

Infants and Children

For infants and children, vitamin D sufficiency is paramount for proper bone development and preventing rickets. The American Academy of Pediatrics (AAP) and other health organizations consistently recommend specific guidelines for this age group. Breastfed infants, who receive limited vitamin D from breast milk, typically require supplementation from birth. Formula-fed infants usually receive adequate amounts from fortified formula, but individual assessment is still important.

As children grow, maintaining adequate vitamin D levels supports ongoing bone growth and overall health. The recommendations often remain consistent with general pediatric guidelines unless specific health conditions warrant adjustments. Pediatricians routinely advise parents on appropriate supplementation, factoring in dietary intake and limited sun exposure due to safety concerns. Ensuring proper vitamin D intake during developmental stages lays a strong foundation for lifelong health and skeletal integrity.

Older Adults

Older adults face several challenges in maintaining adequate vitamin D levels. Their skin’s ability to synthesize vitamin D from sunlight diminishes with age, and they may have reduced dietary intake or spend more time indoors. Consequently, the RDA for adults over 70 years is higher (800 IU/day) compared to younger adults. However, even this increased amount might not be sufficient for all older individuals, particularly those with comorbidities, limited mobility, or residing in care facilities.

Regular monitoring of vitamin D levels is particularly important for older adults to prevent deficiency, which can contribute to bone loss, increased risk of falls, and potentially affect immune function and mood. Geriatricians often tailor supplementation plans based on individual assessment, aiming to support bone density and overall vitality in this demographic. Personalized strategies often involve higher doses under medical supervision to achieve optimal serum values.

Individuals with Darker Skin Tones

Melanin, the pigment that gives skin its color, acts as a natural sunscreen, reducing the skin’s ability to produce vitamin D from sun exposure. Consequently, individuals with darker skin tones, especially those living in higher latitudes, are at a significantly higher risk of vitamin D deficiency. This physiological difference means they may require higher doses of supplementation or more prolonged sun exposure to achieve adequate vitamin D levels, even compared to lighter-skinned individuals living in the same geographic areas.

Awareness of this increased risk is vital for healthcare providers to recommend appropriate screening and supplementation. Education on diversifying vitamin D sources—through fortified foods and consistent supplementation—is crucial to address these disparities and ensure health equity. The recommendations for this group emphasize careful monitoring and potentially higher daily intake to reach optimal levels, moving beyond generalized advice that may not suffice.

Individuals with Certain Health Conditions

Specific medical conditions can impair vitamin D absorption, metabolism, or utilization, putting individuals at higher risk of deficiency. These conditions include:

• Malabsorption Syndromes: Conditions like Crohn’s disease, celiac disease, and cystic fibrosis can hinder fat absorption, and since vitamin D is a fat-soluble vitamin, its absorption is compromised.
• Obesity: Higher body fat can sequester vitamin D, making it less bioavailable, meaning individuals with obesity may require higher doses to achieve adequate blood levels.
• Kidney and Liver Diseases: These organs are crucial for converting vitamin D into its active form. Impaired function in either organ can lead to deficiency.
• Gastric Bypass Surgery: Post-surgical changes in the digestive tract can significantly reduce nutrient absorption, including vitamin D.
• Medications: Certain medications, such as anticonvulsants, glucocorticoids, and some cholesterol-lowering drugs, can interfere with vitamin D metabolism.

For individuals with these conditions, standard vitamin D recommendations are often insufficient. Healthcare providers typically conduct blood tests to assess vitamin D status and prescribe higher, therapeutic doses under careful medical supervision. Regular monitoring is essential to adjust dosages and ensure that optimal levels are maintained, addressing the underlying challenges to vitamin D status effectively.

The tailored approach for these special populations underscores the fact that vitamin D recommendations are not one-size-fits-all. Personalized assessments and ongoing medical guidance are critical to ensure that everyone, regardless of their unique circumstances, can maintain adequate vitamin D levels for optimal health.

Best Practices for Supplementation and Monitoring

Ensuring effective vitamin D supplementation involves more than just taking a pill. It encompasses best practices for choosing the right supplement, understanding proper dosage, and actively monitoring one’s vitamin D status. As of January 2025, the emphasis is increasingly on precision and individualized care, moving away from generic advice toward a more data-driven approach.

Choosing the Right Supplement

When selecting a vitamin D supplement, several factors should be considered. Vitamin D is available in two main forms: D2 (ergocalciferol) and D3 (cholecalciferol). While both forms can raise vitamin D levels, vitamin D3 is generally preferred because it is significantly more effective at increasing and maintaining blood concentrations of 25(OH)D. This biological preference makes D3 the go-to choice for most individuals seeking to optimize their levels.

It’s important to choose reputable brands that undergo third-party testing to ensure product purity, potency, and absence of contaminants. Look for certifications from organizations like USP (United States Pharmacopeia) or NSF International, which provide assurance that the supplement contains what its label claims and is free from harmful substances. The form of the supplement (e.g., capsule, liquid drops) can also matter for absorption if individuals have specific digestive issues or preferences, but for most, D3 in any form is effective.

Dosage and Administration

The optimal dose of vitamin D varies widely among individuals. While the Recommended Dietary Allowances (RDAs) provide a baseline, many people, especially those at higher risk of deficiency, may require more. The most accurate way to determine the correct dosage is through a blood test measuring 25(OH)D levels. Your healthcare provider can then recommend a specific daily or weekly dose to bring your levels into the optimal range, typically between 20 ng/mL and 40 ng/mL.

Vitamin D is a fat-soluble vitamin, meaning it’s best absorbed when taken with food containing fat. Taking your supplement with your largest meal of the day or with a meal that includes healthy fats (like avocado, nuts, or olive oil) can significantly enhance absorption. Consistency is also key; daily intake is generally more effective than sporadic high doses for maintaining stable blood levels. This steady supply allows the body to utilize the vitamin D efficiently over time.

Monitoring and Follow-Up

Regular monitoring of vitamin D levels is a cornerstone of effective supplementation, particularly for individuals starting new regimens or those with existing deficiencies. Initial blood tests establish a baseline, and follow-up tests, typically after 3-6 months, help confirm that the chosen dosage is effective in raising levels into the desired range.

The frequency of monitoring may decrease once optimal levels are achieved, but periodic checks are advisable, especially if there are changes in diet, sun exposure, health status, or medication. A healthcare provider can interpret these results and make necessary adjustments to your supplementation plan. This iterative process ensures that vitamin D levels remain within a healthy range, preventing both deficiency and potential toxicity from excessive intake, which although rare, can occur with very high uncontrolled doses. Always consult with a healthcare professional before making significant changes to your supplementation strategy.

Addressing Vitamin D Deficiency: Diagnosis and Treatment

Vitamin D deficiency remains a widespread public health concern in the US, affecting a significant portion of the population. Recognizing the signs and symptoms, coupled with accurate diagnosis, is crucial for timely and effective intervention. As of January 2025, the approach to managing deficiency is increasingly systematic, emphasizing clinical assessment and targeted therapy.

Symptoms and Risk Factors

The insidious nature of vitamin D deficiency means that symptoms can often be subtle or non-specific, making diagnosis challenging without a blood test. Common indications include generalized fatigue, muscle weakness or pain, bone pain, and frequent infections, reflecting its broad roles in the body. In severe cases, especially in children, deficiency can lead to rickets, characterized by soft and weakened bones. In adults, it can manifest as osteomalacia, leading to bone pain and increased fracture risk. Mood changes, including symptoms of depression, have also been linked to insufficient vitamin D levels.

Several risk factors predispose individuals to deficiency:

• Limited sun exposure due to geographic location, lifestyle, or skin protection.
• Darker skin pigmentation, which reduces UV light absorption.
• Age, particularly older adults whose skin synthesizes less vitamin D.
• Certain medical conditions, such as malabsorption disorders, kidney or liver disease, and obesity.
• Use of medications that interfere with vitamin D metabolism, like certain anti-seizure drugs.

Understanding these symptoms and risk factors helps healthcare providers identify individuals who would benefit most from screening for vitamin D deficiency.

Diagnostic Measures

The definitive diagnostic tool for vitamin D deficiency is a blood test that measures the concentration of 25-hydroxyvitamin D [25(OH)D]. This is the primary circulating form of vitamin D in the body and serves as the best indicator of overall vitamin D status. Blood levels are categorized as follows:

• Deficiency: <20 ng/mL (<50 nmol/L)
• Insufficiency: 20-29 ng/mL (50-74 nmol/L)
• Sufficiency: ≥30 ng/mL (≥75 nmol/L)
• Preferred Optimal Range: 30-60 ng/mL (75-150 nmol/L) by some experts.

While the exact definitions of sufficiency can vary slightly among organizations, generally, levels below 20 ng/mL are considered deficient and warrant intervention. Blood tests are typically ordered by primary care physicians, endocrinologists, or other specialists when deficiency is suspected based on symptoms or risk factors. This objective measurement provides the basis for an evidence-based treatment plan.

Treatment Strategies for Deficiency

Treatment for vitamin D deficiency typically involves therapeutic supplementation with higher doses of vitamin D (usually D2 or D3) for a defined period, followed by maintenance dosing. The specific dosage and duration depend on the severity of the deficiency, the patient’s age, and any underlying health conditions. For severe deficiency, doctors might prescribe high-dose oral vitamin D (e.g., 50,000 IU once a week) for several weeks or months to rapidly replete stores, sometimes followed by daily maintenance doses of 1,000-4,000 IU.

Regular follow-up blood tests are essential to monitor the effectiveness of treatment and adjust dosages as needed. This ensures that levels are brought into the optimal range without over-supplementation. Dietary changes, such as incorporating more vitamin D-rich foods or fortified products, are also encouraged as part of a holistic approach to address and prevent recurrence of deficiency. Ultimately, managing vitamin D deficiency is an individualized process, guided by clinical assessment and ongoing monitoring to restore and maintain optimal vitamin D status.

Future Directions and Research in Vitamin D

The scientific understanding of vitamin D continues to expand, with ongoing research poised to refine our recommendations and therapeutic applications even further. As of January 2025, several exciting avenues of inquiry promise to deepen our insights into this multifaceted nutrient, influencing future public health guidelines and clinical practice.

Genetic and Epigenetic Influences

One of the most promising areas of research explores the role of genetics and epigenetics in vitamin D metabolism and response. We know that individuals respond differently to vitamin D supplementation, and part of this variability may be attributed to genetic polymorphisms in genes related to vitamin D synthesis, transport, and receptor function. For example, variations in the vitamin D receptor (VDR) gene can influence how effectively the body utilizes vitamin D, even when levels are adequate.

Epigenetic modifications, such as DNA methylation, are also being investigated for their influence on gene expression in response to vitamin D. Understanding these genetic and epigenetic factors could pave the way for highly personalized vitamin D recommendations in the future, where dosages are not just based on age and sun exposure but also on an individual’s unique genetic makeup. This precision medicine approach could optimize outcomes and reduce the guesswork currently involved in some supplementation strategies.

Vitamin D and Chronic Disease Prevention

Beyond its well-established role in bone health, research continues to explore vitamin D’s potential in preventing or mitigating chronic diseases. Studies are ongoing to investigate its impact on cardiovascular health, diabetes, certain cancers, autoimmune diseases (like multiple sclerosis and rheumatoid arthritis), and neurodegenerative conditions. While observational studies have often shown associations between lower vitamin D levels and increased disease risk, large-scale randomized controlled trials (RCTs) are crucial to establish causal links and determine if supplementation can truly prevent these conditions.

The results of these trials are mixed, emphasizing the complexity of vitamin D’s systemic effects and the challenges of studying a nutrient with such broad biological roles. Some studies suggest a modest protective effect against certain outcomes, while others find no significant benefit, particularly in individuals who are not overtly deficient at baseline. Future research will likely focus on identifying specific populations or disease subsets that might benefit most from vitamin D intervention, potentially leading to more targeted prevention strategies.

The Microbiome and Vitamin D

An emerging area of interest is the interplay between vitamin D and the gut microbiome. The gut microbiota plays a crucial role in immune modulation and overall health, and there is growing evidence of a bidirectional relationship with vitamin D. Research suggests that vitamin D can influence the composition and function of the gut microbiome, while the microbiome, in turn, may impact vitamin D metabolism and absorption.

Understanding this intricate relationship could open new avenues for therapeutic interventions. For example, optimizing vitamin D levels might indirectly support a healthier gut, and conversely, a healthy gut microbiome might enhance vitamin D bioavailability. This frontier of research holds promise for developing novel strategies to improve vitamin D status and overall health, potentially through dietary interventions or probiotics that support both vitamin D utilization and gut health.

As research progresses in these areas, our understanding of vitamin D will undoubtedly evolve, leading to more refined, personalized, and effective recommendations. The future of vitamin D supplementation is likely to involve a deeper appreciation of individual variability, a more precise targeting of chronic disease prevention, and a comprehensive view of its interaction with other biological systems, including the complex world of the microbiome.

Integration of Diet, Lifestyle, and Supplementation

Achieving and maintaining optimal vitamin D levels is rarely about supplementation alone. A holistic approach that integrates dietary choices, lifestyle habits, and judicious supplementation is increasingly recognized as the most effective strategy. As of January 2025, health professionals are emphasizing this confluence of factors to empower individuals in managing their vitamin D status proactively.

Dietary Sources of Vitamin D

While food sources of vitamin D are relatively limited compared to sunlight exposure or supplements, they play a valuable role in contributing to overall intake. Fatty fish like salmon, mackerel, and tuna are among the best natural sources. Smaller amounts can be found in beef liver, egg yolks, and cheese. However, these natural sources often don’t provide enough vitamin D to meet daily requirements for most individuals, especially those with limited sun exposure.

Fortified foods significantly boost dietary vitamin D intake in the US. Milk, many breakfast cereals, orange juice, and some yogurts are commonly fortified. Checking nutrition labels for vitamin D content can help assess how much is being consumed through diet. Integrating these fortified foods into daily meals can help bridge the gap towards recommended levels, though for many, it still might not be sufficient to reach optimal blood concentrations.

Lifestyle and Sun Exposure

Sunlight remains a potent natural source of vitamin D. When exposed to UVB rays, the skin synthesizes vitamin D3. The amount synthesized depends on several factors: time of day, season, geographic latitude, skin pigmentation, and the amount of skin exposed. For instance, in northern latitudes during winter months, UVB radiation is too weak for effective vitamin D synthesis. Similarly, individuals with darker skin tones require longer sun exposure than those with lighter skin.

While sun exposure is beneficial, it must be balanced with the risks of skin damage and skin cancer. The recommendation is often for short, unprotected sun exposures (e.g., 10-15 minutes on arms and legs) during peak sun hours, especially during appropriate seasons and latitudes. For many, relying solely on sun exposure for adequate vitamin D is either impractical or carries significant health risks, especially if one is aiming for health benefits beyond avoiding overt deficiency. Thus, it is typically seen as a contributing factor, not the sole solution for most.

The Synergistic Approach

The most effective strategy for vitamin D management is a synergistic approach that combines these elements. Individuals should aim to incorporate vitamin D-rich and fortified foods into their diet, practice sensible sun exposure when safe and practical, and then use supplementation to fill any remaining gaps identified through blood tests and healthcare provider guidance. For instance, someone living in a northern state during winter might rely more heavily on supplements, while a person in a sunny region might top up their dietary intake with a modest supplement. For individuals with malabsorption issues, supplementation becomes even more critical and potentially requires higher doses.

This integrated strategy acknowledges the complexity of human physiology and environmental factors. It empowers individuals to take a proactive role in their health by making informed choices about diet, lifestyle, and supplementation, ensuring they maintain optimal vitamin D levels for long-term well-being. Regular consultations with a healthcare provider are key to tailoring this approach to individual needs and adjusting it as circumstances or new research dictate.

Potential Risks and Misconceptions of Over-Supplementation

While the benefits of adequate vitamin D are well-documented, it is equally important to address the potential risks associated with excessive supplementation and to dispel common misconceptions surrounding “more is always better.” As of January 2025, health authorities continue to emphasize the importance of staying within recommended limits to avoid adverse effects.

Understanding Vitamin D Toxicity (Hypervitaminosis D)

Vitamin D toxicity, also known as hypervitaminosis D, is a rare but serious condition typically caused by extremely high doses of vitamin D supplements, not by sun exposure or dietary intake. The Tolerable Upper Intake Level (UL) for most adults is 4,000 IU per day. While some medical conditions or severe deficiencies may warrant higher doses under strict medical supervision, exceeding 10,000 IU/day consistently is where the risk of toxicity begins to significantly increase for general population.

The primary danger of vitamin D toxicity lies in the accumulation of calcium in the blood (hypercalcemia), which can lead to a range of symptoms and complications. High blood calcium can cause:

• Nausea, vomiting, and loss of appetite: Early digestive symptoms that may be dismissed.
• Constipation: A common and uncomfortable gastrointestinal effect.
• Weakness and fatigue: General malaise reflecting systemic impact.
• Frequent urination and increased thirst: Signs of kidney burden.
• Kidney damage: In severe cases, chronic hypercalcemia can lead to kidney stones and even kidney failure.
• Bone pain and impaired bone health: Paradoxically, very high vitamin D can interfere with bone mineralization over time.
• Irregular heart rhythm: Severe hypercalcemia can affect heart function.

If you suspect vitamin D toxicity, it is crucial to seek immediate medical attention. Diagnosis is confirmed by blood tests showing very high levels of 25(OH)D and elevated calcium. Treatment typically involves discontinuing vitamin D supplements and, in severe cases, intravenous fluids and medications to lower calcium levels.

Misconceptions and Responsible Supplementation

One common misconception is that because vitamin D deficiency is prevalent, taking very large doses without medical guidance is always beneficial. This “more is better” mentality can be dangerous. While some individuals may indeed require higher than average doses due to underlying conditions, this should always be determined and monitored by a healthcare professional based on blood test results.

Another misconception is that the UL is a threshold of danger rather than a safe upper limit. The UL is the maximum daily intake unlikely to cause adverse health effects in almost all individuals. It’s a guideline for long-term intake for the general population. Exceeding it consistently increases risk, but toxicity is typically associated with doses far higher than the UL.

Responsible supplementation means:

1. Consulting a healthcare provider: Especially if considering doses higher than the RDA or if you have underlying health conditions.
2. Getting tested: Regular blood tests for 25(OH)D levels are the most accurate way to determine your individual needs and monitor your response to supplementation.
3. Sticking to recommended doses: Unless advised otherwise by a doctor.
4. Understanding interactions: Be aware that some medications can interact with vitamin D absorption or metabolism.

Ultimately, while vitamin D supplementation is a vital tool for many to achieve optimal health, it should be approached with knowledge and caution. Balancing the benefits of adequate intake with the risks of excessive consumption ensures safe and effective management of vitamin D status.

Frequently Asked Questions About Vitamin D