Takeaways
- Vitamin D3 is essential for bone health and calcium absorption
- Sunlight exposure triggers vitamin D3 production in the skin
- Deficiency is common, especially in certain populations
- Blood tests measure 25-hydroxyvitamin D levels
- Supplementation may be necessary to maintain adequate levels
- Regular monitoring helps optimize vitamin D3 status
Understanding Vitamin D3
Vitamin D3, also called cholecalciferol, is a fat-soluble vitamin with a different chemical structure than vitamin D2 (ergocalciferol).[1] Vitamin D3 is naturally found in animal-based foods and is also made by our skin when it’s exposed to sunlight.[2]
Vitamin D3 is essential for several bodily functions, most notably, it facilitates the absorption of calcium from the intestines and helps maintain appropriate calcium levels in the bloodstream.[3] These functions are key to supporting both bone health and muscle function.[4]
Vitamin D3 can be obtained from three primary sources: exposure to sunlight, through the consumption of certain foods, and by taking supplements. Sunlight is the most natural source; however, many people do not get enough sun exposure to meet their daily requirements.[5]
The Sunshine Vitamin: How Our Bodies Make D3
Sun Exposure and Vitamin D3 Production
Our skin produces vitamin D3 when it is exposed to UVB rays from sunlight. This process starts in the epidermis, the outermost layer of skin.[6] When UVB rays reach the skin, they convert a type of cholesterol into vitamin D3.[7]
The amount of vitamin D3 our bodies produce from sunlight can vary based on several factors, including:
- Time of day
- Season
- Latitude
- Skin pigmentation
- Use of sunscreen
During the summer, exposure to the midday sun can produce substantial amounts of vitamin D3.[8] Conversely, during the winter or at higher latitudes, UVB rays are weaker. This reduction in UVB makes it more difficult to produce sufficient vitamin D3 from sunlight alone.[9]
Balancing sun exposure for vitamin D3 production with the risk of skin cancer can be challenging. Short periods of unprotected sun exposure can increase vitamin D3 levels, while excessive exposure increases the risk of skin cancer.[10] For personalized advice, it’s recommended to consult with a healthcare provider.
From Cholesterol to Calcitriol
The production of vitamin D3 in the body involves a series of steps, which can be summarized as follows:
- UVB rays convert 7-dehydrocholesterol in the skin to pre-vitamin D3
- Pre-vitamin D3 becomes vitamin D3
- The liver converts vitamin D3 to 25-hydroxyvitamin D
- The kidneys transform 25-hydroxyvitamin D into calcitriol
Calcitriol is the active form of vitamin D3 and is responsible for most of the vitamin’s effects in the body.[11] Both the liver and kidneys play essential roles in the process of converting vitamin D3 to its active form.[12]
Several enzymes are involved in vitamin D3 metabolism. These include:
- 25-hydroxylase
- 1α-hydroxylase
- 24-hydroxylase
These enzymes help convert vitamin D3 into its various forms as needed by the body.
Functions of Vitamin D3 in the Body
Bone Health
Vitamin D3 is essential for maintaining strong bones as it assists the body in absorbing calcium from the food we eat.[13] Without sufficient vitamin D3, our bodies can’t effectively use the calcium we consume.[14]
Vitamin D3 works in tandem with other nutrients to maintain bone health. Some of these include:
- Calcium
- Phosphorus
- Magnesium
These nutrients help build and maintain bone density. Having adequate levels of vitamin D3 can help prevent conditions like osteoporosis and rickets.[15]
Muscle Function
Vitamin D3 affects muscle strength and performance.[16] Research indicates a link between vitamin D3 levels and muscle function. Individuals with higher vitamin D3 levels tend to demonstrate better muscle strength.[17]
In older adults, vitamin D3 levels can influence the risk of falls. Low levels may lead to muscle weakness and poor balance, increasing the chances of falling.[18] Therefore, maintaining adequate vitamin D3 may help reduce this risk.
Immune System Support
Vitamin D3 plays a role in modulating the immune response in different ways.[19] It impacts both the innate and adaptive immune systems, helping to activate immune cells and regulate their functions.[20]
Some studies suggest that vitamin D3 may help lower the risk of autoimmune diseases, conditions where the immune system attacks the body’s own tissues. Examples include:
- Multiple sclerosis
- Rheumatoid arthritis
- Type 1 diabetes
However, more research is required to understand this link fully.
Immune Cell Type | Function Affected by Vitamin D3 |
---|---|
T cells | Regulates activation and differentiation |
B cells | Modulates antibody production |
Macrophages | Enhances antimicrobial activity |
Dendritic cells | Influences maturation and function |
Other Potential Benefits
Researchers are exploring the effects of vitamin D3 on a variety of health aspects, such as:
- Mood regulation
- Cardiovascular health
- Cancer prevention
- Metabolic health
- Cognitive function
These areas of study show potential, however, more studies are needed to confirm the specific roles of vitamin D3.
Vitamin D3 Deficiency: A Common Problem
Risk Factors
Certain groups of people have a greater risk of experiencing a vitamin D3 deficiency. These groups include:
- Older adults
- People with dark skin
- Those who are obese or have had gastric bypass surgery
- People with limited sun exposure
- Individuals with certain medical conditions
Lifestyle and environmental factors can also contribute to low vitamin D3 levels. These factors include:
- Living in northern latitudes
- Spending most time indoors
- Always wearing sunscreen when outside
- Following a strict vegan diet
Common risk factors for vitamin D3 deficiency are:
- Limited sun exposure
- Dark skin pigmentation
- Obesity
- Malabsorption disorders
- Certain medications
Signs and Symptoms
Vitamin D3 deficiency often has subtle signs, so many people might not realize that they are deficient. Common symptoms include:
- Fatigue
- Bone pain
- Muscle weakness
- Mood changes
Long-term deficiency can lead to more severe health problems, such as:
- Osteoporosis
- Increased risk of fractures
- Weakened immune system
- Depression
Symptom | Potential Impact on Health |
---|---|
Bone pain | Increased fracture risk |
Muscle weakness | Higher fall risk, especially in older adults |
Fatigue | Reduced quality of life |
Frequent infections | Compromised immune function |
Depression | Mental health concerns |
Testing Vitamin D3 Levels
Blood Tests
The 25-hydroxyvitamin D blood test is the standard method used to measure vitamin D levels.[21] This test indicates the amount of vitamin D in the blood from all sources, reflecting both the vitamin D that is made by the body and what is obtained from food or supplements.[22]
Healthcare providers use this test to:
- Diagnose vitamin D deficiency
- Monitor treatment progress
- Assess overall vitamin D status
The test itself is simple, requiring just a small blood sample. The results are typically available within a few days.
Interpretation of Results
Vitamin D3 levels are measured in nanograms per milliliter (ng/mL) or nanomoles per liter (nmol/L). Here is a general guide to understanding the results:
- Deficient: Less than 20 ng/mL (50 nmol/L)
- Insufficient: 21-29 ng/mL (51-74 nmol/L)
- Sufficient: 30-50 ng/mL (75-125 nmol/L)
- High: Above 50 ng/mL (125 nmol/L)
Doctors use these results to guide treatment decisions, while also considering other factors such as:
- Your overall health
- Risk factors for deficiency
- Symptoms you’re experiencing
Steps to take after receiving vitamin D3 test results include:
- Review results with your healthcare provider
- Discuss any symptoms or concerns
- Develop a plan to address deficiency if present
- Consider lifestyle changes or supplementation
- Schedule follow-up testing as needed
Vitamin D3 Supplementation
Choosing the Right Supplement
Vitamin D3 supplements are available in various forms. Common options include:
- Pills or tablets
- Liquid drops
- Gummies
- Sublingual sprays
When choosing a vitamin D3 supplement, you should consider:
- Dosage
- Form (D3 is generally preferred over D2)
- Quality and purity
- Additives or allergens
- Price
When looking for a high-quality vitamin D3 supplement, keep an eye out for these characteristics:
- Third-party tested for purity
- Appropriate dosage
- Easily absorbed form (D3)
- Free from unnecessary additives
- Reputable manufacturer
Dosage Recommendations
The necessary vitamin D3 dosage varies based on several factors, such as:
- Age
- Skin color
- Sun exposure
- Overall health
- Current vitamin D status
While general guidelines do exist, individual needs may vary.[23] Always consult a healthcare provider before starting any new supplements.
Age Group | Recommended Daily Allowance (RDA) |
---|---|
0-12 months | 400 IU (10 mcg) |
1-70 years | 600 IU (15 mcg) |
71+ years | 800 IU (20 mcg) |
Pregnant/breastfeeding | 600 IU (15 mcg) |
These are minimum recommendations; some individuals may require higher doses to reach optimal levels.
Timing and Administration
To optimize vitamin D3 absorption, consider the following:
- Take it with a meal containing some fat
- Consider taking it in the morning or afternoon
- Be consistent with timing
Vitamin D3 can interact with certain medications, including:
- Steroids
- Weight loss drugs
- Cholesterol-lowering medications
Always inform your healthcare provider of all supplements you are taking.
Monitoring and Adjusting Vitamin D3 Levels
Follow-up Testing
After beginning vitamin D3 supplementation, retesting is vital to ensure you’re reaching optimal levels.[24] Most healthcare providers recommend retesting after 3 to 6 months of supplementation.
Factors affecting the timing of a retest include:
- Initial vitamin D level
- Dosage of supplement
- Individual response to treatment
When you are interpreting changes in vitamin D3 levels over time, keep in mind the following:
- Consistency in taking supplements
- Changes in sun exposure or diet
- Seasonal variations
Fine-tuning Your Regimen
Adjusting vitamin D3 intake based on test results and symptoms is a process, and it may take time to achieve the right balance.[25] Working with a healthcare provider is essential to optimize your vitamin D3 levels.
A healthcare provider can help you with:
- Interpret test results
- Adjust dosage as needed
- Address any side effects
- Consider other factors affecting vitamin D status
Steps for adjusting a vitamin D3 supplementation plan include:
- Review latest blood test results
- Discuss any changes in symptoms or health
- Consider factors like season and lifestyle changes
- Adjust dosage if needed
- Plan for follow-up testing
Vitamin D3 and Diet
Food Sources
While sunlight is the main source of vitamin D3, some foods do naturally contain it. These include:
- Fatty fish (salmon, mackerel, sardines)
- Egg yolks
- Beef liver
However, getting sufficient vitamin D3 through diet alone can be challenging, as very few foods naturally contain high amounts.
Food Source | Vitamin D3 Content (per serving) |
---|---|
Salmon (3 oz) | 400-570 IU |
Canned tuna (3 oz) | 150 IU |
Egg yolk (1 large) | 40 IU |
Beef liver (3 oz) | 40 IU |
Fortified Foods
To address widespread deficiency, many countries fortify certain foods with vitamin D. Common fortified foods include:
- Milk
- Orange juice
- Cereals
- Yogurt
Fortification of foods helps to increase vitamin D intake within the population; however, relying solely on fortified foods may not be sufficient for everyone’s needs.[26]
A list of common foods that are fortified with vitamin D3 includes:
- Cow’s milk
- Plant-based milk alternatives (soy, almond, oat)
- Breakfast cereals
- Some brands of orange juice
- Certain types of yogurt
While fortified foods can contribute to vitamin D intake, they should not be the only source. A combination of sunlight, diet, and supplements is often the best approach for maintaining adequate levels.
Vitamin D3 Safety and Precautions
Potential Side Effects
Excessive vitamin D3 intake can lead to side effects. While rare with normal supplementation, symptoms of vitamin D toxicity can include:
- Nausea
- Vomiting
- Poor appetite
- Constipation
- Weakness
- Confusion
Severe cases of vitamin D toxicity can cause kidney problems and dangerously high blood calcium levels. This typically occurs only with extreme over-supplementation.[27]
Special Considerations
Certain groups need to carefully monitor their vitamin D3 intake, including:
Pregnant women: Adequate vitamin D3 is vital for fetal development; however, high doses may pose risks. Consult a healthcare provider for personalized advice.
Infants: Breastfed infants often require vitamin D3 supplements.[28] Formula-fed babies may get enough from fortified formula.[29] Always follow the recommendations of a pediatrician.
Elderly: Older adults often have higher vitamin D3 requirements and may have difficulties absorbing it.[30] Regular monitoring is important.
Some medical conditions require caution when supplementing with vitamin D3, including:
- Kidney stones
- High blood calcium levels
- Certain thyroid conditions
- Sarcoidosis
Always inform your healthcare provider of all vitamin D3 supplementation.
Vitamin D3 in Different Climates
Seasonal Variations
Vitamin D3 production from sunlight varies throughout the year. During summer, midday sun exposure can produce ample vitamin D3; however, the winter months pose a challenge, particularly in northern latitudes.[31]
To maintain adequate vitamin D3 levels year-round, you can:
- Get safe sun exposure when possible
- Increase dietary sources in winter
- Consider supplementation during low-sun months
Consult a healthcare provider for personalized guidance on making seasonal adjustments.
Geographical Considerations
Latitude significantly impacts the production of vitamin D3 from sunlight. People living closer to the equator generally have an easier time maintaining vitamin D3 levels through sun exposure.[32]
In contrast, those living in northern latitudes face a greater challenge. The angle of the sun reduces the amount of UVB radiation, especially during winter, which in turn makes it more difficult to produce vitamin D3 from sunlight alone.[33]
Latitude | Vitamin D3 Production Potential |
---|---|
0-30° | High year-round |
30-50° | Moderate, low in winter |
50°+ | Low, very low in winter |
People living in high-latitude regions often need to rely more on diet and supplements to maintain adequate vitamin D3 levels.
FAQ: People Also Ask
What’s the difference between vitamin D and vitamin D3?
Can you get too much vitamin D3?
How long does it take to correct a vitamin D3 deficiency?
Does vitamin D3 help with weight loss?
Can vitamin D3 improve sleep?
Is it better to take vitamin D3 in the morning or at night?
Can vitamin D3 cause hair loss?
How does vitamin D3 affect thyroid function?
Conclusion
Vitamin D3 plays a crucial role in our overall health. From bone strength to immune function, its effects are wide-reaching throughout the body. Understanding your vitamin D3 status and needs is an important step in maintaining good health.
Remember these key points:
- Sunlight is the primary natural source of vitamin D3.
- Many people don’t get enough vitamin D3 from sun and diet alone.
- Regular blood tests can help monitor your vitamin D3 levels.
- Supplementation may be necessary, especially in certain populations.
- Work with a healthcare provider to determine your individual needs.
By paying attention to your vitamin D3 status, you’re taking a proactive step in supporting your overall health and well-being. Whether through safe sun exposure, diet, or supplementation, maintaining adequate vitamin D3 levels can contribute to your long-term health goals.
Vitamin D3 is produced in the skin when exposed to sunlight and is found in animal-based foods, while vitamin D2 is produced by plants and fungi. Both are fat-soluble but have different chemical structures.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
The body produces vitamin D3 (cholecalciferol) when exposed to UVB radiation from sunlight. It is also naturally present in certain animal foods, such as fatty fish, egg yolks, and liver.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Vitamin D3 is vital for the absorption of calcium in the intestines. This process is key for bone health and other physiological functions that require calcium homeostasis.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Adequate calcium levels, facilitated by vitamin D, are crucial for maintaining bone density and strength. Vitamin D also impacts muscle strength and performance, with deficiencies linked to muscle weakness.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
The body synthesizes vitamin D3 when exposed to UVB radiation, making sunlight a natural source. However, several factors like location, time of day, skin pigmentation, and sunscreen use can limit exposure for many individuals.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
When UVB radiation penetrates the epidermis, it converts 7-dehydrocholesterol into pre-vitamin D3, which is then converted to vitamin D3 in the body.
Source: “Vitamin D Metabolites: Analytical Challenges and Clinical Relevance” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8892115/
Specifically, 7-dehydrocholesterol, a cholesterol precursor found in the skin, is converted to previtamin D3 by UVB light, and then isomerizes to vitamin D3.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
The angle of the sun during midday hours, particularly during summer, results in greater UVB radiation, leading to higher rates of vitamin D3 production in the skin.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
During winter months and at higher latitudes, the sun’s angle decreases, resulting in less UVB radiation reaching the Earth’s surface. This makes it harder for the body to produce sufficient vitamin D3 through sunlight alone.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Moderate sun exposure is sufficient for vitamin D3 synthesis. Prolonged, unprotected exposure increases the risk of skin cancer. It’s important to balance sun exposure with sun safety.
Source: “Relationship between sunlight and range use of commercial free-range hens in Australia” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9154180/
Vitamin D3 is converted to calcidiol in the liver, and then to the active form calcitriol in the kidneys, which can then act on various tissues in the body.
Source: “Combinations of Calcitriol with Anticancer Treatments for Breast Cancer: An Update” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8657847/
Vitamin D3 is first hydroxylated in the liver to form 25-hydroxyvitamin D [25(OH)D], also known as calcidiol, then further hydroxylated in the kidneys to form the active hormone 1,25-dihydroxyvitamin D [1,25(OH)2D] also known as calcitriol.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Vitamin D3 facilitates the absorption of calcium from the gut, a process essential for building and maintaining bone density. Insufficient Vitamin D levels reduces calcium absorption, weakening bones.
Source: “Vitamin D sterols increase FGF23 expression by stimulating osteoblast and osteocyte maturation in CKD bone” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6715148/
Vitamin D3 is crucial for proper calcium absorption from the digestive system. Without enough vitamin D3, calcium intake does not translate into optimal calcium levels in the body, which are essential for many processes, including bone health.
Source: “The Role of Vitamin D and Vitamin D Binding Protein in Chronic Liver Diseases” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9503777/
Vitamin D3 plays a significant role in maintaining bone density and preventing its degradation, helping to prevent osteoporosis in adults. In children, it helps prevent rickets, a disease where bones do not mineralize properly.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Vitamin D receptors are found in muscle tissue. Adequate vitamin D is needed for proper muscle contraction, strength, and overall function, and deficiencies are associated with reduced muscle performance.
Source: “Vitamin D Metabolites: Analytical Challenges and Clinical Relevance” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8892115/
Some research shows that individuals with sufficient vitamin D levels tend to have greater muscle strength and function compared to those with deficiencies.
Source: “Effects of active vitamin D analogues on muscle strength and falls in elderly people: an updated meta-analysis” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10867111/
Vitamin D deficiency can lead to muscle weakness and poor balance, making older adults more susceptible to falls, which can result in fractures and other health issues.
Source: “Bibliometric Analysis on Research Trend of Accidental Falls in Older Adults by Using Citespace—Focused on Web of Science Core Collection (2010–2020)” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7916410/
Vitamin D has been shown to influence both the innate and adaptive immune systems. This role includes helping to activate immune cells and regulate their functions.
Source: “The Role of Vitamin D and Vitamin D Binding Protein in Chronic Liver Diseases” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9503777/
Vitamin D receptors are found on various immune cells. Vitamin D is involved in immune cell differentiation, activation and regulation, impacting both the innate and adaptive immune systems.
Source: “Vitamins D2 and D3 Have Overlapping But Different Effects on the Human Immune System Revealed Through Analysis of the Blood Transcriptome” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8908317/
The 25-hydroxyvitamin D (25(OH)D) blood test is used to measure the total amount of vitamin D in the blood, reflecting both the D2 and D3 forms.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
The 25(OH)D test measures total vitamin D from all sources, including sun exposure, diet, and supplements. It serves as the primary indicator of vitamin D status.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Recommended daily intakes are general guidelines, but individual needs can vary based on age, skin pigmentation, location, health status, and lifestyle factors.
Source: “Analysis of Usual Consumption of Vitamin D Among Adult Individuals in Italy” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11644698/
Monitoring through repeat testing is needed to assess the efficacy of vitamin D3 supplementation. It is important to ensure that optimal levels are achieved and sustained.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Vitamin D levels should be monitored with testing and adjustments to supplementation and/or lifestyle can be made to achieve the desired results. This process may require ongoing testing and modification.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Fortification of some foods like milk and cereals with vitamin D contributes to dietary intake. However, not everyone may consume enough of fortified foods, so relying on it alone may not suffice.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Vitamin D toxicity, though rare, can lead to hypercalcemia (high blood calcium), which can damage the kidneys and other organs. This condition typically only occurs with excessive supplementation and not from sun exposure.
Source: “Vitamin D Metabolites: Analytical Challenges and Clinical Relevance” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8892115/
Breast milk typically contains low levels of vitamin D. As such, health organizations recommend vitamin D supplementation for breastfed infants to meet their requirements and ensure proper development.
Source: “Vitamin D supplementation for term breastfed infants to prevent vitamin D deficiency and improve bone health” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8812278/
Infant formula is often fortified with vitamin D and can supply sufficient amounts to meet the needs of formula-fed infants, if they consume an adequate amount of formula.
Source: “Vitamin D supplementation for term breastfed infants to prevent vitamin D deficiency and improve bone health” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8812278/
Age-related changes like reduced skin production and absorption, coupled with factors like diet and decreased sun exposure, can lead to vitamin D deficiencies. Thus, older adults often require higher vitamin D intake.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
UVB exposure is higher in the summer at midday, leading to greater vitamin D3 production. In the winter and at higher latitudes, UVB radiation decreases and impacts the ability of the skin to synthesize adequate levels.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
The sun’s angle and intensity are greater closer to the equator, leading to higher UVB exposure, enabling more efficient vitamin D3 production through sun exposure.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
At higher latitudes, the angle of the sun and reduced sunlight, especially in winter, decreases UVB radiation making it difficult to synthesize vitamin D3, and therefore supplementation is often needed.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
The term ‘vitamin D’ refers to a group of fat-soluble secosteroids, and includes forms like vitamin D2 and D3, with cholecalciferol being the specific name for D3.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
While both forms can increase vitamin D levels, studies have shown that vitamin D3 (cholecalciferol) is generally more potent and more effective at raising and maintaining blood 25(OH)D levels than vitamin D2 (ergocalciferol).
Source: “Differential Effects of Oral Boluses of Vitamin D2 vs Vitamin D3 on Vitamin D Metabolism: A Randomized Controlled Trial” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6797055/
Vitamin D toxicity is usually caused by excessive supplement intake and not from sun exposure or diet, because the body has built in limits to prevent excess vitamin D production from sun.
Source: “Vitamin D Metabolites: Analytical Challenges and Clinical Relevance” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8892115/
With proper vitamin D supplementation, many individuals begin to see measurable increases in their blood levels within 6 to 12 weeks. However, the exact timeline may vary depending on factors such as initial deficiency and dosage of supplements.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Some research shows an association between low vitamin D levels and obesity; however, it is still being investigated whether vitamin D deficiency plays a causal role in obesity.
Source: “Vitamin D status is heritable and under environment‐dependent selection in the wild” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9545857/
Vitamin D receptors have been identified in brain regions involved in sleep cycles, such as the hypothalamus, which regulates circadian rhythm, suggesting a potential role of vitamin D in sleep regulation.
Source: “The Effects of Vitamin D-Enriched Mushrooms and Vitamin D3 on Cognitive Performance and Mood in Healthy Elderly Adults: A Randomised, Double-Blinded, Placebo-Controlled Trial” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7766163/
Vitamin D is fat-soluble and is best absorbed in the presence of dietary fats. Taking vitamin D supplements with a meal that includes fats can enhance absorption and its bioavailability.
Source: “Vitamin D Metabolites: Analytical Challenges and Clinical Relevance” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8892115/
Vitamin D receptors have been identified in thyroid tissue and some studies suggest vitamin D’s involvement in thyroid function; however, more research is necessary.
Source: “Vitamin D and the Thyroid: A Critical Review of the Current Evidence” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9964959/