Vitamin D: The Sunshine Vitamin for Strong Bones, Immunity, and Overall Health

Understanding Vitamin D: What You Need to Know

Vitamin D, known as the "sunshine vitamin," is crucial for keeping our bodies healthy. Beyond helping with strong bones, it supports our heart, immune system, and even muscles. This article breaks down the latest research on vitamin D’s benefits, risks, the questions scientists are still trying to answer, and who will benefit most from supplementation.

Vitamin D Benefits: Why It’s Essential for Your Health

Vitamin D is a fat-soluble vitamin and a hormone precursor that exists in two forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Both forms are found in food and supplements and are absorbed well, increasing levels of 25-hydroxyvitamin D, the circulating form of vitamin D used to measure its status in the bloodstream.

Vitamin D3 vs. D2: Which One Works Better?

Evidence suggests that vitamin D3 may be more effective than D2 in raising 25-hydroxyvitamin D levels (Tripkovic et al., 2012; van den Heuvel et al., 2023). The difference is  Ergocalciferol (D2) is derived from plants, while cholecalciferol (D3) can be derived from animal products (our D3 1000 IU is suitable for vegans and 3000 IU for vegetarians) and is synthesised in human skin upon exposure to sunlight.

Vitamin D & Calcium Absorption. 

Vitamin D plays a critical role in calcium absorption in the small intestine and, along with parathyroid hormone, supports skeletal mineralisation and maintains calcium homeostasis in the bloodstream. There are studies highlight associations between low vitamin D levels and various diseases, likely due to its anti-inflammatory and immune-modulating properties, as well as its potential effects on cytokine levels (small proteins that regulate inflammation and immunity) (Kulie et al., 2009). 

Muscular strength and Muscle mass

Vitamin D is also seen to have moderate effects on different components of health. For example, in a study conducted on older adults with vitamin D deficiency, it was found that supplementation with moderate doses (1,000 IU) helped increase muscular strength and maintain lean muscle mass. This may be due to the fact that vitamin D receptors are found on skeletal muscle, and these receptors are involved in protein synthesis within the muscle (Cangussu et al., 2015). 

Vitamin D and Cardiovascular profile improvements 

There is also emerging evidence that vitamin D may support cardiovascular health by reducing inflammation and improving lipid profiles, though more research is needed. Additionally, it may modestly lower cancer-related mortality, particularly for those with a deficiency (Ruiz-García et al., 2023).

Vitamin D Deficiency: Causes, Symptoms & Who’s at Risk

Humans can meet their vitamin D requirements through dietary intake or sufficient sun exposure, ensuring adequate synthesis and maintenance of this essential nutrient (Bouillon et al., 2021). However, many people fail to achieve optimal vitamin D levels due to limited sun exposure, dietary insufficiency, and factors like age, skin pigmentation, and geographic location.

However (Amrein et al. (2020) reviewed multiple randomised control trials involving hundreds of thousands of people and found that vitamin D deficiency is a widespread health issue, affecting approximately: 

•  40% of Europeans
•  24% of Americans, with severe deficiency impacting 13% and 5.9%, respectively.
• 20% in regions like India, Pakistan, and Afghanistan, where the population is severely deficient.

People who are more vulnerable to vitamin D deficiencies include: 

• Older adults
• Individuals with chronic illnesses, hospitalised patients. 
• Those from ethnic minorities such as people of Asian, African, and Afro-Caribbean descent as these groups require more sunlight to synthesise adequate vitamin D due to higher skin pigmentation.
• Those living above 52° North latitude, which includes most of the UK, cannot produce enough vitamin D from sunlight between October and March due to the sun's low angle (Cowbrough, 2015).

However different countries have different established levels of vitamin D. Within the UK, a defined serum level of 25-hydroxyvitamin D (25[OH]D) below 50 nmol/L is considered insufficiency, while a severe deficiency is considered to be below 30 nmol/L (Cowbrough, 2015). These lower levels are linked to an increased risk of mortality, infections, and chronic diseases.

Get Your Daily Dose of Vitamin D3 – Shop Now at VitaVault !

At VitaVault, we sell two different Vitamin D products: Vitamin D3 1000 IU and Vitamin D3+K2 MK7 (3000 IU). Both derived from algae, making it low-CO2 and plant-sourced!

For context:

Teenagers (11–18 years) should have 800–2000 IU of Vitamin D per day, while adults (18–75 years) should have 1000–2000 IU, and adults ≥75 years should have 2000–4000 IU daily. The upper tolerable daily intake for all individuals from 11 years and older is 4000 IU (Bleizgys, 2021) however this is only recommended if you hold a severe Vitamin D deficiency as excessive consumption can lead to problems like hypercalcemia etc. 

1. The Goldilocks Dose: Just Right
   Our Vitamin D3 delivers 1,000 IU per capsule, the sweet spot for daily supplementation. It’s:

• Effective: This dosage is scientifically proven to help maintain optimal vitamin D levels in the blood, supporting bone health, immune function, and overall vitality.

• Safe: Unless you have a Vitamin D deficiency, more isn't always better.  High-dose supplementation that is unmoderated can lead to vitamin D toxicity, our 1,000 IU formulation stays within the safe limits recommended by health experts.

2. A Flexible Fit for Your Lifestyle

   • Maintenance or Boost: One capsule is enough for general daily support, but if you’re managing a deficiency under medical supervision, the dosage can be easily adjusted.

   • Year-Round Support: Whether it’s the middle of winter with limited sunlight or the peak of summer, our Vitamin D3 helps ensure your levels stay consistent

Our Vitamin D3+K2 MK7 delivers 3000 IU per capsule, providing an elevated dose of vitamin D to support your health goals. 

• • Safe: While a higher dose, 3000 IU stays well within safe limits for most adults, ensuring you receive the benefits without risking toxicity. Always consult with your healthcare provider if unsure about your specific needs.
    

  • Effective: This higher dosage is perfect for individuals needing extra support for bone health, immune function, and overall vitality, especially in areas with limited sun exposure or for those with higher requirements.

Vitamin D Toxicity: Signs, Risks & Safe Dosage 

Although vitamin D is highly regarded for its health advantages, excessive consumption can have major negative effects. Hypervitaminosis D, another name for vitamin D poisoning, is an uncommon but rising issue as supplement use increases globally.

Vitamin D toxicity occurs when levels of 25-hydroxyvitamin D in the blood exceed 150 ng/mL (375 nmol/L). This condition typically results from prolonged high-dose supplementation or accidental overdoses, leading to dangerously high calcium levels in the blood, known as hypercalcemia. This can cause cardiovascular problems, digestive discomfort, and neuropsychiatric symptoms (e.g., depression, drowsiness). However, you are only at risk of this from high-dose supplementation (10,000 IU a day). The daily recommended intake is between 600–800 IU, with safe upper limits being 4,000 IU a day for adults (Marcinowska-Suchowierska et al., 2018; Taylor and Davies, 2018) which we strictly follow. 

Reference list

Bleizgys, A. (2021). Vitamin D Dosing: Basic Principles and a Brief Algorithm (2021 Update). Nutrients, [online] 13(12), p.4415. doi:https://doi.org/10.3390/nu13124415.

Cangussu, L.M., Nahas-Neto, J., Orsatti, C.L., Bueloni-Dias, F.N. and Nahas, E.A.P. (2015). Effect of vitamin D supplementation alone on muscle function in postmenopausal women: a randomized, double-blind, placebo-controlled clinical trial. Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA, [online] 26(10), pp.2413–21. doi:https://doi.org/10.1007/s00198-015-3151-9.

Marcinowska-Suchowierska, E., Kupisz-Urbańska, M., Łukaszkiewicz, J., Płudowski, P. and Jones, G. (2018). Vitamin D Toxicity–A Clinical Perspective. Frontiers in Endocrinology, 9. doi:https://doi.org/10.3389/fendo.2018.00550.

National Institutes of Health (2024). Vitamin D. [online] National Institutes of Health. Available at: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/.

Ruiz-García, A., Pallarés-Carratalá, V., Turégano-Yedro, M., Torres, F., Sapena, V., Martin-Gorgojo, A. and Martin-Moreno, J.M. (2023). Vitamin D Supplementation and Its Impact on Mortality and Cardiovascular Outcomes: Systematic Review and Meta-Analysis of 80 Randomized Clinical Trials. Nutrients, 15(8), p.1810. doi:https://doi.org/10.3390/nu15081810.

Taylor, P.N. and Davies, J.S. (2018). A review of the growing risk of vitamin D toxicity from inappropriate practice. British Journal of Clinical Pharmacology, 84(6), pp.1121–1127. doi:https://doi.org/10.1111/bcp.13573.

Tripkovic, L., Lambert, H., Hart, K., Smith, C.P., Bucca, G., Penson, S., Chope, G., Hyppönen, E., Berry, J., Vieth, R. and Lanham-New, S. (2012). Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. The American Journal of Clinical Nutrition, [online] 95(6), pp.1357–1364. doi:https://doi.org/10.3945/ajcn.111.031070.

van den Heuvel, E.G., Lips, P., Schoonmade, L.J., Lanham-New, S.A. and van Schoor, N.M. (2023). Comparison of the Effect of Daily Vitamin D2 and Vitamin D3 Supplementation on Serum 25-Hydroxyvitamin D Concentration (Total 25(OH)D, 25(OH)D2, and 25(OH)D3) and Importance of Body Mass Index: A Systematic Review and Meta-Analysis. Advances in Nutrition (Bethesda, Md.), [online] 15(1), pp.S2161-8313(23)013947. doi:https://doi.org/10.1016/j.advnut.2023.09.016.