The Vitamin D3 Emergency
Why Most People Are Still Deficient in Vitamin D3 and How to Address It
In recent years, few vitamins have been discussed and written about as much as Vitamin D3. And rightly so. Once mocked and not taken seriously, it has now been established that Vitamin D3 is one of the most important vitamins for our body, influencing hundreds of metabolic processes.
What is Vitamin D3?
Vitamin D3 is a fat-soluble vitamin synthesized in the skin through the action of UVB rays from sunlight. It cannot be sufficiently obtained from food, making sun exposure essential. It is a prohormone and must be converted into its active form in the body, with the liver and kidneys playing a crucial role. In the liver, Vitamin D3 is converted to calcidiol. An enzyme attaches a hydroxyl group to the vitamin, producing 25-hydroxyvitamin D3. This form is not fully active but is the main circulating form of Vitamin D in the blood and is used as a marker for Vitamin D status. In the kidneys, calcidiol is further hydroxylated, resulting in 1,25-dihydroxyvitamin D3, known as calcitriol, the biologically active form of Vitamin D. This hormone interacts with Vitamin D receptors in various body cells, regulating the expression of hundreds of genes. The conversion of calcidiol to calcitriol in the kidney is tightly regulated, with high levels of calcitriol inhibiting the kidney enzyme to prevent overproduction and potential toxicity.
Importance of Vitamin D3
Vitamin D3 is a hormone that can only be produced in sufficient amounts with sun exposure and functioning liver and kidneys. Unlike other vitamins, it cannot be adequately obtained through diet, despite frequent claims to the contrary.
And what about sunlight? The synthesis of D3 in the skin upon contact with UVB rays only works if no clothing blocks the radiation and no sunscreen is used. Ideally, one would need to be naked at midday, which is still considered improper in our prudish society.
What Blood Concentration is Necessary?
Vitamin D3 status is measured using calcidiol, the once-hydroxylated form. The measure of sufficient supply is the blood level, typically given in ng/mL.
In both the USA and Germany, concentrations of 30 ng/mL are considered sufficient. This might seem understandable from the perspective that the majority of the Western population is deficient, and with low target values, they automatically fall into the normal range. This can influence health statistics but does not promote health.
However, recommendations are now suggesting levels of 50 ng/mL as optimal. Many studies indicate that concentrations above 50 ng/mL can be health-promoting. These studies suggest higher concentrations are associated with increased bone density and a reduced risk of fractures. There are also indications that some cancers, particularly colorectal cancer, may be less common when concentrations exceed 50 ng/mL. Additionally, higher levels might reduce the risk of COVID-19 and other respiratory infections, and muscle function, especially in older adults, could improve with blood levels above 50 ng/mL. Much evidence suggests that Vitamin D levels above 50 ng/mL are recommended and offer health benefits. The toxicity of Vitamin D3 is typically discussed at blood levels above 100 ng/mL. However, caution is advised at such high levels, as health problems can indeed occur around 150 ng/mL. A safe range is generally below 100 ng/mL.
There is also evidence that an adequate Vitamin D level can positively affect the composition of the microbiome and the defense against pathogenic bacteria.
A future Substack article will detail the possible positive effects of a higher Vitamin D3 level (> 30 ng/mL).
Supplementation of Vitamin D3
Despite the benefits of higher Vitamin D levels, the myth persists that supplementation is only necessary during the dark winter months. However, such levels are hardly achievable without taking supplements. Most people continue to avoid sufficient Vitamin D3 supplementation and thus have blood levels in the range of 10-20 ng/mL. These levels are far too low and can have negative health impacts, which can even be life-threatening in extreme cases.
Vitamin D supplement dosages are often given in IU (International Units), a measure of the biological activity or effect of a vitamin, hormone, or drug. The dosage can also be given in micrograms (mcg). The conversion is as follows:
1 IU of Vitamin D equals 0.025 micrograms (mcg)
1 microgram (mcg) of Vitamin D equals 40 IU
Examples include:
400 IU of Vitamin D = 10 mcg
1,000 IU of Vitamin D = 25 mcg
4,000 IU of Vitamin D = 100 mcg
In the USA and Germany, a daily dose of 800 IU is often recommended. This amount may suffice to achieve a level of about 20 ng/mL. In the USA, a daily intake of up to 4,000 IU is considered safe and is recommended by many experts as the upper limit.
Much speculation exists as to why such a low dosage of 800 IU is recommended. However, this is not health-promoting in the sense of significantly reducing essential health risks.
What is the Ideal Dosage for Supplementation?
There can be no universal statement about this. However, before starting Vitamin D3 supplementation, the 25-hydroxyvitamin D3 level in the blood should be measured to know the baseline status. The dosage can then be adjusted accordingly. Higher initial supplementation with 20,000 or more IU for several days or weeks may be necessary if levels are < 20 ng/mL. My personal guidelines are 5,000 IU per day in the summer months and 10,000 IU per day in the winter months. Since each person responds differently to Vitamin D3 supplementation, regular measurement is essential. In Germany, this test is not covered by health insurance, so many people do not know their Vitamin D levels as they are unwilling to pay the 30 EUR themselves. This should be addressed first if Vitamin D deficiency in the population is to be remedied. The benefits of D3 supplementation must also be better communicated.
Practical Steps to Take
Analyze Current Status
Visit your doctor and have your Vitamin D level measured, specifically the concentration of 25-hydroxyvitamin D3. Inform your doctor that you want this information. If you prefer not to see your general practitioner, visit an external lab. Many laboratories now offer this service to private customers.
Achieve a Normal Level
Check your value. If it is less than 30 ng/mL, contact your doctor. Supplementation is necessary. You may need to take a higher dose for several weeks, typically > 10,000 IU per day, and this for several weeks. Since everyone responds differently to Vitamin D3 intake, multiple checks are necessary. A normal level is typically 50 ng/mL.
Define Your Goal
Set a target level for where you want your value to be. Many experts recommend a level of 70-80 ng/mL. Discuss with your doctor how best to achieve this. Some doctors do not see the benefit of a level > 30 ng/mL. In this case, seek a second opinion.Find Your Daily Supplementation Dose
After achieving your target level of around 70-80 ng/mL, find your daily dose. My personal guidelines are 5,000 IU in the summer months and 10,000 IU in the winter months. To find the optimal dosage for you, consult with your doctor and regularly check your levels.
The Role of Vitamin K2 and Magnesium
It is essential that Vitamin D3 supplementation is accompanied by Vitamin K2 and Magnesium.
Vitamin K2 and Vitamin D3 play a synergistic role in supporting bone health and the cardiovascular system. While Vitamin D3 is responsible for the absorption of calcium from the intestine into the bloodstream, Vitamin K2 is necessary for efficiently incorporating the absorbed calcium into the bones. Vitamin K2 also prevents calcium from depositing in the arteries, which could lead to hypercalcemia. This elevated calcium concentration in the blood can cause arterial calcification and kidney stones. Therefore, the combination of Vitamin D3 and Vitamin K2 is necessary to enhance bone health and minimize side effects. My dosage is 200 micrograms (mcg) per day, though this may vary for other individuals.
Magnesium supports the activation and function of Vitamin D3, regulates calcium absorption and utilization, and works synergistically with Vitamin K2 to promote bone and cardiovascular health. Adequate magnesium intake is, therefore, crucial for optimal use of the benefits of Vitamin D3 and Vitamin K2. My dosage is at least 400 milligrams (mg) per day, though this may vary for others.
Overall, it is essential to note that all dosages mentioned in this article are not general recommendations but rather dosages that I personally use. These can vary from person to person and should ideally be coordinated with your general practitioner.
Are There Dangers of Vitamin D3 Overdose?
An overdose is relatively rare but nevertheless possible. It can lead to hypercalcemia, causing symptoms like nausea, vomiting, thirst, and constipation. Long-term effects include kidney damage, kidney stones, and heart problems such as vascular calcification and arrhythmias. High calcium levels can also result in soft tissue calcifications and bone weakness. Gastrointestinal issues and psychological symptoms like confusion may also occur. Therefore, careful dosing and medical supervision are recommended.
Why Regular Monitoring is Important
Everyone responds differently to Vitamin D3 supplementation. Some people need only a small dose of Vitamin D3 to achieve high blood levels of 25-hydroxyvitamin D3, while for others, it is the opposite. No one is the same. Regularly check your blood levels. Do not fly blind! Particularly in the early stages, a check every three months is recommended. Once you know how you respond to supplementation, checking 1-2 times yearly is sufficient. Discuss with your doctor and seek advice.
Why Not All Doctors Are Suitable
It has become widely known among most general practitioners that an increased Vitamin D3 level brings health benefits. Nevertheless, some doctors still see it differently. Discuss it with them, but don't be put off. Only a few general practitioners are unshakable in their views on Vitamin D3; most doctors are aware of the latest studies.
Take Responsibility for Your Health
Don't forget that! Nobody, absolutely nobody, takes care of your health continuously and sustainably. Your family doctor has too little time to deal with you comprehensively. Their focus is on treating your symptoms. There are reasons for this within the healthcare system that will not be discussed here. Be aware that you have to take care of your own health if you want to age healthily. The desire to relieve yourself of this responsibility is understandable. But it is wrong.
You are responsible for yourself.
Only YOU.
This article is for informational purposes only and does not constitute medical advice. Please consult a doctor before taking supplements or changing your diet. Read our full disclaimer.
Sources and further reading:
Amir, E., Simmons, C., Freedman, O., Dranitsaris, G., Cole, D., Vieth, R., Ooi, W., & Clemons, M. (2010). A phase 2 trial exploring the effects of high-dose (10,000 IU/day) vitamin D3 in breast cancer patients with bone metastases. Cancer.
Annweiler, C., Beaudenon, M., Simon, R., et al. (2022). High-dose versus standard-dose vitamin D supplementation in older adults with COVID-19 (COVIT-TRIAL): A multicenter, open-label, randomized controlled superiority trial. PLOS Medicine, 19(1), e1003999. DOI: 10.1371/journal.pmed.1003999.
Bacon, C. J., Gamble, G. D., Horne, A., Scott, M., & Reid, I. R. (2009). High-dose oral vitamin D3 supplementation in the elderly. Osteoporosis International, 20, 1407-1415.
Bor, P., Larsen, A., & Nørgaard, H. (2023). High-Dose Vitamin D Supplementation Significantly Affects the Placental Transcriptome. Nutrients, 15(24), 5032. DOI: 10.3390/nu15245032.
Gallagher, J. C., Smith, L. M., & Yalamanchili, V. (2020). "Dose response to vitamin D supplementation in postmenopausal women: a randomized trial." Journal of Clinical Endocrinology & Metabolism, 105(4), 1290-1301. DOI: 10.1210/clinem/dgz304.
Garland, C. F., French, C. B., Baggerly, L. L., & Heaney, R. P. (2011). Vitamin D supplement doses and serum 25-hydroxyvitamin D in the range associated with cancer prevention. Anticancer Research, 31(2), 607-611. DOI:10.21873/anticanres.1278.
Manson, J. E., Bassuk, S. S., Lee, I. M., et al. (2019). Vitamin D, Omega-3, and Health Outcomes: Vitamin D Supplementation and Prevention of Cancer and Cardiovascular Disease. New England Journal of Medicine, 380, 33-44. DOI: 10.1056/NEJMoa1809944.
McCullough, P., Lehrer, D., & Amend, J. (2019). Daily oral dosing of vitamin D3 using 5000 TO 50,000 international units a day in long-term hospitalized patients: Insights from a seven year experience. The Journal of Steroid Biochemistry and Molecular Biology, 189, 228-239