Meta-analysis: High-dosed vitamin D (50 micrograms) protects against many diseases

Vitamin D is important for our bones, mood, immune defense, blood sugar levels, for regulating inflammation, prevention of cancer, and many other functions. Most attention has been focused on vitamin D’s role in preventing brittle bones rather than its ability to prevent all the other deficiency diseases that are linked to poor well-being, disease, and early death. Vitamin D deficiency is a global problem, and science has not yet come to an agreement with regard to how much vitamin D we humans need. However, according to a new meta-analysis that is published in Nutrients, daily supplementation with 50 micrograms of vitamin D appears to be an adequate and safe dose for most adults.

Over the past decades, a lot of vitamin D research has been published, yet there is still disagreement and uncertainty about how much we actually need and when it is relevant to talk about deficiency.
Also, there is a big difference between the recommended intake level for vitamin D and the amount leading scientists claim to be effective. The new meta-analysis of multiple vitamin D studies looked at how much vitamin D we need on a daily basis to reach an optimal blood level of the nutrient.
In Denmark, the official recommendation for vitamin D intake lies in the range between 5 and 20 micrograms. The highest doses are recommended to vulnerable groups such as seniors and nursing home residents. Nonetheless, these recommendations appear to be too small, which contributes to increased mortality and premature death. In the meta-analysis, the authors point to daily supplementation with 50 micrograms (= 2,000 IU) of vitamin D to prevent and treat vitamin D deficiency in most adults. According to data from randomized controlled studies (RCTs), this dose may be associated with multiple health benefits. This dose is also able to raise blood levels of vitamin D to over 50 nmol/L (lower threshold) in 99 percent of the adult population and to over 75 nmol/L (sufficient) in 90 percent of adults.
According to the many randomized controlled studies, year-long supplementation with 50 micrograms of vitamin D per day is perfectly safe even for those who get plenty of sun exposure and already have enough vitamin D in their blood. The scientists conclude that daily supplementation with 50 micrograms of vitamin D is a simple, effective, and safe dose for preventing and treating vitamin D deficiency in most adults.
It is important to stress that the new recommendations for vitamin D are substantially higher than the current recommendations that need to be reconsidered by health authorities. Some people may need more vitamin D due to genetic factors, overweight, or diabetes, in which cases the body may have difficulty with absorbing or utilizing the vitamin. The ideal goal is always to aim for optimal blood levels of vitamin D. According to EFSA (European Food Safety Authority), the safe upper intake level for daily vitamin D intake is 100 micrograms, an amount that most light-skinned people can synthesize in their skin on sunny summer’s day.

Why is it so important to get enough vitamin D throughout life?

The sun’s UVB rays is our primary source of vitamin D. The vitamin is synthesized when a cholesterol precursor on our skin surface is exposed to sunlight. At our latitudes, however, we can only produce vitamin D during the summer when the sun sits sufficiently high in the sky. There is also vitamin D in foods like oily fish and egg yolks, but the amounts are negligible
In the meta-analysis, the authors describe vitamin D’s role in health and explain how the inactive form of the nutrient (from sunlight and supplements) is converted by the liver to 25(OH)D, which is the form of vitamin D that is measured in the blood and is later converted into the active form by our kidneys, immune cells, and various other tissues.
Science first discovered vitamin D’s role in bone health and as a means of prevention for rickets. Later, science discovered that all cells in the body have vitamin D receptors (VDR). Active vitamin D is considered a steroid hormone that activates and controls hundreds of different genes. Vitamin D therefore plays a key role in the immune defense when it fights infections, regulates inflammatory processes, controls blood levels, mood, and prevents cardiovascular disease, type 2 diabetes, autoimmune diseases, and cancer.

References:

Pawel Pludowsky et al. Vitamin D Supplementation: A review of the Evidence Arguing for a Daily Dose of 2000 International Units (50 µg) of vitamin D for adults in the General Population. Nutrients 2024

Intermountain Healthcare: New study finds current dosing recommendations may not help patients achieve optimal levels. EurekAlert 12-Nov-2023

D-vitamin - Fødevarestyrelsen (foedevarestyrelsen.dk)