Quick version
Vitamin D levels of 75–125 nmol/L are considered sufficient for most individuals, but higher levels (100–150 nmol/L) may be appropriate for certain individuals, especially those in risk groups. Low levels are common in the Nordic countries, particularly during the winter months, and supplementation may be necessary to ensure optimal health.
Research shows that levels above 125 nmol/L do not provide significant additional benefits for most people, and levels over 250 nmol/L may be harmful. Therefore, it is important to measure and monitor vitamin D levels to find a balance that supports both bone health and other health benefits.
What is a Sufficient Vitamin D Level?
According to the Institute of Medicine (IOM) and the Endocrine Society, a level between 75 and 125 nmol/L is considered sufficient to maintain good bone health and prevent diseases like rickets in children and osteomalacia in adults. This range covers the needs of most people and is often used as a reference level in clinical practice.
Vitamin D Levels in the Nordic Countries
In the Nordic countries, low vitamin D levels are common, especially during the winter months when sunlight is insufficient to stimulate the skin's production of vitamin D. This is due to the high latitude, where UVB radiation intensity is too weak for much of the year.
A study from Karolinska Institutet (2017) found that nearly 40% of adults in Sweden had insufficient levels (