Vitamin D: the three authorised claims, and the rest

Vitamin D is among the nutrients best served by authorised claims. Three of them appear in the EU register, reproduced here word for word.

Each describes a contribution to the NORMAL functioning of something. That legal nuance has consequences: “contributes to the normal function of the immune system” does not authorise “boosts your defences”, let alone “protects against infection”. Regulation 1924/2006 explicitly bans any claim to prevent a disease.

The 15 % NRV threshold puts the bar at 0.75 µg per portion, the NRV being 5 µg. That is remarkably low: almost any product containing vitamin D can carry the claims.

This regulatory threshold says nothing about physiological need, which is far higher. Belgian intake recommendations run to tens of micrograms for at-risk groups and fall under medical advice. The threshold authorises speech; it does not certify that the product’s dose covers a need.

That is why a percentage of NRV is more informative than a raw figure: it places the dose against a common reference.

Skin synthesis of vitamin D depends on UVB radiation, whose intensity varies with the sun’s angle. Beyond roughly 40° latitude — Belgium sits at 50° — that angle is too shallow in winter for meaningful synthesis. In practice, from October to March the skin produces almost nothing, however long the exposure.

That sets vitamin D apart from most micronutrients: intake depends not only on diet but on the calendar and the place. The same profile does not have the same need in January and in July.

It is also why our composition engine treats it as a seasonal active rather than a permanent base.

Vitamin D exists in two forms: ergocalciferol (D2), of fungal origin, and cholecalciferol (D3), of animal or lichen origin. Lichen-derived D3 allows a vegan formulation.

The EU register does not distinguish them: the claims apply to “vitamin D”. As with magnesium, a brand attributing a specific claim to D3 steps outside the framework.