Letter #1: Icelandic milk is a vitamin D supplement!

To counteract the risks of vitamin D deficiency during the dark months of the year, 
Iceland has come up with a very special solution: instead of requiring every citizen to pay
 for vitamin D supplements out of pocket, the vitamin is added to a food that most people 
there consume anyway: milk.

My very first direct interaction with an Icelandic person was in the Bónus supermarket (the yellow one with the cute pink piggy) in Keflavik, when I was standing in front of a huge store fridge filled with cartons that looked like milk, but with so many different names on it that I was quite uncertain about what to grab.
While trying to figure out the difference between Fjörmjólk, Undanrenna and Léttmjólk, I saw this woman watching me and I decided not to hesitate or wonder any longer and asked this woman straight up which of all these options was regular whole milk.
Startled, she asked me again whether I really wanted to know what regular milk was, and gestured that all of these cartons were milk. But the particular milk I was looking for was Nýmjólk, cow's milk in a promising blue and white carton. While I was thanking her for her help, she kept watching me with a slightly amused expression, probably pitying a tourist who had become so desperate to find some milk.

In Iceland, milk is not just a dairy product, as it is in Germany, where it is nowadays often replaced by plant-based alternatives. It is something as essential as a supplement, although you would not immediately identify it as one: a very common source of vitamin D.
Milk fortified with vitamin D is something I had never heard of, so I was really surprised when I found out. Primarily produced by MS Iceland Dairies (Mjólkursamsalan), milk in Iceland differs from what I'm used to mainly in the size of the farms, the local production and the organic aspects that come with it. Icelandic milk also has a higher proportion of A2 beta-casein protein than European milk.
Brief exposure of pasteurized milk to ultraviolet light causes the provitamin D3 contained in the milk to be converted into natural vitamin D3 (cholecalciferol).

Fortified with vitamin D, milk is no longer just something that makes baked goods or coffee tastier. It is a very important product with so many health benefits that even the University of Iceland awarded a research group with a grant from the University of Iceland Research Fund for 2025–2027 to study the chemical composition of Icelandic milk and to better understand those benefits. (read more here)