Professor James Bernard Walsh:

If we are looking for a country that could be an example here, Finland would be a good one. Before Finland went into food fortification only a third of the population was vitamin D sufficient. By 2011 that figure was 90%. The good thing about it was that when they measured, the average level was 75.9 nmol/l. That is exactly the kind of level that would be optimal. Therefore, we have a country which became proactive with the fortification of food and did not run into any toxicity levels either. They are the kinds of things which are crucial. It can be done and done safely. Going back to what Dr. McCartney said, the sun is where a person will get 90% of his or her vitamin D. Twenty minutes of exposure to a person's hands is all that is really required to keep a person optimised. However, in this country we do not get any vitamin D from the sun from October to April. It does not happen. Even the little bit of sun that is out there is very low in the sky, and hence food fortification. Vitamin D is stored if a person gets a lot of it but there is a limit to how long that storage lasts. That is why we in Ireland have 70% insufficiency or deficiency levels in winter time, as mentioned earlier. That is why supplementation in tablet form of 800 to 1,000 units per day is important for people if they are not getting a very comprehensive food intake, which we know the majority of us are not.