Professor James Bernard Walsh:

To respond to Deputy Cullinane's question, the Department of Health recently mentioned supplementation of 600 international units daily. We are saying between 800 international units and 1,000 international units daily so there is not much difference. The other reason is that our emphasis is slightly different. A level of 30 nmol per l is a blood level for deficiency and 50 nmol per l is what we normally take as a sufficient level. At 30 nmol per l, there is still a level of secondary hypoparathyroid and the body is struggling to raise the level. We have 7,000 people attending our bone health clinic annually. We aim to get everyone up to 50 nmol per l or even slightly higher because as people get older, we like them to be at a level of between 60 nmol per l and 70 nmol per l because there is a slight reduction in falls as well. The Department recommends 600 international units daily to bring a person up to a level of 30 nmol per l. What we are saying is take between 800 international units and 1,000 international units. Dr. McCartney spoke of how for 800 international units one might see 20 mcg and for 1,000 international units one will see 25 mcg. The are written in two ways but we should think of units because they are very straightforward and that is how clinicians think. Nutritionists often think in milligrams but both measurements are often printed on bottle labels. Between 800 international units and 1,000 international units daily is simple. As Professor Kenny says, there is good evidence showing that people go up to 4,000 international units per day. We do not come near that. Having said that, I take 2,000 international units a day and I do not apologise for that.

Fortified milk is one source. Taking a half litre of super milk provides 400 international units in a day. Cereals are also fortified. Other than fortified milk and cereals, there is very little food available that provides vitamin D. Wild salmon is a source because they feed on plankton but farmed salmon do not get that opportunity and have only one-quarter of the amount of vitamin D that wild salmon have. That was the other source of vitamin D mentioned. The limited number of food sources of vitamin D is the reason people are vitamin D deficient. It is a problem for young people working in factories and hospitals. Paradoxically, the study found a higher level of deficiency in the 36,500 younger people than in many of the older people. We can also consider the potential level of deficiency that has arisen in recent times, with people now indoors, whether for work reasons or in environments such as nursing homes. The study we published recently covered a five-year period. It showed total consistency every year, with levels increasing in summer, although there was still a level of insufficiency or deficiency of 30%, and deficiency of 70% in winter. It is a real epidemic. We have observed the highest incidence of deficiency and insufficiency in the black, Asian and minority ethnic, BAME, communities and seen how they have been so badly struck down with Covid. These are the kinds of issues that worry us and that is why we are here today. We are saying this is a simple solution. It is just giving a bit of sunshine in winter when we do not have any.

Incidentally, vitamin D supplementation is totally safe. Of the 36,500 people in our study, only 21 patients had a level over 250 nmol per l and all of them had normal calcium. No one had any side effects. As regards safety, it is very rare to get high levels unless people are taking, say, 5,000 international units or 7,000 international units daily. It is very rare to come across that. People do not do that; they are sensible.