Professor James Bernard Walsh:

Conditions such as sarcoidosis may result in increased sensitivity to vitamin D. People who have such conditions would be under the care of a doctor anyway and this doctor would advise them. There is also an issue for people who have kidney stones but their problem is often with excess calcium intake. Such people would also have to be monitored. All of these people would, however, be aware of their conditions. I repeat that even the Food Safety Authority of Ireland and others have said that the crucial thing is to measure is the excess calcium or vitamin D in one's blood. We did not find this among the 36,500 cases. That is important. It must not be forgotten that what we are recommending is 800 units to 1,000 units. As people have repeatedly said, internationally up to 4,000 units a day is considered safe. We are not going near that. We are way down at a fraction of that. The Department of Health has recommended 600 units for deficiencies but we are saying that 800 units to 1,000 units would give people sufficient vitamin D, defined as a rate of 20 nmol/l or more. There is not a lot of difference but that statement must be put out quite positively. This has been done in Finland and elsewhere and is now being done in the UK. We must come out strongly to say that we need to optimise not only our bone health but also our immune system.