I don't want to sidetrack Elaine's thread too much but you mentioned magnesium deficiency blossom and I want to comment further.
All that extract (taken from the website you quoted, not the paper itself) shows is that in those populations at those particular times a sample of Americans ate a very unhealthy diet that did not contain sufficient magnesium - which doesn't surprise me! – Also yes I do think the results would be different for the UK because diet for many Americans has been ('still is) notoriously poor – hence a lot of them are fat and unhealthy due to eating junk/fast/fatty/sweet food. OK we are not brilliant in UK but I doubt we are as bad.
Even if we were (as bad - not eating the right foods to get sufficient magnesium in our diet) – it still does not show – nor does anything I read in the web link - that we cannot get sufficient magnesium from our diet (with the exception of a few groups eg those with specific conditions such as Crohn's disease). Just to re-iterate I am not talking about the use of magnesium for medicinal purposes which is not what the article and your comment was about.
I stand by the NHS recommendation and the advice from this website – that we need to eat a diet containing a wide range of fresh ingredients, and get out in the sunshine as much as we can - and we should be able to get sufficient nutrients, minerals and vitamins that we need. The occasional use of certain well chosen supplements may be advised eg iron and Vit D for certain groups of people and in certain circumstances.
Hurdity x