Recommended Daily Allowances

I visited my GP a couple of weeks before Christmas, mainly in order to get a chitty for a routine blood test, which took all of half a minute. So we discussed a number of issues but mainly why I didn’t want the swine flu jab? I put forward my view of risk versus reward (risk of side effects v the reward of not dying from the flu) and he made no attempt to persuade me otherwise. As usual he took my blood pressure and declared it to be the same as previously, but he now thought that it would be best to take a diuretic to get it down a bit and perhaps I should try to reduce my salt intake. Why? Well apparently, they’ve reduced the recommended maximum desirable BP for some one of my age (which will no doubt in turn put up the cost of my holiday insurance).
This morning at breakfast, I was idly reading the back of the cereal box, the pot of marmalade and my wife’s container of artificial butter substitute. All had recommended daily allowances of this, that and the other printed on them. Unfortunately, the weights were all in Napoleonic measurements and my brain only works in Christian measurements at that time of the morning so they were totally meaningless. I then looked at the wrapper of the remains of a bar of Cadbury’s Dairy Milk from which it would appear that last night I had eaten virtually the whole of my day’s fat allowance in one go!
This got me round to thinking “Who decides these allowances”. Who, and on what basis do “They” decide that my blood pressure or BMI is too high ? Who decides that I should only eat so much fat or salt each day. Has the evidence been published for these conclusions? Can anybody tell me the likely additional risk if I don’t reduce my salt intake?
We all know that a few months ago a member of the committee which decided the recommended weekly alcohol intake "let the cat out of the bag" by revealing that there was no particular evidence for the chosen limits that they had recommended, just that “they seemed about right”. Are all these other figures determined in the same way?
In the US, bottles of wine bear a statement that “The Surgeon General recommends that .....”. Surely we should know the origin of all these health recommendations – do they come from the soon-to-resign Chief Medical Officer, because if so, I would feel justified in taking them with an even larger pinch of salt substitute!
Time now to go and have my RDA of Scotch, as recommended by an English Pensioner, and endorsed by Mrs E.P. who will expect something similar at the same time!