I would take a slightly different tack here.
First point - 1 unit of alcohol in UK usage = 10ml ethanol. That’s 8 grams. owing to the density difference compared with water. That needs to be borne in mind as the alcohol content on the back of your bottle is “by volume”, i.e. v/v (volume in volume), whereas a lot of the scientific papers address weight of alcohol consumed.
Take a look at this graphic -
(Incidentally, this is the data on drinkers - non-drinkers have been removed from the data set). I think it is a reasonable interpretation to say that there appears to be no evidence of adverse effect until you reach somewhere between 100 and 150 g/week. After that there is an effect proportionate to intake over that limit.
Or in other words, you can draw a graph using two straight lines, and the point where they intersect is the highest weekly intake where the population shows no adverse effects on mortality, statistically. It does seem reasonable to draw the line where the intersection point occurs around 110g/week. Which is 140ml per week (14 units), which is the new guideline. So I do think it is justifiable from a government point of view.
HOWEVER - these are comments on entire populations - it is inadmissible to assume that individuals will follow the population data. It always is in statistics! But what you can do is to try to find a more specific subset that describes your circumstances more closely, in the hope that you can learn more about how alcohol may affect your risk of added mortality. And finally this is only about mortality. In a way that is a sort of aggregation of all the potentially life-threatening conditions that may come with alcohol. You could still suffer some chronic side-effects, but if they are not life-threatening they won’t show up here.
Right - that’s all I wanted to say on the 14 units a week business.