I think I need you to define "no safe limit" before I'll be able to know how to respond, but I'll give my view as a starting point.
If something does not show any apparent negative impact on my all cause risk of mortality, nor my general health, I do not care how much it increases my risk of mortality from some specific illness. The boundary point for a safe limit, for me, would be the point at which it could be demonstrated that consuming a specific amount of alcohol increased my all cause risk of mortality or harmed my general health. So, let's say 2 beers a night increased my relative risk for death from cirrhosis of the liver by 100% but doesn't change my absolute risk of death from all causes, then 2 beers a night is within safe limits by my definition. If it could be demonstrated that cooking with a little red wine or adding vanilla extract to a recipe raised my absolute risk of all cause mortality, then I would agree that for all practical purposes, there was not a safe limit for alcohol consumption.
I hate to use Wikipedia as a source but I think it's accurate enough for the current purpose:
Observational Study vs
Randomized Controlled Trial
There is some debate about what can be concluded from observational studies. The Cochrane Reviews, for example, has claimed that there is little difference in the results of randomized controlled trials and modern observational studies but last I looked at this there was still a lot of argument around the topic. Until recently, observational studies were essentially always considered to have low empirical value and many researchers would make statements along the lines of, "If you're reading a paper and you see it's based on an observational study you can just stop reading." Again, there's still debate about how much credibility they represent.
As to the part in
bold, that may very well be a solid, practical approach for a medical practitioner, but it isn't scientific. Unless maybe you've done a well conducted study that tells you how much people lie about their drinking first, or a clinical study where you directly measure the impact of alcohol consumption on the liver, in order to establish a relationship between the two. My weight is my weight on the scale, but my liver function on a blood test is not my drinking history, unless we have some way to establish that it is.
Studies can only talk about groups and can't say much about individuals. Even if we had a fantastic, perfectly conducted study we couldn't say that you or I would respond like the median participant in the study. Not only size, but genetics and other lifestyle choices are likely to come into play. So, we can't actually say that a random, 6'9" dude is going to have less impact on his liver than you without directly comparing both of your current biological states. We can make some generalized predications, that will be more or less accurate depending on how close you both hew to the norm.
In response to the part in
bold - As I said above, I don't care if something is bad for my liver if it doesn't actually increase my real risk of death or poor health, which seems to be the case with moderate alcohol consumption. To re-phrase, I think it's reasonable to say that alcohol consumption damages the liver*. I don't think it's reasonable to say that any liver damage is unsafe if it doesn't actually have any measurable impact on my perceived health, quality of life, or actual longevity.
It also sometimes seems like you are arguing that if we know someone's level of liver function we know how much they drink. I don't know how you think we can know this if we are basing those metrics off of self reported data about drinking. It seems like a circular argument, unless I'm missing something.
*Does any alcohol consumption, no matter how small, damage the liver for the average person? If not, how much does it take to cause damage? The liver can heal over time, how much time needs to pass between drinking sessions for the liver to have completely recovered? If we don't know the answer to these questions we can't speak very knowledgeably about this piece of the puzzle.
Now that I read this point, I see that we're on the same page about much of what I said in the point above.
I also think I now see the crux of our disagreement. Your definition of "safe" seems to mean proven safe, or absent any indication of risk. I think that's an unreasonable standard and rapidly becomes absurd. We may not know the absolute limits for everyone, but the data we have certainly seem to indicate there's no reason to think that even daily drinking of 1 or 2 alcoholic beverages makes a significant difference in health span nor lifespan for the average individual in terms of the direct toxic effects of alcohol*.
Statements like, "there is no safe limit for alcohol consumption", become just so much noise and without meaning if that is our metric. By that standard there is no safe limit for exercise nor for being sedentary, nor for walking down the street as they all increase risk of some negative outcome. Why are we bothering with news articles and press releases over this? How is it relevant to anyone's life? I think we apply it to alcohol more freely and frequently than many other things that are similarly dangerous (or not dangerous) for moralistic, rather than scientific or practical reasons.
*The study you posted also takes alcohol related accidents and other injuries into account, so when including indirect effects such as these they conclude that it's a net detriment. Based on my other readings on this topic, these concerns are particularly relevant for men in their 20's and almost irrelevant for women in their 60's, but mostly means it's not a big factor for most, if not all, of those participating in this thread, unless I'm very wrong in my estimations about the demographic being represented.
Depends on the study and which experts. To claim we have anything close to a consensus at this point seems unreasonable.
As above,
some world class experts.
This study, published in 2018, based on the criteria they selected, leads this set of researchers to conclude that, "Alcohol use contributes to health loss from many causes and exacts its toll across the lifespan, particularly among men. Policies that focus on reducing population-level consumption will be most effective in reducing the health loss from alcohol use." Their definition of safe and their evaluation of risk may (or may not) be accurate for those stated goals when looking at a global population of drinkers, including Russia*. Other studies, using different metrics and data, have come to different conclusions. Those of us who don't live in Russia, are over 50, and don't seem to have a predisposition for liver problems may have a substantially different risk profile. Regardless, I still think we're a long way from a consensus.
*From the study:
"Failing to address harms from alcohol use, particularly at high levels of consumption, can have dire effects on population health. The mortality crisis in Russia is a striking example, where alcohol use was the primary culprit of increases in mortality starting in the 1980s and led to 75% of deaths among men aged 15ā55 years."