All organic solvents are a cancer risk for the same reason: they imitate water (an inorganic solvent) inside our cells, but they're not water. Therefore, every single chemical reaction inside the cell is a bit different. Whether inhibited or triggered, or slowed, or sped up. So more reactions are likely to go wrong; perhaps creating free radicals that can rip up any molecule they touch, including DNA.
We are immensely better than other mammals at coping with alcohol (which yeast uses to poison other organisms and so preserve its food sources such as fruit.) Our livers prioritize neutralizing and excreting alcohol; letting other chemicals pile up meanwhile. Hence, just about any medication becomes more toxic if you drink alcohol at the same time.
We like the brain effects, but in truth every chemical reaction in the body is affected.
Speculating, however: some of the cancer risk from modern alcohol sources, however, may come from very long storage. Wine put down for more than the three years nec to sediment out lousy-tasting tannins continues to form Frankenstein flavor molecules (flavinoids) that have unusual tastes because they're random, they don't occur in nature. While flavinoids promote health, the Frankenstein versions of them likely don't and may be a potent extra source of cancer risk, even though we highly value those rare, weird flavors. Evolution hasn't necessarily shaped us to cope with these novel molecules, since we wouldn't have encountered them.
Of course, wine retains many of the very significant health-enhancing virtues of grape juice so it may often not do net harm (esp if the wine hasn't been put down for too long) but you can also buy grape juice.
It's a very recent trait evolutionarily but seems to predate deliberate alcohol production for the most part. It's been thought that when the human population became very small during an ice age, the ability to eat old fruit under snow might have been very important. But you're right, populations used to deliberate fermentation for thousands of years, such as in China seem to be much better protected.
Whereas, middle and South America did have a tradition of alcohol in Pre-Columbian times. However, alcohol was often exclusively reserved for those who had attained extreme old age.
We are immensely better than other mammals at coping with alcohol (which yeast uses to poison other organisms and so preserve its food sources such as fruit.) Our livers prioritize neutralizing and excreting alcohol; letting other chemicals pile up meanwhile. Hence, just about any medication becomes more toxic if you drink alcohol at the same time.
We like the brain effects, but in truth every chemical reaction in the body is affected.
Speculating, however: some of the cancer risk from modern alcohol sources, however, may come from very long storage. Wine put down for more than the three years nec to sediment out lousy-tasting tannins continues to form Frankenstein flavor molecules (flavinoids) that have unusual tastes because they're random, they don't occur in nature. While flavinoids promote health, the Frankenstein versions of them likely don't and may be a potent extra source of cancer risk, even though we highly value those rare, weird flavors. Evolution hasn't necessarily shaped us to cope with these novel molecules, since we wouldn't have encountered them.
Of course, wine retains many of the very significant health-enhancing virtues of grape juice so it may often not do net harm (esp if the wine hasn't been put down for too long) but you can also buy grape juice.