The original answer, figured out in the hoary pre-historic caveman times, was because it preserves the food for a long time without any real refrigeration. It was how people kept alive from harvest to harvest, because in many places (certainly where my ancestors are from), there ain't much growing out of the ground in January. But we have refrigeration now, so that doesn't matter much to people any more. For most people, eating asparagus in November or green beans in March doesn't strike anyone as unusual (but more on that later).
Of more concern to us are the health benefits of fermented goodies. Though they had no idea of WHY these foods made them healthier, they knew something made them easier to digest and increased their strength. And here's why:
Fermented foods have been found to do the following:
- Since they're all raw, the foods have all their vitamins, antioxidants and enzymes
- The process actually MAKES vitamins and antioxidants (my understanding is that they are both by-products of the eating of the sugars and starches by the bacteria, as well as the actual dead bodies of the bacteria themselves)
- Some of the antioxidants, especially isothiocyanates, have been shown to have some anti-cancer effects (though I am by no means suggesting that fermented foods cure cancer or anything like that)
- The process makes the vitamins and minerals that are in the product easier for your body to absorb (called "bioavailablity")
- The foods are chock-full of probiotic Lactobacilli, which help your digestive and immune health (assuming you don't cook them)
- They make the foods easier to digest (because basically, the lactobacilli "pre-digest" the starches/fibers and sugars in the foods)
- The lactic acid that is made in the fermentation acts as a pH balancer in your digestive sysem
- The lactic acid also drops the pH down low enough to kill off pathogenic bacteria
- If made properly, they taste really, really good.
Check out these links to find out more. There's a lot of info out there on this:
The Life Bridge by Paul Schulick, et al: A great book by New Chapter, Amazon link below:
There's a lot of other stuff also. One of these blogs, I'll go into the health benefits of probiotics. They are many and well-documented, but there's a lot of chatter of the viability of the probiotic bacteria in the gut, which means that the studies that are out there usually only concern very specific strains that are given in pills and such. Personally (from my own empirical experience), I feel that already-acidic foods are just as effective and have greater benefits as outlined above, but that's just me. Before I go too far out on a limb, I need to do more research myself on the viability matter.And even if it's not all true, all the time, isn't it better than dead, cooked foods filled with preservatives and sugars?