thermionic, last one first (because it is easy!) - the stomach is only very dilute acid and yes, a small amount of bicarb is lost through reaction, which is why many people burp immediately after taking, but most of the bicarb carries through to the gut. That's why some people recommend taking a couple of hours before meals to give the chance for the stomach to recover.
It doesn't have to be maple syrup. It has worked with molasses. It has worked with no sugars at all. Maple syrup is 60% sucrose. Molasses has a lot of sucrose. Why not use ordinary sugar (sucrose)? I don't know. Or pure glucose?
Sucrose is two other sugar molecules combined - fructose and glucose. The supposition is that the bicarb "attaches" itself (reacts with?) the glucose part of the sucrose, and after the body has broken down the sucrose into fructose and glucose+bicarb, the cancer cells, which looooove glucose, suck in the glucose+bicarb and the alkalinity kills the cancer cell ..... personally I doubt all that very much! Sucrose doesn't react with bicarbonate, if it did I suspect the cancer cell wouldn't recognise a glucose+bicarb molecule the same way as it recognises a glucose molecule, and anyway, as I said above, it works without any sugar at all (but there is plenty of glucose in your blood anyway). But it makes it taste nicer!
Maybe the bicarb attaches to the glucose in the blood stream - but I don't see how.
