This is a simple conclusion of my previous post on the fructose content of fruits: neither Coke (the regular variety) nor apple juice is really a healthy drink, but arguably Coke is healthier than apple juice in the grand scheme of things…
Now before I get flamed in the comments, I do understand that the aspect I will discuss is only one aspect in the comparison, and there might be others. For example, and in no particular order,
- Coke contains caffeine,
- apple juice might contain other valuable nutrients,
- apple juice can be prolonged with water
I will ignore all of those arguments in this post, simply as my conclusion is that neither Coke nor (pure) apple juice are suitable for drinking in large quantities (ie they are treats, like ice cream, or dessert). Also, it should be clear already that “Coke” is used as a placeholder, and mutatis mutandis (cool word, hein?) the same reasoning applies to all kind of soft drinks. Now you might not find that surprising, but until I did run the numbers below I still thought that something like apple juice is borderline acceptable for my daughter, whilst Coke really is not.
Now as to the numbers. For simplicity, I will compare 1 can of Coke with the same amount of apple juice (330ml), and I will also provide the numbers per liter for reference. Looking at the data, Coke contains about 11g sugar per 100ml (sources for US here and UK here). The sugar content in apple juice is actually pretty much the same (see eg here), as is the one of most major sodas and fruit juices (one exception being grape juice, which is about 18g/100ml).
For simplicity I will ignore the difference between US sodas that are sweetened with HFCS (55% fructose, 45% glucose) and European sodas (of the same brands) that tend to be sweetened with sucrose (effectively 50% glucose, 50% fructose) and will in the following assume the latter. So for Coke (and many other sodas) the sugar content is 36g/can or 110g/l, giving a fructose content of about 18g/can and 55g/l.
For apple juice it is probably safe to assume that the ratio between fructose and glucose is the same as in the fruit, ie 70%. So 1 can (or 330ml) / 1l of apple juice will provide the same amount of overall sugars, ie 36g/can and 110g/l. However, the effective fructose content of this will be at 25g/can and 77g/l respectively. This should be compared to the maximal intake of 50g fructose / day suggested in the other post. It should also be noted that the 50g number is for adults, and whilst naive scaling might or might not work, it is probably a good first guess to assume that (a) a liver half the size can only deal safely with half the fructose, and (b) that the size of the liver of a child is roughly determined by its lean body weight. So if we assume that the 50g suggestion holds for the 60kg average (lean) adult, then it should be half that for a lean child of 30kg.
I dont want to get too hung up on the detailed numbers here, as it is very clear that whatever the exact result is, any meaningful amount of either Coke or apple juice will quickly use up (or significantly exceed) every reasonable daily fructose threshold, especially for kids, and especially when consumed very quickly, in a highly bio-available format. My clear conclusion: either of them should be avoided, except in very rare occasions as a treat (and then in lieu of, and not together with ice cream). However, from a fructose point of view (and I now believe that one is key), Coke is actually more healthy (less unhealthy actually) than apple juice.
One might argue of course that sodas with non-sugar sweeteners are the way to go, but this is the subject of a future post…