Food has long been seen as a delivery vehicle for public health - mostly for kids. We add vitamin D to milk to prevent rickets, iodine to salt, even flouride to water - all as a way to get certain substances into the diets of the maximum amount of people. It's always been an intriguing bit of paternalism - a government (usually) mandating an addition for the benefit of the people, whether they want it or not. Typically, the added ingredients are simple, almost benign vitamins and minerals. And the additions have little to do with the actual substance they're bolstering: Folic acid was first added to flour and cereal in 1998 not because iron makes sense as a baking ingredient, nor because most Americans want more iron, but rather as a way to raise the folic acid level in prenatal women, thus preventing neural tube defects (which afflict 2,500 newborns a year). Why cereal? No real reason â€“ the acid is found in leafy green vegetables in nature â€“ except that cereal is widely eaten, and therefore a good vector for the additive.
That's all backstory to a recommendation out of Oxford University today that we start adding deuterium and other isotopes to food as a way of lengthening our lifespans. These are stable isotopes - they're not radioactive - but the basic idea is that the isotope prevents cancer cells from replicating. This one seems like a longshot - it's only been tested on nematode worms so far - but it's a pretty remarkable idea, and a relatively predictable progression of the drug-delivery-through-the-food-supply idea. But boy, it's a long way from vitamin D.