Free Penny le Couteur & Jay Burreson by Napoleon's Buttons: How 17 Molecules Changed History Page B

can be lethal for humans or family pets.
    Interestingly, it is not ethylene glycol but what the body turns it into that is the toxic agent. Oxidation of ethylene glycol by enzymes in the body produces oxalic acid.

    Oxalic acid occurs naturally in a number of plants, including some that we eat, such as rhubarb and spinach. We usually consume these foods in moderate amounts, and our kidneys can cope with the traces of oxalic acid from such sources. But if ethylene glycol is swallowed, the sudden appearance of a large amount of oxalic acid can cause kidney damage and death. Eating spinach salad and rhubarb pie at the same meal will not hurt you. It would probably be difficult to consume enough spinach and rhubarb to do any harm, except perhaps if you are prone to kidney stones, which build up over some years. Kidney stones consist mainly of calcium oxalate, the insoluble calcium salt of oxalic acid; those prone to kidney stones are often advised to avoid foods high in oxalates. For the rest of us, moderation is the best advice.
    A compound that has a very similar structure to ethylene glycol and also tastes sweet is glycerol, but glycerol in moderate amounts is safe to consume. It is used as an additive in many prepared foods because of its viscosity and high water solubility. The term food additive has had a bad press in recent years, implying that food additives are essentially nonorganic, unhealthy, and unnatural. Glycerol is definitely organic, is nontoxic, and occurs naturally in products such as wine.

    Glycerol
    When you swirl a glass of wine, the “legs” that form on the glass are due to the presence of glycerol increasing the viscosity and smoothness characteristic of good vintages.

SWEET NOTHING
    There are numerous other nonsugars that taste sweet, and some of these compounds are the basis for the billion-dollar artificial sweetener industry. As well as having a chemical structure that in some way mimics the geometry of sugars, allowing it to fit and bind to the sweetness receptor, an artificial sweetener needs to be water soluble and nontoxic and, often, not metabolized in the human body. These substances are usually hundreds of times sweeter than sugar.
    The first of the modern artificial sweeteners to be developed was saccharin. Saccharin is a fine powder. Those who work with it sometimes detect a sweet taste if they accidentally touch their fingers to their mouth. It is so sweet that only a very small amount triggers the sweetness response. This is evidently what happened in 1879, when a chemistry student at Johns Hopkins University in Baltimore noticed an unusual sweetness in the bread he was eating. He returned to his laboratory bench to systematically taste the compounds that he had been using in that day’s experiments—a risky but common practice with new molecules in those days—and discovered that saccharin was intensely sweet.
    Saccharin has no calorific value, and it did not take long (1885) for this combination of sweetness and no calories to be commercially exploited. Originally intended as a replacement for sugar in the diet of diabetic patients, it quickly became an accepted sugar substitute for the general population. Concern about possible toxicity and the problem of a metallic aftertaste led to the development of other artificial sweeteners, such as cyclamate and aspartame. As you can see, the structures of these are all quite different and are very different from sugars, yet they all have the appropriate atoms, along with the specific atomic position, geometry, and flexibility that is necessary for sweetness.

    No artificial sweetener is completely free of problems. Some decompose on heating and so can be used only in soft drinks or cold foods; some are not particularly soluble; and others have a detectable side taste along with their sweetness. Aspartame, although synthetic, is composed of two naturally occurring amino acids. It is metabolized by the body, but as it is over