When did "chemical" become a dirty word? Forty or so years ago, chemistry -- which had been recognized as a miracle-making boon to humanity - somehow became associated with warfare, sinister food additives, "toxins" and pollution. It's a situation that Dr. Joe Schwarcz aims to put into perspective. Yes, there's a downside to chemistry, he says, but this is dwarfed by its enormous benefits. Dr. Joe's new collection of commentaries will inspire an appreciation for the science of everyday life, and equip you to spot the muddled thinking, misunderstandings and deceptions in media stories and advertising claims. Does organic food really always equal better food? Are vaccines dangerous? Will the latest health fad make you ill? Do expensive wrinkle creams do the job? What are the best ways to avoid cancer? The answers to such questions often lie in an understanding of the chemistry involved. Ask Dr. Joe. Science, Sense and Nonsense celebrates chemistry's great achievements, lambastes its charlatans, and explores its essential connections to our wellbeing. And does so in authoritative, highly readable, good humoured style. DR. JOE SCHWARCZ is director of McGill University's Office of Science and Society, where he teaches courses on nutrition and the applications of chemistry to everyday life. Among his many honours are the Royal Society of Canada's McNeil Award, and the American Chemistry Society's renowned Grady-Stack Award, of which he is the only non-American recipient. Schwarcz is the host of a weekly radio show on CFRB in Toronto and CJAD in Montreal, and writes a weekly column for the Montreal Gazette. ANTIOXIDANTS ARE MAGICAL. At least when it comes to marketing. Just slap the word on the label of a food or beverage and watch sales zoom. That’s because even people who have no idea what antioxidants are want more of these substances in their life than less. And they could be right. Or not. It seems the “free radical theory” of disease and aging may not be on as firm a ground as we have been led to believe. And if that is the case, antioxidants may not live up to their exalted status as the key to good health and longevity.   Back in the 1950s, Dr. Denham Harman proposed a theory that at the time seemed rather radical. Many ailments, including cancer and heart disease, as well as the aging process itself, he suggested, were the result of cumulative damage caused by reactive molecular species called free radicals. Since these were byproducts of metabolic reactions involved in energy production, their formation in the body was inevitable. Why? Because nutrients derived from food are slowly combusted in mitochondria— the small, membrane-enclosed regions of cells. And, as in any combustion process, oxygen is required. Unfortunately, as oxygen reacts with nutrients to produce energy, it also unleashes some “friendly fire” in the form of the notorious free radicals.   Different types of free radicals can appear, but they all descend from a highly reactive species of oxygen known as superoxide. Radicals are hungry for electrons and try to satisfy their appetites by feeding on innocent molecular bystanders. Since electrons are the glue that binds atoms in a molecule together, molecules that become the targets of free radical attack tend to fragment. Such damage in turn translates to disease, particularly when the victims of free radical onslaught are proteins, fats or molecules of DNA. Harman hypothesized that our bodies deal with free radicals by mounting “antioxidant defences.” Vitamins E and C, along with enzymes such as superoxide dismutase, catalase and glutathione peroxidase, were quickly labelled as antioxidants, acknowledging their ability to neutralize free radicals in the test tube. Harman then buttressed his theory by feeding antioxidants to mice, claiming that the animals lived longer. The free radical theory was off and running.   Over the next couple of decades, researchers tested more and more substances in the laboratory for free radical–neutralizing effects, discovering a plethora of antioxidants. The likes of polyphenols, carotenoids and lipoic acid, all found in fruits and vegetables, obliterated free radicals in laboratory experiments. Since populations consuming more fruits and vegetables were known to be healthier, a seemingly obvious explanation now emerged: antioxidants in food prevent disease! A corollary was that dietary antioxidant supplements should also prevent illness, an idea that gave rise to a new market trend. Touting their antioxidant potential, vitamins, minerals, various seed and bark extracts, teas and exotic fruit juices began to vie for the public’s attention. And they did so successfully. Sales of antioxidant supplements skyrocketed. Even skin creams joined in the game, hyping the efficacy of their antioxidant ingredients in the battle against the ravages of age.   But now the wheels on the antioxidant bandwagon are developing some squeaks. Since the 1990s, numerous r