I have had the privilege of teaching high school science (biology, chemistry and physics) for the last thirty years. For the last ten years, I’ve had the additional privilege and responsibility of developing and teaching an elective we simply call “Food Science.” It’s not your usual health class dietary guidelines, nor does it rehash the familiar mantras of counting calories and exercising to balance intake. Instead, we study the cultural, historical, scientific, political and economic contexts of our food system and how that system impacts our environments, both external and internal. This in turn enables students to make much more informed decisions about what they want to put in their bodies.
When it comes to sugars, confusion is the name of the game. There are dozens of ingredients that mark the presence of sugars in our food: maltodextrin, dextrose, invert sugar, cane sugar, high fructose corn syrup and starch, to name a few. Regardless of what the food industry calls them, your body sees basically three end products of their digestion: glucose, fructose and galactose. Which ones you eat, and how much, will dictate both their value and their danger to you.
You may have heard of three additional sugars — lactose, sucrose and maltose. Lactose is a combination of one glucose and one galactose. Also known as “milk sugar,” lactose is the nemesis of lactose-intolerant individuals who lack sufficient quantities of the enzyme that can digest it. Instead, bacteria that reside in their intestines get to process it, making painful amounts of gas as a by-product. Galactose can be converted to glucose in your body, but most individuals do not consume enough dairy to make this a source of concern.
Maltose is another type of sugar. It is a pairing of two glucose units and is the namesake for maltodextrin, etc. Consuming foods with maltose adds glucose to your diet — worth keeping track of as part of your total glucose consumption.
However, the most likely source of sugars in your diet is either sucrose or high fructose corn syrup. Sucrose, known also as table sugar, can be derived from sugar cane (cane sugar) or sugar beets (sugar.) Like lactose and maltose, sucrose is a paired structure, made of one glucose subunit and one fructose subunit. That is what your body absorbs regardless of the source (even organic.)
Sparing you the science behind its production, high fructose corn syrup is approximately half glucose, and half fructose too. Regardless of the marketing efforts by the Sugar Association and the Corn Refiners Association to make you believe one is better for you than the other, they end up, metabolically, in a virtual tie. Debating which to consume is a distraction from the consequences of consuming too much of either, or both.
The consumption of sugar (the term is legally owned by the Sugar Association as the sole name for sucrose) used to be limited by the relative expense and difficulty in obtaining it from its tropical source. Now the record levels of corn production in America have made it relatively cheap to produce and distribute sugar’s nearly identical-tasting competitor, high fructose corn syrup. You can find it in soda for sure, but also in pickles, peanut butter, ketchup and pretty much anywhere sugar might be used for additional appeal to consumers.
This has paved the way for the combined consumption of these sweeteners to reach more than 150 pounds per year per person in America. This far surpasses the 60 pounds per year considered by some experts to be the maximum amount that can be metabolized without ill consequences including diabetes, cardiovascular disease, fatty liver, cataracts, personality and cognitive dysfunction, some cancers and (by the way) obesity.
Tying glucose and fructose consumption to the metabolic consequences noted above requires further discussion. And now, you are properly prepared for those lessons. As we say in Food Science class, “Chow!”
Chris Zenyuh is a science teacher at Harborfields High School and has been teaching for 30 years.