Sucrose naturally occurs in many fruits and veggies, but it’s also refined into granulated table sugar. It’s virtually impossible to eat enough plant foods that natural sucrose could pose a health problem, but it’s quite easy to consume too much refined sucrose via baked goods, candy and desserts. Sucrose rapidly increases blood sugar levels, which triggers a series of events that can be bad for you, especially if you’re diabetic.
Sucrose is a disaccharide sugar comprised of one molecule of glucose and one molecule of fructose. Fructose is the main sugar in most fruits and sweet vegetables, although sucrose is also widely found in plants, particularly in pineapples, apricots, dates, sugar beets and some other root vegetables. Plants use sucrose, as well as starch, to store energy. Sucrose is refined mainly from sugarcane, but also from sugar beets, date palms and maple tree sap. Sucrose is much sweeter than starch or lactose, which is why it’s traditionally been used for making soda pop, candy, cakes, iced cream and other desserts. In more recent times, high fructose corn syrup has replaced the use of refined sucrose in many sweet beverages and foods because it’s even sweeter.
Sucrose is rapidly broken down into glucose and absorbed into your bloodstream, which is good if you need a quick source of energy, but not good if you overdo it. A rapid rise in blood glucose levels triggers excess insulin release from your pancreas. The role of insulin is to shuttle glucose from your blood to cells where it can be burned to make energy. The main problems with releasing large amounts of insulin are that it overworks your pancreas and often takes too much glucose out of your blood, which leads to the infamous “sugar crash.” If not enough insulin is secreted, the high levels of glucose in the blood can be toxic and damaging to tissues.
Diabetics, including those who don’t produce enough insulin and those who don’t respond to it, need to be very cautious with sucrose and other easily metabolized sugars because they can’t shuttle the glucose into their cells. With time, and especially if untreated, the toxic effects of glucose on the arteries and nerves of their eyes, feet, hands and internal organs can lead to blindness, amputations and organ failure.
If you can’t immediately use all the energy supplied from the metabolism of sucrose, the excess glucose is either stored as glycogen in your liver or as body fat. So if you overload on sucrose-sweetened goodies, your waistline is likely to expand, which can put you at increased risk for Type 2 diabetes, high blood pressure and cardiovascular disease.
Overconsumption of sucrose also promotes tooth decay. Sucrose provides a feast for the bacteria in your mouth, which convert some of the sugar into acids that erode the protective enamel covering on your teeth. Tooth erosion combined with the proliferation of bacteria leads to cavities, tooth decay, gingivitis and bad breath.
- Encyclopedia of Human Nutrition; Benjamin Caballero et al.
- General and Systematic Pathology; Paul Bass et al.
- Textbook of Functional Medicine; David S. Jones
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.