Your Health: Holiday Sweets Can Be Health Hazards
Rallie McAllister, M.D., M.P.H.
No matter how tempted you are by holiday cakes, cookies, and candies, you might want to do yourself a favor and step away from the dessert tray. Eating too much sugar does more than just pile on the pounds -- it can turn off the genes that regulate levels of active sex hormones in the body. That's the word according to researchers at the Child and Family Research Institute in Vancouver, Canada. The results of their study, published in the November 2007 issue of the Journal of Clinical Investigation, showed that when eaten in excess, sugars like fructose and glucose can wreak havoc with testosterone and estrogen levels.
Fructose and glucose aren't always easy to sidestep since they're exceedingly abundant in the American diet, both individually and in a combined state. When a molecule of glucose is chemically bound to a molecule of fructose, the resulting compound is table sugar, also known as sucrose. Glucose is a simple sugar found naturally in plant foods and is commercially manufactured from cornstarch. Fructose is the sweetest of the naturally occurring sugars: It's found in honey, a variety of fruits, and some root vegetables, including beets and sweet potatoes. Regardless of their food of origin, both sugars are metabolized in the liver after consumption. When there's an excess of these sugars in the diet, the liver converts them to fat. While the liver's busy transforming dietary sugar into body fat, it's less able to manufacture a protein known as sex hormone binding globulin, or SHBG, which plays a key role in controlling the amount of available sex hormones in the body.
Reduced production of SHBG means higher levels of active testosterone and estrogen, which isn't necessarily a good thing. Higher levels of testosterone and estrogen are associated with the development of acne, excessive hair growth, infertility and certain cancers of the reproductive tract. Reduced production of SHBG is also linked to the development of the metabolic syndrome, a cluster of dangerous conditions including high blood pressure, abdominal obesity, low levels of heart-healthy HDL cholesterol, and elevated blood sugar and triglycerides. While each condition is an independent risk factor for cardiovascular disease, having the combination of these conditions dramatically increases the likelihood of experiencing a heart attack or stroke.
Currently, nearly a quarter of Americans currently suffer from the metabolic syndrome, according to data published by the American Heart Association. It's becoming increasingly common in children in recent years, affecting an estimated one in 10 youngsters between the ages of 12 and 19. A growing body of scientific evidence suggests that of all the sugars, fructose is most closely linked to the development of metabolic syndrome. Over the past three decades, fructose consumption has increased dramatically in the United States, thanks to the commercial development of high fructose corn syrup. In 2005, the average American consumed more than 62 pounds of high fructose corn syrup, compared to 59 pounds of table sugar. Because high fructose corn syrup is typically both sweeter and cheaper than table sugar, more U.S. food and beverage manufacturers are relying on the ingredient to sweeten their products -- and their profits. High fructose corn syrup is a common ingredient in non-diet sodas and soft drinks, fruit juice mixes, baked goods, canned fruits, dairy products, jams and jellies. A number of studies suggest that in spite of its sweet taste and high calorie content, fructose doesn't make us feel full. In fact, fructose actually may suppress signals of satiety and fullness, causing us to eat more than we might otherwise.
Not surprisingly, increased consumption of high-fructose corn syrup in the United States closely mirrors the rapid increase in obesity. According to a report published in the American Journal of Clinical Nutrition, consumption of high fructose corn syrup in beverages is likely an important contributor to the obesity epidemic in the United States. Researchers at Saint Louis University recently used sedentary rats to evaluate the effects of a diet high in fat and high fructose corn syrup, similar to a diet consumed by many Americans during the holiday season. After just four weeks, the rats exhibited early signs of types 2 diabetes, including elevated liver enzymes and increasing blood sugar levels. If you've been eating a steady diet of sweet treats since Thanksgiving, it's time to step away from the dessert tray. Cutting back on your sugar consumption could save you more than just a few pounds -- it could save your life.