Fructose is a monosaccharide, or simple sugar, which is an important source of energy for the body. Widely distributed in plants, it is also called “fruit sugar” as it is especially abundant in fruits.
Other sources of fructose include honey, some vegetables (beets, sweet potatoes) and sugarcane. Fructose is also obtained from the digestion of sucrose, a disaccharide consisting of glucose and fructose that is broken down by enzymes during digestion. Fructose is the sweetest naturally occurring sugar. It is much sweeter, estimated to be twice as sweet as sucrose (table sugar); hence less is needed to achieve the same taste.
High Fructose Corn Syrup
High fructose corn syrup (HFCS) is a liquid sweetener which is widely used these days in the manufacture of foods and beverages. HFCS is made up of almost half glucose and half fructose, the most common form being HFCS-55, which contains 55% fructose and 45% glucose. Though sucrose (50% fructose and 50% glucose) and HFCS have similar sweetness intensity and HFCS can be tolerated and absorbed as well, the problem arises with the excessive use of HFCS in various foods.
Most of us can handle small quantities of fructose which are naturally present in foods. However, our bodies are not very well equipped to handle very large quantities of sugars, including fructose. Over the last few decades, HFCS use in foods has been on the rise. From the manufacturing point of view, HFCS has more advantages than sucrose as it is slightly sweeter, is easier to handle, has longer shelf life and is much cheaper than sucrose. As a result, HFCS has found its way in a number of foods in the modern diet, resulting in an increased fructose intake.
Foods Containing HFCS
A wide variety of manufactured foods contain HFCS as a sweetener. It is present in soft drinks, fruit juice concentrates, sports drinks, packaged foods, candies, jams, yogurts, canned foods, cakes, biscuits and other sweetened foods. Since refined sweeteners lack bulk, it is easy to consume large quantities of it. Further, fructose being perceived as the natural sweetener, it can lead to an unusually high consumption as an alternative to other artificial sweeteners.
Fructose has been recommended for diabetics for years as it has a low glycemic index compared to cane sugar, does not require insulin and does not cause a rapid rise in blood sugar. However, the current thinking is that these benefits of fructose for diabetics may be overshadowed by the cardiovascular concerns and the adverse effects on plasma lipids with high fructose.
A small amount of fructose is desirable in that it stimulates glucose metabolism. But larger amounts cannot be processed by the liver fast enough and are in turn converted into fats and released into the blood as triglycerides. The increased level of triglycerides poses a health risk as a causative factor in heart disease. Other health concerns include combining (chelation) of micronutrients especially copper and zinc with fructose, which may lead to their deficiency.
It has also been speculated that high fructose levels can cause obesity as it does not produce a feeling of fullness. The hormones which control hunger and food intake are not stimulated and it can lead to greater food intake. However, this still needs to be confirmed and is based only on preliminary research.
Apart from these effects, fructose intake can cause abdominal pain, bloating, diarrhea and flatulence in people who have fructose intolerance – a condition where fructose cannot be metabolized in the body.
Though more research is needed to establish the detrimental effects of fructose on human health, it is safer to consume naturally sweet foods like fresh fruits, freshly squeezed fruit juices, honey etc. in place of the artificially sweetened foods. Refined sugars offer only “empty calories” and it would be healthier to reduce the total amount of sugar in the diet, along with reducing the consumption of processed foods containing fructose.