Fructose is a simple monosaccharide or simple sugar present in several foods, such as fruits, honey, berries and even some vegetables, which is utilized by our body to generate energy. It is a white solid substance that easily dissolves in water. As intake of fructose does not result in extreme rise in blood sugar (having a low glycemic index), it was once believed that fructose could be replaced with sucrose (table sugar). On the contrary, sucrose is a disaccharide obtained from the concentration of fructose and glucose.
Often crystalline fructose and high fructose corn syrup are mistaken to be identical products. Actually, crystalline fructose is generally obtained from a corn syrup rich in fructose content. In effect, high fructose corn syrup is generally a combination of around equal amounts of fructose and glucose. Fructose is found in several foods in the form of monosaccharide, also known as free fructose, or as a disaccharide, known as sucrose. Free sucrose or monosaccharide is not absorbed by our body. Nevertheless, when fructose is ingested as sucrose, it is usually absorbed completely in the upper parts of the small intestine. When sucrose comes in touch with the small intestine membranes, an enzyme called sucrase acts as a medium in the chasm of sucrose to produce one glucose and fructose element. In fact, when fructose goes through the small intestine, it is almost unaffected. Subsequently, fructose passes through the portal vein and heads in the direction of the liver.
Is fructose harmful?
Many people often ask if fructose is detrimental for their health. It may be noted here that consuming a little amount of fructose, for instance the amount of the simple monosaccharide present in majority of the vegetables and fruits is not really harmful. Actually, it has been confirmed that taking a small amount of fructose may assist your body to treat glucose appropriately. On the other hand, taking large amounts of fructose at the same time may devastate your body’s capability to process glucose. According to rough estimates, these days approximately 10 per cent of all contemporary diet originates from fructose.
It may be mentioned here that the majority of the carbohydrates we consume comprise glucose chains. When glucose goes into the bloodstream, out body secretes insulin to assist the body to adjust the level of glucose in the bloodstream. Contrary to this, fructose is processed in the liver. Describing the issue in simple words, when excessive fructose goes into the liver, the liver is unable to treat it rapidly enough to enable the body to use it as sugar. As an alternative, the liver begins to manufacture fats from the fructose and direct them to the bloodstream in the form of triglycerides.
Why fructose is bad
There are no less than three major reasons why we consider fructose to be basically detrimental for our health. And these reasons are as follows:
- The liver converts the excess fructose into triglycerides and sends it to the blood stream. When the intensity of these triglycerides is high in the bloodstream, it poses a risk for developing heart ailments.
- Fructose has been found to get out of the usual signaling system that shows the carving for food. As a result, the hormones that control appetite fail to set off giving rise to a feeling of dissatisfaction. Perhaps this is one of the reasons why people consuming too much fructose end up gaining undesired weight.
- There is sufficient evidence that shows that consuming too much of fructose may actually help in insulin resistance and this may ultimately result in the person developing type II diabetes (diabetes mellitus).
Nevertheless, it needs to be noted that a number of these consequences may also be owing to the chemicals present in soda that interact with high fructose corn syrup.
Corn syrup fructose vis-à-vis fructose in other foods
There is a misconception among some people that the corn syrup fructose and fructose present in other foods are different. However, the fact remains that all types of fructose functions in the same manner in our body. Irrespective of the fact that whether fructose is obtained from cane sugar, corn syrup, beet sugar, onions, strawberries or tomatoes, they all work similarly in the body. The only difference in this case is the amount of fructose present in the different foods. For instance, while a can of normal (non-diet) soda provides 23 grams of fructose, an extremely large size of soda contains 62 grams of fructose. On the other hand, a cupful of sliced tomatoes provide only 2.5 grams of fructose.
Foods enclosing high fructose corn syrup and other sugars
These days, when you are consuming just about any packed food, be certain that it contains sugar in some form or the other and this sugar invariably comprises plenty of fructose. It may be noted that honey and high fructose corn syrup possess an equal ratio of fructose/ glucose. In fact, different fruit juice concentrates available in the market and also known as ‘healthy sweeteners’ normally contain sufficient amounts of fructose. In addition, during the processing of these fruit juice concentrates, they lose much of their dietary value. If you carefully check the list of ingredients on the labels of packaged foods, you will come across the sources of fructose contained in them.
Foods containing fructose
Fructose is primarily resourced from foods such as fruits, vegetables and honey. Fructose is present in these foods either in the form of unbound and simple monosaccharide or as sucrose, a disaccharide formed when fructose is attached to glucose. In fact, all three – fructose, glucose and sucrose, may be present simultaneously in the same food. However, amounts or levels of these three sugars will vary in different foods.
It has been usually observed that when fructose is present in foods as a simple monosaccharide, the proportion of fructose to glucose is around 1:1. In other words, foods containing fructose also enclose the same amount of glucose. When the value is more than 1, it denotes the presence of a higher percentage of fructose compared to glucose, while a value less than 1 signifies that the food contains lesser amount of fructose compared to glucose present in it. There are a number of fruits that enclose more amounts of fructose compared to glucose, while there are other fruits that contain more quantities of glucose in comparison to fructose. For instance, fruits like apples and pears enclose twice the amount of free fructose or the simple monosaccharide compared to glucose. On the other hand, the fructose content in apricots is less than half of the glucose they enclose.
It may be mentioned here that pediatricians take particular interest in apple and pear juices since they contain excessive intensity of free fructose that may result in diarrhea in small children. Enterocytes or the cell lining in the intestines of small children are not as capable of absorbing fructose in comparison to glucose or sucrose. When the fructose remains unabsorbed, it produces higher osmolarity (concentration of an osmotic solution) in the small intestine. As a result, it drags water into the gastrointestinal tract leading to osmotic diarrhea.
Both sugar cane as well as sugar beet contain high intensity of sucrose and are primarily used to prepare unadulterated sucrose. All solids and impurities are removed from the juice extracted from sugar cane or sugar beet and subsequently a concentration is prepared by getting rid of the surplus water present in it. Finally, you get sucrose that is approximately 99.9 per cent pure. The common table white granulated sugar, powdered sugar as well as brown sugar contain sucrose.