Nutrition tip: A look at fructose
Nutrition tip: A look at fructose
For a long time, fructose was considered to be the ideal alternative to ordinary household sugar and, in particular, the ideal sugar substitute for diabetics. Recent studies, however, provide new findings and insist on a certain level of awareness when it comes to the use of fruit sugar. (Foto: fotolia©PhotoSG)

What has been true thus far?

Fructose (fruit sugar) is a simple sugar, which is naturally present in fruits and honey, but it is also a component of various other types of sugar, including sucrose (household sugar). In its pure form, fruit sugar is, however, also available as a sweetener and is often used to sweeten beverages and other foodstuffs. Of all the sugars, fructose has the strongest sweetening power and, with a calorie content of 406 kcal/100 g, it is as rich in energy as sucrose, glucose, lactose or maltose. Since fructose results in a lower insulin secretion than glucose, it has long been regarded as the sugar for diabetics. Many dietary foods were sweetened using only fruit sugar. However, the current scientific status discourages the use of fructose as a substitute for sugar.

Glucose and fructose

As a source of energy, all body cells prefer glucose. With the help of the hormone insulin, it reaches the cells faster than fructose, which can only be used in a roundabout way to produce energy and which flows very slowly from the small intestine into the blood.

The quantity makes a difference

In a healthy body, the digestion of normal quantities of fructose in fruits and vegetables is no problem. To cause negative effects, one would have to regularly consume a whole kilogram of apples. The problem is therefore not the typical consumption of fruit but rather the large quantities of fructose contained in soft drinks and other finished products. It is only through the consumption of these groups of products that fructose is ingested in quantities that can cause health problems and that were unimaginable up to a few decades ago. But two simple reasons make the use of fructose so popular: it is twice as sweet as glucose and is cheaper to produce.


Low saturation
Because the appetite centre in the brain does not respond to fructose, it results in lower satiety. Fructose is thought to affect the release of certain hormones responsible for regulating hunger and satiety and could lead to a lower release of leptin as well as a possibly higher secretion of ghrelin. This results in a lower sense of fullness and increased caloric intake. The desire to eat increases, as does the risk of weight gain or obesity.

Fatty liver
In healthy people, fructose appears to stimulate the formation of fat (lipogenesis) and the storage of fats from food more strongly than glucose. This could also lead to the development of a non-alcoholic fatty liver. In a study, it was shown that individuals with non-alcoholic fatty liver had a two to three-fold higher consumption of fructose than the control group.

Uric acid
During the breakdown of large amounts of fructose, uric acid is produced, which indirectly increases blood pressure and can cause mild inflammation of the vascular system – a risk factor for heart attacks and strokes. In addition, Swiss researchers have proved the hypothesis that fructose stimulates the growth of the heart muscle beyond healthy levels in people who are already suffering from hypertension.

One study found that, even with a daily intake of 80 g of fructose over a three week period, healthy, normal weight subjects were less sensitive to insulin. As a result, the cells absorbed less glucose, leading to an increase in blood sugar levels. Over the long term, this development can lead to diabetes.
For example, the following three products together deliver 100 g of fructose: a large bottle of orange juice, bread with honey and a ready-made pizza.

Intestinal lining
There is also clear evidence that fructose – unlike glucose – can damage the intestinal lining, which in turn causes bacteria to enter the body and cause inflammation there.


A daily serving of fruit has no negative consequences, but rather contributes to a balanced diet because of its fibre content, phytochemicals, vitamins and minerals. There are considerable quantities of fructose in beverages and ready-made products, which can cause health problems in the body. Of course, such diseases are not one-dimensional and do not only arise because of fructose. However, excessive consumption can cause the side effects mentioned.

If you would like to find out more about fructose, we recommend the following website:

The Kornspitz team is always happy to hear from you. If you have any questions, requests, suggestions or tips, please send an email to

Mag. Gerda Reimann-Dorninger
Nutrition Scientist

Facebook comments

Close Recommend

Required fields