Letzte Aktualisierung am 18. December 2023 von Dr. Michael Zechmann-Khreis

Those who suffer from intestinal fructose intolerance are often faced with the dilemma: How do I sweeten my food? What other sweet sins are possible? In the following, we would like to explain a few terms and shed some light on this darkness. We want to look at sugar, sugar substitutes and artificial sweeteners in terms of their relevance for fructose intolerance. The list does not claim to be exhaustive! At the end you will find a list of tolerated sweeteners for fructose intolerance as well as FAQs on which sugars are tolerated by people with fructose malabsorption.

Sugar – what is it anyway?

A distinction is made between monosaccharides, disaccharides and polysaccharides. Only simple sugars can be absorbed in the intestine. A disaccharide consists of two monosaccharides bound together, a polysaccharide consists of more than two such monosaccharides. These sugars are broken down into their individual sugars by enzymes during the digestive process. This is because only these individual sugars can pass through the intestinal wall. Some of the long-chain sugars cannot be broken down at all and are then either metabolized by bacteria in the large intestine or excreted unchanged.

Fructose (fruit sugar)

Fruit sugar or fructose is a simple sugar that is mainly found in honey or fruit. It is the main problem in intestinal fructose intolerance .

In nature, fructose is mainly found in the fruits of plants. It is mainly absorbed in the intestine via the GLUT-5 transporter and broken down in the liver.

Glucose (dextrose)

Glucose, also known as dextrose, is another simple sugar. It is very well tolerated by people with fructose intolerance and even helps to absorb the fructose. However, you should not consume too much, as firstly it can have a fattening effect from 100g per hour and secondly it promotes insulin resistance in the long term.

Glucose syrup / glucose-fructose syrup (isoglucose)

Glucose syrup/fructose syrup is best known for the“High Fructose Corn Syrup (HFCS)” commonly used in the USA. At 55% fructose, this high-fructose syrup is used as a sugar substitute in almost all foods in the USA. As a result, glucose syrup also gained a reputation in Europe for containing fructose. However, this is not always the case, as glucose syrup can contain fructose, but it can also be completely fructose-free. You can estimate this from the name:

less than 5% fructose in dry matter: “glucose syrup” – tolerated by fructose intolerance.

more than 5% fructose in dry matter:
1) “Glucose-fructose syrup” or “dried glucose-fructose syrup” if more glucose than fructose is present; can cause fructose intolerance as it contains a maximum of the same amount of fructose as normal Household sugar.
2) “Fructose-glucose syrup”, or “dried fructose syrup”. Fructose-glucose syrup if more fructose than glucose is present; for Fructose intolerance not tolerated.

Galactose (mucilage sugar)

Galactose is called mucilage sugar in German. It is often a component of polysaccharides, but also occurs naturally as a single sugar. Galactose is tolerated by people with fructose intolerance, but in reality is not used as a sweetener or additive. Together with glucose, galactose forms the components of lactose (milk sugar).

Sucrose (household sugar)

When we say sugar, we probably always mean household sugar, although sugar is only an umbrella term for all sweet-tasting saccharides is. The “normal” sugar (household sugar / sucrose / sucrose) is made from beet or sugar cane (in which case it is called cane sugar). “Sugar” is a disaccharide and consists of 50 % from fruit sugar (fructose) and 50 % from grape sugar (glucose).

Other names: Raw sugar, cane sugar, whole cane sugar, whole sugar, brown sugar, sucrose, sucrose, candy sugar, coconut blossom sugar …

Maltose (malt sugar)

Malt sugar consists of two molecules of glucose, which is why it is unproblematic for fructose intolerance and in the elimination diet.

Lactose (milk sugar)

Lactose is also a disaccharide. It consists of one molecule of galactose and one molecule of glucose. It is safe for fructose intolerance, but should be avoided for lactose intolerance .

Lactulose

Lactulose is also a disaccharide and should not be confused with lactose . Lactulose consists of galactose and fructose, but cannot be broken down in the intestine. It is metabolized by bacteria in the large intestine. It is therefore basically harmless for both lactose intolerance and fructose intolerance – apart from the possible bloating effect.

Oligosaccharides

So-called polysaccharides are chains of sugar molecules. In most cases, fewer than 10 sugars are linked, but there can also be hundreds.
Examples are raffinose, stachyose or verbascose. Incidentally, these are the flatulent carbohydrates in pulses. They are only partially tolerated by people with fructose intolerance because, on the one hand, fructose is often involved – i.e. the sugars are broken down into their individual sugars by enzymes (amylases), which means that we then have fructose in the small intestine – and, on the other hand, many of these sugars are not broken down by us and thus reach the bacteria in the large intestine, which metabolize them and thus lead to flatulence (“every little bean, a little sound”). Therefore, legumes and leek vegetables should be avoided during the elimination phase and must be tested individually in the permanent diet. However, they should definitely be included in the diet again.

Polysaccharides

These are chains of more than 10 sugar molecules. If they consist of fructose molecules, they are called oligofructose, fructans or fructooligosaccharides. One example of this is inulin, which consists of around 100 fructose molecules. They are not broken down by us, but they are broken down by the bacteria in the large intestine. Therefore, they have a flatulent effect and are not tolerated in large quantities, but are tolerated in small quantities after the elimination phase. Above all, because they cannot be broken down by the body and can therefore be described as dietary fiber – an important point, because many people are afraid when they read oligofructose or inulin in the list of ingredients. This concern is unfounded because our body cannot break down long fructose chains. Nevertheless, it is best to try it after the elimination diet. Since bacteria can break down such chains, tolerance also depends on the intestinal flora.
Starch is an important polysaccharide. Starch consists of long glucose chains that are broken down into their individual sugars and digested. It is safe for people with fructose and lactose intolerance.

Sweetener

Sugar substitutes and artificial sweeteners are grouped together under the term “sweeteners” under food law.

Sugar substitutes

Sugar substitutes are sweet-tasting carbohydrates that are absorbed by the body more slowly or not at all than sugar. These are mostly sugar alcohols (polyols). Some sugar alcohols taste sweet; the industry can use them to reduce the real sugar content of the product on offer and sell it as a diet product in our modern age. However, the impression must not be given that these substances do not also occur in nature! Many fruits contain sorbitol or xylitol, for example. Sugar alcohols are therefore also found in nature. The suffix -ol always indicates the chemical class of an alcohol. Sugar substitutes should be avoided during the elimination diet; after the elimination diet, certain sugar substitutes that are tolerated by many patients (e.g. xylitol or erythritol) can be reintroduced into the diet.

Why are sugar substitutes used in the food industry?

Sugar alcohols are used to sweeten foods and to retain moisture in food. As these substances in the body do not raise the blood sugar level, they are often used in light drinks. and diabetic products. Enjoyed in large quantities, they they also cause diarrhea in “normal” people, which is why products, the warning “May be harmful to health if ingested. excessive consumption has a laxative effect”.

Why avoid sugar alcohols with fructose intolerance?

We don’t know that exactly. It is assumed that they have a negative effect on the transport mechanisms and “block” the transporters , so to speak, which transports the fructose through the intestinal wall. As people with fructose malabsorption this transport mechanism is disturbed or only is working poorly, any further interference should be avoided. Takes So a person with fructose malabsorption only eats sorbitol, but at the same time (up to 48h!) no fructose, so there is theoretically no Problems. These only arise with the simultaneous intake of Fructose. However, as this cannot be avoided in practice, the These substances should be avoided as far as possible. But here too Everyone has to find out for themselves how much they can tolerate and how much not.

Sweeteners

Sweeteners are chemical substances that imitate the sweet taste and have little to no calories. These are, for example, saccharin, aspartame, cyclamate, sucralose, stevia or acesulfame K. These substances are well tolerated by people with fructose intolerance, do not have a flatulent effect and are not metabolized by bacteria. However, most experts generally advise against excessive consumption. Apart from stevia, it seems sensible to avoid these sweeteners during the elimination diet. After that, everyone has to decide for themselves whether they want to eat them or not. As mentioned, stevia is also a sweetener, or rather steviol glycosides.

12 sweeteners are approved in the EU:

• Acesulfame K (E 950)
• Aspartame (E 951)
• Aspartame-acesulfame salt (E 962)
• Cyclamate (E 952)
• Saccharin (E 954)
• Sucralose (E955)
• Thaumatin (E957)
• Neohesperidin DC (E 959)
• Neotame (E961) Advantame (E 969)
• Steviol glycosides from stevia (E960a) and enzymatically produced steviol glycosides (E960c)

Stevia

Stevia is a highly sweetening, herbaceous plant that has been used for centuries as a sweetener, especially in South American regions. Stevia has been approved in the EU since December 2, 2011, more precisely: Steviol glycosides (“Stevia”, E 960) have been approved as food additives for certain products in the EU since December 2, 2011. Stevia is very well tolerated by people with fructose intolerance, even during the elimination diet. Stevia should never be used pure, as no proper dosage can be made due to the extremely high sweetening power and the extremely small amount required. Stevia should therefore always be used in combination products.

Sweetening for fructose intolerance

Well tolerated (even during the elimination diet):

• Spelt syrup – made from glucose and maltose
• Erythritol (erythritol, E 968) – moderate, rather at the end of the grace period
• Cereal sugar – mainly from glucose, good baking properties as bound water is reduced
• Glucose (dextrose, grape sugar) – often makes doughs sticky (due to approx. 10% bound water)
• Glucose syrup – depending on composition (see above)
• Lactose – not for lactose intolerance
• Maltodextrin (dextrin)
• Maltose
• Rice syrup – made from glucose and maltose
• Rice sweetener – dried rice syrup
• Steviol glycosides (“Stevia”, E 960)
• artificial sweeteners such as saccharin, aspartame, cyclamate, sucralose or acesulfame K – due to their fundamental problematic nature, it is still better to use them only after you have stopped using them

Individually compatible after elimination diet

• Coconut blossom sugar – consists of 97% glucose & fructose, so is equivalent to normal sucrose
• Lactitol (Lactitol, E 966)
• Lactulose
• Oligo- and polysaccharides such as inulin or oligofructose, fructans, Oligosaccharides – even though it contains the word “fructose”! These Sugar chains are not broken down into fructose in the intestine. Exact explanation see above.
• Sucrose (household sugar, raw (r)sugar, sucrose) – should be part of your permanent diet, do not avoid it strictly!
• Glucose-fructose syrup (see above)
• Xylitol (xylitol, E 967, “birch sugar”) – habituation effect possible

Xylitol is extremely toxic for pets (dogs, ferrets, rabbits, …) and can lead to death even in small quantities!

Not compatible

• Agave syrup
• Maple syrup – Maple syrup can also contain tolerable sugars, the composition of this natural product is not regulated – therefore better avoid.
• Fructose, fructose syrup
• Honey – no matter from which blossoms!
• Invert sugar (syrup)
• Isomalt (E 953)
• Corn syrup, fructose-glucose syrup / glucose-fructose syrup
• Maltitol (maltitol, E 965, maltitol syrup)
• Mannitol (mannitol, E 421)
• Sorbitol (sorbitol, E 420)

Sorbate is not the same as sorbitol! Sorbate is a salt and is often used as a preservative. It is usually used as potassium sorbate or calcium sorbate (E202 and E203). Sorbate is described in the literature as safe for Incompatibilities classified.

Rumor mill and FAQ

You can simply replace sugar with glucose.

No. You shouldn’t, it’s unhealthy for many reasons. To the On the one hand, glucose increases the release of insulin, on the other hand a lot of glucose can lead to a bacterial imbalance, or this support. This applies to caries as well as small intestinal colonization. So always use dextrose sparingly.

Sugar must always be avoided with FI.

No, this only applies to the elimination diet. It should then be returned to introduce the diet. Otherwise the situation usually deteriorates dramatic.

Cereal sugar is better than glucose

No. Grain sugar is glucose without bound water. I.e. Cereal sugar is physiologically the same as glucose. He is only better suited for baking because of the lack of water.

Rice syrup is better than glucose

Partly yes. It also contains a lot of glucose (and maltose) and should therefore also be used with moderation and purpose.

Coconut blossom sugar is okay for fructose intolerance

No. This is not true or only partially true!
Coconut blossom sugar (palm sugar, palm honey, coconut sugar) consists of 97% glucose and fructose, which is the same as normal sucrose (sugar) and is also nutritionally and with regard to fructose intolerance.

Rumor: Sorbitol, xylitol … in toothpaste and mouthwash should be avoided!

No. That’s not true! The problems these substances as soon as they reach the intestine. And if you you don’t intend to eat your toothpaste, you don’t need to worry about it. to make! On the contrary, due to the caries-inhibiting effect of xylitol such pastes are even highly recommended! The only problem is, when it comes to people who use large quantities of toothpaste swallowed (e.g. children).

Sorbitol becomes fructose

No, or well… The enzyme sorbitol dehydrogenase converts sorbitol in the body sorbitol, which was made from glucose, into fructose. This is a very important process in the body that has nothing to do with fructose malabsorption. has to do! It is often said that sorbitol should be avoided because it is (or in the body) is converted to fructose. That’s not true! Sorbitol is produced in the body (e.g. the liver) as an intermediate stage to produce glucose into fructose. So yes: sorbitol turns into fructose in the body; But no: not in the intestine, but in the body.

Although this statement is true, it has nothing to do with fructose intolerance.

Sorbitol must be strictly avoided

No, you don’t have to give up sorbitol completely, but you should always consider what you have eaten during the day (the more fructose, the worse) and how much you personally can tolerate. Sweets and Chewing gums with sorbitol usually have too much sorbitol, but small amounts in Some types of fruit or vegetables are often harmless and can be consumed after tolerated well during the waiting period. Sorbitol can therefore after the grace period and should not be completely excluded from the diet. be deleted.

Sources including:

Römpp, H; Falbe, J; Regitz, M; “Römpp Lexikon Chemie”, 9th edition, Thieme Verlag, 1992.
Opinion of the Scientific Committee on Food on Erythritol; EUROPEAN COMMISSION HEALTH & CONSUMER PROTECTION DIRECTORATE-GENERAL;SCF/CS/ADD/EDUL/215 Final; March 24, 2003;
Dunayer, E. K. (2004). Hypoglycemia following canine ingestion of xylitol-containing gum. Veterinary and Human Toxicology, 46(2), 87-8. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/15080212
Roberts, A., Renwick, A. G., Sims, J., & Snodin, D. J. (2000). Sucralose metabolism and pharmacokinetics in man. Food and Chemical Toxicology, 38(SUPPL. 2), 31-41. doi:10.1016/S0278-6915(00)00026-0
Rumessen, J. J., & Gudmand-Høyer, E. (1988). Functional bowel disease: malabsorption and abdominal distress after ingestion of fructose, sorbitol, and fructose-sorbitol mixtures. Gastroenterology, 95(3), 694-700.
Schuttert, J. B., Fiedler, G. M., Grupp, C., Blaschke, S., & Grunewald, R. W. (2002). Sorbitol transport in rat renal inner medullary interstitial cells. Kidney International, 61(4), 1407-1415. doi:10.1046/j.1523-1755.2002.00285.x
Ordinance on types of sugar of October 23, 2003 (BGBl. I p. 2098), as amended by Article 7 of the Ordinance of February 22, 2006 (BGBl. I p. 444)