Glucose-Fructose Syrup (Starch-Based Sugar)

What is glucose-fructose syrup?

Maize, wheat or potato starch is broken down with enzymes to make glucose syrup. Part of the glucose is then converted into fructose, again using enzymes. The result is a liquid sugar made of glucose and fructose, close to table sugar in sweetness.

Under EU rules, glucose syrup containing more than 5% fructose in dry matter is labelled “glucose-fructose syrup” if glucose predominates, or “fructose-glucose syrup” if fructose predominates; the Turkish Food Codex Communiqué on Sugar uses the same names. In the US, a similar product is known as “high-fructose corn syrup” (HFCS). In Türkiye, the production of starch-based sugar is limited by a quota set by presidential decision for each marketing year under the Sugar Law.

Why is it used so widely?

• Because it is liquid, it mixes easily into drinks and doughs
• It does not crystallise and keeps products soft and moist
• It improves colour and browning and extends shelf life
• It is usually cheaper than granulated sugar

Which products contain it?

• Fizzy drinks, fruit-flavoured drinks and iced teas
• Biscuits, cakes, wafers and sweets
• Ice cream, ready-made desserts and fruit yoghurts
• Ketchup, barbecue sauce and some ready-made sauces
• Breakfast cereals and cereal bars

Is it more harmful than sugar?

Table sugar (sucrose) is also split half and half into glucose and fructose during digestion. So the effects of glucose-fructose syrup and sugar in the body are largely similar. The scientific view is that what matters is not the type of sugar but the total amount.

High fructose intake is known to be linked to fatty liver and raised blood fats; however, this effect applies to every source of fructose (including sugar, honey and fruit juice concentrate). It is also important that liquid sugars do not make you feel full and are easy to overconsume.

The World Health Organization (WHO) recommends that free sugars make up less than 10% of daily energy, ideally reduced to below 5%. For an adult eating 2,000 calories a day, 10% corresponds to about 50 grams of sugar and 5% to about 25 grams (roughly 6 teaspoons).

Who should be careful?

• People with diabetes or insulin resistance: It raises blood sugar quickly; take particular care with drinks.
• Children: Sugary drinks increase the risk of both tooth decay and excess weight.
• People with fatty liver: Reducing fructose-containing sugars is generally recommended; you can ask your doctor about a dietary plan.

What to do when you see it on a label

The ingredient list is ordered by quantity; if glucose-fructose syrup is near the top, the product is noticeably sugary. Looking at the “sugars” line in the nutrition table is the most practical way. If the same product contains more than one sweetener, such as sugar, dextrose, maltodextrin or fruit juice concentrate, the total sugar may be higher than you expect.