What Is High-Fructose Corn Syrup? Why It's Used in Juice and Sports Drinks
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Written by: Shingo YoshizakiReviewed by: Tomonobu Someda
What exactly is the 'fructose-glucose syrup' (high-fructose corn syrup) listed on juice and sports drink labels?
Fructose-glucose syrup is a liquid sugar made by enzymatically converting part of the glucose from corn (or other) starch into fructose. In Japan, JAS standards classify it into three types by fructose content: 'glucose-fructose syrup' (under 50% fructose), 'fructose-glucose syrup' (50-90%), and 'high-fructose syrup' (90%+). It stays sweet and dissolves easily even when cold, which is why it's widely used in soft drinks and sports drinks served at room temperature or chilled.
How it's made
Starch from corn (or other crops) is enzymatically broken down into a glucose solution, and part of that glucose is then converted into fructose using an isomerizing enzyme (glucose isomerase). Because this process converts some glucose into fructose, the product is also called 'isomerized sugar' in Japan. The starch source isn't limited to corn — potato and sweet potato starch are also used domestically.
What's the difference between the two common Japanese labels?
The two common label names differ based on which sugar — fructose or glucose — is more abundant. Japan's JAS standard defines under 50% fructose as 'glucose-fructose syrup,' 50-90% as 'fructose-glucose syrup,' and 90%+ as 'high-fructose syrup,' with the more abundant sugar named first. Soft drinks and sports drinks mainly use 'fructose-glucose syrup' (50-90% fructose).
- Under 50%
- Fructose content: glucose-fructose syrup
- 50–90%
- Fructose content: fructose-glucose syrup
- 90%+
- Fructose content: high-fructose syrup
How does its composition differ from table sugar (sucrose)?
Sucrose (table sugar) is a disaccharide with glucose and fructose bound 1:1, which must be broken apart by the enzyme sucrase in the gut before becoming free glucose and fructose. Fructose-glucose syrup, by contrast, already exists as free glucose and fructose dissolved together. After digestion and absorption, both appear in the bloodstream in essentially the same form, and the difference in fructose content between the two is typically only a few percentage points. A meta-analysis pooling 767 participants found no significant difference between the two in major metabolic markers such as weight, blood glucose, or lipids (see source).
Why is it used in beverages?
Fructose-glucose syrup is easy to handle as a liquid and stays dissolved without crystallizing even when cold, making it well-suited to chilled or room-temperature soft drinks and sports drinks. Fructose also tastes sweeter at lower temperatures, pairing well with chilled beverages. On the manufacturing side, it's easier to dose and mix into production lines than granulated sugar, with more stable costs.
Related research
Sources
Published:
Written by
Shingo YoshizakiSoftware Engineer / Research Writer at BODYDATA
An engineer's job is verification. I read the source before I trust gym lore — same as code.
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Reviewed by: Tomonobu Someda
Content reviewed from the perspective of coaching practice and supplement-industry experience
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