Chicory Syrup

"Chicory syrup" is the name on two products with almost nothing in common: a fibre syrup that feeds gut bacteria and blunts the blood-sugar rise, and a fructose syrup that is simply sugar with a plant name. Only the nutrition label tells them apart, and even the good kind is limited by how much fibre your gut will tolerate.

Read the label. If it's mostly fibre, use it in small amounts — at most about a tablespoon a day, split across meals — and skip it if you have irritable bowel syndrome. If it's mostly sugars, count it as added sugar, like honey.

Two products, one name

Chicory root stores inulin, a starch-like fibre made of chains of up to about 60 fructose units. What happens to that fibre decides which syrup you get.

The fibre kind. Partly breaking inulin down gives short chains of 2–8 units, called oligofructose or fructo-oligosaccharides (FOS). A pure grade is about 95% fibre and 5% ordinary sugars by dry weight, and about a third as sweet as table sugar;^[1] manufacturers also sell lower-purity grades with more sugar. Your small intestine can't digest the fibre, so gut bacteria ferment it in the colon and it yields only about 1.5–2 kcal per gram against sugar's 4.^[2]

The sugar kind. Breaking inulin down all the way gives its building block, fructose. EU law calls this "inulin syrup" and requires only 10% fructose to use the name. One "chicory syrup" classified by US customs was described by its importer as a syrup whose solids were 85% fructose and 15% glucose,^[3] and a 2004 ruling on another gave 83% and 12%. Nutritionally that is a free-fructose syrup, and everything on the Sweeteners page about fructose applies.

How to tell them apart

Per 100 g	Fibre syrup	Fructose syrup
Fibre	roughly 55–70 g	little or none
Sugars	under about 15 g	60 g or more

Go by the back of the pack, not the front.

Why the sugar kind is harder on the gut than corn syrup

Fructose is absorbed better when glucose comes with it. Abnormal breath tests, a sign that fructose wasn't absorbed, occurred in 68% of people after fructose alone against 26% after high-fructose corn syrup,^[4] and more than half of 15 healthy adults failed to absorb a 25 g fructose dose.^[5] A syrup that is 85% fructose and 15% glucose should therefore upset the gut more easily than corn syrup — an inference from these studies, not a direct test.

Fructose does produce a lower immediate glucose and insulin peak than sugar,^[6] which is how these syrups get sold as "diabetic-friendly". That says nothing about the load on the liver.

What the fibre kind does

Blood sugar after a meal. Replacing part of the sugar in a food with chicory fibre lowers the glucose and insulin rise roughly in proportion to the sugar removed. In two trials of about 40 healthy adults each, swapping 20% of the sugar in a yogurt drink lowered the glucose response by about 14%, and swapping 30% in a fruit jelly by about 16%. The paper was co-written by staff of a chicory-fibre manufacturer.^[7]
Weight and blood fats. Pooled across 55 trials and 2,518 people, inulin-type fibres took off about 1 kg of body weight and slightly lowered LDL ("bad") cholesterol and triglycerides, all at low or very low certainty, with little or no effect on blood sugar or blood pressure. Effects were larger with six weeks' use or more and in people with overweight.^[8] In the best single weight trial, 21 g of oligofructose a day for 12 weeks led to about 1 kg of weight loss against a 0.5 kg gain on placebo^[9] — but 21 g is more than most people tolerate from a syrup.
Diabetes and prediabetes. Here it does better: across 33 trials, about 10 g a day for six weeks or more lowered fasting glucose by about 0.6 mmol/L and long-term blood sugar (HbA1c) by about 0.6 of a percentage point.^[10]
Gut bacteria. It reliably increases bifidobacteria, the bacteria it is sold to feed, in a review with industry-affiliated authors.^[11] Whether that improves health in healthy adults is not established. The EU's approved bowel-function claim covers long-chain chicory inulin at 12 g a day or more, not the short-chain fibre in syrups.

The limit is your gut

In single doses, 5 g of oligofructose was well tolerated but 10 g clearly increased wind and bloating.^[12] Over a week, excess wind set in at 20 g a day, while 10 g a day was tolerated and still raised bifidobacteria.^[13] A 15 g spoonful of fibre syrup holds about 9–10 g of fibre, so it can replace only a few teaspoons of sugar a day.

Chicory fibre is a FODMAP, one of the fermentable carbohydrates behind irritable bowel syndrome (IBS) symptoms. In people with IBS who also absorbed fructose poorly, and whose symptoms a low-FODMAP diet had already controlled, fructans brought symptoms back in 77% against 14% on glucose.^[14] A pooled analysis of prebiotics in IBS found no overall benefit, with inulin-type fibres making wind worse.^[15]

Safety and teeth

In mice with disturbed gut bacteria, and in ordinary mice on an inulin-rich high-fat diet, added inulin caused liver cancer that depended on the gut bacteria.^[16] Nothing like it has been reported in people, but it is a reason to treat refined inulin as a food ingredient, not a supplement to take in rising doses. Severe allergic reactions (anaphylaxis) to inulin exist but are confined to case reports.

Unlike sugar alcohols, chicory fibre is not known to be tooth-friendly. In lab tests, mouth bacteria turned it into acid and plaque about as readily as sugar, and no trial has tested it on cavities.^[17] The fructose kind is simply a sugar your mouth bacteria can use.

What to do

Check the label before you buy: fibre 55 g or more and sugars under about 15 g per 100 g is the fibre kind.
Fibre kind: at most about a tablespoon a day, split across meals. Skip it if you have IBS, especially if a low-FODMAP diet has helped you.
Fructose kind: treat it as added sugar, on the same limit as honey and corn syrup.
Don't treat it as a supplement. Its benefits in healthy people are small and uncertain, and your gut caps the dose. For where the fibre evidence does lie, see that page.

For the other ways to replace sugar, see Sugar substitutes.