E412

Guar Gum

Last reviewed: 8 May 2026

The plant fibre thickening UK plant milks and gluten-free bread — with a FODMAP flag for IBS

If you've moved to plant milks, gluten-free bread, ice cream or low-calorie sauces, guar gum is doing a lot of the texture work behind the label. It's an actual plant fibre, not a synthesised additive — but it carries a FODMAP flag that matters if you've been told to manage IBS symptoms.

This page covers what guar gum actually is, where it shows up in real UK products, why low-FODMAP guides single it out, the historical 1980s diet-pill story that comes up if you search for it, and how it differs from xanthan gum (E415) — the other gum you'll see on the same labels.

What guar gum actually is

E412 is guar gum, a galactomannan polysaccharide extracted from the seed endosperm of Cyamopsis tetragonoloba — the guar bean. The crop is grown mainly in India, Pakistan and the US Southwest, where it tolerates dry conditions better than most legumes.

The seeds are split, dehusked and milled, and the central endosperm is ground into a fine cream-coloured powder. That powder is pure soluble fibre — long chains of mannose with galactose side branches that swell on contact with water and trap it. Because it's plant cell wall material rather than a synthesised molecule, you'll sometimes see it sold loose in health-food shops as "guar gum powder" alongside xanthan gum and psyllium husk.

Chemically it's a hydrocolloid: a polymer that disperses in water to form a viscous gel. A small amount goes a long way — 1 part guar gum will noticeably thicken several hundred parts water. That's why food manufacturers reach for it; it costs little, dissolves in cold liquid without heat, and leaves no flavour at typical use levels.

What it does in food

Guar gum earns its place on UK ingredient lists through four jobs, often more than one at once:

• Thickening. Even at 0.1% concentration it adds noticeable viscosity. This is what gives a low-fat sauce or a plant milk its body without using cream or starch.
• Emulsion stabilising. In dressings and sauces that mix oil and water, the viscous water phase holds the oil droplets in suspension so they don't separate on the shelf.
• Anti-ice-crystal. In ice cream and frozen yoghurt, guar gum binds free water so it can't form coarse crystals during temperature fluctuations in the freezer cabinet. The result is a smoother, creamier-feeling product.
• Gluten substitute. Wheat gluten gives bread its stretchy, gas-trapping network. Gluten-free flours have nothing comparable, so bakers use guar gum (often paired with xanthan) to mimic that elastic structure and stop the loaf collapsing.

Where it turns up on UK labels

Guar gum is one of the most widely used hydrocolloids in UK manufacturing. Categories where you'll see it most often:

• Plant milks (oat, almond, soy, coconut) — typical use 0.05–0.2%. The gum keeps the drink from separating in the carton and gives it the mouthfeel that makes it pour and foam like dairy.
• Gluten-free bread, cakes and pasta — at higher levels (often 0.5–1%) to provide the elastic, water-binding network gluten would normally supply.
• Ice cream, frozen yoghurt, sorbet — for anti-crystallisation and that slow-melt mouthfeel.
• Low-fat and low-calorie sauces, dressings and soups — when you remove fat or sugar, you remove body. Guar gum thickens the remaining water phase so the product still coats a fork.
• Yoghurts, cream cheeses and other dairy — to prevent whey separation and improve set.
• Ready meals — gravies, sauces, pasta bakes — to hold the sauce on the food rather than pooling at the bottom of the tray.
• Pet foods — same role: thickening jellies and gravies in wet pouches.

On the label it appears as "E412", "guar gum", "stabiliser: guar gum", or "thickener: guar gum", depending on which job the manufacturer is declaring.

Guar gum, FODMAP and IBS

This is the part most people don't expect from a plant fibre. Guar gum's galactomannan structure is fermented by bacteria in the colon — which is what makes it act as a prebiotic for many people, but also what makes it a problem for others.

Monash University, who develop and maintain the FODMAP framework that NHS dietitians use, classify guar-gum-containing foods at meaningful serving sizes as high-FODMAP. Guar gum sits in the oligosaccharide group: a fermentable carbohydrate that some people with IBS struggle to digest comfortably, producing bloating, wind and altered bowel habits.

That doesn't mean guar gum causes IBS, and it doesn't mean everyone needs to avoid it. It means that on a structured low-FODMAP elimination diet — the kind run with a registered dietitian — products containing guar gum are usually restricted during the elimination phase, then reintroduced in measured amounts to test individual tolerance. If you've been pointed at low-FODMAP eating for symptom management, talk to your GP or a NHS-referred dietitian about how guar gum fits your plan; we're a tracking tool, not a clinical service.

GI effects at higher doses

At the levels guar gum is actually used in food (well under 5 g/day from a normal diet, even one heavy on plant milks and gluten-free bread), most people experience no GI complaints. The fibre passes through, gets fermented in the colon, feeds bacteria, and adds to overall soluble fibre intake.

Bloating, wind and loose stools tend to show up at higher doses — typically more than 10–15 g/day, the kind of intake you'd only reach from a fibre supplement, a powdered weight-management product, or stirring large quantities of raw guar gum into drinks. The mechanism is twofold: rapid colonic fermentation (gas production) and an osmotic effect (the soluble fibre binds water and softens stools, sometimes too much).

The food-form vs supplement-form distinction is the important one here. A litre of oat milk delivers a fraction of a gram of guar gum, already hydrated and dispersed through the drink. A scoop of pure guar gum powder taken on its own is a different proposition.

The 1980s Cal-Ban 3000 story

If you search for guar gum and "danger" you'll quickly land on Cal-Ban 3000 — a US weight-loss supplement sold in the late 1980s that contained around 3 grams of guar gum per dose. The product was marketed as an appetite suppressant: swallow the dry tablet, the gum hydrates and swells in the stomach, you feel full.

The problem was the route. Dry guar gum that hydrates inside the oesophagus or stomach can swell rapidly enough to cause obstruction. The US FDA recorded multiple cases of oesophageal blockage, several requiring surgical intervention, and at least a small number of deaths. The product was withdrawn from the US market in 1990.

This was a dose-and-formulation problem — concentrated dry powder hitting moisture in a confined tube — not a property of guar gum in food. By the time guar gum reaches you in a plant milk, a slice of gluten-free bread or a scoop of ice cream, it's already fully hydrated and dispersed through the matrix. The Cal-Ban mechanism doesn't apply to food-form use; the story persists in search results because it's the kind of historical incident that anchors people's mental model of the ingredient.

E412 (guar gum) vs E415 (xanthan gum)

Guar gum and xanthan gum are the two hydrocolloids you'll see most often on UK labels, frequently on the same one. They're not interchangeable, and the differences matter if you're trying to decode an ingredient list:

• Source. Guar gum is extracted from a plant (the guar bean). Xanthan gum is produced by bacterial fermentation — Xanthomonas campestris grown on a glucose or sucrose substrate. Both are technically natural; one comes from a seed, the other from a microbe.
• Behaviour in water. Guar gum dissolves in cold water on contact and gives a soft, viscous solution. Xanthan gives a more shear-thinning gel — thick at rest, thinner when stirred.
• Acid stability. Xanthan holds its texture across the full pH range. Guar gum performs less reliably in strongly acidic foods (vinaigrettes, citrus drinks), so manufacturers reach for xanthan there.
• Mouthfeel. At higher concentrations xanthan can read as slightly slimy. Guar gum tends to feel cleaner and more neutral in the mouth.
• Cost. Guar gum is generally cheaper than xanthan, which is why low-cost sauces and plant milks reach for it first.
• FODMAP status. Both are flagged in low-FODMAP guides at meaningful serving sizes, though they ferment differently. Anyone using a structured low-FODMAP plan should treat both as ingredients to check.

In gluten-free baking the two are often used together: guar gum provides bulk water-binding, xanthan provides the elastic, gas-trapping film. Each on its own gives a more compromised loaf than the combination.

Regulatory status

The European Food Safety Authority re-evaluated guar gum in 2017 and confirmed its acceptable use as a food additive, setting an acceptable daily intake at "not specified" — the regulatory shorthand for quantum satis, meaning use as needed for the technological purpose. EFSA's opinion notes that high intakes can produce gastrointestinal effects (the bloating and laxative behaviour discussed above), which is why the ADI carries that practical caveat rather than a numerical limit.

In the United States, the FDA classifies guar gum as "Generally Recognized as Safe" (GRAS) for its intended food uses.

UK and EU labelling rules require it to be declared by category function and either name or E-number — typically "thickener: guar gum", "stabiliser (E412)", or simply "guar gum" on the ingredients list.

Vegan, vegetarian and gluten-free

Guar gum is plant-derived and contains no animal inputs at any stage of production, so it's suitable for vegan and vegetarian diets. It contains no gluten — no wheat, rye, barley or oats are involved — and is in fact one of the workhorse ingredients of the gluten-free baking aisle precisely because it can stand in for gluten's structural role. Coeliac UK does not flag it as a gluten-related concern.