Quick reference: 25 confusing ingredients
25 ingredients
- MaltodextrinGenerally suitableGenerally suitable. Check: source and any other ingredients
- Modified starchDepends on source or productDepends on source and product. Check: allergen declaration and product information
- Glucose syrupGenerally suitableGenerally suitable, including many wheat-derived forms. Check: complete label
- DextroseGenerally suitableGenerally suitable. Check: complete label
- Barley malt extractSpecial considerationRequires care. Check: gluten-free claim or reliable product guidance
- Malt flavouringDepends on source or productDepends on source. Check: whether barley or another gluten-containing cereal is involved
- Malt vinegarSpecial considerationRequires product-specific guidance. Check: processing and suitability
- Yeast extractDepends on source or productDepends on source and manufacture. Check: gluten-containing cereal ingredients and product information
- Brewer's yeastDepends on source or productDepends on production. Check: source and cross-contact
- Nutritional yeastGenerally suitableOften suitable. Check: added ingredients and cross-contact
- OatsSpecial considerationSpecial consideration. Check: gluten-free oats and individual tolerance
- Oat milkDepends on source or productDepends on product. Check: gluten-free claim
- BuckwheatGenerally suitableNaturally gluten-free. Check: added wheat and cross-contact
- SemolinaContains glutenUsually contains gluten. Check: whether made from wheat
- SpeltContains glutenContains gluten. Check: a type of wheat
- CouscousContains glutenUsually contains gluten. Check: grain used
- Soy sauceContains glutenOften contains gluten. Check: wheat ingredients and gluten-free claim
- TamariDepends on source or productDepends on product. Check: wheat and gluten-free claim
- CornflourGenerally suitableNaturally gluten-free when made from maize. Check: ingredients and cross-contact
- Rice flourGenerally suitableNaturally gluten-free. Check: other ingredients and cross-contact
- Hydrolysed vegetable proteinDepends on source or productDepends on source. Check: wheat, barley and other cereal sources
- SeitanContains glutenContains gluten. Check: made primarily from wheat gluten
- Xanthan gumGenerally suitableGenerally suitable. Check: complete product information
- Caramel colourGenerally suitableGenerally suitable. Check: other ingredients and product-specific information
- Barley grassDepends on source or productDepends on processing. Check: seed contamination, testing and product claims
Editorial guidance for gluten-free shopping, not a clinical safety rating. Always check the finished product.
Use this table as a starting point, not as a substitute for checking the finished product.
| Ingredient | Gluten-free status | What to check |
|---|---|---|
| Maltodextrin | Generally suitable | Source and any other ingredients |
| Modified starch | Depends on source and product | Allergen declaration and product information |
| Glucose syrup | Generally suitable, including many wheat-derived forms | Complete label |
| Dextrose | Generally suitable | Complete label |
| Barley malt extract | Requires care | Gluten-free claim or reliable product guidance |
| Malt flavouring | Depends on source | Whether barley or another gluten-containing cereal is involved |
| Malt vinegar | Requires product-specific guidance | Processing and suitability |
| Yeast extract | Depends on source and manufacture | Gluten-containing cereal ingredients and product information |
| Brewer's yeast | Depends on production | Source and cross-contact |
| Nutritional yeast | Often suitable | Added ingredients and cross-contact |
| Oats | Special consideration | Gluten-free oats and individual tolerance |
| Oat milk | Depends on product | Gluten-free claim |
| Buckwheat | Naturally gluten-free | Added wheat and cross-contact |
| Semolina | Usually contains gluten | Whether made from wheat |
| Spelt | Contains gluten | A type of wheat |
| Couscous | Usually contains gluten | Grain used |
| Soy sauce | Often contains gluten | Wheat ingredients and gluten-free claim |
| Tamari | Depends on product | Wheat and gluten-free claim |
| Cornflour | Naturally gluten-free when made from maize | Ingredients and cross-contact |
| Rice flour | Naturally gluten-free | Other ingredients and cross-contact |
| Hydrolysed vegetable protein | Depends on source | Wheat, barley and other cereal sources |
| Seitan | Contains gluten | Made primarily from wheat gluten |
| Xanthan gum | Generally suitable | Complete product information |
| Caramel colour | Generally suitable | Other ingredients and product-specific information |
| Barley grass | Depends on processing | Seed contamination, testing and product claims |
Important: A product without obvious gluten ingredients is not automatically proven to contain less than 20 ppm gluten.
For coeliac disease, use appropriate gluten-free labelling and reliable product-specific guidance.
First, what does gluten-free actually mean?
Gluten is associated with proteins found in cereals including wheat, barley and rye.
For people with coeliac disease, gluten triggers an autoimmune response that can damage the small intestine.
In the UK, foods labelled gluten-free must contain no more than 20 parts per million of gluten.
That is 20 milligrams per kilogram of food.
This is a regulated threshold, not a claim that absolutely no gluten molecules exist.
What about wheat-free?
Wheat-free and gluten-free are not interchangeable.
A wheat-free product can contain barley or rye.
A gluten-free product can sometimes contain specially processed wheat-derived ingredients.
Read our gluten-free versus wheat-free guide.
25 ingredients explained
1. Is maltodextrin gluten-free?
Generally suitable for a gluten-free diet.
Maltodextrin is a carbohydrate ingredient made by processing starch.
It can be produced from different sources, including maize, potato and wheat.
What if maltodextrin comes from wheat?
Wheat-derived maltodextrin is highly processed and is generally considered suitable for a gluten-free diet.
Under UK allergen labelling rules, wheat-based maltodextrins are among the specifically exempted products when the applicable conditions are met.
This means the word maltodextrin should not automatically trigger the same interpretation as wheat flour.
Where might you find it?
- Crisps
- Sauces
- Sweets
- Powdered drinks
- Seasoning mixes
- Processed foods
What should you check?
Read the complete product information and look for appropriate gluten-free labelling when required.
Wheat allergy note: A gluten-related processing exemption is not a substitute for personalised wheat allergy advice.
2. Is modified starch gluten-free?
It depends on the starch source and the finished product.
Modified starch is starch that has been processed to change its functional properties.
It may be used to thicken or stabilise foods.
Possible sources include:
- Maize
- Potato
- Tapioca
- Wheat
Does modified mean genetically modified?
Not necessarily.
The word refers to changes in the starch's properties and does not automatically mean genetic modification.
What if it's made from wheat?
Applicable UK labelling rules generally require the relevant wheat source to be identified when required, subject to exemptions.
You might see:
Modified wheat starch
or another source declaration.
What should you check?
Look for the starch source, allergen information and any gluten-free claim.
Don't automatically treat all modified starch as gluten-containing.
3. Is glucose syrup gluten-free?
Generally suitable, including many wheat-derived glucose syrups.
Glucose syrup is a carbohydrate ingredient made from starch.
Possible sources include wheat and maize.
What about wheat glucose syrup?
Wheat-based glucose syrups, including dextrose, are covered by specific UK allergen labelling exemptions under applicable conditions.
Processing removes or substantially reduces the relevant protein fractions.
Where is glucose syrup used?
- Sweets
- Ice cream
- Desserts
- Sauces
- Baked goods
What should you check?
The finished product, rather than assuming the syrup itself makes the food unsuitable.
4. Is dextrose gluten-free?
Generally suitable.
Dextrose is a form of glucose.
It may be manufactured from starch sources including wheat.
Wheat-based dextrose is included within the relevant UK exemption for wheat-based glucose syrups.
Is dextrose the same as wheat flour?
No.
They are very different ingredients.
Dextrose should not automatically be flagged as containing gluten merely because wheat can be used during its manufacture.
5. Does barley malt extract contain gluten?
It requires careful product-specific checking.
Barley contains gluten.
Barley malt extract is made from malted barley and can contain residual gluten.
Where is it used?
- Breakfast cereals
- Biscuits
- Chocolate products
- Malted drinks
- Sauces
- Confectionery
Can a product containing barley malt extract be gluten-free?
Some finished products containing barley-derived ingredients can meet gluten-free requirements.
However, you cannot determine the final gluten concentration simply by looking at how far down the ingredients list barley malt extract appears.
What should you check?
Look for a suitable gluten-free claim or reliable product-specific information.
Do not assume that all barley malt extract products have the same gluten content. For more on malt extract, malt vinegar and malted drinks, read does malt contain gluten?.
6. Is malt flavouring gluten-free?
It depends on the source.
Malt flavouring can be derived from barley or other materials.
Barley-derived malt ingredients are relevant to a gluten-free diet.
Is malt always barley?
No.
The term can be used in different contexts, and the exact ingredient source matters.
What should you check?
The complete ingredient declaration and, where needed, confirmation from the manufacturer.
Avoid guessing from the word malt alone.
7. Is malt vinegar gluten-free?
It needs product-specific interpretation.
Malt vinegar is traditionally produced using malted barley.
Fermentation and processing can affect gluten proteins.
However, the starting ingredient and processing method do not by themselves tell a consumer the final gluten concentration.
Is malt vinegar the same as cider vinegar?
No.
Cider vinegar is made from apples.
Wine vinegar is made from wine.
Malt vinegar is traditionally barley-derived.
What should you check?
Current Coeliac UK guidance and reliable information about the particular product. Coeliac UK currently lists barley malt vinegar under ingredients you need to check.
Do not assume all malt vinegars or all vinegar-containing sauces are identical.
8. Is yeast extract gluten-free?
It depends on the source and manufacturing process.
Yeast extract is used to add savoury flavour to foods.
It is not automatically gluten-containing.
However, some yeast extracts may be associated with barley-derived materials or other gluten-containing sources.
Where might you find yeast extract?
- Stock cubes
- Soups
- Gravies
- Crisps
- Seasonings
- Savoury spreads
Is yeast itself gluten?
No.
Yeast is a microorganism, not a gluten-containing cereal.
The concern is the source materials and manufacturing process.
What should you check?
The product's gluten-free status, allergen information and manufacturer guidance where relevant.
9. Is brewer's yeast gluten-free?
Not always.
Brewer's yeast is associated with brewing processes.
Depending on how it is produced and recovered, it may be exposed to barley-derived materials.
Other yeast products are grown using different processes.
Does every brewer's yeast supplement contain gluten?
No.
You cannot assume that all brewer's yeast products have the same composition.
What should you check?
The specific product, manufacturing source and gluten-free information.
10. Is nutritional yeast gluten-free?
Often, but check the product.
Nutritional yeast is commonly grown specifically for food use.
It is different from simply collecting yeast from beer production.
Plain nutritional yeast may be gluten-free, but added ingredients or cross-contact can matter.
What about flavoured nutritional yeast?
Flavoured products may include seasonings or other ingredients.
Check the entire ingredients list.
11. Are oats gluten-free?
Oats require special consideration.
Pure oats do not contain the same gluten proteins as wheat, barley and rye.
However, ordinary oats can be contaminated with gluten-containing cereals during growing, harvesting, transport or processing.
What are gluten-free oats?
Gluten-free oats are produced under appropriate controls and must meet the applicable gluten-free standard when labelled as such.
What is avenin?
Avenin is a protein naturally present in oats.
A small proportion of people with coeliac disease may react to avenin, even in gluten-free oats.
What should you check?
Look for appropriate gluten-free oat products and follow individual dietetic guidance.
12. Is oat milk gluten-free?
Not automatically.
Oat drinks are made using oats, but the gluten-free status depends on the oats and manufacturing process.
Why are some oat drinks labelled gluten-free?
Manufacturers may use appropriately controlled oats and processes that allow the finished product to meet gluten-free requirements.
What about ordinary oat milk?
An ingredients list showing only water, oats and oil does not establish that the drink meets the gluten-free threshold.
What should you check?
The specific product's gluten-free claim and reliable product information.
13. Is buckwheat gluten-free?
Buckwheat is naturally gluten-free.
Despite its name, buckwheat is not wheat.
It is used in:
- Pancakes
- Porridge
- Flour
- Noodles
- Breakfast products
Are buckwheat noodles gluten-free?
Not necessarily.
Some soba noodles contain both buckwheat and wheat flour.
What should you check?
The full ingredients list.
A product name containing the word buckwheat does not prove the finished food is gluten-free.
14. Is semolina gluten-free?
Ordinary semolina contains gluten.
Semolina is generally made from durum wheat.
It is commonly used in:
- Pasta
- Couscous
- Puddings
- Baked goods
Are there gluten-free alternatives?
Yes.
Some products use maize, rice or other gluten-free grains.
Check the actual ingredient rather than assuming every product called semolina is identical.
15. Is spelt gluten-free?
No. Spelt contains gluten.
Spelt is a type of wheat.
It may be marketed as an ancient grain, but that does not make it gluten-free.
Is spelt suitable for coeliac disease?
No.
Is spelt suitable for wheat allergy?
Spelt is wheat and is relevant to wheat allergy.
Do not assume it is a safe alternative.
16. Is couscous gluten-free?
Traditional couscous contains gluten.
Ordinary couscous is generally made from durum wheat semolina.
What about gluten-free couscous?
Some alternatives are made from maize, rice or other grains.
What should you check?
The grain used and any gluten-free claim.
17. Is soy sauce gluten-free?
Traditional soy sauce often contains wheat.
A typical recipe may contain:
- Soybeans
- Wheat
- Water
- Salt
Is all soy sauce made with wheat?
No.
Recipes and production methods vary.
Can soy sauce be gluten-free?
Yes.
Some products are formulated and labelled gluten-free.
What should you check?
The ingredients and gluten-free claim.
For wheat allergy, check wheat-derived ingredients separately.
18. Is tamari gluten-free?
Some tamari is gluten-free, but not all.
Tamari is a type of soy sauce.
Some varieties are produced without wheat, while others may contain wheat or be affected by cross-contact.
What should you check?
Look for a suitable gluten-free claim on the actual product.
Do not rely on the word tamari alone.
19. Is cornflour gluten-free?
Pure maize cornflour is naturally gluten-free.
In the UK, cornflour usually means finely milled maize starch.
This is different from the US use of the term corn flour, which may describe finely ground whole maize.
Can cornflour products contain gluten?
Plain maize starch is naturally gluten-free, but added ingredients or cross-contact may matter.
What should you check?
The ingredients and relevant gluten-free information.
20. Is rice flour gluten-free?
Rice flour is naturally gluten-free.
Rice does not naturally contain wheat, barley or rye gluten.
Rice flour is commonly used in:
- Gluten-free baking
- Noodles
- Batter mixes
- Flour blends
Are rice noodles always gluten-free?
No.
Some noodles contain additional wheat ingredients.
What should you check?
The finished product's ingredients and gluten-free information.
21. Is hydrolysed vegetable protein gluten-free?
It depends on the source.
Hydrolysed vegetable protein, sometimes abbreviated HVP, is used as a flavour-enhancing ingredient.
It can be produced from different plant proteins.
Possible sources include:
- Soy
- Wheat
- Maize
- Other plant materials
Does HVP always contain wheat?
No.
What if it's wheat-derived?
The ingredient source and processing matter.
Applicable allergen declaration rules and any relevant exemptions must be considered.
What should you check?
The declared source, allergen information and the finished product's gluten-free status.
22. Is seitan gluten-free?
No. Seitan is made primarily from wheat gluten.
Seitan is a plant-based protein food commonly used as a meat alternative.
It is sometimes called:
- Wheat meat
- Vital wheat gluten
- Wheat protein
Is seitan suitable for coeliac disease?
No.
Is seitan suitable for wheat allergy?
No. It contains wheat protein.
Does vegan mean gluten-free?
No.
Seitan is an excellent example of why vegan and gluten-free are completely different claims.
23. Is xanthan gum gluten-free?
Generally suitable for a gluten-free diet.
Xanthan gum is a thickener produced through fermentation.
It is frequently used in gluten-free baking to improve texture and structure.
Does xanthan gum contain wheat?
Xanthan gum is not inherently wheat gluten.
However, manufacturing sources and the finished product should be considered where a particular allergy is involved.
What should you check?
The complete product information, especially when managing a diagnosed wheat allergy rather than coeliac disease.
24. Is caramel colour gluten-free?
Generally suitable for a gluten-free diet.
Caramel colour is a food colouring produced by controlled heating of carbohydrates.
It can be made from different carbohydrate sources.
Does caramel colour always contain barley?
No.
The term does not automatically mean barley malt.
What should you check?
The finished product and any relevant allergen declarations.
Do not confuse caramel colour with barley malt extract merely because both can create a brown colour.
25. Is barley grass gluten-free?
It depends on the material and processing.
Barley grass refers to the young leaves of the barley plant.
The concern is whether gluten-containing grain material is present, including through harvesting or processing.
Is barley grass the same as barley grain?
No.
The leaves and grain are different parts of the plant.
Does that mean barley grass powder is automatically gluten-free?
No.
Commercial powders and supplements can vary in composition and manufacturing controls.
What should you check?
Reliable product-specific gluten-free information.
For coeliac disease, avoid assuming suitability simply because the product is described as grass rather than grain.
Ingredients that sound like gluten but usually aren't
Some names cause unnecessary concern.
Glutamate
Glutamate is not gluten.
Monosodium glutamate, or MSG, is not automatically gluten-containing.
Glutamic acid
Glutamic acid is an amino acid.
Its name does not mean the ingredient contains gluten.
Glutinous rice
Glutinous rice is a type of sticky rice.
The term refers to texture, not gluten content.
Plain glutinous rice is naturally gluten-free.
Lactic acid
Lactic acid is not gluten.
Its name also does not automatically mean it is derived from milk.
Lecithin
Lecithin is an emulsifier that can come from sources such as soy or sunflower.
It is not inherently gluten-containing.
Similar-sounding names are not reliable evidence that an ingredient contains gluten.
Ingredients that need particular care
These are the ingredient names worth recognising immediately:
- Wheat
- Barley
- Rye
- Spelt
- Durum wheat
- Semolina
- Bulgur
- Ordinary wheat couscous
- Seitan
- Wheat gluten
- Barley malt ingredients
Other ingredients, such as oats, yeast extract and modified starch, require more context.
How to read a UK label when checking for gluten
Step 1: Look for a gluten-free claim
For coeliac disease, a suitable gluten-free claim provides information about the finished product meeting the applicable gluten threshold.
Step 2: Read the ingredients list
Look for wheat, barley, rye and relevant cereal-derived ingredients.
Step 3: Check the allergen emphasis
UK labels generally emphasise regulated allergen sources within the ingredients list, subject to applicable rules and exemptions.
Step 4: Don't assume every wheat-derived ingredient contains gluten
Highly processed ingredients such as wheat-based glucose syrup and maltodextrin have specific regulatory treatment.
Step 5: Treat oats separately
Check whether oat products are appropriately labelled gluten-free.
Step 6: Read precautionary statements
'May contain' information is different from deliberate ingredients.
Follow individual dietary and medical guidance.
Step 7: Check the product every time
Manufacturers can change recipes, suppliers and precautionary statements.
Read our full guide to reading food labels.
Five supermarket examples
Example 1: Crisps containing maltodextrin
Crisps
Ingredients: Potatoes, sunflower oil, salt, maltodextrin, flavouring.
What matters: Maltodextrin is generally suitable for a gluten-free diet. The flavouring and finished product still need checking.
Example 2: Breakfast cereal containing barley malt extract
Breakfast cereal
Ingredients: Maize, sugar, barley malt extract (barley), salt.
What matters: Barley malt extract requires product-specific assessment. Don't assume the cereal is gluten-free.
Example 3: Gluten-free bread containing wheat starch
Gluten-free bread
Ingredients: Gluten-free wheat starch (wheat), water, yeast, oil, salt.
What matters: The gluten-free claim is relevant for coeliac disease, while the wheat-derived ingredient is separately relevant to wheat allergy.
Example 4: Buckwheat noodles containing wheat
Buckwheat noodles
Ingredients: Buckwheat flour, wheat flour, water.
What matters: The product contains wheat despite the buckwheat name.
Example 5: Oat drink without a gluten-free claim
Oat drink
Ingredients: Water, oats, sunflower oil, salt.
What matters: The ingredients alone do not establish whether the finished drink meets gluten-free requirements.
Can a barcode tell you whether a product is gluten-free?
A barcode scanner may retrieve stored information about a product, including its ingredients and dietary claims.
However, the information depends on the product record and how recently it has been updated.
A label-reading tool can help you review the information printed on the packaging in your hand.
Neither approach can measure the actual gluten concentration of a food.
Why does the current label matter?
Manufacturers may change:
- Recipes
- Ingredient suppliers
- Production sites
- Allergen warnings
- Gluten-free claims
The packaging you are holding should be checked rather than relying solely on an earlier purchase.
Read our barcode versus ingredient label guide.
How ClearaScan helps with confusing ingredient names
ClearaScan reads photographs of ingredient labels and checks recognised text against personalised Ingredient Guard rules.
Check actual ingredients
Photograph the label on the product you're considering.
Use personalised rules
Different people may need to check wheat, gluten-containing cereals or other ingredients.
Check multiple profiles
One captured label can be checked against different family members' Ingredient Guards.
Recognise the limitations
ClearaScan cannot measure gluten parts per million, verify gluten-free certification or establish whether a product is suitable for coeliac disease.
It cannot reliably infer the source of an ambiguous ingredient when that source is not provided on the label.
When you read a label yourself, remember that modified starch is not automatically wheat, and maltodextrin is not automatically gluten-containing.
A result showing no flagged ingredient matches is not a guarantee that the food is gluten-free.
Always verify the original label and use appropriate gluten-free product information.
