Soya protein – does it contain gluten and lactose? - Blog

In 1941, Henry Ford unveiled a suit made from fibres derived from soya, demonstrating the wide range of applications this raw material could have. Today, soya protein is used primarily in the food industry, including in the production of protein supplements and plant-based meat substitutes. Soya is a popular raw material because it is gluten-free and lactose-free. It is worth noting, however, that the final composition of soya products depends on the additives used and the production conditions.

soya protein supplement

Does soya protein contain gluten?
The presence of lactose in soya protein
Who is soya protein suitable for?
What should you look out for when buying soya protein?
FAQ – frequently asked questions about soya protein

Does soya protein contain gluten?

Protein extracted from soya beans is naturally gluten-free. Gluten is a group of proteins found in wheat, rye and barley, whilst soya is a legume. Both soya protein isolate and concentrate can therefore form part of a gluten-free diet. However, this does not mean that every soya-based supplement is suitable for people with coeliac disease.

Gluten may be present in a ready-made mixture due to additional ingredients, such as those containing wheat or barley malt. Cross-contamination is also possible during the transport of raw materials, processing or packaging in a facility that also handles gluten-containing cereals. Particular attention should be paid to flavoured and multi-ingredient supplements, the composition of which is not limited to soya protein alone.

Under European Union regulations, the term "gluten-free" may be used when the finished product contains no more than 20 mg of gluten per kilogram of food. People with coeliac disease should choose products bearing this label and check the information regarding the possible presence of gluten-containing cereals.

The presence of lactose in soya protein

Lactose is a sugar that occurs naturally in mammalian milk. It is not a component of soya beans, which is why pure soya protein isolate or concentrate does not contain it by virtue of the raw material’s origin. Nutritional supplements based solely on soya protein can therefore be consumed by people with lactose intolerance, provided that the finished product does not contain any dairy additives containing this sugar.

Some protein blends combine plant-based and animal-based ingredients. The label may list, amongst other things, milk powder, whey, lactose or chocolate ingredients containing milk. Such additives may introduce lactose into the product, even though soya remains the main source of protein.

Estimated nutritional value of typical soya protein isolates per 100 g

Ingredient	Typical content per 100 g
Energy	330-390 kcal
Protein	80-90 g
Fat	0,5-4 g
Carbohydrates	0-6 g

Who is soya protein suitable for?

soya protein

Soya protein is one way of supplementing protein intake for those on a vegan or vegetarian diet, as well as for people who limit their consumption of dairy products. It can be used in smoothies, porridge, baked goods and other meals, without the need to include ingredients of animal origin. It is also suitable for physically active people.

Soya contains all the essential amino acids that the body cannot produce on its own. However, their proportions differ from those found in dairy proteins. Among other things, soya protein has a relatively lower content of sulphur-containing amino acids, particularly methionine.

Soya supplements may be suitable for those with lactose intolerance, and the certified gluten-free variant is also suitable for coeliac disease. However, they should not be used by anyone with a soya allergy, as soya is one of the allergens requiring mandatory labelling.

What should you look out for when buying soya protein?

When choosing a supplement, it is worth first checking whether the product contains an isolate, a concentrate or a protein blend. Isolates usually have a higher protein content and fewer other components of the soya bean, such as fat and carbohydrates. The serving size is also important. For example, 30 g of powder containing 80 g of protein per 100 g provides 24 g of protein, not 30 g.

If you have coeliac disease, look for the ‘gluten-free’ label, and if you have lactose intolerance, check both the ingredients list and whether it is labelled ‘lactose-free’. In the case of an allergy to milk or other ingredients, the phrase ‘may contain’ – referring to the accidental presence of allergens – is also important. Soya is itself an allergen and must therefore be clearly indicated on the label.

"Soya protein is naturally gluten-free and lactose-free, but this does not mean that every soya-based supplement has the same properties. The finished product may contain dairy ingredients, additives containing gluten or trace amounts of allergens resulting from the manufacturing process. Therefore, it is particularly important to check the label carefully if you have coeliac disease, lactose intolerance or food allergies." Anna Zięba – Dietitian

FAQ – frequently asked questions about soya protein

Does soya protein contain gluten?

No, soya is naturally gluten-free. However, ready-made soya supplements may contain gluten-containing ingredients or be accidentally contaminated with them during production. People with coeliac disease should choose products labelled "gluten-free".

Does soya protein contain lactose?

Pure soya protein does not contain lactose, as it is plant-based and lactose is a milk sugar. However, multi-ingredient supplements may contain added milk, whey or lactose itself.

Is soya protein suitable for people with lactose intolerance?

Yes, provided that the finished product does not contain lactose derived from additional ingredients. It is best to choose supplements with a simple ingredient list and to check the manufacturer’s declaration regarding lactose content.

Can people with coeliac disease consume soya protein?

Yes, but they should choose products labelled "gluten-free". Under EU regulations, this means the product contains no more than 20 mg of gluten per kilogram of food. The terms "plant-based" or "soya" alone do not guarantee safety for people with coeliac disease.

Is soya protein a complete protein?

Yes, soya protein contains all nine essential amino acids. However, its amino acid profile differs from that of dairy proteins, notably in its lower relative proportion of methionine. It can be a valuable source of protein in a varied diet.

How does soya protein isolate differ from soya protein concentrate?

Isolate is a more purified form of protein and usually contains around 80–90 per cent protein. Concentrate generally has a lower protein content and a higher proportion of other soya components. The exact figures depend on the manufacturer and production technology.

Is soya protein suitable for building muscle?

Soya protein provides the amino acids needed for muscle recovery and growth, so it can be used by those doing strength training. However, it is not essential for achieving training results. An adequate amount of protein can also be obtained from ordinary food.

Can soya protein cause an allergy?

Yes. Soya is one of the food allergens that must be labelled in the European Union. People with a diagnosed soya allergy should also avoid soya protein isolates and concentrates.

Is soya protein suitable for vegans?

Yes, as it is derived from soya beans and does not require the use of animal-derived ingredients. However, you should check the full list of ingredients, as some blends may contain milk proteins or other animal-derived additives.

How much protein does one serving of a soya supplement provide?

This depends on the protein content of the product and the serving size. For example, 30 g of a supplement containing 80 g of protein per 100 g provides 24 g of protein. You should therefore check the nutrition facts table rather than relying solely on the weight of the powder.

Sources:

Koerner, T. B., Cleroux, C., Poirier, C., Cantin, I., La Vieille, S., Hayward, S., & Dubois, S. (2013). Gluten contamination of naturally gluten-free flours and starches used by Canadians with celiac disease. Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment, 30(12), 2017–2021. https://doi.org/10.1080/19440049.2013.840744
van den Berg, L. A., Mes, J. J., Mensink, M., & Wanders, A. J. (2022). Protein quality of soy and the effect of processing: A quantitative review. Frontiers in nutrition, 9, 1004754. https://doi.org/10.3389/fnut.2022.1004754
Katz, Y., Gutierrez-Castrellon, P., González, M. G., Rivas, R., Lee, B. W., & Alarcon, P. (2014). A comprehensive review of sensitization and allergy to soy-based products. Clinical reviews in allergy & immunology, 46(3), 272–281. https://doi.org/10.1007/s12016-013-8404-9