Soy Protein vs Pea Protein

In the world of plant-based protein sources, soy and pea proteins stand as two popular contenders, each with its unique attributes and benefits. As dietary preferences evolve, particularly among older adults, and Registered Dietitians working with the elderly seek to address the specific nutritional needs of their clients, understanding the differences between these two protein options becomes pivotal.

Whether you’re a seasoned senior embracing a plant-based diet or a Registered Dietitian looking to optimize nutrition plans for elderly clients, this examination of soy and pea protein will provide insights that support a healthier, more sustainable lifestyle in the golden years.

What is Pea Protein?

Pea protein is a type of plant-based protein that is derived from yellow peas, also known as Pisum sativum. It has gained popularity in recent years as a protein source, particularly among individuals who follow vegetarian, vegan, or plant-based diets. Pea protein is known for its high protein content and is considered a valuable alternative to animal-based protein sources.


What is Soy Protein?

Soy protein is a plant-based protein derived from soybeans, which are legumes native to East Asia. It is recognized for its high protein content and versatility in various food products. Soy protein is considered a complete protein, containing all essential amino acids.

It is often used in meat alternatives, dairy substitutes, and protein powders, making it a valuable source of protein for vegetarians, vegans, and those seeking plant-based dietary options.

soy beans.

Differences Between Soy Protein and Pea Protein

Soy protein and pea protein are both plant-based protein sources, but they have some key differences in terms of composition, health benefits, uses, and potential considerations.

Here’s a comparison of the two:


  • Soy Protein
    • Protein Content: Soy protein is typically high in protein, containing around 90-95% protein by weight.
    • Amino Acid Profile: Soy protein is a complete protein, meaning it provides all the essential amino acids that the body requires.
    • Isoflavones: Soy contains isoflavones, which are phytochemicals with potential health benefits. They may have estrogen-like properties and could be associated with reduced risk of certain chronic diseases, although research is ongoing.
  • Pea Protein
    • Protein Content: Pea protein is also high in protein, generally containing around 80-90% protein by weight.
    • Amino Acid Profile: While pea protein is not a complete protein on its own, it is usually slightly deficient in methionine but contains a good balance of other essential amino acids. It can be complemented with other plant-based protein sources to ensure a balanced amino acid profile.
soy beans and soy bean flour.

Health Benefits:

  • Soy Protein
    • Potential Cardiovascular Benefits: Soy protein may have a positive impact on heart health by reducing LDL cholesterol levels.
    • Isoflavones: The isoflavones in soy have been studied for their potential benefits, such as reducing the risk of certain cancers and improving bone health.
  • Pea Protein
    • Easy Digestibility: Pea protein is generally well-tolerated and easy to digest for most people.
    • May Be More Allergen-Friendly: Pea protein is naturally free from common allergens like soy, dairy, and gluten, which can be beneficial for those with food allergies or sensitivities.


  • Soy Protein
    • Versatile: Soy protein is used in a wide variety of products, including tofu, tempeh, soy milk, soy yogurt, and meat substitutes like veggie burgers and faux meats.
    • Meat Substitutes: Soy is a common base for many meat analogs because it can mimic the texture of meat and absorb flavors well.
  • Pea Protein
    • Protein Powders: Pea protein is commonly used in protein powders and supplements for athletes and fitness enthusiasts.
    • Meat Alternatives: It’s also used in some meat alternatives, but it may have a slightly different texture and flavor compared to soy-based options.

Things to Consider

  • Soy Protein
    • Allergies: Some people have soy allergies and need to avoid soy-based products.
    • GMO Concerns: Soybeans are often genetically modified (GMO), so if you prefer non-GMO options, look for products labeled as such.
  • Pea Protein
    • Slight Amino Acid Deficiency: Pea protein is not a complete protein by itself but can be combined with other plant-based sources to address this issue.
    • Texture and Taste: Pea protein may have a slightly different texture and taste compared to soy protein, which can affect its suitability in some culinary applications.

Making Pea Protein

Pea protein is made by harvesting and cleaning yellow peas, separating the protein from other components, solubilizing the protein in water, precipitating it with pH and heat treatment, dehydrating it into a powder, and packaging it for various food products. The specific processes may vary among manufacturers. Pea protein is known for its sustainability and allergen-friendliness.

Making Soy Protein

Soy protein is made by harvesting soybeans, removing their outer hulls, extracting oil with solvents, precipitating protein, drying it, grinding it into powder, and packaging it for various foods. Hexane is commonly used in extraction, but some manufacturers opt for hexane-free methods. Soy protein is versatile but can trigger allergies in some individuals.

Is Pea Protein Inflammatory?

Pea protein is not inherently inflammatory. In fact, it is often considered a hypoallergenic and anti-inflammatory protein source

Individual responses to pea protein can vary, and some people may experience digestive discomfort or mild bloating when consuming pea protein products. This is not due to inflammation but may be related to the fiber content in pea protein or individual digestive sensitivity. 

Using a high-quality pea protein isolate, which has a lower fiber content, may reduce the likelihood of these issues.  In general, pea protein is considered a well-tolerated and non-inflammatory protein source.

Allergens in Soy Protein

The main allergens in soy protein are the soybean proteins themselves, such as glycinin and conglycinin. Additionally, cross-contact with other allergenic foods during processing can be a concern for those with soy allergies. Reading food labels and being aware of potential cross-contamination is essential for managing soy allergies.

Pea Protein and the Kidneys

Pea protein, like most other sources of dietary protein, is not inherently hard on the kidneys for the average healthy individual. In fact, protein is an essential nutrient necessary for various bodily functions, including muscle maintenance and repair, immune system support, and enzyme production.

However, excessive protein intake, regardless of the source (animal or plant-based), may place a higher load on the kidneys over time. This is primarily a concern for individuals with pre-existing kidney issues or conditions, as their kidneys may have a reduced capacity to process excess protein.

For most healthy individuals, consuming moderate amounts of pea protein as part of a balanced diet is not likely to be detrimental to kidney health. The key is to ensure that protein intake aligns with your specific dietary and health needs.

If you have kidney disease or concerns about your protein intake, it’s essential to consult with a healthcare professional or a registered dietitian who can provide personalized guidance based on your individual health status and dietary preferences.

peas and pea pancakes on a plate.

Cautions With Eating Soy

Eating soy products isn’t for everyone, here’s a few things to consider before you start adding soy to your diet.

  • Be cautious of soy allergies.
  • Watch for digestive discomfort in some individuals.
  • Consider thyroid health, especially in excessive amounts.
  • Choose minimally processed soy products.
  • Check for GMO labels if you prefer non-GMO soy.
  • Diversify your protein sources.
  • Moderate soy’s impact on hormones, as moderate consumption usually has minimal effects.
  • Favor whole soy foods over isolated soy proteins.
  • Consult a healthcare professional for personalized guidance on soy consumption.

Pea Protein and Estrogen

Pea protein is not high in estrogen. While soy products contain compounds known as isoflavones, which are phytoestrogens that can have estrogen-like effects in the body.  Pea protein does not contain significant amounts of these compounds. In fact, pea protein is often chosen as a protein source because it is lower in phytoestrogens compared to soy.

Soy-based products like tofu and soy milk contain higher levels of isoflavones, but pea protein is generally considered a low-estrogen protein source and is unlikely to have notable hormonal effects in the body. The amount of estrogen containing products you can have will be individual.

Pea Protein, a Complete Protein?

Pea protein is not considered a complete protein on its own because it is slightly deficient in one essential amino acid, methionine. A complete protein contains all of the essential amino acids the human body needs in adequate amounts.

It can still be complemented with other plant-based protein sources that are rich in methionine, such as grains or seeds like rice, quinoa, or hemp, to create a balanced and complete amino acid profile. This combination of complementary proteins is often referred to as “protein combining” and is a common practice in vegetarian and vegan diets to ensure that all essential amino acids are obtained.

Comparing Amino Acids

The amino acid content in soy and pea protein varies, and each has a distinct amino acid profile.

Here’s a general comparison of the amino acid content between these two plant-based protein sources:

Soy Protein:

  • Complete Protein: Soy protein is considered a complete protein because it contains all essential amino acids in sufficient quantities. It provides a well-balanced amino acid profile.
  • High in Lysine: Soy protein is particularly rich in the amino acid lysine.
  • Moderate Methionine: Soy protein contains a moderate amount of methionine, an essential amino acid.

Pea Protein:

  • Not Complete: Pea protein is not a complete protein on its own because it is slightly deficient in methionine.
  • Higher Methionine: Pea protein typically has a higher methionine content compared to soy protein, but it’s still slightly lower than the recommended levels of this essential amino acid.
  • Rich in Lysine: Pea protein is generally rich in lysine, another essential amino acid.

In practice, both soy and pea protein can be part of a well-balanced diet when used in combination with other protein sources to ensure that you obtain all the essential amino acids. Some individuals choose to consume a variety of plant-based proteins to achieve a more complete amino acid profile.

Protein Digestibility

The digestibility of pea protein and soy protein can vary among individuals, but some general comparisons can be made:

Pea Protein:

  • Easy on Digestion: Many people find pea protein to be easy on the digestive system and experience fewer digestive discomforts like gas and bloating compared to other plant-based protein sources.
  • Hypoallergenic: Pea protein is naturally free from common allergens like gluten and dairy, making it a hypoallergenic choice for those with food sensitivities or allergies.
  • Gentle Fiber: Pea protein typically contains a moderate amount of dietary fiber, which can be beneficial for digestive health. However, for those with very sensitive digestive systems, choosing a pea protein isolate with lower fiber content may be preferable.

Soy Protein:

  • Generally Well-Tolerated: Soy protein is usually well-tolerated by many people, but some individuals may experience digestive discomfort, particularly when consuming large amounts or highly processed soy products.
  • Potential Allergenicity: Soy is a common allergen, and some individuals have soy allergies, which can lead to allergic reactions and digestive issues.

Both pea protein and soy protein are generally well-tolerated by most people, pea protein is often considered easier on the digestive system and has a lower allergenic potential. Individual reactions can vary, so it’s important to pay attention to your body’s response and choose the protein source that works best for you.


Pea Protein:

  • Mild and Neutral Flavor: Pea protein is known for its mild and neutral flavor profile. Many people appreciate it for its subtle taste, which allows it to blend easily into a wide range of recipes without dominating the overall flavor.
  • Less Earthy or Bean-like: Compared to some other plant-based proteins, such as hemp or certain varieties of soy, pea protein is often considered less earthy or bean-like in taste. This makes it a popular choice for those who prefer a cleaner and less pronounced taste.
  • Versatility: The mild taste of pea protein makes it highly versatile. It’s commonly used in smoothies, protein shakes, baked goods, and savory dishes. The mild flavor makes it easier to incorporate into both sweet and savory recipes.

Soy Protein:

  • Distinctive Flavor: Soy protein, by contrast, often has a more distinctive flavor. Some describe it as having a slightly earthy or bean-like taste. The taste of soy can be more noticeable in some soy-based products, particularly highly processed varieties.
  • Variability: The taste of soy protein can vary between different products. For example, tofu tends to have a milder flavor compared to certain soy-based meat substitutes. The extent to which the soy flavor is noticeable can depend on the specific product and how it’s prepared.
  • Versatility: While soy protein has a distinct taste, it can still be versatile in recipes that complement or highlight its flavor. For some, the taste of soy protein is part of the appeal, particularly in dishes where the flavor pairs well, such as Asian-inspired cuisine.
hand holding peas.

Closing Thoughts

Ultimately, the choice between pea protein and soy protein often comes down to personal taste preferences and how the protein will be used in recipes. Some individuals prefer the neutral taste of pea protein for its ease of integration into various dishes, while others appreciate the distinctive flavor of soy protein in specific culinary contexts.

If you’re an older adult or a Registered Dietitian looking to put some pea or soy protein into recipes, make sure there is no one with allergies taking them. Pea and soy protein powder can be great ways to add extra protein into recipes.

My recommendation is both are worth a try! It can add some great flavour to recipes, a different flavour and extra protein. It can also be a great source of fiber if you add some extra pea protein powder to the next meal.

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Michelle Saari is a Registered Dietitian based in Canada. She has a Master's Degree in Human Nutritional Sciences and is a passionate advocate for spreading easy to understand, reliable, and trustworthy nutrition information. She is currently a full time online entrepreneur with two nutrition focused websites.

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