Soy Protein vs Pea Protein: A Dietitian Analyzes

Protein is a cornerstone of a healthy diet, essential for muscle repair, immune function, and energy. In the quest for optimal health, many are turning to plant-based sources, with pea and soy protein leading the charge.

As a seasoned Registered Dietitian, I breakdown pea protein vs soy protein. I don’t want to make the choice for you, but I’ll present the comparison and YOU decide which one you think is best for you.

Whether you’re navigating dietary restrictions, seeking sustainable options, or simply aiming to boost your protein intake, understanding the differences between these two plant-based powerhouses can guide your path to better health.

What is Pea Protein?

Pea protein is a high-quality, plant-based protein extracted from yellow peas, also known as split peas. It’s become increasingly popular as a supplement and ingredient in various food products, especially among vegetarians, vegans, and those with certain food intolerances.

Here’s a detailed breakdown of pea protein, including its forms, benefits, and considerations.

Forms of Pea Protein

  1. Pea Protein Isolate: This is the most concentrated form of pea protein, typically containing around 80-90% protein. It’s produced by removing the pea’s carbohydrate and fiber content, resulting in a powder that’s rich in protein and low in fats and carbs. Pea protein isolate is commonly used in protein powders, shakes, and bars.
  2. Pea Protein Concentrate: While not as common as the isolate, pea protein concentrate contains a slightly lower percentage of protein (about 70-75%) because it retains more of the natural pea components. It’s used in various food products, including plant-based meat substitutes and baked goods.
  3. Textured Pea Protein: Similar to textured soy protein, textured pea protein is processed to mimic the texture of meat, making it a popular choice for vegan and vegetarian meat alternatives, such as burgers and sausages.

Nutritional Benefits

  • Hypoallergenic: Pea protein is naturally gluten-free and soy-free, making it an excellent protein source for individuals with allergies or sensitivities to common allergens like wheat, soy, and dairy.
  • Rich in Iron: Pea protein is a good source of iron, with some products offering up to 5-7.5 mg per serving, which can help support energy levels and overall health, especially in vegan and vegetarian diets.
  • Muscle Growth and Repair: Like other protein sources, pea protein aids in muscle growth and repair due to its high-quality amino acid profile, including branched-chain amino acids (BCAAs) that are crucial for muscle protein synthesis.
  • Heart Health and Kidney Function: Some studies suggest that pea protein may have beneficial effects on heart health by lowering high blood pressure and improving kidney function, although more research is needed in these areas.


  • Amino Acid Profile: While pea protein is rich in many essential amino acids, it’s lower in methionine compared to animal proteins. Combining pea protein with other plant-based proteins can ensure a complete amino acid profile.
  • Taste and Texture: Some people may find the taste and texture of pea protein less appealing than other protein sources. However, many products are designed to minimize this, and blending pea protein with flavorful ingredients can enhance its palatability.
  • Digestibility: Pea protein is generally considered easy to digest, but as with any high-protein product, it’s important to consume it as part of a balanced diet to avoid digestive discomfort.

What is Soy Protein?

Soy protein is a plant-based protein derived from soybeans, a legume native to East Asia but now cultivated worldwide. It’s a complete protein, meaning it contains all nine essential amino acids necessary for human health. Soy protein is used in various forms and products, making it a versatile option for many diets.

Here’s a breakdown of what soy protein is, its forms, benefits, and considerations:

Forms of Soy Protein

  1. Soy Protein Isolate: This is the most refined form of soy protein, containing about 90-95% protein. It’s made by removing the majority of the fats and carbohydrates from defatted soy flour. Soy protein isolate is commonly found in protein shakes, bars, and meat substitutes.
  2. Soy Protein Concentrate: Containing about 70% protein, this form retains more of the soybean’s original nutrients than isolate. It’s produced by extracting protein from the soybean meal. Soy protein concentrate is used in baked goods, breakfast cereals, and some meat products.
  3. Textured Soy Protein (TSP): Also known as textured vegetable protein (TVP), TSP is made from soy protein concentrate by giving it a texture similar to that of meat. It’s often used as a meat substitute in vegetarian and vegan recipes.

Nutritional Benefits

  • Complete Protein: Soy protein provides all essential amino acids in sufficient amounts for human health, making it an excellent protein source for vegetarians and vegans.
  • Heart Health: Studies have shown that consuming soy protein can lower blood cholesterol levels and reduce the risk of heart disease.
  • Weight Management: High in protein and low in fat, soy protein can help with satiety and weight management as part of a balanced diet.
  • Bone Health: Some research suggests that soy protein, rich in isoflavones, may have a positive effect on bone health, although more studies are needed.


  • Allergies: Soy is one of the eight major allergens. Individuals with soy allergies should avoid soy protein products.
  • Phytoestrogens: Soy contains isoflavones, a type of phytoestrogen that can mimic estrogen in the body. While studies have shown benefits for various health conditions, there’s ongoing research into their effects, particularly in large amounts.
  • GMOs: A significant portion of soy grown worldwide is genetically modified (GM). Those concerned about GMOs can look for organic or non-GMO certified soy products.
soy beans.

Comparing Soy Protein vs Pea Protein

Here are the top 5 differences between soy protein vs pea protein, focusing on their nutritional profiles, sources, allergenic potential, environmental impact, and health benefits:

  1. Source and Composition:
    • Soy Protein: Derived from soybeans, soy protein is a complete protein containing all nine essential amino acids necessary for human health. It’s available in various forms, including isolates, concentrates, and textured soy protein.
    • Pea Protein: Extracted from yellow split peas, pea protein is rich in many essential amino acids but is slightly lower in methionine. It’s primarily found as pea protein isolate, which is highly concentrated in protein.
  2. Allergenic Potential:
    • Soy Protein: Soy is one of the eight major allergens. Some individuals may have or develop an allergy to soy, making soy protein unsuitable for their diet.
    • Pea Protein: Generally considered hypoallergenic, pea protein is a safer option for individuals with common food allergies, including soy. However, it’s important to note that some people may still have sensitivities to peas.
  3. Nutritional Benefits:
    • Soy Protein: Beyond being a complete protein, soy protein contains isoflavones, compounds that may offer health benefits such as improved heart health, reduced risk of certain cancers, and potential bone health benefits.
    • Pea Protein: While not a complete protein, pea protein is rich in iron and arginine. It’s particularly beneficial for muscle growth, heart health, and is a good option for those looking to increase their protein intake without the risk of major allergens.
  4. Environmental Impact:
    • Soy Protein: Soy cultivation can have significant environmental impacts, including deforestation and the use of GMOs. However, sustainably sourced soy protein can mitigate some of these concerns.
    • Pea Protein: Peas have a lower environmental footprint, requiring less water and nitrogen fertilizer. Pea cultivation can also contribute to soil health, making pea protein a more sustainable choice.
  5. Digestibility and Use:
    • Soy Protein: Soy protein is known for its versatility in cooking and food production. It can be easily incorporated into a wide range of dishes, from shakes to meat substitutes, but its digestibility can vary among individuals.
    • Pea Protein: Pea protein is often praised for its digestibility and is commonly used in protein powders and health supplements. Its mild flavor makes it a flexible addition to smoothies and baked goods, although its texture might be less versatile in cooking compared to soy protein.

These differences highlight the unique attributes of soy and pea protein, making them suitable for various dietary needs, preferences, and environmental considerations.

Common Questions About the Proteins

Is soy protein bad for your kidneys?

Soy protein is generally safe and can be beneficial for most people, including those with kidney concerns. It’s a complete protein that’s easier on the kidneys compared to some animal proteins because the phosphorus in soy, which needs to be monitored by people with kidney disease, is less absorbable by the body. This characteristic makes soy protein a potentially better choice for those managing kidney health.

For individuals with chronic kidney disease (CKD), managing protein intake is crucial, and soy protein might offer a protective effect. It’s associated with lower risks of conditions like proteinuria, where excess protein is found in the urine, indicating kidney stress. However, the total amount of protein consumed should still be monitored to avoid overburdening the kidneys.

It’s important for anyone with kidney issues or dietary concerns to consult with a healthcare provider or dietitian. They can provide personalized advice on incorporating soy protein into a diet that supports kidney health without exceeding protein needs. Whole soy foods, in particular, can be a nutritious part of this approach, offering additional health benefits beyond protein.

Is pea protein a complete protein?

Pea protein is often considered a complete protein because it contains all nine essential amino acids that the human body cannot synthesize on its own. However, it’s worth noting that pea protein is relatively low in one essential amino acid, methionine. Despite this, for most dietary purposes, pea protein can effectively support the body’s protein needs, especially when included as part of a varied diet that includes other protein sources to ensure a balanced amino acid profile.

Incorporating a mix of plant-based protein sources can help ensure you’re getting a well-rounded array of amino acids. For example, combining pea protein with rice protein can complement each other, as rice protein is higher in methionine. This approach allows for a more balanced amino acid intake, making pea protein a viable protein source for vegetarians, vegans, and those looking to reduce their consumption of animal proteins.

Which is better for building muscle?

For muscle building, both pea protein and soy protein offer significant benefits, but their differences might sway your choice depending on personal health goals and dietary preferences. Soy protein, with its complete amino acid profile including branched-chain amino acids (BCAAs), is particularly effective for muscle synthesis and recovery. Its comprehensive nutrients make it a strong candidate for those aiming to enhance muscle growth efficiently.

Pea protein, while slightly lower in methionine, is rich in arginine, another key amino acid for muscle development. It stands out as an excellent option for individuals with soy allergies or those seeking a soy-free protein source. Its hypoallergenic nature and digestibility make it a viable alternative for supporting muscle building in a plant-based diet.

Ultimately, the choice between pea and soy protein for muscle building should align with your dietary needs, allergies, and taste preferences. Incorporating a variety of protein sources can also help achieve a balanced amino acid profile, essential for optimal muscle repair and growth. Whether you choose pea, soy, or a combination of plant-based proteins, consistency in your diet and workout regimen is key to achieving your muscle-building goals.

Which protein is better for seniors?

For seniors, selecting the right protein source is key to supporting their unique nutritional needs. Soy protein, with its complete profile of essential amino acids, supports muscle and bone health, making it a strong option for maintaining strength and mobility. Its isoflavones can benefit heart health and potentially aid in bone density, important factors for aging adults. However, those with specific health conditions like thyroid issues may need to be cautious with soy.

Pea protein offers an excellent alternative for seniors, especially for those with dietary sensitivities or allergies to soy. It’s easily digestible and provides valuable nutrients such as iron and arginine, which are beneficial for heart health and circulation. While it’s slightly lower in methionine, a varied diet can easily compensate for this.

Choosing between pea and soy protein for seniors ultimately depends on individual health considerations and dietary preferences. Both can be part of a healthy diet, but it’s important to consult with a healthcare provider to ensure the protein source aligns with the senior’s health goals and medical advice, ensuring optimal nutrition and well-being.

Final 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 dietitian
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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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