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Soy vs Soy Protein Isolate: How Are They Different?

This article explains the key similarities and differences between soy and soy protein isolate, foods from the legumes and legume product group. Read on to learn more about the soy vs soy protein isolate comparison.
Michael Whaley, Health Writer

Written by Michael Whaley, Health Writer. Updated on January 19, 2023.

Soy and soy protein isolate belong to the legumes and legume products food group, one of the staple food groups for people on a plant-based diet.

Legumes and most legume products are an affordable source of plant protein, dietary fiber, B vitamins, and minerals such as iron, calcium, potassium, and zinc, minerals that are usually harder to get on a plant-based diet.

This article will thoroughly compare soy and soy protein isolate and help you learn more about their similarities and differences.


Soybeans (Glycine max) are a type of legume native to East Asia.

They are a popular ingredient in many vegan and vegetarian dishes due to their high protein and fiber content. Soy protein is one of the complete sources of a plant-based protein.

Soybeans can be enjoyed in a variety of dishes, including tofu, soy milk, and soy-based meat substitutes, and can also be ground into flour and used in baked goods such as bread and cookies.

In addition to being a tasty and nutritious food, soybeans have been shown to have many potential health benefits.

They are a good source of antioxidants and have been linked to lower cholesterol levels and improved blood sugar control.

Soybeans are also a good source of several important minerals, including iron, zinc, and magnesium.

Soy are an excellent source of Vitamin B1 (Thiamine), Vitamin B2 (Riboflavin), Vitamin B9 (Folate), and Vitamin K.

They also contain a good amount of Vitamin B3 (Niacin), Vitamin B5 (Pantothenic acid), and Vitamin B6 (Pyroxidine) and some Vitamin C, and Vitamin E.

Soy Protein Isolate

Soy protein isolate is a highly purified form of protein derived from soybeans.

It is made by removing most of the fats and carbohydrates from soybeans, leaving mostly protein behind. It is a popular ingredient in many processed foods, such as protein bars and powders, as well as in meat and dairy alternatives.

Soy protein is also used as a binder and emulsifier in various foods.

Soy protein isolate is a good source of essential amino acids, which are the building blocks of protein. It is also low in fat and cholesterol-free, making it a heart-healthy option.

Additionally, it may help to lower cholesterol levels, improve bone health and support weight management. It can also be a good source of protein for vegetarians and vegans.

Soy Protein Isolate is an excellent source of Vitamin B9 (Folate).

It also contains a good amount of Vitamin B1 (Thiamine) and some Vitamin B2 (Riboflavin), Vitamin B3 (Niacin), and Vitamin B6 (Pyroxidine).

Soy vs Soy Protein Isolate Nutrition

Now that we’ve described the origin, taste, and usage of these foods, we can move to the most interesting part – comparing soy vs soy protein isolate.

This comparison will start by comparing the caloric value of soy and soy protein isolate and their macronutrients and then go more in-depth by analyzing their vitamin and mineral content.

SoySoy Protein Isolate
Energy446 kcal335 kcal
Carbs30.2 g0 g
Sugar7.33 g0 g
Fiber9.3 g0 g
Protein36.5 g88.32 g
Fat19.9 g3.39 g
Saturated Fat2.88 g0.422 g

Soy vs Soy Protein Isolate Calories

Most calories in raw legumes come from carbs. Peanuts are an exception here, but they are often considered a nut instead of a legume because of their nutritional profile.

Comparing soy protein isolate vs soy for weight loss, soy protein isolate is slightly lower in calories, with 335 calories per 100 grams, compared to 446 calories per 100 grams of soy.

However, both soy and soy protein isolate can and should be a part of a healthy diet, and neither one shouldn’t be avoided if you’re looking to lose weight.

Soy vs Soy Protein Isolate Protein

Legumes and most legume products, including soy and soy protein isolate, are important sources of plant-based protein.

Soy Protein Isolate offers around 59% more protein than soy.

Soy Protein Isolate has 88.3 grams of protein per 100 grams, while soy have 36.5 grams of protein per 100 grams.

Soy vs Soy Protein Isolate Carbs

Counting carbs can be important for some people for different reasons, including blood sugar control, weight management, or athletic performance.

It’s also important for people on a keto diet, so let’s compare the carbs content in soy and soy protein isolate.

The total amount of carbohydrates is around 100% higher in soy than in soy protein isolate. They have 30.2 grams per 100 grams, compared to 0 grams in soy protein isolate.

There’s less sugar in soy protein isolate than in soy, 100% precisely.

One handful of soy protein isolate (28 grams) contains 0 grams of sugar, while the same amount of soy contains 2.1 grams.

Lastly, let’s take a look at the dietary fiber in soy and soy protein isolate.

Dietary fiber keeps the digestive system healthy and helps with weight management by promoting a sense of fullness.

With 2.6 grams of fiber per portion, soy are a better source of fiber than soy protein isolate which soy offer 0 grams per portion.

Soy vs Soy Protein Isolate Fats

Like most other legumes, with the exception of lupins and peanuts, soy and soy protein isolate are low in fat.

Fats in soy and soy protein isolate are mostly healthy unsaturated fats. They are naturally cholesterol-free and trans-fat-free.

Total fat in soy and soy protein isolate:

  • Soy: 19.9 grams per 100 grams
  • Soy Protein Isolate: 3.4 per 100 grams

Speaking of saturated fats, soy protein isolate is 86% lower in saturated fats.

Soy Protein Isolate and soy contain 0.4 grams and 2.9 grams of saturated fat per 100 grams, respectively.

Soy vs Soy Protein Isolate Vitamins Content

This section will discuss the vitamin content of soy and soy protein isolate.

Vitamins are micronutrients, meaning we need only a small amount. However, they are very important for many processes in our bodies.

However, soy protein isolate has a higher amount of vitamin A, vitamin C, vitamin B1 (Thiamine), vitamin B2 (Riboflavin), vitamin B3 (Niacin), vitamin B5 (Pantothenic acid), vitamin B6 (Pyroxidine), vitamin B9 (Folate), vitamin E, and vitamin K.

Soy and soy protein isolate contain the same amount of vitamin D, and vitamin B12 (Cobalamin).

The following table shows the exact amount of vitamins soy and soy protein isolate contain side by side, so you can easily compare them.

SoySoy Protein Isolate
Vitamin A22 IU0
Vitamin C6 mg0
Vitamin D00
Vitamin B1 (Thiamine)0.874 mg0.176 mg
Vitamin B2 (Riboflavin)0.87 mg0.1 mg
Vitamin B3 (Niacin)1.62 mg1.438 mg
Vitamin B5 (Pantothenic acid)0.793 mg0.06 mg
Vitamin B6 (Pyroxidine)0.377 mg0.1 mg
Vitamin B9 (Folate)375 µg176 µg
Vitamin B12 (Cobalamin)00
Vitamin E0.85 mg0
Vitamin K47 µg0

Soy vs Soy Protein Isolate Minerals Content

Minerals are important for our body to function properly. We need only a small amount of minerals, so they are called micronutrients.

Some minerals, like iron, calcium, zinc or, iodine, are relatively hard to get on a plant-based diet, so it’s important to choose your foods thoughtfully. This part of the soy and soy protein isolate comparison focuses on their mineral content.

Soy are a better source of phosphorus, and sodium than soy protein isolate.

On the other hand, soy protein isolate is a higher amount of calcium, copper, fluoride, iron, magnesium, manganese, potassium, selenium, and zinc.

Check out the table below to learn how soy and soy protein isolate compare when it comes to mineral content.

SoySoy Protein Isolate
Calcium277 mg178 mg
Copper1.66 mg1.599 mg
Fluoride2.2 µg0
Iron15.7 mg14.5 mg
Magnesium280 mg39 mg
Manganese2.52 mg1.493 mg
Phosphorus704 mg776 mg
Potassium1800 mg81 mg
Selenium17.8 µg0.8 µg
Sodium2 mg1005 mg
Zinc4.89 mg4.03 mg

The Final Word

Soy and soy protein isolate are highly nutritious and a great addition to a plant-based diet.

Both soy and soy protein isolate are high in specific vitamins and minerals, and including them in your diet will give you the most benefits they offer.

Antioxidants found in beans and legumes can help to protect cells from damage and may reduce the risk of certain diseases and the effects of aging.

Additionally, the fiber and other nutrients in these foods can support the health of the digestive system and may even help to prevent certain digestive cancers.

Legumes are versatile food that can be incorporated into any meal of the day, including breakfast, lunch, or dinner. They can be served hot or cold, making them a convenient and tasty addition to a variety of dishes.


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How we ensure this article is accurate?
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  2. We cite relevant studies and trusted sources.
  3. It's regularly updated.

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