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Flax Seeds vs Soy: Which One is Better for You?

This article explains the key similarities and differences between flax seeds and soy, foods from the grains and legumes food groups. Read on to learn more about the flax seeds vs soy comparison.
Esther Bumpus, Health Writer

Written by Esther Bumpus, Health Writer. Updated on March 5, 2023.

Although flax seeds and soy belong to different food groups, and it’s not that common to compare foods from different groups, people are often interested in these comparisons as well.

While flax seeds belong to the nuts and seeds group, soy belong to legumes food group.

That’s why we decided to create an in-depth article that compares flax seeds and soy, their nutritional values, similarities, differences, macronutrients, and micronutrients – vitamins and minerals.

Generally speaking, foods from nuts and seeds group are usually higher in healthy fats and lower in carbs than legumes, but both are valuable addition to a plant-based diet.

Now, let’s see how flax seeds and soy compare specifically.

Flax Seeds

Flax seeds (Linum usitatissimum) are small, golden, or brown seeds that have a nutty and slightly earthy flavor.

These seeds have been used for centuries as food and for their medicinal properties and are now gaining popularity as a health food.

Flax seeds are a good source of fiber, protein, and omega-3 fatty acids, making them a valuable addition to a plant-based diet.

They are also high in lignans, which are plant compounds that have been shown to have antioxidant and estrogen-like effects.

There are many ways to incorporate flax seeds into your diet. They can be eaten raw or ground into a meal and can be added to various dishes, including smoothies, baked goods, and even savory dishes.

Flax seeds are also available in oil form, which can be used as a healthy alternative to vegetable oil in cooking.

It is important to note that flax seeds should be ground before consumption, as the whole seeds may pass through the digestive system undigested.

They should also be stored in the refrigerator or freezer to keep them fresh and prevent them from going rancid.

If you want to add more fiber, protein, and healthy fats to your diet, consider giving flax seeds a try. They are versatile, nutritious, and may have various health benefits.

Flax Seeds is an excellent source of Vitamin B1 (Thiamine), and Vitamin B6 (Pyroxidine).

It also contains a good amount of Vitamin B2 (Riboflavin), Vitamin B3 (Niacin), Vitamin B5 (Pantothenic acid), and Vitamin B9 (Folate) and some Vitamin K.


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.

Flax Seeds vs Soy Nutrition

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

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

Flax SeedsSoy
Energy534 kcal446 kcal
Carbs28.9 g30.2 g
Sugar1.55 g7.33 g
Fiber27.3 g9.3 g
Protein18.3 g36.5 g
Fat42.2 g19.9 g
Saturated Fat3.66 g2.88 g

Flax Seeds vs Soy Calories

Comparing soy vs flax seeds for weight loss, soy are slightly lower in calories, with 446 calories per 100 grams, compared to 534 calories per 100 grams of flax seeds.

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

Flax Seeds vs Soy Protein

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

Soy offer around 50% more protein than flax seeds.

Soy have 36.5 grams of protein per 100 grams, while flax seeds has 18.3 grams of protein per 100 grams.

Flax Seeds vs Soy 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 flax seeds and soy.

The total amount of carbohydrates is around 4% higher in soy than in flax seeds. They have 30.2 grams per 100 grams, compared to 28.9 grams in flax seeds.


There’s less sugar in flax seeds than in soy, 81% precisely.

One handful of flax seeds (28 grams) contains 0.4 grams of sugar, while the same amount of soy contains 2.1 grams.

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

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

With 7.6 grams of fiber per portion, flax seeds is a better source of fiber than soy which flax seeds offers 2.6 grams per portion.

Flax Seeds vs Soy Fats

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

Total fat in flax seeds and soy:

  • Flax Seeds: 42.2 grams per 100 grams
  • Soy: 19.9 per 100 grams

Speaking of saturated fats, soy are 22% lower in saturated fats.

Soy and flax seeds contain 2.9 grams and 3.7 grams of saturated fat per 100 grams, respectively.

Flax Seeds vs Soy Vitamins Content

This section will discuss the vitamin content of flax seeds and soy.

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

Flax Seeds has a higher amount of vitamin A, vitamin C, vitamin B2 (Riboflavin), vitamin B9 (Folate), vitamin E, and vitamin K.

However, soy have a higher amount of vitamin B1 (Thiamine), vitamin B3 (Niacin), vitamin B5 (Pantothenic acid), and vitamin B6 (Pyroxidine).

Flax Seeds and soy contain the same amount of vitamin D, and vitamin B12 (Cobalamin).

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

Flax SeedsSoy
Vitamin A022 IU
Vitamin C0.6 mg6 mg
Vitamin D00
Vitamin B1 (Thiamine)1.64 mg0.874 mg
Vitamin B2 (Riboflavin)0.161 mg0.87 mg
Vitamin B3 (Niacin)3.08 mg1.62 mg
Vitamin B5 (Pantothenic acid)0.985 mg0.793 mg
Vitamin B6 (Pyroxidine)0.473 mg0.377 mg
Vitamin B9 (Folate)87 µg375 µg
Vitamin B12 (Cobalamin)00
Vitamin E0.31 mg0.85 mg
Vitamin K4.3 µg47 µg

Flax Seeds vs Soy 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 flax seeds and soy comparison focuses on their mineral content.

Flax Seeds is a better source of calcium, copper, fluoride, iron, manganese, phosphorus, potassium, and zinc than soy.

On the other hand, soy are a higher amount of magnesium, selenium, and sodium.

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

Flax SeedsSoy
Calcium255 mg277 mg
Copper1.22 mg1.66 mg
Fluoride02.2 µg
Iron5.73 mg15.7 mg
Magnesium392 mg280 mg
Manganese2.48 mg2.52 mg
Phosphorus642 mg704 mg
Potassium813 mg1800 mg
Selenium25.4 µg17.8 µg
Sodium30 mg2 mg
Zinc4.34 mg4.89 mg

The Final Word

Flax Seeds and soy are highly nutritious and a great addition to a plant-based diet.

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

Antioxidants found in nuts, seeds 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, nuts and seeds are a 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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