Science & Nature • Crop

Soy

Soy is a legume crop native to Asia, grown for its protein- and oil-rich seeds.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

Soy is a legume crop native to Asia and now grown worldwide. It is cultivated for its protein- and oil-rich seeds, and plays a major role in human food, animal feed, and industrial products. Soy is a key source of complete plant protein and is widely used in vegetarian and vegan diets.

Botany and origin

Soy refers to the cultivated soybean (Glycine max), a legume belonging to the family Fabaceae. The crop is native to Asia and has been a staple in Asian cuisines for thousands of years. It is now grown across many regions globally.

Uses

Soybeans are processed into a variety of foods, including tofu, soy milk, tempeh, miso, and soy sauce. Soybean oil is used in cooking and industrial applications, while soybean meal is widely used as animal feed. Soy-based materials also appear in some industrial products.

Nutrition

Soy is valued for its high-quality protein, fiber, vitamins, minerals, and isoflavones. It is considered a complete plant protein because it contains all nine essential amino acids, making it a common meat and dairy substitute in vegetarian and vegan diets.

Health research

Soy has been studied for potential effects on cholesterol, heart health, menopause symptoms, and cancer risk. Public-health sources generally describe soy as safe for most people who do not have a soy allergy; individuals with hypothyroidism may seek medical advice.

Key facts

Soybeans are a legume cultivated globally for their oil and protein content.
Soy foods provide complete plant protein, containing all nine essential amino acids.
Soy contains isoflavones, plant compounds often studied for health effects.
Common soy foods include edamame, tofu, tempeh, miso, soy milk, and soy sauce.
Soybean meal is widely used in animal feed, while soybean oil is used in cooking and industry.

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Canadian context

Soy is relevant in Canada as a major crop and food ingredient used in plant-based foods, cooking oils, animal feed, and processed foods.

Frequently asked questions

What is soy?

Soy is a legume crop, usually referring to the soybean, grown for food, oil, and feed.

What is soy used for?

Soy is used in foods such as tofu, soy milk, tempeh, miso, and soy sauce, as well as soybean oil and animal feed.

Is soy a complete protein?

Yes. Soy is considered a complete protein because it contains all nine essential amino acids.

Where did soy originate?

Soy is native to Asia and has been a staple in Asian cuisines for thousands of years.

What are isoflavones?

Isoflavones are plant compounds in soy, often described as phytoestrogens because they can interact weakly with estrogen receptors.

Is soy safe to eat?

For most people, soy foods can be part of a healthy diet. People with a soy allergy should avoid soy, and some sources note that individuals with hypothyroidism may need medical advice.

References

Medical News Today — https://www.medicalnewstoday.com/articles/320472
Supports: Soy is a legume of Asian origin, is high in plant protein, and is used in many food forms.
Harvard T.H. Chan School of Public Health — https://nutritionsource.hsph.harvard.edu/soy/
Supports: Soy contains isoflavones, is nutrient-dense, and is a source of high-quality protein.
Better Health Channel — https://www.betterhealth.vic.gov.au/health/healthyliving/soybeans
Supports: Soybeans are legumes, have been a staple of Asian cuisines, and are a complete protein.
ScienceDirect — https://www.sciencedirect.com/topics/food-science/soybean
Supports: Soybeans are a leguminous plant native to Asia and are cultivated globally for oil and protein.
Soy Connection — https://www.soyconnection.com/nutrition-and-research/soy-myths-facts
Supports: Soy foods are generally safe for most people and soy protein can have cholesterol-lowering effects.