Which food has all 9 essential amino acids?

October 8, 2025 •

4 min read

Did you know that out of the 20 amino acids your body needs, nine are considered 'essential' and must be obtained through your diet? Learning which food has all 9 essential amino acids, known as complete proteins, is key for building muscle, producing hormones, and repairing tissues. This guide explores the best complete protein sources for both omnivores and plant-based eaters.

Quick Summary

The body cannot produce nine essential amino acids, requiring them from food, which is why a 'complete protein' is one containing all nine. Both animal products like meat, eggs, and dairy, as well as several plant-based foods such as quinoa and soybeans, are excellent sources of complete proteins.

Key Points

Complete Proteins: Foods containing all nine essential amino acids are called 'complete proteins'.
Animal Sources: Meat, poultry, fish, eggs, and dairy are all reliable and highly bioavailable complete protein sources.
Plant-Based Options: Quinoa, soy (tofu, edamame), buckwheat, hemp seeds, pistachios, and spirulina are notable plant-based complete proteins.
Complementary Proteins: Combining two or more incomplete plant proteins, like rice and beans, ensures all essential amino acids are obtained over a day.
Dietary Variety: Eating a varied diet is the most effective way for both omnivores and plant-based eaters to meet their essential amino acid needs.
Amino Acid Function: These vital molecules are crucial for muscle growth, tissue repair, hormone production, and supporting the immune system.

What are Essential Amino Acids?

Your body requires 20 different amino acids to function, serving as the building blocks for protein. While the body can synthesize 11 of these, the remaining nine, known as essential amino acids (EAAs), must come from your diet. The nine essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. A complete protein is any food source that contains all nine of these EAAs in sufficient amounts.

Animal-Based Complete Protein Sources

Animal proteins are the most widely known and recognized sources of complete proteins. Their amino acid profiles closely match the human body's needs, making them highly bioavailable. This means the body can absorb and utilize the amino acids effectively.

Meat, Poultry, and Fish

Lean meats like chicken breast, turkey, beef, and pork are classic examples of complete proteins. A 3-ounce serving of chicken breast provides a substantial amount of complete protein, crucial for muscle repair and growth. Similarly, fish like salmon and tuna are excellent sources, offering not only complete protein but also heart-healthy omega-3 fatty acids.

Eggs and Dairy Products

Eggs are often referred to as nature's perfect protein source, providing all essential amino acids in high proportions. A single egg contains approximately 6 grams of complete protein. Dairy products, including milk, cheese, and yogurt, are also fantastic sources of complete protein. Greek yogurt, for instance, offers a significant protein boost in a small serving.

Plant-Based Complete Protein Sources

While many people believe plant proteins are incomplete, several plant-based foods naturally contain all nine essential amino acids. These are vital options for vegetarians, vegans, and those seeking to diversify their diet. Even traditionally incomplete plant proteins can be combined to form a complete profile over the course of a day.

Quinoa

Technically a seed, but classified as a whole grain, quinoa is one of the most celebrated plant-based complete protein sources. A single cooked cup contains about 8 grams of protein along with other vital nutrients like fiber, manganese, and phosphorus.

Soy Products

Soybeans and their derivatives, such as tofu, tempeh, and edamame, are a cornerstone of plant-based nutrition due to their complete protein content. A half-cup serving of firm tofu, for example, can provide about 15 grams of complete protein.

Buckwheat

Another pseudocereal, buckwheat is a versatile gluten-free seed that offers a complete protein profile. It can be used as a grain, ground into flour, or eaten as groats.

Other Complete Plant Proteins

Hemp Seeds: Known for their rich protein and healthy fat content, hemp seeds provide all essential amino acids.
Pistachios: Recently recognized as a complete protein source, roasted pistachios provide adequate levels of all nine EAAs.
Spirulina: This blue-green algae is a nutrient-dense superfood and a complete protein source.
Mycoprotein: This is a fungus-derived protein often used as a meat substitute (e.g., Quorn) and is considered a complete protein.

Comparison of Complete Protein Sources


Food Type	Example	Protein Content (approx.)	Amino Acid Profile	Best For
Animal	Eggs	6g per egg	Complete, highly bioavailable	Quick, versatile meals; muscle synthesis
Animal	Chicken Breast	26g per 3oz serving	Complete, lean source	Main course protein, muscle repair
Plant	Quinoa	8g per cooked cup	Complete, gluten-free	Salad bases, side dishes
Plant	Tofu	15g per 3oz serving	Complete, soy-based	Versatile cooking, vegan source
Plant	Hemp Seeds	9g per 3 tbsp	Complete, also high in fats	Smoothie booster, salad topper

The Complementary Protein Approach

For a balanced vegetarian or vegan diet, relying on complementary proteins is an effective strategy. This involves combining incomplete protein sources throughout the day to ensure all essential amino acids are consumed. For instance, combining rice (low in lysine) with beans (low in methionine) creates a complete amino acid profile. The body can draw from its amino acid pool to form complete proteins, so this pairing does not need to occur in a single meal. Classic examples include hummus and pita bread, or lentils with whole-grain bread.

Conclusion: Sourcing All Essential Amino Acids

Whether you consume animal products or follow a plant-based diet, obtaining all nine essential amino acids is very achievable with a varied diet. Animal products like meat, dairy, and eggs are reliable sources of complete protein. For plant-based eaters, dedicated complete proteins like quinoa, soy, and hemp seeds are excellent options. Furthermore, a smart approach to complementary proteins ensures that even non-complete plant sources can contribute to your body's full amino acid needs over the course of a day. By focusing on dietary variety, you can easily fuel your body with the necessary building blocks for health and vitality.

For more information on protein and amino acids, you can consult reliable sources like the Cleveland Clinic's articles on the topic.

Frequently Asked Questions

A complete protein is a food source that contains all nine essential amino acids (EAAs) that the human body cannot produce on its own.

No, vegetarians can easily get all essential amino acids by including a variety of plant-based protein sources in their diet throughout the day. Combining complementary proteins is a proven strategy.

Yes, quinoa is a great example of a complete plant-based protein. Although technically a seed, it is classified as a whole grain and provides all nine essential amino acids.

Most animal proteins like meat, eggs, and dairy are complete protein sources. However, some, like collagen, are technically incomplete because they lack tryptophan.

No, the body can combine amino acids from different foods consumed over the course of a day. The 'need' to combine them in one meal is an outdated myth.

Other complete plant proteins include buckwheat, hemp seeds, pistachios, and spirulina.

Essential amino acids are crucial for many bodily functions, including building and repairing muscle, creating hormones, producing enzymes, and supporting immune function.