Is There a Nut That is a Complete Protein? The Surprising Facts About Nuts, Seeds, and Amino Acids

October 5, 2025 •

4 min read

The human body requires nine essential amino acids from dietary sources to build and repair tissue. This raises a key question for those on plant-based diets: Is there a nut that is a complete protein? While most nuts are incomplete, a few notable exceptions and simple food pairings can provide all the essential amino acids needed for a balanced diet.

Quick Summary

This article explores the concept of complete and incomplete proteins, revealing that while most nuts lack one or more essential amino acids, pistachios are a complete protein. It also covers other plant-based complete protein sources like hemp and chia seeds, and provides simple strategies for pairing incomplete proteins to meet dietary needs.

Key Points

Pistachios are a Complete Protein: Unlike most nuts, roasted pistachios contain all nine essential amino acids, qualifying them as a complete protein source for those over five years old.
Hemp and Chia Seeds are Complete: Seeds like hemp and chia are also complete proteins and are frequently included in nutritional discussions about nuts, offering great versatility for plant-based diets.
Most Nuts are Incomplete: Nuts like almonds and cashews are considered incomplete proteins because they are deficient in one or more essential amino acids, such as lysine or methionine.
Complementary Proteins are Key: The concept of combining different incomplete protein sources, like nuts with whole grains or legumes, can create a complete protein profile over the course of a day.
Dietary Variety is Paramount: Relying on a mix of plant-based protein sources, rather than a single food, is the most effective way to ensure all amino acid needs are met for a healthy and balanced diet.
Nuts Offer More Than Just Protein: Incomplete nuts are still highly nutritious, providing healthy fats, fiber, vitamins, and minerals that contribute to overall health.

What Defines a Complete Protein?

Proteins are fundamental to life, involved in everything from building muscle to producing hormones. They are composed of smaller units called amino acids. Of the 20 amino acids, nine are considered “essential” because the body cannot produce them on its own. A "complete protein" is a food source that contains all nine of these essential amino acids in sufficient quantities. Traditionally, animal products like meat, eggs, and dairy are known as complete proteins. However, some plant-based foods can also fit this criteria. Most nuts and legumes, for example, are considered “incomplete” because they are deficient in one or more essential amino acids, most commonly lysine or methionine. This doesn't mean they aren't healthy or useful; it simply means they need to be complemented by other foods.

The Unique Case of Pistachios and Other Plant-Based Complete Proteins

While it’s true that most nuts are incomplete, recent research has put a spotlight on a few plant-based powerhouses. Pistachios and certain seeds stand out for their exceptional amino acid profiles.

Pistachios: The Complete Nut Protein

For years, the idea of a complete protein from a nut was a rarity. However, studies have confirmed that roasted pistachios contain all nine essential amino acids in adequate amounts, making them a true complete protein for individuals over five years old. A ¼ cup serving of pistachios offers around 6 grams of high-quality plant protein, along with other benefits such as healthy fats, fiber, and important vitamins. Their rich nutritional profile, along with being one of the lower-calorie nuts, makes them an excellent addition to any diet.

Seeds that Act Like Complete Nuts

Beyond pistachios, several seeds that are often consumed similarly to nuts also qualify as complete protein sources.

Hemp Seeds: These nutty-flavored seeds are a complete protein and a superb source of omega-3 and omega-6 fatty acids, fiber, and essential minerals like magnesium, iron, and zinc. Just three tablespoons provide nearly 10 grams of protein.
Chia Seeds: The versatile chia seed is also a complete protein source, offering a strong boost of protein, fiber, and healthy omega-3 fats, making it a great addition to smoothies, oatmeal, and baked goods.

The Importance of Complementary Proteins

Even if a nut is not a complete protein on its own, it can still play a vital role in meeting your protein needs. This is done through the concept of complementary proteins, where you combine two or more incomplete protein sources to form a complete amino acid profile. The notion that complementary proteins must be eaten in the same meal is an outdated myth; consuming a variety of protein sources throughout the day is sufficient.

Combining Nuts and Other Foods for Complete Protein

Pairing nuts and seeds with other plant-based foods is an effective and simple way to create a complete protein meal. This approach is fundamental to a well-rounded vegan or vegetarian diet.

Common Combinations:

Grains + Nuts/Seeds: Peanut butter on whole-grain toast is a classic example. The peanut butter and whole wheat bread complement each other perfectly to deliver all nine essential amino acids.
Legumes + Nuts/Seeds: Sprinkling sunflower seeds or walnuts on a lentil salad or a bean chili can complete the protein profile of the meal.
Nuts + Legumes: A trail mix containing nuts, seeds, and roasted chickpeas or edamame is another effective combination for a complete protein snack.

Comparing the Protein Profiles of Nuts and Seeds

The following table illustrates the protein content per 100 grams for some popular nuts and seeds, along with their completeness status. It highlights why certain combinations are so effective and points to the standout complete protein sources.


Nut/Seed	Protein (g per 100g)	Completeness Status	Limiting Amino Acid(s)	Complementary Foods
Pistachios	~20	Complete	None	Not required for completeness
Hemp Seeds	~31	Complete	None	Not required for completeness
Almonds	~21	Incomplete	Lysine	Legumes (lentils, chickpeas)
Cashews	~18	Incomplete	Methionine	Grains (rice, quinoa)
Peanuts*	~26	Incomplete	Methionine	Grains (whole-wheat bread)
Walnuts	~15	Incomplete	Lysine	Grains, legumes
*Technically a legume but nutritionally similar to nuts.

Conclusion: Embracing Variety for Optimal Nutrition

So, is there a nut that is a complete protein? Yes, pistachios, along with seeds like hemp and chia, offer a complete amino acid profile. However, it's important to remember that most nuts are not complete on their own. This does not diminish their nutritional value, as they are still fantastic sources of protein, healthy fats, fiber, and a wide array of vitamins and minerals. For those following a plant-based diet, the key lies not in finding a single perfect food, but in embracing dietary variety. By combining different plant foods, you can easily meet your protein needs throughout the day. A handful of pistachios for a snack or a trail mix with almonds and seeds can contribute significantly to your overall nutritional intake. The old-fashioned wisdom of eating a diverse diet is still the best strategy for reaping all the health benefits that nuts and seeds have to offer.

For more detailed nutritional information and guidance on creating a balanced plant-based diet, resources like the American Institute for Cancer Research provide excellent insights on getting sufficient protein from a variety of plant sources.

Frequently Asked Questions

No, it is not necessary to combine complementary proteins in the same meal. The human body maintains a pool of amino acids throughout the day, so eating a variety of plant-based protein sources over the day is sufficient to meet your needs.

No, peanuts are a legume and are considered an incomplete protein because they are low in the amino acid methionine. However, pairing them with a complementary food, like whole-grain bread, creates a complete protein.

While pistachios are the only true nut definitively identified as a complete protein, seeds often grouped with nuts, such as hemp seeds and chia seeds, are also complete proteins.

Good complementary foods include grains like rice or quinoa, legumes such as lentils and beans, and seeds. For instance, pairing a handful of almonds with a lentil salad helps create a complete protein.

If you eat a varied diet that includes a wide range of plant-based foods, such as grains, legumes, nuts, and seeds, you can easily get all the essential amino acids you need. Variety is the most important factor.

Yes, all nuts contain some amount of protein. However, the amount and amino acid profile vary significantly. Peanuts, for instance, have a very high protein content compared to other nuts like pecans, but are still considered an incomplete protein.

You can incorporate more complete proteins by snacking on pistachios, adding hemp or chia seeds to smoothies and oatmeal, or using soy products like tofu and edamame. You can also build meals using complementary protein combinations.