What Amino Acids Does Broccoli Contain? A Complete Guide

January 3, 2026 •

2 min read

Over 70% of the world's population increases its vegetable protein intake annually, and broccoli is a key player in this trend. This powerhouse vegetable, revered for its vitamins and minerals, also contains a broad spectrum of amino acids, the building blocks of protein. While not a complete protein source on its own, its amino acid profile is surprisingly robust and offers significant nutritional value.

Quick Summary

Broccoli contains numerous essential and non-essential amino acids, contributing significantly to a plant-based diet. Its profile includes key essential amino acids like leucine, lysine, and methionine, among others. By combining it with other plant foods, it helps form a complete protein intake, supporting various bodily functions and overall health.

Key Points

Contains all nine essential amino acids: Broccoli provides all nine essential amino acids, though not in sufficient quantities to be a standalone complete protein.
Rich in non-essential amino acids: It is also an excellent source of non-essential amino acids, such as glutamic acid and aspartic acid.
Not a complete protein source alone: Broccoli does not qualify as a 'complete' protein in a single serving because it's limited in certain essential amino acids.
Easily complemented with other foods: The protein completeness can be achieved by combining broccoli with other plant-based foods throughout the day, like grains or legumes.
Provides building blocks for vital functions: The amino acids in broccoli support crucial bodily functions, including muscle repair, immune response, and the synthesis of hormones.
Health benefits beyond protein: In addition to amino acids, broccoli is packed with other beneficial compounds like vitamins, minerals, and fiber, contributing to overall health.

Broccoli's Complete Amino Acid Profile

Broccoli contains a variety of both essential and non-essential amino acids. Essential amino acids must come from the diet, as the body cannot produce them. Broccoli provides some of these crucial building blocks, as well as numerous non-essential amino acids.

The Essential Amino Acids in Broccoli

Broccoli provides a range of essential amino acids vital for muscle synthesis, energy metabolism, and tissue repair. These include the branched-chain amino acids (BCAAs) Leucine, Isoleucine, and Valine. It also contains Lysine, important for protein synthesis; Methionine, a sulfur-containing antioxidant; Threonine, for immune function; Phenylalanine; Tryptophan, which influences mood and sleep; and Histidine, essential for growth.

The Non-Essential Amino Acids in Broccoli

Broccoli also supplies many non-essential amino acids, which the body can produce but benefits from obtaining through food. These include Glutamic Acid, the most abundant in broccoli protein and a key neurotransmitter; Aspartic Acid, important for hormone production; Cysteine, another sulfur-containing antioxidant; Alanine, Arginine, Glycine, Proline, Serine, and Tyrosine, which support glucose metabolism, cell division, collagen synthesis, and other metabolic processes.

Complete Protein vs. Complementary Proteins

While some sources suggest broccoli is a complete protein, it's generally considered an incomplete protein due to lower levels of certain essential amino acids. However, the body can combine amino acids from different foods eaten throughout the day to form complete proteins. This is known as protein combining. Combining broccoli with other plant foods like grains or beans can help ensure all essential amino acids are consumed, making it easy for those on plant-based diets to meet protein needs through a variety of whole foods.

A Comparison of Amino Acid Content: Broccoli vs. Other Plant-Based Sources


Amino Acid	Broccoli (mg/100g, approx)	Quinoa (mg/100g, cooked)	Black Beans (mg/100g, cooked)
Leucine	~129	~220	~140
Isoleucine	~79	~120	~80
Lysine	~135	~160	~150
Methionine	~38	~50	~20
Tryptophan	~33	~30	~40

Note: Values are approximate and can vary based on growing conditions and cooking methods. This table illustrates how combining different plant foods can provide a complete amino acid profile.

How Cooking Affects Amino Acids

Cooking methods can slightly affect nutrient content. While boiling can lead to some loss of water-soluble nutrients, steaming or stir-frying are better for preservation. The overall amino acid composition, however, remains relatively stable across common cooking methods, ensuring a broad nutrient intake regardless of preparation.

Conclusion

Broccoli is a valuable source of both essential and non-essential amino acids, making it a beneficial addition to any healthy diet, including plant-based ones. While not a complete protein on its own, its amino acids can be complemented by consuming a variety of other whole foods. Its diverse amino acid profile supports numerous bodily functions, from tissue repair to mood regulation. Combining broccoli with complementary plant foods is an effective strategy to maximize its health benefits and compounds like methionine and tryptophan. To learn more about the health benefits of cruciferous vegetables like broccoli, visit the National Institutes of Health website.

Frequently Asked Questions

The protein in broccoli is considered a high-quality plant-based protein, though not as bioavailable as animal protein. It provides a full spectrum of amino acids but requires pairing with other foods to meet all essential amino acid needs in sufficient quantities.

Vegans can get complete protein by practicing protein combining. This involves pairing broccoli with complementary foods throughout the day, such as grains (like rice or quinoa) and legumes (like beans or lentils).

While cooking, especially boiling, can cause some water-soluble nutrients to leach out, the amino acid content of broccoli remains relatively stable. Steaming or stir-frying are effective methods for preserving nutrients.

Glutamic acid is the most abundant amino acid found in broccoli's protein. It is a non-essential amino acid that plays a significant role in various biological processes.

Broccoli contains the amino acid tryptophan, a precursor to serotonin and melatonin, both of which are involved in regulating sleep patterns. Including it in your diet can support healthy sleep cycles.

While broccoli is not a primary source of protein for muscle growth, it contains branched-chain amino acids (BCAAs) like leucine, isoleucine, and valine, which are important for muscle protein synthesis. For significant muscle growth, it should be part of a diet with higher overall protein content.

Broccoli's amino acid profile is notably comprehensive compared to many other vegetables. While some, like spinach or legumes, may have higher concentrations of specific amino acids, broccoli offers a wide range of essential and non-essential types.