Do Potatoes Contain Lysine? Exploring the Amino Acid Profile

November 19, 2025 •

3 min read

Recent nutritional studies have confirmed that potatoes, though often dismissed as a simple carbohydrate source, are surprisingly rich in essential nutrients. A common question that arises is: do potatoes contain lysine? The short answer is yes, and what's more, their protein quality is considered very high for a plant-based food source.

Quick Summary

Potatoes contain all nine essential amino acids, including lysine, making them a complete protein source, though total protein content is low. The protein quality is high, often comparable to animal proteins, demonstrating a balanced amino acid profile, particularly in lysine relative to other grains.

Key Points

Complete Protein Source: Potatoes contain all nine essential amino acids, including lysine, making them a 'complete' protein for human dietary needs.
High Biological Value: The protein quality of potatoes is exceptionally high for a plant, often compared favorably to animal proteins like whole eggs.
Significant Lysine Ratio: The amount of lysine per gram of protein in potatoes is notably higher than in many common grains such as pasta and rice.
Nutrient-Dense Skin: The highest concentration of protein and many nutrients, including lysine, is found just beneath the potato's skin.
Moderate Total Protein: Despite high protein quality, the overall protein content of a potato is relatively low, so it should be combined with other protein sources.

The Protein Profile of Potatoes

While potatoes are best known for their high carbohydrate content, they also provide a modest amount of protein that is remarkably high in quality for a plant-based food. A medium-sized potato contains about 3 grams of protein, a figure that is often overlooked when evaluating its nutritional value. Unlike many plant-based protein sources, potatoes contain all nine essential amino acids, making them a 'complete' protein. The specific presence of lysine is a key factor contributing to this high biological value.

Lysine in Potatoes: The Complete Picture

Lysine is an essential amino acid, meaning the human body cannot produce it and must obtain it through diet. The presence of lysine in a food is a primary determinant of its protein quality. In a nutritional analysis, potatoes stand out, containing a higher ratio of lysine to other essential amino acids compared to common staples like white rice and pasta.

Here are some key facts about lysine in potatoes:

Potatoes provide approximately 0.119 grams of lysine per 100 grams, contributing a small but valuable amount to your daily intake.
For context, a medium-sized baked potato (around 175g with skin) provides approximately 250mg of lysine.
This makes potatoes a notable source, especially for individuals following a vegan or vegetarian diet who need diverse plant sources to meet their amino acid needs.
The lysine is present in the tuber's protein and is concentrated just under the skin, making it beneficial to consume potatoes whole or with the skin on.

Comparison of Amino Acid Profiles

Comparing the amino acid profiles of potatoes to other common staples highlights their high protein quality, particularly regarding lysine. The table below illustrates the amount of lysine and other essential amino acids (in mg per gram of protein) in potatoes versus other grains based on Institute of Medicine (IOM) recommended patterns.


Amino Acid	IOM Pattern (mg/g protein)	Potato (mg/g protein)	Pasta (mg/g protein)	White Rice (mg/g protein)
Lysine	51	61	22.6	36.1
Methionine + Cysteine	25	28.8	30.3	44.1
Threonine	27	36.3	35	35.7
Tryptophan	7	15.5	14	11.8

As the table clearly shows, potato protein contains a higher concentration of lysine per gram than the IOM reference pattern, surpassing pasta and white rice significantly. While the total protein content of a potato is lower, the quality of that protein is exceptionally high due to this balanced amino acid profile.

Factors Affecting Amino Acid Content

The amino acid composition of a potato can be influenced by several factors. These include:

Cultivar: Different potato varieties can have slightly different nutritional profiles. For instance, some varieties bred for protein content may offer higher levels of essential amino acids.
Growing Conditions: The agroclimatic conditions and fertilizer levels, particularly nitrogen, can affect the total amino acid content.
Cooking Method: While cooking can alter the content of some nutrients, studies show that boiling with the skin on helps retain more of the water-soluble vitamins and nutrients.
Storage: The duration and conditions of storage can also impact the levels of individual amino acids over time.

Incorporating Potatoes for Lysine Intake

Including potatoes in a balanced diet is an excellent way to contribute to overall nutritional intake. For optimal nutritional benefits, consider the following methods:

Baked with Skin: This method preserves the nutrients concentrated just beneath the skin, including a significant portion of the lysine and fiber.
Boiled and Cooled: Cooling cooked potatoes increases their resistant starch content, which provides prebiotic benefits for gut health.
Pairing for Balance: While high in quality, potato protein is limited in quantity. Pair potatoes with other plant-based lysine sources like lentils, chickpeas, or quinoa to boost total protein intake.

Conclusion

In conclusion, the answer to the question, do potatoes contain lysine, is a definitive yes. Not only is this essential amino acid present, but its proportion relative to the other essential amino acids is exceptionally high for a plant-based food. While they may not be a primary protein source due to their lower total protein content, the high biological value of potato protein makes them a valuable component of a healthy diet. By cooking them with the skin and incorporating them into meals with other diverse protein sources, you can maximize their nutritional contribution to your overall health.

For further reading on potato protein quality, an excellent resource is a publication in ScienceDirect.

Frequently Asked Questions

Lysine is an essential amino acid, which means it cannot be produced by the human body and must be obtained from food. It plays a crucial role in protein synthesis, calcium absorption, and the production of hormones and enzymes.

While potatoes are not a high-protein food by volume, the protein they do contain is considered very high-quality because it includes all essential amino acids, particularly a strong profile of lysine.

The lysine, along with many other important nutrients, is most concentrated in the thin layer of flesh located directly under the potato's skin.

The protein in potatoes has a very high biological value, sometimes rated similarly to that of egg protein. However, the total amount of protein in a potato is significantly lower than in most animal products.

Cooking methods like boiling or baking do not significantly diminish the lysine content, particularly if the skin is left on. However, nutrient content can vary slightly with different cooking and storage methods.

While potatoes contain lysine, the total amount is relatively small. A balanced diet with diverse protein sources, such as legumes, nuts, and other vegetables, is necessary to meet daily lysine requirements.

No, the amino acid composition can vary between different potato cultivars, though they all contain lysine. However, this variation is generally minor, and all varieties offer high-quality protein.