Which Amino Acid is Absent in Roti? The Truth About Lysine Deficiency

December 1, 2025 •

4 min read

According to research published by the National Institutes of Health, wheat, the primary ingredient in roti, is deficient in a crucial amino acid. This essential building block of protein, which the body cannot produce on its own, is what makes roti an incomplete protein source.

Quick Summary

The essential amino acid lysine is the most limiting amino acid in roti, a product of wheat flour. By combining roti with lysine-rich foods like legumes, a complete protein profile can be achieved. This strategy is vital for vegetarians and vegans.

Key Points

Lysine is the Limiting Amino Acid: The essential amino acid lysine is the most deficient amino acid in roti, which is made from wheat flour.
Roti is an Incomplete Protein: Due to its lysine deficiency, roti is classified as an incomplete protein source, meaning it lacks all nine essential amino acids in sufficient quantities.
Combine with Legumes: To form a complete protein, roti should be paired with legumes like dal, lentils, chickpeas, or beans, which are rich in lysine.
Dietary Variety is Key: Vegetarians and vegans need to ensure they consume a variety of complementary protein sources throughout the day to meet their essential amino acid requirements.
Choose Nutrient-Dense Pairings: Opt for high-lysine foods like dairy, soy products, eggs, or seeds to supplement your diet when consuming roti.
Homemade Roti vs. Commercial Bread: Homemade whole wheat roti typically has fewer additives and preservatives compared to commercial whole wheat bread, which can contain added sugars and higher sodium.

The Limiting Amino Acid: Lysine

Wheat, the grain used to make roti, contains protein but is not considered a complete source of protein. The primary reason for this is its low content of the essential amino acid lysine. An essential amino acid is one that the human body cannot synthesize on its own and must obtain from food. When a protein source lacks one or more of these essential amino acids, it is termed an "incomplete protein." In the case of roti and other wheat-based products, lysine is the most limited amino acid, meaning there is not enough of it to support optimal protein synthesis in the body.

When one essential amino acid is insufficient, it limits the body's ability to use the other available amino acids effectively. This means that even if a meal provides enough of the other essential amino acids, the overall protein utilization is capped by the low level of the limiting one, which is lysine for roti. The refining process to produce white flour can sometimes further reduce the nutritional value, although whole wheat flour is still deficient in lysine.

How to Achieve a Complete Protein Profile

For those who consume roti regularly, especially in vegetarian or vegan diets, understanding how to compensate for this deficiency is vital. The solution lies in combining different foods to create a "complete protein." This concept involves pairing an incomplete protein with another food that provides the missing amino acids, a concept known as protein complementation.

The Power of Complementary Proteins

Complementary proteins do not need to be consumed in the same meal, but over the course of a day, a varied diet is key to ensuring all essential amino acids are consumed. In many traditional cuisines, including Indian cuisine, this practice has been part of the dietary culture for centuries. For instance, pairing roti (a grain) with a legume-based dish like dal or chana provides the necessary lysine to complement the wheat protein, forming a complete protein meal.

High-Lysine Foods to Pair with Roti

To easily boost your lysine intake, consider incorporating the following foods into your diet alongside roti:

Legumes: Lentils (dal), chickpeas (chana), and beans are excellent sources of lysine.
Dairy Products: If your diet includes dairy, cheese (especially Parmesan) and yogurt are rich in lysine.
Soy Products: Tofu and soybeans are high in lysine and provide a fantastic plant-based option.
Eggs: For those who eat eggs, they are a complete protein source and rich in all essential amino acids, including lysine.
Other Plant-based Options: Pumpkin seeds, spirulina, and quinoa also offer a good amount of lysine.

Roti vs. Whole Wheat Bread: A Nutritional Comparison

While both roti and whole wheat bread are wheat-based, their preparation and typical ingredients can affect their nutritional value. Here is a comparison based on standard preparations:


Feature	Roti (Whole Wheat)	Whole Wheat Bread (Commercial)
Key Ingredient	Whole wheat flour (atta) and water	Whole wheat flour, water, yeast, salt, sugar, preservatives
Fiber Content	High, as it uses whole grain flour.	Can be high, but varies; some brands use a mix of refined and whole wheat.
Protein Content	Contains protein from whole wheat, but is lysine-deficient.	Contains protein, but is also lysine-deficient. May have added gluten.
Additives	Typically contains zero additives or preservatives.	Often contains added sugars, emulsifiers, and preservatives.
Sodium Content	Generally lower, as only a small amount of salt is used.	Often higher due to added salt in commercial preparation.
Glycemic Index (GI)	Lower GI (~50-55) due to high fiber and complex carbs.	Varies widely; some whole grain bread may have a GI similar to or lower than roti, but white bread has a high GI.

The Importance of Protein Combining

The practice of pairing foods is crucial for anyone seeking a nutritionally complete diet, especially for those on plant-based diets. Protein combining is not about consuming all complementary proteins in a single meal, but rather about ensuring a varied diet over the course of the day or week. By being mindful of the foods you pair with your roti, you can effortlessly fill the lysine gap and ensure your body receives all the essential amino acids it needs for health and repair.

A Link to Authoritative Information: For more detailed research on the amino acid composition of wheat, you can explore studies available through the National Institutes of Health.

Conclusion

In summary, the amino acid absent in significant amounts from roti is lysine. This deficiency, inherent in wheat, means that roti is not a complete protein source on its own. However, this nutritional limitation is easily overcome through dietary diversity. By combining roti with complementary, lysine-rich foods such as dal, other legumes, or dairy, you can create a complete and balanced protein meal. This simple understanding of nutritional synergy empowers you to build healthier eating habits without needing to abandon this staple food.

Frequently Asked Questions

Roti is made from wheat flour, which is naturally deficient in the essential amino acid lysine. Because it lacks sufficient amounts of all nine essential amino acids, it is considered an incomplete protein source.

The most limiting essential amino acid in roti is lysine. Without enough lysine, the body cannot effectively utilize the other amino acids from the wheat protein.

You can create a complete protein meal by pairing roti with complementary foods that are rich in lysine. Excellent pairings include lentils (dal), chickpeas (chana), beans, or a side of yogurt.

Yes, as whole wheat bread is also made from wheat, it shares the same deficiency in the essential amino acid lysine. It is also an incomplete protein, though some commercial varieties may have additives.

No. The body maintains a pool of amino acids, so you do not need to eat complementary proteins in the same meal. As long as you consume a varied diet throughout the day that includes both grains and legumes, your amino acid needs will be met.

Yes, many plant-based options can be paired with roti to form a complete protein. Tofu, soybeans, lentils, chickpeas, and a variety of beans are all excellent, lysine-rich foods.

Consistent deficiency in lysine can lead to various health issues, as the body cannot produce it. Some potential symptoms of a severe and prolonged lysine deficiency include impaired growth, fatigue, and difficulty concentrating.

While the baking or cooking process can cause some minor loss of amino acids, research indicates that the inherent low level of lysine in wheat is the main issue, not the cooking method. The deficiency is present in the raw wheat flour itself.