What is the Difference Between True Protein and Protein?

Did you know the protein content on a food label might not be entirely accurate? The difference between true protein and protein (crude protein) comes down to how it's measured.

Quick Summary

True protein accurately measures protein content by excluding non-protein nitrogen (NPN), unlike crude protein. This affects accuracy in nutrition tracking and supplement quality. This distinction is vital for consumers.

Key Points

• Measurement Accuracy: True protein measures a food's actual protein content, while the term "protein" on labels often refers to crude protein, which can be an overestimation due to the inclusion of non-protein nitrogen (NPN).

• NPN Impact: Crude protein includes NPN compounds like urea, which do not offer the same nutritional benefits as true protein. This can misrepresent the actual protein value.

• Consumer Implications: Understanding the distinction is vital for consumers, particularly for those tracking protein intake, using supplements, or following high-protein diets, to ensure accurate nutritional assessment.

• Industry Standards: Industries like dairy are adopting true protein measurements for fairer payments and to reflect the true value of milk for product manufacturing.

• Supplement Quality: To ensure the intake of true protein from supplements, check for third-party certifications and transparent amino acid profile labeling.

What is the Difference Between True Protein and Protein?

In the realm of nutrition, the terms "protein" and "true protein" are often used, but they represent different methods of measurement and can significantly impact the understanding of a food's nutritional value. This article explores the key distinctions, implications, and practical applications of these two concepts to help you make informed dietary choices.

Crude Protein vs. True Protein: The Basics

The fundamental difference lies in the way each type of protein is measured. "Protein," as listed on many food labels, typically refers to "crude protein." This measurement is based on the total nitrogen content in a food sample. The Kjeldahl method, an established and internationally recognized process, is commonly used to measure this. However, this method doesn't differentiate between nitrogen from protein and nitrogen from other non-protein sources.

True protein, in contrast, focuses specifically on the protein-bound nitrogen or peptide bonds present in a food. This means that it measures the actual amino acids that make up the protein, excluding non-protein nitrogen (NPN).

The Role of Non-Protein Nitrogen (NPN)

Non-protein nitrogen (NPN) includes various nitrogen-containing compounds that are not proteins, such as free amino acids, urea, and ammonia. While these compounds contain nitrogen, they do not provide the same nutritional benefits as true protein. The presence of NPN can inflate the crude protein value, potentially misrepresenting the actual protein content and nutritional value of a food.

The Impact on Nutritional Assessment

The difference between true protein and crude protein has implications for the accuracy of nutritional assessments, especially for those with specific dietary needs, such as athletes or individuals on high-protein diets. Since crude protein values may include NPN, the amount of actual protein consumed may be less than what is indicated on the label. This can lead to miscalculations in macronutrient intake and affect the ability to meet specific health or fitness goals.

Industry Applications

The distinction between true and crude protein is particularly relevant in certain industries, such as dairy and animal nutrition. The dairy industry, for example, has started using true protein measurements to determine payments to farmers. This shift recognizes that NPN, such as urea, does not contribute to the valuable casein and whey proteins that are essential for manufacturing products like cheese. By basing payments on true protein content, the industry incentivizes higher milk quality and more accurate valuations. Similarly, in animal nutrition, modern practices consider the metabolic differences between NPN and true protein to create balanced diets.

Implications for Consumers

For consumers, understanding the difference between true and crude protein can affect dietary choices, particularly when selecting protein supplements. Many supplements list crude protein values, which may be inflated due to protein spiking. To ensure that you are getting true protein, examine labels for comprehensive amino acid profiles and look for third-party certifications. These certifications can ensure the product’s contents match the label claims.

Summary Table

Feature	Crude Protein	True Protein
Measurement Basis	Total Nitrogen Content	Protein-bound Nitrogen
NPN Inclusion	Yes	No
Accuracy	Can be misleading	Precise; reflects biological value
Main Uses	Nutrition labeling, animal feed	Dairy payment, nutritional research

Ensuring You Get "True" Protein

To ensure you are consuming true protein, consider these strategies:

1. Prioritize Whole Foods: Consume high-quality, whole food sources of protein, such as grass-fed beef, wild-caught fish, and eggs. These foods naturally contain a high proportion of true protein and provide a more complete amino acid profile.
2. Read Labels Carefully: Pay close attention to supplement labels and look for information about the amino acid profile. This provides a more accurate picture of the protein content. Companies that provide this level of detail are usually committed to high-quality products.
3. Choose Certified Supplements: Select protein supplements that have been certified by independent third-party organizations. These certifications verify that the product's contents match the label and are free from contaminants and fillers.
4. Consult Professionals: Consult a registered dietitian or nutritionist to get personalized advice on your protein needs and how to make informed choices that align with your health and fitness goals.

Conclusion

The distinction between true protein and the broader term "protein" is vital for accurate nutritional assessment, fair industry practices, and informed consumer choices. True protein provides a more precise measure of the actual protein content by excluding NPN, which can be misleading on nutritional labels. By understanding these differences and prioritizing high-quality protein sources, consumers can make informed decisions to meet their nutritional needs effectively. For further understanding, explore resources on dietary protein quality and modern evaluation methods, including the DIAAS score.

Resources

For more information on protein quality and measurement, consider these resources:

• The Importance of Dietary Protein Quality in Mid- to High Income Countries - ScienceDirect.com

Frequently Asked Questions

What is non-protein nitrogen (NPN)?

Non-protein nitrogen (NPN) refers to nitrogen-containing compounds in a food source that are not true protein, such as urea, free amino acids, and ammonia. When crude protein is measured, the nitrogen from these compounds is included, leading to an inflated protein value.

Why are food labels often based on crude protein?

Historically, the Kjeldahl method for measuring total nitrogen was the standard, and its result is the basis for most nutritional labeling. It is an internationally recognized standard, but its use can be misleading as it doesn't differentiate between protein and non-protein nitrogen.

Does the difference between true and crude protein affect everyone?

For the average person, the difference is likely negligible. However, for those on high-protein diets, athletes, or individuals who use protein supplements, the difference can impact the accuracy of their nutrient intake tracking and supplement quality assessment.

How can I check if my protein powder has a high true protein content?

Look for a supplement company that provides transparent information, such as a full amino acid profile, on its packaging or website. Third-party testing certifications, which verify the product's contents, are also a strong indicator of quality.

Is it bad to consume non-protein nitrogen (NPN)?

NPN compounds like urea are naturally occurring and not necessarily harmful in small amounts. However, they do not offer the same nutritional benefits as actual proteins. The issue arises when products are deliberately spiked with NPN to deceptively increase the labeled protein percentage.

Why did the dairy industry switch to true protein measurement?

The switch was made to ensure fairer payments to dairy farmers based on the milk's actual economic value. True protein, which measures functional caseins and whey, is a more accurate indicator of the milk's value for manufacturing products like cheese.

Is true protein always a complete protein?

No. True protein is a measurement method, not a descriptor of a protein's completeness. A true protein measurement from a plant source could still indicate an incomplete protein profile. A complete protein contains all nine essential amino acids.

Is there a difference in the digestibility of true protein versus crude protein?

Yes, true protein is typically more digestible as it represents intact protein molecules. Crude protein includes non-protein nitrogen, which the body cannot readily utilize and may have to eliminate, resulting in a lower net protein utilization.