Why Are Plant Proteins Incomplete?
Have you ever heard of the term incomplete protein? In the field of diet and nutrition science, when your dietary intake of protein is not balanced through those foods that do not contain whole protein (animal as well as plant protein), it means that you are taking more incomplete proteins only. In other words, all those foods categorized under incomplete proteins are those that do not have the essential amino acid composition in them as plant proteins commonly.
Though most of the plant-derived protein sources would be termed or categorized as under the incomplete protein category, it is important to go beyond dietary restrictions for healthy individuals and ideally incorporate both plant and animal proteins from varied food sources to sustain all the essential amino acids that are needed for the bodily metabolism.
Complete proteins derived from plant, as well as animal protein sources, are whole proteins, meaning that they contain all of the essential amino acids that your body cannot produce on its own and must be obtained through your diet, in contrast to non-essential amino acids that are protein sources that your body can synthesize and which you can obtain through food as well.
- Isoleucine.
- Leucine.
- Lysine.
- Methionine.
- Histidine.
- Phenylalanine.
- Threonine.
- Tryptophan.
- Valine.
Why Is the Amino Acid Content Limited?
So why are these limiting amino acids or lesser amounts of essential amino acids in plant-based foods only incomplete proteins? Why are they still not called complete protein sources in nature?
This is because, in spite of plant-based elements comprising these essential amino acids that are listed above, in a plant-based diet only, certain essential amino acids may be limited or even missing such as:
- Lysine is either limited or absent in most cereal grains.
- Methionine and cysteine are present in lower amounts in legumes, beans, peas, and most lentils.
- Tryptophan is lower in corn.
These examples are pivotal. Plant proteins may have a lowered content or, in other words, limiting amounts of essential amino acids. This is the reason why the incomplete protein concept in nutrition science helps decipher how best a healthy individual needs to incorporate proteins that are derived from animal sources as well, to balance out the protein requirements such as dairy products, whole milk, seafood, lean meats, and poultry.
Also, plant-based foods that comprise these limited amounts of essential amino acids are suited to vegan or vegetarian individuals. However, these individuals would need more of these compared to individuals who intake both animal and plant-based proteins, to compensate for the protein requirements ideally needed for your body's metabolism, muscle sustenance, synthesis, and immunity.
What Are the Benefits of Plant Proteins and Recommendation Chart?
Current nutrition research also weighs in on the pros of plant proteins or benefits over animal proteins. A vegan diet is generally advocated to be more economical, and friendlier to our ecosystem and planet, while also holding an abundance of micronutrients, macronutrients, and essential heart-healthy fiber with promising potential to ward off chronic diseases. They cannot be underestimated compared to animal protein sources in nature.
If you are not consuming meat, seafood, or poultry, you can still obtain the essential amino acids (though in limited quantities) from the inclusion of varied groups such as fresh or frozen vegetables, whole grains, legumes, nuts, and seeds.
Currently, the protein recommendations on the whole, whether you are taking complete or incomplete proteins, are listed as follows based on gender and age:
- Males: 1.98 ounces.
- Females: 1.63 ounces.
- Pregnancy and Lactation: 2.5 ounces.
Daily protein needs for children and adolescent groups are:
- Infants, 0 to 6 months: 0.32 ounces.
- Infants, 7 to 12 months: 0.39 ounces.
- Children, 1 to 3 years: 0.46 ounces.
- Children, 4 to 8 years: 0.67 ounces.
- Males and females, 9 to 13 years: 1.13 to 1.19 ounces.
- Males and females, 14 to 18 years: 1.59 to 1.83 ounces.
How Can Vegans Incorporate Incomplete Plant Proteins Effectively?
So are limiting amino acids or incomplete proteins from plant proteins enough for your metabolism or body's functioning? Yes, in all healthy individuals with a moderately balanced diet. However, it may not be sufficient without supplementation, particularly for individuals like athletes or bodybuilders, according to current nutrition research. This is the reason why many nutritionists across the world commonly prescribe added supplements to vegan diets, to counteract the challenges faced by vegan or vegetarian lifestyles.
A plant-based diet can support systemic health similarly to a combined plant and animal protein diet, according to current research. However, the drawback is only with the limiting amino acids or quantity of essential amino acids that may not be enough for most individuals. In athletes or endurance professionals who may be following a vegan or vegetarian diet, the body's nutritional requirements are much higher, and only vegan proteins may not be sufficient to sustain the metabolic needs or higher metabolic rate. In such cases, nutrition experts commonly recommend added supplements to compensate for these metabolic demands.
Conclusion:
It is a common misconception that vegan proteins that are incomplete by virtue of their protein content are lesser than animal proteins. It is not so. It is only the fact that individuals who consume both sources, that is, animal and plant proteins, are ideally more able to fulfill the protein requirements easily than those who consume only plant proteins. The key to counteracting your protein challenges effectively if you are a vegan or vegetarian is to incorporate a variety of plant-based foods that contain these limited essential amino acids from varied plant sources or food groups.
By accommodating more dietary elements from plant sources alone, you can increase your scope for gaining the benefits of plant proteins. Vegans or vegetarian followers, however, do not need to worry about their consumption of limited essential amino acids or incomplete proteins. This is because this depends on your body's metabolic requirements and should be ideally deciphered by your registered healthcare professional or nutritionist, who can guide you to implement more plant sources or dietary elements within your scope, to balance your needs or compensate for the proteins needed for your system.
