Which is Superior: Animal or Plant Protein?

The Basics

What is protein?

Protein is one of the three primary macronutrients in the human diet (the others are carbohydrates & fats).

Proteins are made up of smaller building blocks called amino acids which are joined together like links in a chain.

While there are many amino acids in nature, the human body relies on 20 standard amino acids to synthesize its own proteins.

Think of amino acids as the letters of the alphabet: just as countless words can be formed from 26 letters, your body creates numerous proteins by combining the same 20 amino acids in various ways, each protein serving a unique role.

However, your body can only make 11 of these amino acids on its own. The remaining 9, known as essential amino acids (EAAs), must come from your diet.

There are two things to keep in mind:

1. For your body to synthesize protein, it needs all the 20 amino acids to be available in adequate amounts.

2. If there’s an insufficient amount of any of the 9 EAAs obtained from the diet, the protein synthesis process is stopped.

What’s the role of protein in the body?

Protein serves as the major building block for nearly every structure in the body, from your organs to your skin, hair, and nails.

Beyond structural roles, it performs a variety of critical functions, including:

• Growth, repair, and maintenance of tissues in the body, especially muscle tissue which relies heavily on protein.

• Production of disease-fighting antibodies.

• Production of hormones and neurotransmitters that regulate various processes like blood sugar control and mood.

• Production of enzymes that help in processes like digestion, energy production, and blood clotting.

• Production of substances that help carry molecules throughout the body e.g. hemoglobin which transports oxygen in blood.

Basically, you need protein in order to live.

What are the sources of protein?

Dietary protein is obtained from both animal and plant sources:

• Animal proteins: Meat (beef, pork, lamb, chicken, turkey), fish, seafood, eggs, milk, and dairy products.

• Plant proteins: Legumes (beans, chickpeas, peas, lentils), cereals (wheat, rice, oats, maize, quinoa), nuts and seeds (peanuts, almonds, chia seeds), vegetables (broccoli, spinach, peas), and soy products (soy milk, tofu, tempeh, edamame).

However, these protein sources are not created equal. They differ in quality and nutritional benefits.

This has led to the battle of the proteins: which is the superior protein source—animal or plant?

Let’s break it down.

Animal vs Plant Protein: Which is Better?

Short answer: Animal protein.

BUT, it’s a little more nuanced than that…

When deciding which protein source is better, quality is the key parameter.

Protein quality refers to how effectively a protein source provides all the 9 essential amino acids that your body cannot produce on its own.

It’s a combination of two things:

1. Amino acid composition - how closely the amino acid profile of a protein matches your body’s needs to perform all its functions.

2. Digestibility of the protein - how easily your body can break down a protein into absorbable amino acids for use.

Here’s how animal and plant protein quality compare:

Animal proteins:

1. Amino acid profile

They’re considered complete proteins because they contain all the 9 EAAs in adequate quantities required by your body.

2. Digestibility

They have excellent digestibility and bioavailability. That is, they’re easily and completely broken down into amino acids and absorbed in your gut.

Therefore, all the amino acids you consume are made available for use.

3. Protein content

They have a high protein content per serving, making it easier and more convenient for you to achieve your protein goals.

Plant proteins:

1. Amino acid profile

They’re considered incomplete proteins because unlike animal protein, they have an insufficient amount of at least one EAA.

For example:

• Plant 1 might be rich in amino acid “A” but low in “B”.

• Plant 2 might have the opposite amino acid profile, with plenty of “B” but not enough “A”.

If you only ate plant 1, your body wouldn’t be getting adequate amounts of amino acid “B”. And if you only ate plant 2, you wouldn’t get enough amino acid “A”.

But if you ate both plant 1 and 2, you’ll get enough of both amino acids “A” and “B”.

Amino acids “B” in plant 1 and “A” in plant 2 are known as limiting amino acids.

A limiting amino acid is the essential amino acid that is present in the smallest amount in a protein source, relative to what the body requires for protein synthesis.

When the body tries to build proteins, it needs all the essential amino acids in the right proportions.

If one of these amino acids is in short supply, it becomes the "limiting factor" and restricts the body's ability to produce complete proteins, even if all the other amino acids are present in sufficient quantities.

By combining different plant protein sources (e.g., beans with rice), you can create a more complete amino acid profile and overcome this limitation.

2. Digestibility

Plant-based protein is often wrapped in fiber, which makes it harder for your body to digest compared to animal protein.

This means that the amount of amino acids available for absorption and use may be lower.

However, evidence shows that you can improve the digestibility of plant proteins through soaking or fermentation.

3. Protein content

Plant proteins are generally less protein-dense than animal proteins.

This means that you need to consume more in order to obtain the same amount of protein in one serving of animal protein.

Verdict:

Based on the fact that animal protein has a high digestibility and a complete amino acid profile, it’s considered a more convenient, higher-quality protein source.

However, you can still meet your protein needs on a plant-based diet if you consume a variety of high-protein plant foods to ensure a complete amino acid profile.

Animal vs Plant Protein: Which is Healthier?

The “healthiness” of a protein source is determined by factors beyond just amino acid profiles.

It depends on the whole food package—all the other nutrients and compounds that come along with the protein and how they affect your health.

Here’s how animal and plant protein health profiles compare:

Animal protein:

It’s a rich source of essential vitamins and minerals that are harder to get from plants alone:

• Vitamin B12 - essential for nerve function and the production of red blood cells.

• Zinc - plays a crucial role in immune function, wound healing, and DNA synthesis.

• Omega-3 from fatty fish - essential for healthy heart function and prevents inflammation.

• Heme-iron - more absorbable then non-heme iron from plants. Vital for oxygen transportation in the blood.

However, animal protein is also often paired with saturated fats, especially in red and processed meats.

As such, several studies have shown that consumption of high amounts of red and processed meats, especially as part of an overall unhealthy diet, is associated with a higher risk of heart disease and diabetes.

There has also been some evidence that link red meat to colon cancer. This risk is attributed to heme-iron and other compounds that are formed during high-heat cooking.

Plant protein:

Plant proteins are generally low in saturated fats, and are rich in other nutrients that promote overall health:

• Fiber - supports a healthy gut microbiome, which in turn improves digestion, reduces inflammation, and strengthens the immune system.

• Flavonoids & Polyphenols - potent antioxidants that protect cells from damage caused by free radicals.

These additional compounds contribute to plant proteins being associated with a reduced risk of chronic illnesses, such as type 2 diabetes, cardiovascular disease, and certain types of cancer.

Recent studies have also linked diets rich in whole plant foods, like the Mediterranean diet, to a longer, healthier life.

Verdict:

From a health perspective, plant protein has an edge over animal protein.

The protective compounds in plant-based proteins, such as fiber and antioxidants, contribute to a lower risk of chronic diseases and better long-term health outcomes.

While animal protein provides unique nutrients like Vitamin B12 and heme iron, its association with saturated fats and certain health risks makes plant proteins the healthier option overall.

The Takeaway

You can meet all your protein needs from both animal and plant proteins.

Due to its high protein content, animal protein offers convenience, making it a great option for those looking to increase their protein intake without much effort.

Plant protein, on the other hand, requires a bit more thought. To ensure you’re getting all the essential amino acids, you’ll need to include a variety of high-protein plant foods in your meals.

Combining both animal and plant proteins in your diet allows you to enjoy the best of both worlds—getting high-quality amino acids alongside a variety of other nutrients, like fiber and antioxidants, which contribute to long-term health.

Thanks for reading! I hope you found something valuable :)

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