Plant Protein vs. Animal Protein: Health Comparison | Signos

Protein is an essential part of your diet. Learn about plant and animal proteins and their their role in a balanced diet to support your body and metabolism.

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Chelsea Rae Bourgeois, MS, RD
— Signos
Health writer
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Updated by

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Science-based and reviewed

April 23, 2024
November 7, 2022
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Table of Contents

Protein is (dare we say it) the most important macronutrient. Why? Because the body doesn't store protein like it does other macronutrients. Instead, we have to get it from our diet, and it’s important that we do so because protein is an essential part of the human body. It can be found in everything from our muscles and organs to our bones, skin, and hair.

So, just what does protein do? Our bodies use the protein we eat to build and repair our tissues and make hormones and enzymes.

You can get protein from plant and animal sources, but the two have some differences. Since not all protein sources are created equal, what type of protein is better for our health? Each offers its own benefits and shortcomings. Together we’ll break down the plant protein vs animal protein debate, so you can decide what’s best for you.


Plant Protein vs. Animal Protein: What Is The Difference?

Proteins are made up of different amino acids, and while there are hundreds of amino acids found in nature, we only need 20 of them to make all the proteins in the human body. Our bodies can produce 11 of these necessary building blocks (which we call non-essential amino acids), but we must get the other nine from our diet. These are called essential amino acids, and they include:

  • Isoleucine
  • Leucine
  • Lysine
  • Methionine
  • Histidine
  • Phenylalanine
  • Threonine
  • Tryptophan
  • Valine

Animal proteins are considered complete proteins because they contain all nine of the essential amino acids we need. Plant proteins, however, do not (except for soy). So if you adhere to a vegan or vegetarian diet, it’s important that you eat multiple sources of plant protein to piece together a full amino acid profile.

High-protein foods also have varying carbohydrate content. Plant-based protein tends to be higher in carbohydrates and calories compared to animal sources that provide the same amount of protein. You may choose one over the other, depending on your energy needs.

Lastly, plant and animal proteins differ in their bioavailability or the rate at which the human body can absorb them. Generally speaking, when it comes to animal protein vs plant protein absorption, the body can absorb animal proteins better than plant-based proteins. And since high protein intake has anabolic effects, bioavailability is key when trying to build muscle mass.

Plant-Based Protein Benefits

Plant-based diets are rich in nutrients, antioxidants, and fiber that can support your overall health through a variety of benefits.

Stroke Prevention

Because of its high fiber content, a plant-based diet can be associated with a lower risk of stroke. Research shows that plant-based diets can lower blood pressure and total and LDL cholesterol.¹,²

Cancer Prevention

Plant foods contain phytochemicals, which have been linked to a reduction in cancer risk. These incredible components are responsible for our food’s color, taste, and smell, but they also help protect us against environmental and ingested carcinogens. Phytochemicals support our antioxidant enzymes and enhance our DNA repair pathways.³

Plants are also rich in other natural compounds, such as vitamins, that support antioxidant activity. For example, vitamin E is a lipid-soluble antioxidant, which protects our cell membranes, and vitamin C helps protect against oxidative stress-induced cellular damage.⁴

Heart Disease Protection

A diet rich in plant-based proteins has been proven to reduce the risk of cardiovascular disease compared to a diet rich in animal protein. This is because plant-based protein sources are lower in fat and cholesterol than animal sources, lowering the risk of build-up in your arteries. Plant proteins also contain more fiber, which helps prevent cholesterol absorption in the digestive tract.⁵

Protein in grains

Type 2 Diabetes Protection

Studies indicate that plant-based proteins may reduce risk of type 2 diabetes. A 2015 study found that substituting just 5% of typical animal protein intake with vegetable protein resulted in a 23% reduced risk of type 2 diabetes. Researchers also found that consuming 20 grams of yellow pea protein helped lessen the glycemic response to a high-carbohydrate meal just 30 minutes later.⁶ While more research is needed, initial findings are promising. 

Increased Gut Microbiota Diversity

Current research indicates that a plant-based diet helps promote a diverse ecosystem of good bacteria that helps support our overall health. This includes plant proteins, especially when compared to animal-based proteins.⁷ 

The gut microbiota is an ever-changing ecosystem of bacteria influenced by what we eat. For instance, a diet high in animal protein, specifically red meat and dairy products, can lead to an increase in bile-tolerant bacteria that can play a role in cardiovascular disease and inflammatory bowel disease.¹¹

Has Plant-Based Protein Any Downsides? Things to Consider

If all or most of your protein intake comes from plant-based sources, take time to consider a few things. While you can meet your nutrition needs on a vegetarian or vegan diet, you’ll need to get strategic about specific nutrients, including protein.

Those who only eat plant-based proteins should aim to consume a variety of sources to get all the essential amino acids they need. You may also need to supplement certain micronutrients like vitamin D, vitamin B12, and iron.

Last but not least, many plant proteins are known allergens, including soy, pea, and wheat proteins. So, if you have a known allergy, be mindful of the foods you choose.

Animal Protein Benefits

While animal-based proteins may have a few downsides compared to their plant-based counterparts, they offer health benefits that plant proteins simply cannot.

Good Sources of Vitamins D and B12

Animal-based proteins are good sources of certain micronutrients, including B vitamins and vitamin D. Fatty fish like salmon are rich in vitamin D, with egg yolks, cheese, and beef liver not far behind. Additionally, vitamin B12 is necessary for DNA synthesis and can only be found in sources of animal origin.

Rich in Heme Iron

Iron deficiency anemia is one of the more common nutritional deficiencies in the world. Iron plays a role in hemoglobin, a protein in our red blood cells that carries oxygen from the lungs to the rest of the body. Without enough iron in your system to transport oxygen sufficiently, you’ll experience significant fatigue. Iron is also responsible for many biological processes in the brain including oxygen transportation and DNA synthesis.¹³

Iron is categorized into two types; heme and non-heme iron. Heme iron is absorbed more effectively in the body than non-heme iron and is richest in animal sources such as meats, poultry, and seafood.

Aid Healthy Brain Function

Since iron and vitamin B12 are essential to healthy brain function, animal-based dietary proteins support brain health. Research has shown a connection between cognitive impairment and low vitamin B12 levels, emphasizing the importance of vitamin B12-rich food sources such as beef, milk, yogurt, and salmon.¹² 

Piece of meet in a wood table

Better Weight Management

It's essential to get enough protein in your diet if your health goals involve weight loss or building muscle. A recent systematic review determined that animal protein is more favorable compared to plant protein when it comes to maintaining lean muscle mass. Per the review, animal protein is considered high-quality protein because it provides all the essential amino acids in sufficient quantities.⁸

Is Animal Protein Bad For You? Things to Consider

There are a few things to consider when it comes to meat consumption. Animal proteins tend to be higher in fat and lower in fiber compared to plant proteins, creating more of a risk for heart disease. Increased fat intake also runs the risk of lipid accumulation in the muscle and liver, which can ultimately lead to insulin resistance and type 2 diabetes.⁹

Perhaps more concerning, research has shown that the daily intake of half a serving of red meat, either processed or unprocessed, was associated with an increased risk of mortality. A daily half-serving of processed red meat was associated with a 13% increased risk of death.¹⁰ Of course, that doesn’t mean we have to skip the neighborhood barbeque. We can still enjoy high-fat protein sources; just in moderation. 

What Are The Best Sources of Protein?

Increasing our protein intake, whether through plant-based or animal-based foods, can offer many benefits to our overall health. Animal proteins provide all the amino acids the body needs, and plant-based food sources come with high-quality fiber content. So, where can we find these incredible sources of protein?

Animal Protein Sources

  • Fish
  • Shellfish
  • Red meat
  • Chicken
  • Turkey
  • Eggs or egg whites
  • Cottage cheese
  • Milk
  • Greek yogurt
  • Whey protein

Plant Protein Sources

  • Quinoa
  • Legumes
  • Nuts
  • Tofu
  • Lentils
  • Certain Fruits
  • Green peas
  • Spirulina
  • Soy milk
  • Oats and oatmeal

Which Type of Protein Is Better for Health?

We all have unique nutrition needs, but including a wide variety of food sources helps ensure we get the nutrients we need. The same is true for protein sources. When it comes to meeting your protein needs, keep a few things in mind:

  • Animal proteins are complete proteins because they provide a full amino acid profile since they contain all nine essential amino acids.
  • If you only eat plant protein, you must mix and match your plant food sources to make sure you get all the essential amino acids.
  • While plant sources can be rich in protein, they also have more carbohydrate content than animal protein sources.
  • Plant proteins are high in fiber, helping with digestibility.
  • Animal-based protein usually has a higher bioavailability than plant-based protein.

If you have questions about your protein intake, consider working with a registered dietitian to address your individualized nutrition needs. To learn more about nutrition’s role in metabolic health, explore the Signos blog for the latest and greatest.

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About the author

Chelsea Rae Bourgeois is a registered dietitian nutritionist with several years of experience working in the clinical setting. Once a track and field athlete on a competitive stage, she now finds joy in combining her passions as a health writer to help people embrace their wellness through nutrition and fitness.

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Please note: The Signos team is committed to sharing insightful and actionable health articles that are backed by scientific research, supported by expert reviews, and vetted by experienced health editors. The Signos blog is not intended to diagnose, treat, cure or prevent any disease. If you have or suspect you have a medical problem, promptly contact your professional healthcare provider. Read more about our editorial process and content philosophy here.

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