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According to the dictionary, an ‘essential’ is something that is absolutely necessary.

Something ‘non-negotiable’.

So today we are discussing essential amino acids—those protein building blocks so key to a healthy, vibrant life.

We will pull back the curtain on all the myths that still swirl around this subject, including whether we need to source these essential amino acids from an animal or a plant-based diet.

It’s time to explore the real truth about this most ‘essential’ subject…

Essential Amino Acids… a Definition

Before we talk about essential amino acids, let’s first briefly discuss the definition of an amino acid.

Amino acids are organic compounds that combine to form proteins, which allow growth and regulate nearly every biochemical reaction in the body.

It is not an exaggeration to say that amino acids, and the proteins they create, are quite literally the building blocks of life.  Amino acids account for 75% of dry body weight, 95% of muscle (and heart), and 100% of hormones, neurotransmitters and neuropeptides.

The human body uses 20 amino acids in various combinations to form the proteins our cells need to function.

The body itself can create 11 of the 20. The other 9—the essential amino acids—are amino acids that the body cannot make on its own; they must come from our diet.

The 9 essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

(It’s worth noting there is a debate raging in protein science around whether the correct number is 8 or 9 essential amino acids. Today, most experts say 9, because they include histidine since it’s not synthesized in adults. However, others treat histidine as “conditionally” essential and some continue to exclude it completely.)

Animal or Plant-Derived Proteins–Which Is the Best Way?

The question then becomes…what foods best provide us with these 9 essential amino acids?

Many argue that the ‘only’ way to get your essential amino acids is by eating animal products while others endorse a plant-based diet as the superior route.

The main two areas of contention center on two issues:

  • The idea that animal-derived proteins have a higher quality.
  • The belief that only animal-based proteins can deliver a ‘complete protein’.

Are Animal-Derived Proteins Really of a Higher Quality?

To begin with, many argue that protein sources from an animal-based diet are superior in quality because they promote growth more rapidly than plant-derived protein.  However, there is a negative side to this growth because animal protein increases ALL cellular growth.

Studies have confirmed this, showing a clear link between animal-derived protein and cancer cell growth via increase of IGF-1 levels.

To make matters worse, animal protein also increases expression of TOR, the enzyme responsible for aging.

The reality is that when it comes to both health and longevity, plant-derived proteins win hands down.

Secondly, and very much unlike animal proteins, plant proteins actually decrease IGF-1 levels, thus discouraging cancer cell growth.

As for the aging process, plant-based proteins are a far superior choice given the lower levels of the essential amino acid leucine (present in higher amounts in animal proteins), which is believed to increase expression of the enzyme TOR.

The Protein ‘Combination’ Debate

The second big confusion around the ‘animal versus plant’ debate is that many believe that plant-derived proteins don’t contain ‘complete’ proteins.  (A complete protein defined as one that contains sufficient amounts of all essential amino acids).

All whole foods contain these nine essential amino acids.  All of them.  And if you’re taking in enough calories from whole foods, you’re taking in plenty of protein.

To confuse matters even further, there has been a long-held belief that the only way to get a ‘complete’ protein from a plant-based diet is through combining the right types of plant foods (otherwise known as ‘protein complementing’). However, studies have shown that the intestinal tract maintains an impressively similar ratio of essential amino acids due to the mixing of endogenous and dietary protein.  Now we know that intentional combining of plant foods is not necessary for absorption of essential amino acids, as long as you:

  • Consume enough calories to maintain a healthy weight.
  • Eat mainly unprocessed or minimally processed vegetables, intact legumes and whole grains.
  • Limit processed and refined foods.
  • Do not base your diet on fruits alone.

Even the American Heart Association agrees that “plant proteins alone can provide enough of the essential and nonessential amino acids, as long as sources of dietary protein are varied and caloric intake is high enough to meet energy needs.”

How Much Protein Do We Really Need?

In the end, one of the most important questions in this essential amino acid debate is how much protein do we actually need?

Even among us whole-food plant-based folks, it is important not to go overboard with proteins.

There really can be “too much of a good thing“.

The World Health Organization recommends that adults get at least 5% of their calories from protein.  Physicians and researchers in the plant-based community double that number (to be safe) and recommend that 10% of your daily calories come from protein.

When you consider that rice contains 8% protein, corn 11%, oatmeal 15%, and beans 27%, protein deficiency is virtually impossible when meeting your calorie needs with unprocessed starches and vegetables.

Simply put, you can enjoy all of the delicious foods included in a whole food, plant based diet even more, now that you know you’re getting all of your essential amino acids needs met — without the use of animal-derived proteins or having to “combine” foods to make the protein complete.

Rosane Oliveira, DVM, PhD

President & CEO, Plant-Based Life Foundation | Dr. Rosane Oliveira combines a lifelong passion for nutrition with 25 years of genetics research to create programs that help people develop healthy habits on their journey towards a more plant-based lifestyle. She is a Visiting Clinical Professor in Public Health Sciences and was the founding director of the first Integrative Medicine program at the UC Davis School of Medicine. She completed her postgraduate studies in Brazil and did her postdoctoral training in immunogenetics and functional genomics at the University of Illinois at Urbana-Champaign.