Pea Protein Versus Soy Protein: What's The Difference?

26 April 2021

They’re both popular sources of plant-based powder. Each one contains the amino acids your body needs for good health. And, when it comes to high levels of quality protein, they’re so alike that it’s hard to choose between them. But when it comes to benefits and potential risks, soy and pea protein are actually very different.

In the blue corner there’s soy-based protein, the near-ubiquitous ingredient found in everything from protein powders and bars to processed foods like ice cream. In the red corner there’s the pea protein, made by isolating the protein found in yellow peas and not nearly as widespread as its counterpart.

But which one is best? Well there’s only one way to find out… fight! Or rather, read our pea vs soy protein guide.

Want to find out how much protein you really need as a vegan? Read our ultimate guide.

Soy protein

The soy protein in your powder is made of soybeans, a type of legume that originally heralds from East Asia but are now so in-demand that they’re grown world-wide.

That’s because soy isn’t just the major ingredient in a lot of popular plant-based protein powders and bars. It’s also found its way into many of the processed foods that we like to eat, such as baked goods, cereal, salad dressings, ice cream and even crisps.

Manufacturers love soybeans for one reason - they’re an extremely cheap and abundant source of protein. But because they’re such a good way to increase profits, it means we could be eating far more processed soy than we realise - and that’s before we add two daily protein shakes full of yet more soy into our daily diets.

Is soy-based protein bad for you?

We’re repeatedly told that tofu, tempeh and edamame are all healthy forms of plant-based protein. So soy protein shakes must be practically a superfood, right?

We’re sorry to have to break it to you. Yes, in their wholefood form, soybeans are a great source of protein, giving you a complete amino acid profile along with other nutrients such as calcium, zinc, iron, magnesium, folate, riboflavin and thiamin.

But the soy in your protein powder? That’s a different story. Made of a highly refined, isolated soy it still has a complete amino acid profile, it’s true. But that’s where the health benefits end.

Soy is now the largest crop produced by the United States, second only to corn. And more than 90% of this soy crop is genetically modified and sprayed with a herbicide called Roundup, known to have adverse health consequences.

Choosing a soy-based protein powder means you’ll also be getting a lot of phytates along with your pesticides. This so-called 'anti-nutrient' binds to important minerals such as calcium, magnesium and zinc and removes them from the body. But that’s not all. Phytic acid also reduces the amount of amino acids your body can assimilate, meaning you may be getting far less than you think.

Is soy protein bad for your kidneys?

It can be if you’re prone to forming kidney stones. The most common type of kidney stones are called calcium oxalate stones, and they’re formed when the calcium in your urine binds with oxalate. Oxalate is found in high amounts in many healthy, whole plant foods, with spinach, rhubarb, almonds and soybeans being particularly high in the stone-forming chemical.

People prone to calcium kidney stones who are following a low oxalate diet are usually told to eat these kinds of foods sparingly. But while no one is going to find it hard to cut down on their spinach and rhubarb intake, the same can’t be said about soy.

Not only is soy harder to avoid as it’s a hidden ingredient in so many processed foods, people are also drinking soy protein shakes for the presumed health benefits. The result? Those who are already prone to kidney stones could be getting far too much oxalate for their kidneys to handle.

Pea protein

Soy may be a plant based protein source with a complete amino acid profile, but that’s where its benefits end. Luckily, there are many safe and even superior alternatives available that don’t come with any question marks attached, and one of those is pea protein.

Pea protein can also be used to make plant based protein powders, and it’s well known for having an exceptionally high protein content. Basically the protein that’s extracted from yellow peas, it’s also FODMAP-diet friendly and allergen-free.

Is pea protein powder really a complete protein?

While pea protein powders contain a full profile of all nine of the essential amino acids your body can’t make for itself, they’re slightly lower in methionine than other sources. But it’s easy to get methionine in your daily diet to make up for the shortfall, or you can choose a pea protein blended with hemp for extra peace of mind.

But where pea protein really shines is in its levels of branched chain amino acids. It’s exceptionally high in the lean muscle-building superstars leucine, isoleucine and valine, and it’s loaded with arginine, another essential when it comes to improving your performance in the gym.

To make sure you’re really getting the most out of your pea protein powder, look for the words 'raw' or 'cold processed' on the label. Conventional pea protein is processed at high heat which can denature the amino acids, making them harder for your body to absorb.

Our PERFORM Raw Plant Protein & BCAA uses bio fermented pea protein and cold pressed hemp, so the amino acids remain in their optimal state.

Can pea protein cause bloating?

If peas, beans or lentils normally make you feel a bit gassy, you may be worried that a shaker cup full of the stuff would have similar unwanted consequences. But that’s normally down to the high fibre content in the whole food variety. The pea protein you’ll find in a plant-based protein powder has most of the starch and fibre content removed.

Our protein powders have another trick up their sleeve to make them more digestible. They’re made from raw and fermented plant based protein sources, which are the easiest forms of protein for your body to digest.

Does pea protein help build muscle?

Pea protein not only contains good amounts of BCAAs, it has three times more arginine than whey, something that’s particularly important if you’re looking for gym gains. Arginine has been found to increase growth hormone response and therefore increase muscle mass. Also it has an impact on insulin, which is another important anabolic hormone.

Is pea protein as good as whey?

When it comes to building muscle and athletic performance, pea protein is just as effective as whey. In a 2019 study, a group of men completed an eight-week resistance training course. Half supplemented with whey, the other with pea. At the end of the course, both groups had achieved impressive results, with little to no difference in either body composition, muscle gain, performance or strength.

Is pea protein safe for peanut allergy?

Peanuts are a legume, peas are a legume. So does it stand to reason that if you’re allergic to peanuts you can’t eat peas?

While extreme caution is always wise when you have a potentially life-threatening allergy, the number of people with peanut allergy who react to other legumes is relatively small, according to Anaphylaxis.org.uk. But while most people with a peanut allergy find they can tolerate other legumes without a problem, talk to your allergy specialist for specific advice.

Pea versus soy protein

Time for the final showdown. Let’s see what happens when these two protein powerhouses go head-to-head...

Amino acid profile

Result: peas win

The amino acid profile of both soy and pea protein is excellent - on paper. Soy has a complete profile, but because it contains the anti-nutrient phytic acid, you may be absorbing less than you realise. Pea lacks slightly in methionine, but that can easily be made up through other sources, or by choosing powders such as PERFORM Raw Plant Protein & BCAA that are blended with hemp.

Branched chain amino acids

Result: peas win

Pea protein and soy protein contain branched-chain amino acids you need for optimal performance. However, pea protein has elevated levels compared to soy.

Muscle growth

Result: peas win

Research shows that pea protein is just as effective at promoting muscle synthesis as whey. This could be because it’s the plant protein that’s highest in the amino acids leucine and arginine.

Protein content

Result: a tie

Both pea and soy protein are very protein-dense at around 90% protein content.

Allergens

Result: peas win

Soy protein is a common allergen, while pea protein is hypoallergenic.

Pesticides

Result: peas win

Peas fix nitrogen into the soil, reducing the need for nitrogen fertilisers. And, unlike soybeans, peas are not currently genetically modified for herbicide resistance.

Environmental impact

Result: peas win

Peas have a lower environmental impact, taking less water, energy and land to produce than soy.

Which is better, pea or soy protein?

Soy and pea may both be protein heavyweights. But when it comes to building muscle and avoiding health risks, pea wins by a knockout.

But pea based proteins aren’t just better for you, they’re better for the health of the planet - and we can all drink to that.

Want to give your own plant-based protein powder regime a shake-up? 100% raw and with organic ingredients like bio fermented peas and cold-pressed hemp, none of the protein powders we sell here at Vivo Life contains soy, either.