Is potato-derived protein as good as milk in building muscle mass?

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Potatoes contain a small amount of protein and are a good source of aminoacids. Yuji Sakai/Getty Images
  • Past research has reported that animal protein may work better than plant-based alternatives when it comes to the synthesis of muscle protein.
  • Studies have shown that potatoes can provide adequate amounts of all the essential amino acids humans need but they have failed to confirm their muscle-building effects.
  • Researchers in the Netherlands have now found that a potato-derived protein concentrate powder may support muscle repair and growth as well as animal milk protein in males.

A shift favoring more plant-based foods has been steadily gaining momentum worldwide within the medical and athletic communities. However, some individuals continue to express concern regarding using plants as protein sources in sports nutrition products.

Sports nutritionists have long believed that certain compounds in plants may lower the bioavailability of proteins. Further, some research suggests that plants don’t provide all the essential amino acids available from meat-based sources.

A new study challenges these notions, suggesting that the humble potato may be as dependable a protein source as animal milk.

The research, which was partially funded by the Alliance for Potato Research & Education, appears in Medicine & Science in Sports & Exercise.

Researchers at Maastricht University in the Netherlands conducted a study to evaluate how potato proteins foster anabolic reactions that increase muscle mass.

Dr. Luc J.C. van Loon, a professor of physiology of exercise and nutrition at Maastricht University Medical Centre, was the lead investigator.

Speaking with Medical News Today, Dr. van Loon shared:

“The [study’s] main outcome is that potato-derived protein ingestion can increase muscle protein synthesis rates at rest and exercise, and that this response does not differ from ingesting an equivalent amount of milk protein.”

“[P]lant-derived proteins can be as effective as high quality animal-derived proteins to stimulate muscle protein synthesis rates in vivo in humans.”
— Dr. Luc J.C. van Loon

Muscle protein synthesis (MPS) is the process by which amino acids become skeletal muscle proteins. Protein ingestion and exercise are vital for MPS to maintain and build skeletal muscle mass.

Protein consumed during recovery from exercise can increase MPS rates. These rates vary by protein source.

Potatoes, the world’s third most consumed crop, contain only 1.5% protein based on their fresh weight. However, a protein concentrate can be extracted from potato juice residue that is used for feed or discarded.

Dr. van Loon and his co-authors found that the amino acid composition of potato protein resembles that ofmilk protein closely. They also said that the tuber “provides sufficient amounts of all individual essential amino acids according to the WHO/FAO/UNU amino acid requirements, with no apparent deficiencies.”

The team hypothesized that ingesting potato protein concentrate could increase MPS rates at rest and during recovery from exercise.

They also hypothesized that potato protein may induce the same MPS response as milk protein.

To test their ideas, Dr. van Loon and his team recruited 24 healthy, active males for a trial held between April 2018 and February 2020. The participants ranged in age from 18 to 35.

All the subjects ate a standardized meal and fasted the night before the test days. Dr. van Loon told MNT that the special diet and fasting protocol was designed so as not to “affect the anabolic response to protein ingestion the following day.”

The researchers inserted a catheter into each participant’s upper arm for an amino acid infusion, which served as a tracer to measure MPS rates. They also inserted a second catheter into the opposite arm for blood sampling to measure concentrations of blood amino acid, insulin, and glucose.

The young male participants worked out on a seated knee-extension machine and leg press with increasing loads.

After letting the subjects rest, the researchers drew blood samples and took muscle biopsies to determine MPS rates at rest and during exercise recovery.

Then, the researchers randomly assigned the participants to drink a beverage with 30g (approximately 2 ½ tablespoons) of potato protein or milk protein. They followed it with more blood sampling and muscle biopsies.

The study concluded that “[…] ingestion of 30g protein was shown to strongly stimulate muscle protein synthesis during recovery from exercise,” said Dr. van Loon.

This double-blind study allowed researchers to observe MPS in exercised and non-exercised muscle. It also added to research demonstrating how potato protein can benefit exercise and recovery.

However, the current study also had several limitations.

The study sample size was quite small. Dr. van Loon acknowledged that “further dose-response studies in broader populations are undoubtedly necessary[…]”

Further, the trial only involved males. The researchers of a 2021 study cautioned that gender differences in physical build, hormones, and metabolism can make it difficult to apply research from males to females.

Additionally, participants were young adults, whose skeletal muscle anabolic resistance to protein ingestion might differ from that of older individuals. The above-mentioned research did mention, though, that older and younger male athletes may share similar protein metabolism.

As the market for protein supplements continues to expand, some researchers maintain that these products pale in comparison to whole foods in terms of nutritional benefits.

Dr. Stuart Phillips, a professor and Tier 1 Canada research chair in kinesiology at McMaster University in Ontario, who was not involved in this study, believes “[…]food trumps a supplement.”

In an interview with Auburn University, Dr. Phillips acknowledged that the greatest appeal of protein supplements is their convenience.

He pointed to his 2015 study suggesting that people who get protein from foods “have a greater nutrient density in their diet.”

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