Protein from plant-based meats may not be absorbed as well

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Plant-based meat substitutes may be good sources of protein but may not be as easily absorbable, new research suggests. Sophia Hsin/Stocksy
  • Researchers compared the protein intake between vegetable meat and chicken meat.
  • The protein intake was higher for chicken meat than for vegetable meat.
  • The researchers concluded that the nutritional value of plant-based meats can be improved by adjusting the formulation and production conditions.

In recent years, plant-based meats have become more common as a way to “enjoy the taste of meat” without harming animals or the environment.

While the low fat and cholesterol content of plant-based meats may help reduce the risk of obesity and cardiovascular disease, studies show they may be less digestible than meats of animal origin.

Knowing more about how plant proteins are digested could help assess their feasibility as a main source of dietary protein.

Recently, researchers compared the protein intake of vegetable meat with chicken meat. They discovered that vegetable protein was absorbed less during an in vitro digestion process than protein from chicken.

The research is published in the Journal of agricultural and food chemistry.

For the study, the researchers created a vegetable ‘chicken meat’ from soybean concentrate and wheat gluten. The final product had a protein content of 24.2%.

The vegetable meat was then cooked together with chicken meat, ground to simulate the chewing process and passed through a 2.36 mm sieve to avoid effects on the digestion of the two samples caused by the sample size.

The resulting ‘meat lumps’ then underwent several in vitro tests to model protein uptake during digestion.

From these tests, the researchers found that the water solubility of vegetable meats gradually increased during in vitro digestion, reaching about 8% after stomach digestion and then 14% at the end of intestinal digestion.

However, they found that chicken peptides were consistently more soluble in water than vegetable peptides.

In addition, they noted that of the 110 peptides identified in the vegetable meat, about 50% remained after the digestion process.

Meanwhile, of the more than 500 peptides identified in chicken meat, only 15% remained after digestion. This, they wrote, suggested that peptides in chicken are more readily absorbed than those from plant sources.

When asked what might explain why human cells absorb less protein from plant-based meats than chicken, Dr. Da Chen, a postdoctoral researcher at Ohio State University and author of the study, Medical news today:

“Proteins are digested before being absorbed by human intestinal epithelial cells. After digestion, proteins mainly become peptides. The size and polarity of peptides have been reported to be closely related to their absorption.”

“In our study, the peptides produced by the digestion of vegetable meat were larger [and less water soluble]making them pass through the epithelial cells more slowly compared to chickens, resulting in less efficiency of absorption,” he explained.

Professor VM (Bala) Balasubramaniam, of the Department of Food Science and Technology at Ohio State University, who was not involved in the study, agreed.

“I agree with the author’s comment on this. As they noted, chicken meat proteins showed better swelling ability, which helps promote digestive enzymes. The soy proteins contain certain anti-nutritional factors (e.g. phytate and tannins) that can limit protein hydrolysis [water solubility],” he told MNT

“In addition, structural differences between plant and animal foods can also affect how proteins are released,” he added.

David Julian McClements, distinguished professor in the Department of Food Science at the University of Massachusetts, who was also not involved in the study, noted that digestibility and absorption depend on several factors, including:

  • protein type
  • protein denaturation
  • protein aggregation
  • food matrix effects
  • anti-nutritional factors
  • processing and cooking methods

So he said the findings of this study may not apply to all plant-based meat comparisons.

An example of this is that wheat gluten is not water-soluble and has stiffer structures than soy and chicken proteins, making it less digestible. Since the meat-based meat in this study was 28% wheat, the current findings may not apply to plant-based meats made purely from soybeans.

The authors concluded that the nutritional value of plant-based meats can be improved by adjusting the formulation and production conditions.

“When assessing the quality of plant-based meats, not only the texture but also the protein nutrition should be considered,” said Dr. Da Chen. MNT.

“The research results are beginning to provide some insight into how different plant and animal proteins affect human health. This will enable food processors to understand the benefits and limitations of different food processing technologies and ingredients.”
– Prof. Balasubramaniam

dr. Chen also emphasized that plant-based meats are still viable sources of protein.

“For consumers, plant-based meat would still provide valuable protein nutrition because it contains a good amino acid profile. Whether consumers should eat more plant-based meats to get equivalent nutrition is beyond the scope of this study because it depends on daily protein intake, which has not been conducted,” he said.

When asked about the study’s limitations, Dr. Chen: “We only used soy/wheat proteins as the main protein source for the production of meat analogues. For those who made with other proteins or other formulations, the results could be different.”

“Our Study” [also] used only in vitro digestion, it may show some differences compared to that of in vivo digestion. Future [studies] should be more focused on clinical trials,” he added.

dr. McClements nevertheless noted that this study, and other similar studies, are crucial. He said: “If we’re going to replace animal foods with plant-based alternatives, we don’t want to have any adverse effects on human nutrition and health.”

“Therefore, it is important to design plant foods with similar or better nutritional profiles and digestibility/absorption behaviors as animal foods to replace them,” he concluded.

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