Neither is good or bad, they are just not the same: report
Plant-based meat substitutes taste and chew in a remarkably similar way to real beef, and the nutrition labels list — vitamins, fats and protein — make them seem essentially equivalent.
However, a Duke University team’s examination of the nutritional content of plant-based meat alternatives, using a sophisticated branch of science known as ‘metabolomics’ has demonstrated that they are very different.
Meat-substitute manufacturers have gone to great lengths to make the plant-based product as meaty as possible, including adding leghemoglobin — an iron-carrying molecule from soy — and beetroot, berries and carrot extracts to simulate ‘bloodiness’. The texture of near-meat is thickened by adding indigestible fibres like methyl cellulose. And to bring the plant-based meat alternatives up to the protein levels of meat, they use isolated plant proteins from soy, peas, and other plant sources. Some meat-substitutes also add vitamin B12 and zinc to further replicate meat’s nutrition.
However, many other components of nutrition do not appear on packaging labels, but that is where the plant-based products differ widely from meat, according to the study published in Scientific Reports, in July.
The metabolites that the scientists measured are building blocks of the body’s biochemistry, crucial to the conversion of energy, signalling between cells, building of biochemical structures, and tearing them down, and a host of other functions.
There are thought to be more than 100,000 of these molecules in biology and about half of the metabolites circulating in human blood are estimated to be derived from our diets.
“To consumers reading nutritional labels, they may appear nutritionally interchangeable,” said Stephan van Vliet, a postdoctoral researcher at the Duke Molecular Physiology Institute who led the research. “But if you peek behind the curtain, using metabolomics, and look at expanded nutritional profiles, we found that there are large differences between meat and a plant-based meat alternative.”
The Duke Molecular Physiology Institute’s metabolomics core lab compared 18 samples of a popular plant-based meat alternative to 18 grass-fed ground beef samples, taken from a cattle ranch in Idaho. The analysis of 36 carefully cooked patties found that 171 out of the 190 metabolites they measured varied between beef and the plant-based meat substitute.
The beef contained 22 metabolites that the plant substitute did not. The plant-based substitute contained 31 metabolites that meat did not. The greatest distinctions occurred in amino acids, dipeptides, vitamins, phenols, and types of saturated and unsaturated fatty acids found in these products.
Several metabolites known to be important to human health were found either exclusively, or in greater quantities, in the ground beef patties. These included creatine, spermine, anserine, cysteamine, glucosamine, squalene, and the omega-3 fatty acid DHA.
“These nutrients have potentially important physiological, anti-inflammatory, and or immunomodulatory roles,” the authors said in the paper.
“These nutrients are important for our brain and other organs including our muscles” said van Vliet, while adding: “But some people on vegan diets, can live healthy lives — that’s very clear. Besides, the plant-based meat alternative contained several beneficial metabolites not found in beef such as phytosterols and phenols.”
“It is important for consumers to understand that these products should not be viewed as nutritionally interchangeable. But that is not to say that one is better than the other,” said van Vliet, who described himself as an omnivore, enjoying a plant-heavy diet which also included meat.
“Plant and animal foods can be complementary, because they provide different nutrients.”
He said more research is needed to determine if there are short-, or long-term effects, of the presence, or absence, of metabolites found in meat or plant-based meat alternatives.
CITATION: “A Metabolomics Comparison of Plant-Based Meat and Grass-fed Meat Indicates Large Nutritional Differences Despite Comparable Nutrition Facts Panels,” Stephan van Vliet, James Bain, Michael Muehlbauer, Frederick Provenza, Scott Kronberg, Carl Pieper, Kim Huffman. Scientific Reports, July 5, 2021. DOI: 10.1038/s41598-021-93100-3