Insufficient protein intake is an important cause of malnutrition and disease. It can also cause heart disease, high cholesterol, bone loss, hair loss, muscle wasting, poor growth, glucose control, and immunity (Wu, 2016).
United Kingdom nutrition guidelines recommend that adults performing minimal physical activity consume 0.75g of protein per kilogram of body weight daily to maintain nitrogen balance (COMA, 1991). However, research suggests that this amount of protein may be insufficient for optimum health for most adults who exercise. Besides, all protein is not created equal.
Both animal and plant foods are excellent sources of different nutrients, e.g., meat is a rich source of vitamin B12, while green leafy vegetables are rich folate sources. Despite this, animal foods generally provide nutrients that are easy to digest and absorb than plant foods. Furthermore, animal proteins provide higher quantities and more balanced proportions of amino acids that humans need compared to plant foods.
With the rise of vegan diets, climate change and its environmental impact, most Western governments have begun encouraging their citizens to eat less animal protein and more plant proteins. In a 2017 press release, the British Dietetic Association renewed its memorandum of understanding with The Vegan Society stating that properly planned vegan diets provide all the nutrients, including protein, needed for well-being in people of all ages.
“We are pleased to have renewed this memorandum with The Vegan Society so that we can continue our positive working relationship,” Andy Burman, BDA Chief Executive said.
“It is important that people choosing to eat a vegan diet can get the right advice from the right sources and know to visit a dietitian for advice on tailoring their nutrition and diet. The BDA will continue to work with The Vegan Society to promote this message,” Burman added.
With plant-based food companies expected to make up 7.7% of the global protein market by 2030 (currently valued at over $162 billion), many plant-based food companies have emerged. Most of them produce many processed foods, including plant-based ‘meats’ with supposedly similar nutrient profiles, taste, and texture to meat to encourage consumers to eat less animal protein.
While a good initiative for the planet, few studies have critically assessed the long-term health implications of eliminating animal protein from the diet. And no studies have directly compared the digestibility, nutrient density and health benefits of meat and plant-based alternatives in humans. . It is worth noting that recent studies have linked a low protein diet to an increased risk of non-alcohol fatty liver disease (Ampong et al., 2020).
Now, a new study has shown that meat, whether pasture-raised or grain-fed is an easier to digest and more nutritious source of protein than Beyond Burger – a popular plant-based alternative.
The study, “Plasma amino acid appearance and status of appetite following a single meal of red meat or a plant-based meat analog: a randomised crossover clinical trial,” was published in Current Developments in Nutrition.
In the study, 30 healthy men were required to four breakfast burrito-style wrap containing either minced pasture-raised beef, grain-finished beef, pasture-raised lamb or Beyond Burger on four separate occasions. All meals had similar fat and protein content. Before and after each meal, the scientists collected blood samples from the participants to measure blood glucose, insulin, total amino acids, branched chain amino acids (BCAAs), essential amino acids (EAAs), non-proteinogenic amino acids (NPAAs) and non-essential amino acids (NEAAs) over four hours. All participants also completed questionnaires to rate their satiety levels before and after each meal.
The average age of the participants was 28 years, with a BMI of 24.5. The participant’s body weight, exercise levels and eating behaviours remained constant over the trial period.
Blood levels of total amino acids, BCAAs, NPAAs, and EAAs, were significantly higher after eating all red meat-containing meals compared with the beyond burger.
“Concentrations of plasma TAA, BCAA, EAA, and NPAA were significantly lower following the BB [Beyond Burger] meal compared to the red meat meals…Food producers may claim nutrient equivalence between PBMA [plant-based meat analogues] and meat, but our results indicate that the protein content of this exemplar PBMA is less able to increase plasma amino acid availability,” the researchers wrote.
There are different groups of amino acids with a range of functions in the human body. EAAs can only be obtained from food and cannot be made in the body. BCAAs, such as leucine, are vital for stimulating protein synthesis in the whole body and muscle growth.
In the study, lamb contained the highest proportion of EAAs and BCAAs, followed by beef, while beyond burger had the least. All red meat also provided hydroxyproline, an amino acid required for collagen production, but the beyond burger provided minimal quantities. And while the beyond burger raised blood glucose levels higher than the other meats, all four types of meat offered similar levels of fullness and satisfaction.
“While meat analogues are designed to mimic the taste, smell, texture and nutrition of meat, our results show that the bioavailability of their protein is lower compared to red meat,” they wrote.
These new plant-based proteins are sources of nutrients, but this study clearly shows that they are inferior to meat, and completely replacing beef with them may affect long-term diet quality and health. It may be wise to consider incorporating them into a healthy balanced diet rather than eliminating animal protein sources.
“In the context of wider environmental concerns associated with the production of red meat, the global supply of alternatives has increased substantially. However, reliance on plant-based substitutes may have implications for overall diet quality if adopted on a grand scale…
Given the findings in the present investigation that demonstrate a protein quality that is unmatched by the plant-based alternative, a balanced approach of moderation and diversity in dietary protein types is warranted,” they concluded.
Protein is an essential component of diet and health, and it is required for many functions in the body, including antibody and hormone production. Protein is present in both animal and plant foods, but animal foods tend to contain all the amino acids needed for health in appropriate quantities. Moreover, protein from animal foods is easier to digest and absorb than plant proteins.
Because of the environmental impact of climate change, the general message from the government is that people reduce their meat intake and adopt plant-centred diets. Many companies are now producing plant-based meat alternatives, with many manufacturers claiming that their products are as nutritious as meat.
This study shows that while plant-based alternatives may contain similar amounts of total protein, they have much less essential and branched-chain amino acids we need for health. So, instead of eliminating animal protein from the diet, eating a balanced diet containing both animal and plant foods is wiser.
- Wu, G. (2016) Dietary protein intake and human health. Food & Function, 7: 1251-1265.
- Committee on Medical Aspects of Food Policy (1991). Dietary reference values for food energy and nutrients for the United Kingdom. Report of the panel on dietary reference values of the committee on medical aspects of food policy. Reports on Health and Social Subjects (London), 41: 1-210.
- Among, I., Watkins, A., Gutierrez-Merino, J., Ikwuobe, J & Griffiths, H.R. (2020). Dietary protein insuffiency: an important consideration in fatty liver disease? British Journal of Nutrition, 123(6): 601-609.