We have all heard about the significance of including protein in our diet. While protein provides us with the much-needed energy, it is also important for the growth and development in children, teens and pregnant women. One of the most important components of the human diet, protein also supports lean mass growth, which is associated with desirable health outcomes and reduced mortality risks.
The protein in food is broken down into parts called amino acids during digestion. The quality and digestibility of these amino acids depend upon protein sources, which can be either animal-based or plant-based.
Now, this is where a debate has been raging on for decades—is animal protein better than plant protein, or vice versa?
“In terms of quality, animal protein is A-class if we compare it with plant protein, which has a reduced content of essential amino acids (EAAs). A significant reduction of limiting amino acids (methionine, lysine, tryptophan) means lower protein synthesis. But if we use mutual supplementation and choose sensibly, we can strike a balance,” says Dr Priyanka Rohatgi, chief clinical dietician at Apollo Hospitals, Bengaluru.
The superiority debate has the world of medical science divided with opinions ranging from animal protein aggravating kidney issues to plant-based diets providing adequate amounts of the essential nutrient. “For young and middle-aged people with active lifestyles, a well-balanced plant-based diet can provide sufficient protein, as long as it includes a variety of protein sources. For older individuals, animal protein is often rated higher due to their amino acid profile and ease of digestion, which can be beneficial as age-related issues may affect nutrient absorption,” adds Dr Rohatgi.
Experts suggest it is possible for one to optimise plant-based diets but that requires eating more to get the desired quantity of protein. In reality, it is much easier to accomplish if one sticks to an animal-based diet. For instance, depending upon the quality of protein, each 100 gm of animal-source food gives one 25 to 30 gm of protein. To get the same amount of protein intake from plant-source food, one would have to eat quite a lot, which will also increase the intake of carbohydrates. “One can combine foods that have complementary amino acid profiles. For instance, beans and rice together provide a more complete set of essential amino acids than each food [taken] separately. One must pay attention to protein-intake quantity to ensure you’re getting enough total protein in your diet to meet your daily protein needs. Some plant-based foods like plant-based milk and cereals are fortified with additional nutrients, including essential amino acids,” suggests Dr Bharathi Kumar, a Bengaluru-based dietician at Fortis Hospital.
Building blocks
Proteins are made up of chemical building blocks called amino acids. Our body uses these amino acids to build, repair muscles and bones. They also aid the production of essential hormones and enzymes, in addition to acting as a source of energy. According to a recent Harvard Medical School report, “The Recommended Dietary Allowance (RDA) for protein is a modest 0.8 grams of protein per kilogram of body weight or 0.36 grams per pound. The RDA is the amount of a nutrient you need to meet your basic nutritional requirements.” The same research points out that the amount of protein the body needs can vary from person to person, depending on the age and lifestyle factors. According to the same research, “For a 50-year-old woman who weighs 140 pounds and is sedentary (does not exercise), that translates into 53 grams of protein a day.”
Several human studies and randomised controlled trials (RCT) have concluded that a higher protein diet also supports weight loss. The major cause of both diabetes and high blood pressure is obesity, which also depends on lifestyle factors. So, an active lifestyle relying on a combination of regular exercise and high-protein diet is essential for healthy living. Some grain and cereal-based products are also sources of protein, but are generally not as high in protein as meat and meat-alternative products. “Legumes (beans, lentils, chickpeas) are generally considered the best sources of protein quality among plant-based proteins because they contain a good balance of amino acids and are high in fibre, vitamins, and minerals. Animal protein like chicken, lean cuts of beef, and fish are often considered good sources for lean muscle growth due to their high protein content, amino acid profile, and low fat content. However, plant-based options like tofu and tempeh can also support muscle growth when incorporated into a balanced diet,” Dr Kumar says.
Diet over diabetes?
Some studies have suggested the relative lack of EAAs in plant protein may result in the amino acids being directed towards urea synthesis. There also exists evidence that suggests people who rely on plant protein for their daily nutrition needs end up consuming less protein and more carbohydrates which can impair insulin sensitivity in some cases, especially in middle-aged and old individuals. That is because the quality of amino acids present in plants is quite low, which means an individual has to eat more for sufficient quantity of protein that also impacts digestibility.
Dieticians also recommend shifting to a plant-based diet to people who have kidney problems. “The breakdown of excess amino acids, including essential amino acids, can lead to the production of urea, which the kidneys must excrete. This is a normal metabolic process and generally not problematic in healthy individuals. However, excessive consumption of protein, whether from animal or plant sources, can strain the kidneys over time. If someone already has kidney issues, they may need to monitor their protein intake, but this is not limited to plant-based protein and can apply to high-protein diets in general,” explains Dr Kumar.
While this may be true for some, medical practitioners argue that because animal protein is connected to muscle health, it should remain an essential part of the daily diet of those prone to diabetes. “Our muscle health depends upon our protein intake and our longevity depends upon our muscle health. Both are interlinked. It is better for those who are prone to diabetes or are diabetic not to derive protein solely from plants because that impacts our insulin resistance,” says Dr Abdullah Saad Siddiqui, a Saudi-based functional medicine practitioner.
Dr Siddiqui opines that India is “the diabetes capital of the world” because doctors are not paying attention to this aspect of promoting plant-based diets. In fact, he believes a diet based on animal protein is safe for those in the early stages of kidney disease, and essential for diabetics. “There are no randomised controlled trials to prove that intake of animal protein can aggravate kidney problems. Unless, one is in stage four and five, of course. It is a myth—there is no science behind it,” he adds.
Smart choice
Considerable research has gone into drawing conclusions on smart protein or alternative protein, which is being marketed as environment-friendly substitutes of meat and other foods. Another selling point of this lab-produced protein is that it can address the impending implications caused by the global growth in demand for animal-source foods. According to a report published a few years ago in the journal Science, “Meat and dairy use 80% of the world’s farmlands and are responsible for 60% of agricultural greenhouse gas emissions.”
Another report published in 2019 notes, “Today’s food supply chain creates 13.7 billion metric tonne of carbon dioxide equivalent (CO2 eq) (26%) of anthropogenic GHG emissions. A further 2.8 billion metric tonne of CO2 eq (5%) are caused by non-food agriculture and other drivers of deforestation… These emissions can fundamentally alter the species composition of natural ecosystems, reducing biodiversity and ecological resilience. The farm stage dominates, representing 61% of food’s GHG emissions (81% including deforestation), 79% of acidification, and 95% of eutrophication.”
It is debatable if this sustainable protein should substitute real food, even if it is for the sake of saving the environment, food security and supporting natural ecosystems. “That is not food because it is made in labs. Imagine what it will do to our health—it is a big risk people are taking and its impact will show in a few years’ time. We all took these vaccines and after 2-3 years people are facing health issues. Smart proteins are not natural. Being a doctor, I would never recommend them,” Dr Siddiqui adds.