Protein is commonly a top concern when one hears vegetarian or vegan. Which is understandable as protein is essential for many functions including building and repairing tissue, synthesizing enzymes, and maintaining immune function. Fortunately, meeting proper protein needs is 100% achievable through plants alone as protein is created initially by plants; utilizing nitrogen from the atmosphere to synthesize amino acids.
Amino acids are the “building blocks” of protein; meaning that proteins are made up of amino acids. There are 22 amino acids in total, humans are able to synthesize 10 AA under normal healthy conditions, these are called non-essential AA. Your body has the ability to create energy through anabolism or catabolism, building up or breaking down (food) compounds, respectfully. Thus, your body is able to either:
- Build up proteins by gathering amino acids from different plant sources to create a complete protein (directed by your genetic code), or
- Consume a complete (animal) protein and break down/separate all the amino acids to each be used to build a new protein according to an individual’s genetic code.
Eating a complete protein from an animal product is simply consuming a protein that has already been created through anabolism of plant amino acids. Some research has shown that it could actually require more energy for humans to digest a previously created protein from animal sources than it does to build our own protein from plants.
General Protein Recommendations
General healthy (BMI 18-25) adult with light/moderate physical activity:
(0.8 g protein) per (kg body weight)
Female with no current health conditions/diseases
165 cm, 57 kg (BMI = 21)
Multiply 0.8 x 57 kg = 45 grams protein per day
Endurance Athletes 1.2-1.4 g/kg
Strength Athletes 1.6-1.8 g/kg
*Protein needs are increased during periods of rapid growth such as in infancy, adolescence, puberty, and pregnancy/lactation; as well as during times of physical stress such as surgery, burns, or damage to the integrity of skin/tissue. Furthermore, some research has shown that protein absorption slows as age increases.
Creating Complete Proteins
Complete proteins are foods that contain all of the essential amino acids required to synthesize protein. In most cases, complete proteins are of animal origin: milk, cheese, eggs, chicken, fish, and red meat. The well-known, plant-based complete protein is the soybean; sources including tofu, tempeh, and edamame beans. More examples of plant-based complete protein include quinoa, amaranth, and buckwheat. The important thing to grasp is that just because other food sources are missing an essential amino acid (earning the name incomplete protein), does not render them useless. For example, rice is an example of an incomplete protein, as it is missing the essential amino acid lysine. When paired with black beans, an incomplete protein lacking methionine, together they create a complete protein. While we have a limiting number of amino acids, there are an infinite amount of combinations to create a complete protein. Science no longer supports the necessity to consume two complementary incomplete protein food sources during the same meal; it is only vital that these combinations occur in the same day.
According to the Physicians Committee for Responsible Medicine: as long as one is eating a variety of plant foods in sufficient quantity to maintain one’s weight, the body gets plenty of protein. Let this challenge, to create complete protein combinations, act as a motivator to bring variety to your diet; which will only further support you to meet all of your necessary nutrient needs. Stay tuned next week for: Iron, an important mineral for vegetarians and vegans.