Optimizing Protein Intake for Dancers: Part 1

Ensuring we get enough protein in our diets is something we hear about all the time. Getting adequate protein in our daily meals is incredibly important for everyone, but even more so for competitive athletes such as dancers. The increased physical exertion, muscle growth and repair, and cardiovascular demand means that athletes need to be even more careful that they are reaching protein adequacy daily. Understanding protein requirements can be complicated as you need to weed through the biochemistry, nutritional science, and sometimes misinformation. Let’s break it all down so you are fueled with protein for every workout, dance practice, and competition day. 

What we’re going to talk about: 

• What is protein and why do we need it?

• Essential vs non-essential amino acids

• How much protein do we need? How do we calculate individual protein requirements? 

• Considerations for a vegan or vegetarian diet; how to ensure adequate protein 

• Changes in protein requirement for athletes 

• Examples of protein sources (with exact amounts of protein in each) 

• Severe protein deficiencies; protein energy malnutrition 

• Examples of high protein foods and snacks for dancers on the go 

• Supplemental protein sources 

What is protein and why do we need it?

​​In the simplest of terms, proteins are amino acids joined together by peptide bonds. These bonds twist and fold in 3-dimensional space, producing centers which facilitate biochemical reactions. Proteins are precursors to hormones and cytokines, they maintain blood osmolarity, and act as transporters for various molecules. Evidently they are critical for many functions in the human body. They are also critical for muscle repair and growth, making them even more important for those participating in vigorous physical activity. Additionally, amino acids are minor but significant contributors to oxidative metabolism, meaning they are a fuel source for the body (more on this for athletes later!). Estimates suggest approximately 5% of energy is supplied by amino acids. The loss of 30% or more of body protein stores (muscle) results in profound reductions in muscle strength (including affecting the ability to breath), reduced immune function, and reduced organ function.

Essential vs non-essential amino acids

            These are terms you’ve probably heard before; essential and non-essential amino acids. There is plenty of biochemistry you can explore further on the topic, but in the simplest of terms essential amino acids cannot be synthesized by the body so they are needed from the diet. In contrast, the body can make non-essential amino acids from other amino acids so are not critical to get in the diet. There exist 20 amino acids; 9 are considered essential. Essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine (note: Alanine and histidine are conditionally essential meaning they are only essential during certain life stages). If an essential amino acid is present in insufficient quantities, the body’s total production of protein will be decreased. Even though all other amino acids may be present in abundance, an absence of one essential amino acid during protein production in the body results in the synthesis of the entire protein being aborted. This is why not only is protein quantity important, but also the quality of the protein. Protein quality refers to what percentage of amino acids in that protein are essential. The higher the percentage of amino acids that are essential the higher the quality. For example, egg whites have the highest proportion of their amino acids as essential amino acids. 

How much protein do we need? How do we calculate individual protein requirements? 

            The standard accepted amount of protein for an average adult is 0.8g/kg/day. This standard is calculated based on studies on omnivores (those who consume animal and plant based foods). There is a higher requirement for vegetarians and especially vegans due to lower protein quality. For example, the amount of essential amino acids in lentils is lower than in chicken. Vegetarian adults require 1.1g/kg/day. It is estimated that vegan adults require 1.3-1.4g/kg/day. For example, a 55kg female requires 44g protein per day to achieve 0.8g/kg/d, and 55g to achieve 1.0g/kg/d. More on how these numbers change for athletes to ensure protein adequacy below!

Due to rapid growth in early life, the protein requirement for youth is expectedly greater than that of adults: 0-6 months - 2.2g/kg/d, 6-12mo – 1.6g/kg/d, 1-3yr – 1.2g/kg/d, 4-6yr – 1.1g/kg/d, 7-14yr – 1.0g/kg/d, 15-18yr – 0.9g/kg/d.

Considerations for a vegan or vegetarian diet; how to ensure adequate protein 

            In addition to the previously discussed increased protein intake needed to ensure adequacy for vegans or vegetarians, there are other considerations to be taken into account to ensure optimal nutritional status. The majority of plant based protein sources do not contain all essential amino acids, although there are some exceptions (ie soy based products such as tofu). Additionally, this problem can easily be solved by mixing plant based protein sources at meals to ensure all essential amino acids are consumed. Grains are typically limited in lysine, threonine, and leucine. Beans and nuts are most significantly limited in sulfur containing amino acids such as methionine and cysteine. Limitations in threonine, tryptophan, and lysine are also of concern with these foods. 

            Another consideration for plant based protein sources is the deactivation of protein digestion inhibitors, specifically trypsin inhibitors. Beans (including soy) contain “trypsin inhibitors”. Trypsin is the enzyme responsible for digestion of protein in the small intestine. If thoroughly cooked, trypsin inhibitors are deactivated. If not deactivated the result is a lack of bioavailability of not only the bean’s protein, but also of all other protein consumed with that meal. To optimize plant protein absorption, thorough cooking of products such as beans and tofu is recommended. Eggs, whey protein, and soy products such as tofu are considered complete protein sources, with no limiting amino acids. These are great choices for vegans or vegetarians. 

Changes in protein requirement for athletes 

            Evidently athletes such as dancers are exerting their bodies and straining their muscles more than the average sedentary adult. This difference in activity and energy damage means that protein requirements for optimal health and nutrition are different. As mentioned earlier, amino acids are minor but significant contributors to oxidative metabolism (how our bodies make fuel with oxygen). Estimates suggest approximately 5% of energy is supplied by amino acids through a biochemical process called gluconeogenesis (the conversion of protein to glucose during prolonged exercise). Elite endurance athletes have higher protein requirements than elite body builders for this reason. During a prolonged endurance activity, such as dance or running, the body burns through its stores of glycogen (how we store glucose) and then begins using alternative fuels such as lipids and amino acids. In a study by Tarnopolsky et al., sedentary controls were compared to elite bodybuilders and elite endurance athletes. Conclusions from the study stated that body builders required a protein intake 1.12x greater than sedentary individuals, whereas endurance athletes required a protein intake 1.67x greater than sedentary individuals. This would suggest a protein requirement of 0.9g/kg/day for body builders, and 1.3g/kg/day for endurance athletes. For those athletes who consumed a vegetarian diet, estimates are that body builders require 1.1g/kg/day and endurance athletes require 1.6g/kg/day. Endurance athletes have a significantly increased protein requirement in order to meet energy demands during prolonged aerobic activity due to the increase in oxidation of amino acids for fuel.