Deck 5: Proteins

Question 1

How do proteins differ from carbohydrates and fats in regard to their molecular structure?

Answer 1

Proteins are made up of amino acids (monomer of protein). A series of amino acids are found in a linear fashion called polypeptide chain. All amino acids have a similar structure. Amino acids have central carbon atom that is bind with a carbon side chain, a hydrogen atom, an amino group and a carboxylic acid group. The structure of protein are differ from carbohydrates and fats in following ways-
1. Proteins are made up of carbon, hydrogen, oxygen and nitrogen , whereas carbohydrates and fats are mainly made by carbon hydrogen and oxygen.
2. Proteins are hydrophilic in nature like carbohydrate. But the fat molecules are hydrophobic in nature.

Question 2

Discuss the various roles of proteins in the body. How does each of these roles apply to training, recovery, and/or sport performance?

Answer 2

Proteins are made up of amino acids (monomer of protein). A series of amino acids are found in a linear fashion called polypeptide chain. Proteins have an important role in major body functions that are following-
1. Protein form constituent parts of many structures as bones, ligaments, tendons, hair, nail, muscles, teeth and organs. The elastin and collagen are also protein that is found in connective tissues. With inadequate amount of protein in diet, these structure cannot well respond in training.
2. Dietary proteins are also important in the formation of enzymes. These enzymes help to control the rate of metabolic reactions and digestion in the body. If the diet has low in protein then the metabolic reaction of an athlete's body is also low. So, insufficient protein in diet is directly linked with the formation of inadequate ATP (adenosine triphosphate) for exercise.
3. Proteins are very important in the immune function of the body. Protein derived antibodies that help to destroy micro-organism, which causes illness. So, if protein is low in diet then immune system cannot function properly and it causes illness in athlete.
4. The certain types of hormones are also derived from proteins. These hormones are very important in endocrine system of the body. So, dietary protein is very important for normal hormone production in the athlete's body.
5. Protein also important in circulating system of body, it helps to maintain fluid balance of the body. It also helps to maintain an osmotic pressure within the blood. So, inadequate blood protein can cause sometime swelling or edema in the athlete's body.
6. Protein is also important in the formation of hemoglobin that is a transporter molecule. It helps to transport oxygen in the blood. If the hemoglobin is low in the body then it affect the exercise capacity and endurance,

Question 3

How would the nitrogen balance of an athlete be determined? Once determined, what does nitrogen balance indicate?

Answer 3

The nitrogen balance is the monitoring of nitrogen status in the body. The nitrogen balance has been achieved in the body, when the input of nitrogen through diet is equals to the output of nitrogen from the body.
Nitrogen status= (nitrogen in) - (nitrogen out)
The amount of 'nitrogen in' can be calculated by the daily protein intake. The determination of 'nitrogen out' is more complicated. The nitrogen can be release from the body through urea in the liver or also as ammonia. The nitrogen loss can be estimated by the measuring the urine level and sweat.
The body is in nitrogen balance when the difference between dietary protein intake and urea excreted is zero. A positive nitrogen balance shows that dietary protein intake is greater than protein loss through the body. It is used to make lean tissue in the body. It is important in the formation of muscle mass in weight training. A negative nitrogen balance shows when dietary protein intake is lesser than protein loss through the body. It is found in endurance athlete who training intensely but do not eat enough.

Question 4

What are "complete proteins," and what food sources provide them? What are the ramifications of eating foods that do not provide complete sources of protein?

Question 5

What are "incomplete proteins," and what food sources provide them? Give several examples of complementary incomplete protein sources that provide all essential amino acids.

Question 6

What are branched chain amino acids? What relationship, if any, do they have to athletic performance?

Question 7

Discuss the relationship between carbohydrate intake and protein requirements.

Question 8

What are the recommended protein intake levels for athletes? Discuss why requirements for athletes are higher than for sedentary individuals.

Question 9

What dietary protein intake recommendations would you make to an elite athlete training for a marathon? How would those recommendations compare to recommendations for an Olympic weightlifter training 12 to 15 hours a week?

Question 10

What factors should be considered when determining the protein needs of an athlete?

Question 11

Provide two suggestions for well-balanced preactivity meals containing protein, as well as two examples of quick and easy postexercise snacks containing 15 grams of protein.