Unit 4 - Protein and Amino Acid Supplementation for Skeletal Muscle Mass Building

Question 1

How much does the skeletal muscle mass account for?

Answer 1

for more than 40% of the body weight of healthy adults.

Question 2

The skeletal muscle not only plays an important role in…

Answer 2

physical activities but also affects the whole- body metabolism.

Question 3

What is skeletal muscle mass the basis of?

Answer 3

skeletal muscle function and is often affected by many factors.

Question 4

Adequate and balanced nutrition in combination with exercise are important counter measures for…

Answer 4

muscle dysfunction associated with disease and aging.

Question 5

The role of maintaining muscle mass during weight loss and aging has implications for…

Answer 5

chronic disease prevention, functional capacity, and quality of life.

Question 6

Maintenance of muscle mass is also essential for the…

Answer 6

peak performance of athletes.

Therefore, it is important to consider the scientific merits of the effects of established nutritional factors, such as proteins and amino acids on building muscle mass

Question 7

Growth of skeletal muscle (herein referred to as muscle mass) can occur in three ways. By an increase in:

Answer 7

1. Muscle fiber (muscle cell) numbers.
2. Muscle fiber diameter.
3. Muscle fiber length.

Question 8

What is the growth in cell #’s limited to?

Answer 8

to the prenatal and immediately postnatal period,
with humans being born with or soon reaching their full complement of muscle cells.

Question 9

What does growth occur by?

Answer 9

by either hypertrophy of the existing muscle fibers by adding additional myofibrils to increase the muscle mass or by adding new sarcomeres to the ends of the existing muscle fibers to increase their length. Both mechanisms occur during the growth process.

Question 10

What is the dynamic nature of the growth phase challenged by?

Answer 10

muscle breakdown due to inadequate nutrition, aging, inactivity, and disease.

Question 11

What do both the growth phase & muscle breakdown involve?

Answer 11

protein turnover, which is the continuing cellular processes of protein synthesis from amino acids to make peptides, and protein breakdown by degrading peptides into amino acids.

Question 12

What does an inequality b/t muscle protein synthesis & muscle breakdown can lead to?

Answer 12

muscle protein hypertrophy (e.g. nutrition and exercise training) or muscle loss/ atrophy due to malnutrition (Figure 1).

Question 13

Protein breakdown & Synthesis:

Answer 13

Muscle protein
1. Muscle breakdown
2. AA’s (go in & out of blood)
3. Muscle Synthesis

Question 14

Hypertrophy occurs when…

Answer 14

muscle synthesis > muscle breakdown

Question 15

Skeletal muscle is an integral body tissue playing important roles in…

Answer 15

performance, physical
function, and metabolic regulation.

Question 16

Maintaining muscle mass during aging or chronic disease is
important because…

Answer 16

it can affect functional capacity and quality of life.

Question 17

Several factors affect the
maintenance of skeletal muscle:

Answer 17

1. An acute exercise stimulus, particularly resistance exercise, stimulates muscle protein synthesis and growth.
2. Protein consumption before or after resistant exercise stimulates muscle mass building
   through a positive protein balance.
3. Resistant training/exercise & protein consumption are synergistic for building muscle mass.
4. Aging results in a gradual loss of muscle function, & there are predictable age-related alterations in skeletal muscle function. The typical adult will lose muscle mass w/ age, & the level of muscle activity.
5. Hormones such as growth hormone (GH), insulin-like growth factor-I (IGF-I) and
   androgens are the main anabolic regulators of muscle metabolism in health and disease.
   In contrast, glucocorticoids have direct catabolic effects and induce muscle protein loss.
6. Loss of muscle mass can occur as a systemic response to fasting and diseases like cancer.

Question 18

Do Foods Supply enough Vitamins and Minerals?

Answer 18

Eating a healthy diet provides us with the necessary vitamins and minerals. Any extra supply of these nutrients poses a risk of toxicity. There is little risk of deficiency or toxicity of vitamins and nutrient from a well-balanced diet. The best approach to prevent diet inadequacies is to improve our food choices and eating patterns, rather than resorting to the use of supplements.

Question 19

Some people may need supplements if they suffer nutrient deficiencies due to disease, alcohol, or drug abuse, or other conditions that affect food intake. The following people may benefit from the appropriate dose of nutrient supplements:

Answer 19

• People with specific nutrient deficiencies.
• People with particularly low energy intake.
• Vegans who need vitamin B12.
• Older adults with atrophic gastritis.
• People who have lactose intolerance.
• People who have diseases, infections, or injuries, or who have undergone surgery that
  interfere with the intake, absorption, metabolism, or excretion of nutrients.
• People taking medications that interfere with the bodies use of nutrient.
• People in different stages of the life cycle who have increased nutrient requirements.
• People who have inadequate intakes of milk or milk products, limited sun exposure, or
  heavily pigmented skin may need vitamin D.

Question 20

Popular Protein and Amino acid Supplements:

Answer 20

People often take protein and AA supplements, and their use is increasing. Athletes take them to build muscle for strength, physical performance, and endurance, while dieters may take them to spare their bodies’ protein during weight loss. There are other therapeutic reasons why people claim to use protein and AA supplements, including relieving depression.

Question 21

Nevertheless, do proteins and AA supplements really affect body composition and cure certain diseases in healthy, exercising adults eating adequate and balanced diet?

Answer 21

They do not do these things. However, in some very specific conditions, they may have positive effects.

Question 22

Some of the popular supplements for used for health, physical performance, and muscle mass are:

Answer 22

• Creatine (CM)
• Whey protein
• Plant-based Proteins
• Arginine
• Beta-alanine
• Carnosine
• L-Citrulline (CIT)
• Glutamine
• Essential Amino Acids (EAAs) & Branch-chained Amino Acids

Question 23

Creatine (CM):

Answer 23

CM in the form of creatine monohydrate (CrM) has been called the most ergogenic (i.e. related to improvement in physical performance) and safe supplement that is legally available. At present, creatine monohydrate is the most widely studied and clinically tested for use in nutritional supplements in terms of muscle uptake and resistant exercise (RE) and resistant exercise training (RET). Recently, alternative forms of creatine, such as creatine ethyl ester (CEE) and Kre Alkalyn (KA) have been marketed as superior forms of creatine to CM; however, as of this time these claims have not been supported by scientific studies. Further, a greater portion of CEE and KA are degraded in the stomach than CM.

Question 24

Whey protein:

Answer 24

Whey protein (WP) supplements have received increasing attention by consumers due to the high nutritional value of the proteins and amino acids they provide. However, some WP supplements may not contain the disclosed amounts of the ingredients listed on the label, compromising the nutritional quality and the effectiveness of these supplements. The WPs typically contains lactalbumin (α-LA), β-lactoglobulin (β-LG), free essential amino acids (free EAA), and free branched-chain amino acids (free BCAA).

Question 25

Plant-based Proteins:

Answer 25

There are several types of commercial plant-based protein powders used as supplements representing an array of the main sources of protein. For example, yellow pea protein (Pisum sativum), brown rice protein (Oryza sativa), soybean protein (Glycine max), hemp seed protein (Cannabis sativa), quinoa protein (Chenopodium quinoa), chia seed protein (Salvia hispanica), and pumpkin seed protein (Cucurbita sp.) in both single and multi-ingredient products.

Question 26

Arginine:

Answer 26

Arginine is commonly classified as a conditionally essential amino acid and has been linked to nitric oxide production and increases in blood flow that are purported to then stimulate enhanced nutrient and hormone delivery and favorably impact resistance training adaptations.

Question 27

Beta-alanine:

Answer 27

ß -alanine (BA), a non-essential amino acid, is becoming an increasingly popular supplement among bodybuilders. Once consumed, BA enters the circulation and is taken up by skeletal muscle where it is used to synthesize carnosine. Some studies have suggested short-term side effects of BA as paresthesia and lower concentration of histidine in muscles and plasma.

Question 28

Carnosine:

Answer 28

Carnosine is a dipeptide comprised of the amino acids, histidine, and BA, that is particularly important during anaerobic exercise such as sprinting or weightlifting. It is an effective buffer, antioxidant, heavy metal chelator, and antiglycation agent in muscle. It is converted by carnosinase to BA and histidine. Thus, several intervention studies have suggested benefits on muscle performance in neurodegenerative and age-related disorders, metabolic syndrome including reduction in fasting plasma glucose concentration in overweight or obese-prediabetic individuals, and inflammatory bowel disease. Chronic side effects are mainly due to excess levels of BA and histidine.

Question 29

L-Citrulline (CIT):

Answer 29

There are positive short-term effects of CIT on cardiovascular disorders, muscle wasting, obesity, and insulin resistance. It is parenterally given to patients with intestinal bowel resection and those with decreased concentration of arginine in plasma. Long-term studies of CIT intake indicate cardiovascular and renal risks since its mediators are nitric oxide and arginine.

Question 30

Glutamine:

Answer 30

Glutamine is the most plentiful non-essential amino acid in the body and plays several important physiological roles. It is an important energy fuel for rapidly proliferating cells, including immune and intestinal cells; act as precursor for glucose, ammonia, and nucleic acids synthesis; and plays a role in many cell signalling processes, including expression of genes.

Question 31

Essential amino acids (EAAs) and Branch-chained amino acids:

Answer 31

Research examining the impact of combined essential amino acids on stimulating muscle protein synthesis is an extremely popular area. While the EAAs are comprised of nine separate amino acids, some individual EAAs have received considerable attention for their potential role in affecting protein translation and muscle protein synthesis. In this respect, the branched-chain EAAs (valine, leucine, and isoleucine) have been highlighted for their predominant effect on muscle mass.

Question 32

Efficacy, Safety, and Adverse Effects of Protein and Amino acid Supplements for Muscle Tissue Building:

Answer 32

The International Society of Sports Nutrition (ISSN) has provided a well-referenced overview of the current evidence on the efficacy of proteins and AA supplemental intakes for building muscle tissue, their safety and adverse events, which is based on systematic and meta-analytic reviews. Here is a summary of the opinions of the ISSN*

Question 33

Arginine Safety:

Answer 33

Some studies have reported gastrointestinal distress, such as nausea and diarrhea. Since arginine has been linked to nitric oxide synthesis, excessive intake of arginine may lead to hypotension due to over stimulation of nitric oxide-mediated vasodilatation. This effect had been observed in individuals taking large dose of arginine intravenously.

Question 34

Branched-Chain Amino Acids (BCAA): leucine, isoleucine, and valine Safety:

Answer 34

BCAA supplements decrease exercise-induced protein degradation and/or muscle enzyme release (an indicator of muscle damage) possibly by promoting an anti-catabolic hormonal effect. In addition, BCAAs do mitigate recovery from damaging exercise muscles. Some studies suggest that increased BCAA concentrations and their derivatives are associated with insulin resistance and diabetes-related complications.

Question 35

Creatine Safety:

Answer 35

Creatine monohydrate is the most effective nutritional supplement available to athletes to increase high intensity capacity training, body mass and/or muscle mass during training. The gains in muscle mass appear to be because of an improved ability to perform high intensity exercise enabling an athlete to train harder, thereby promote greater training adaptations, and muscle hypertrophy. There are no apparent short-term side effects of creatine monohydrate in healthy adults, those with no liver or kidney problems, according to position statements of the ISSN. An internationally renowned team of experts has confirmed the statements after performing an evidence-based scientific evaluation of literature.

Question 36

Glutamine Safety:

Answer 36

Glutamine has been reported to increase cell volume and stimulate protein and glycogen synthesis. Excessive intake of glutamine may exert adverse effects, due to hyperammonemia, in subjects with liver disease or urea cycle disorders. This effect in astrocytes contributes to the cerebral edema in acute hepatic failure and neurotoxicity. Thus, glutamine should be restricted in cirrhotic patients.

Question 37

Essential Amino Acids Safety:

Answer 37

Collectively, data indicates that ingesting combined EAAs in the absence of feeding and prior to and/or following resistance exercise stimulates protein synthesis, with this response being largely independent of the protein source or food type. However, the increase in muscle mass protein synthesis is greater when the EAAs doses are provided in an intact source, highlighting the need of high-quality protein diets to cause overall positive effects on muscle mass, rather than individual AA supplements. Leucine is accepted to be the primary driver of acute changes in muscle mass. Some studies have associated increased intake of EAAs with hepatic enlargement and increased ammonia and glutamine and decreased branched-chain amino acids in blood plasma. Thus, some EAAs supplementations are inappropriate for patients with liver disease.

Question 38

Whey Protein Safety:

Answer 38

Whey protein is one of the highest-quality proteins given its amino acid content (high essential, branched-chain, and leucine amino acid content) and rapid digestibility. Consumption of whey protein supplements has a robust ability to stimulate muscle protein synthesis and increase muscle mass and strength. Analysis revealed that chronic and without professional guidance use of whey protein supplementation may cause some adverse effects specially on kidney and liver function

Question 39

In general, chronic intake of amino acid supplements and their derivatives can cause imbalance in metabolic processes and alter cellular functions especially in the liver and kidneys. These changes in metabolic pathways and cellular dysfunction can lead to:

Answer 39

1. Increased production of ammonia that is dangerous in individuals with hepatic or renal insufficiency, causing hyperammonemia and its toxic effects on the brain and central nervous system. 2. Nausea and vomiting. 3. Diarrhea. 4. Muscle cramping. 5. Reduction in the absorption of some amino acids in the gut.

Question 40

Key points:

Answer 40

The International Society of Sports Nutrition (ISSN) provides objective and critical review related to the intake of protein, protein, and amino acid supplements for healthy, exercising adults.

Question 41

Based on current literature, the ISSN has made the following position statements for:

Answer 41

- Dietary Protein - Protein & AA Supplementation

Question 42

What are 6 points on Dietary Protein?

Answer 42

1. Dietary protein is necessary for building muscle tissue. 2. An acute exercise stimulus, particularly resistance exercise, stimulates muscle mass building. 3. Dietary protein and exercise are synergistic when protein consumption occurs before or after resistance exercise. 4. Higher protein intakes may be needed to maximize the retention of lean body mass in resistance-trained adults during hypocaloric periods. 5. Weight loss dieters may benefit from consistently consuming the appropriate DRI- recommended protein intake. 6. Dietary proteins are safe.

Question 43

What are 11 points on Protein and Amino Acid Supplementation?

Answer 43

1. Proteins and AA supplements have no significant effects on muscle mass and athletic performance beyond the gains made from well timed, adequate, and balanced diets consumed by healthy athletes. 2. Extra proteins from powders, beverages, and pills do not prevent appetite further. Hence, they do not cause weight loss. This is against common sense because the extra proteins can lead to extra calories. 3. Proteins and AA supplements do not cause weight loss. 4. When combined with a heavy resistance-training program, protein and EAA supplements may promote increase in skeletal muscle mass. 5. Creatine supplements may have some positive effects on building muscle mass and are safe. 6. EAA supplements may have positive effects on building muscle tissue. 7. Overall, BCAA supplements do not have significant effects on muscle mass. 8. The safety of EAAs is uncertain. 9. Arginine, glutamine, or D-aspartic acid do not increase muscle mass, but their safety is uncertain. 10. Protein or AA supplements cannot be assumed to be safe for all individuals because of very limited safety research data. 11. Individuals should be cautious about consuming protein or AA supplements, which exceed levels in their daily dietary intake.