REVIEW: Effects of Amino Acid Derivativeson, Physical, Mental and Physiological Activities.

This is a useful review of five ergogenic amino acid supplements (creatine, tyrosine, carnitine, HMB, and taurine) used frequently to enhance exercise performance, mental activity as well as body strength and composition.

Creatine, carnitine, HMB, and taurine are reported to delay the onset of fatigue, improve exercise performance, and body strength. Tyrosine has been proved to be very effective in fighting stress, improving mood and cognitive performance particularly in sleep-deprived subjects. Creatine is the most examined supplement with proven results, carnitine and taurine needs more comprehensive researches to provide evidence for their ergogenic role.

Download full PDF text: Effects of Amino Acid Derivativeson Physical, Mental, and Physiological Activities. (Feby Luckose , Mohan Chandra Pandey & Kolpe Radhakrishna a Freeze Drying and Animal Products Technology, Defence Food Research Laboratory, Mysore, India Accepted author version posted online: 26 Nov 2013.)

Table 1: Ergogenic action, type of exercise performed, and recommended dosage of the four amino acid derivatives

Supplements	Ergogenic action	Type of exercise	Recommended dosage
Creatine	Increased muscle mass, strength, fat free mass and fatigue resistance	Short term endurance exercise, resistance exercise, anaerobic exercise	20 g/day-acute dose 3–5 g/day- chronic dose
Tyrosine	Improved cognitive performance, accelerated neurotransmitter synthesis, stress resistance	Stress related tasks	Up to 100 mg/kg body weight
Carnitine	Increased fat metabolism, energy production and fatigue resistance	Long term endurance exercise	2 g/day
HMB	Increased body strength, fat free mass, muscle mass, body fat loss and reduced muscle damage	Resistance training, anaerobic exercise	3 g/day
Taurine	Antihypertensive, increased maximal performance, reduced oxidative stress and body weight	Endurance exercise	3 g/day

The creatine substance.

Creatine has been in use as an effective performance enhancing aid in many sports especially in track and field athletics for the past few decades. Since no harmful side effects have been found even at very large doses, its use is not prohibited by the governing bodies of sport (Maughan, 1999).

In mammals, creatine is synthesized naturally in the body from the amino acids, L-arginine, and glycine. In the kidney, the amino acids undergo L-arginine: glycine amidinotransferase-catalyzed reaction to give L-ornithine and guanidinoacetic acid. Guanidinoacetate is transported through the blood to liver where it is methylated to creatine in the presence of the enzyme S-adenosyl- L-methionine: N-guanidinoacetate methyltransferase.
Creatine is then supplied to creatine requiring tissues such as muscle and brain by the blood through an active transport system. In the muscles, creatine and phosphocreatine are converted to creatinine which is excreted by the kidneys into the urine (Wyss and Kaddurah-Daouk, 2000).

Approximately 94% of creatine is found in muscle tissue. Creatine stored in free and phosphorylated forms in skeletal muscles is important in maintaining a high ATP:ADP ratio during high-intensity exercise. Intense short-duration exercise results in phosphocreatine depletion from skeletal muscles. Inability to supply energy to rephosphorylate ADP to ATP, consequently leads to fatigue development and decline in physical performance (Chanutin, 1926; Hultman and Green haff, 1991; Greenhaff, 1997; Sahlin et al., 1998; Benzi and Ceci, 2001).

Creatine supplementation increases creatine and phosphocreatine concentrations in muscles, resulting in increased rate of ATP resynthesis and enhanced performance during high-intensity short-duration exercise (Sahlin et al., 1998; Benzi and Ceci, 2001).*(1)

ATP is critical for muscle contractions because it breaks the myosin-actin cross-bridge, freeing the myosin for the next contraction.*(2)

The Cross-Bridge Muscle Contraction Cycle  Source: Boundless. "ATP and Muscle Contraction".*(2)

So, in simple words, ATP (Adenine Tri-Phosphate) is the body's energy source molecule bond. When creatine enters the body (or after it is produced by the body) it firsts binds with a phosphate molecule to form Creatine Phosphate. Every time we squeeze our muscles a chemical reaction occurs inside the muscle, energy release in the form of heat and the ATP bond breaks. What remains, ADP (adenine Di-phosphate), a molecule bond unable to give any chemical reaction (muscle fatigue). It needs to combine again with a phosphate molecule to form a new ATP bond (energy source). Creatine Phosphate provides this phosphate molecule (recharge) allowing us to train harder and longer.*(3)

*(1) Source: Effects of Amino Acid Derivativeson Physical, Mental, and Physiological Activities (FEBY LUCKOSE, MOHAN CHANDRA PANDEY, and KOLPE RADHAKRISHNA).

*(2) Source: (https://www.boundless.com/biology/textbooks/boundless-biology-textbook/the-musculoskeletal-system-38/muscle-contraction-and-locomotion-218/atp-and-muscle-contraction-826-12069/)

*(3) Source: Creatine: Fact And Fiction! by Layne Norton (http://www.bodybuilding.com/fun/layne13.htm)

What does ergogenic means?

Ergogenic means to increase the capacity of the body or mind to perform a task. Ergogenic aids are substances, devices, or practices used to improve exercise and athletic performance. They work mainly by enhancing energy utilization and delaying the onset of fatigue. Ergogenic aids can be of several types like physical, mechanical, physiological, psychological, and nutritional (Bucci, 1993; Sobal and Marquart, 1994; Theinet al., 1995).

Nutritional ergogenic aids are dietary substances such as food or drugs that are consumed before, during, or after the exercise to enhance physical performance (Bucci,1993).

They enhance performance by either stimulating the central or peripheral nervous system, increasing energy production during exercise (by increasing the concentration of substrates that supply fuel or inhibiting substances that interfere with energy productions) or, by reducing muscle damage and enhancing recovery (Ivy, 1994).

Nutritional ergogenic aids can be broadly classified into three categories:

• Macronutrients such as water, carbohydrates, proteins, and lipids.
• Micronutrients like minerals, vitamins, and metabolic intermediates.
• Nonessential dietary substances like bicarbonates, caffeine etc.

Source: Effects of Amino Acid Derivativeson Physical, Mental, and Physiological Activities (FEBY LUCKOSE, MOHAN CHANDRA PANDEY, and KOLPE RADHAKRISHNA).