Creatine: Composition, Therapeutic use, Treatment. Creatine effects. Reactions with other drugs.

Last modified: Thursday, 26. March 2009 - 4:44 am

Official names: Creatine monohydrate, creatine phosphate
Street names: Legal steroid, muscle candy, ergogenic aid, performance-enhancing substance
Drug classifications: Not scheduled, dietary supplement

 

Key terms

AMINO ACIDS: Organic molecules that make up proteins. The human body requires 20 amino acids to function properly. Essential amino acids are supplied by food and non-essential amino acids (including creatine) are produced within the body.
ANAEROBIC EXERCISE: Exercise that isn’t fueled by oxygen intake (as aerobic exercise is). Anaerobic exercise is defined by short, vigorous, and frequent muscle contractions, and includes activities like sprinting and weight lifting.
ANTIOXIDANT: A substance that prevents oxidation and protects cells from free radicals. Free radicals are molecules that contain an odd number of electrons. They can cause tissue death and damage.
ATHEROSCLEROSIS: A cardiovascular condition which causes arteries to narrow, or clog, with plaque build-up from excess blood cholesterol.
CONGESTIVE HEART FAILURE: Apotentially fatal condition in which the heart loses its ability to pump an adequate volume of blood. As blood flow slows, fluid builds up in tissues throughout the body.
DIETARY SUPPLEMENT HEALTH AND EDUCATION ACT (DSHEA): Passed in 1994, this law allows manufacturers to sell dietary and nutritional supplements without federal regulation. According to this act, supplements can be regulated only after they are proven to be harmful to users.
ERGOGENIC: Something that increases work output.
INBORN ERROR OF METABOLISM: An inherited genetic defect present from birth that causes a deficiency in the body’s essential enzymes and impairs metabolism.
U.S. PHARMACOPEIA (USP): A non-profit organization that provides standards for prescription and over-the-counter drugs, nutritional and dietary supplements, and health care products. USP publishes its standards in the United States Pharmacopeia and the National Formulary (USP-NF), which are officially recognized by the U.S. Food and Drug Administration (FDA). USP also has a dietary supplement verification program (DSVP).

 

Overview

Creatine was first discovered and isolated in muscle tissue in 1832 by French chemist Michel Chevreul. The compound is a naturally occurring, non-essential amino acid found in red meat, pork, dairy products, and fish. Most people take in approximately 1-2 grams (g) of dietary creatine from these sources daily (vegetarians somewhat less). Together, the kidneys, liver, and pancreas produce an additional 1-2 g of creatine daily, synthesized from the amino acids L-arginine, glycine, and L-methionine. Both creatine and phosphocreatine (which is creatine bound to phosphate; PCr, Crphos) are stored in skeletal muscle, organs, and body tissues. Phosphocreatine helps to power muscle contractions and decrease the amount of time the muscle takes to recover and “refuel.”
Oral creatine supplements first gained popularity among athletes in the early 1990s following the publication of a Karolinska Institute study that found that subjects who took creatine supplements experienced a significant increase in total muscle creatine content. In theory, increased creatine stores would increase PCr stored in the muscles, which would in turn provide a larger power supply for anaerobic muscle activity and exercise (short bursts of exercise which don’t require oxygen).
Creatine was thrust onto the global athletic scene in 1992 when British sprinters Linford Christie and Sally Gunnel won Olympic gold in Barcelona after reportedly training with the aid of creatine supplementation. Since that time, a number of clinical studies have looked at both the ergogenic (output enhancing effect) and therapeutic benefits of creatine.
Because creatine is considered a nutritional supplement, it is available legally and without a prescription in the United States. As of early 2002, creatine supplementation was not explicitly prohibited by the U.S. Olympic Committee (USOC), the National Collegiate Athletic Association (NCAA), the Major League Baseball (MLB), the National Football League (NFL), and other major national athletic organizations. However, a lack of well-designed clinical studies of creatine’s long-term effects combined with loose regulatory standards for creatine supplement products manufactured in the United States has caused some athletic associations, including the USOC, to caution against its use without banning it outright.
Despite these issues, creatine remains well-known as a nutritional, performance-enhancing supplement used by athletes to improve high-intensity muscle endurance and performance. Bodybuilders and weightlifters supplement with creatine to bulk up muscles, and athletes involved in team sports train with creatine to increase their energy for sprints and other short and intense muscular tasks. Statistics show that the use of creatine by adolescent and adult athletes is growing. Yet research is still largely inconclusive on exactly how and in what situations supplements help athletes out of the laboratory and on the field.

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