Creatine supplements

From: http://www.wikipedia.com/

Main article: Creatine supplements
Creatine supplements are sometimes used by athletes, bodybuilders, and others who wish to gain muscle mass, typically consuming 2 to 3 times the amount that could be obtained from a very-high-protein diet. A survey of long-time use gives the creatine content of several foods.[7] The Mayo Clinic states that creatine has been associated with asthmatic symptoms and warns against consumption by persons with known allergies.[8]
While there was once some concern that creatine supplementation could affect hydration status and heat tolerance and lead to muscle cramping and diarrhea, recent studies have shown these concerns to be unfounded.[9][10]
There is less concern today than there used to be about possible kidney damage from creatine, although there are reports of kidney damage, such as interstitial nephritis; patients with kidney disease should avoid use of this supplement.[8] In similar manner, liver function may be altered, and caution is advised in those with underlying liver disease although studies have shown little or no adverse impact on kidney or liver function from oral creatine supplementation.[11]
In theory, creatine may alter the activities of insulin. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a health-care professional, and medication adjustments may be necessary.
Long-term administration of large quantities of creatine is reported to increase the production of formaldehyde, which has the potential to cause serious unwanted side-effects. However, this risk is largely theoretical because urinary excretion of formaldehyde, even under heavy creatine supplementation, does not exceed normal limits.[12]
Extensive research over the last decade has shown that oral creatine supplementation at a rate of 5 to 20 grams per day appears to be very safe and largely devoid of adverse side-effects [13] while at the same time, effectively improving the physiological response to resistance exercise, increasing the maximal force production of muscles in both men and women.[14][15]
[edit] Pharmacokinetics
Endogenous serum or plasma creatine concentrations in healthy adults are normally in a range of 2–12 mg/L. A single 5 g (5000 mg) oral dose in healthy adults results in a peak plasma creatine level of approximately 120 mg/L at 1–2 hours post-ingestion. Creatine has a fairly short elimination half-life, averaging just less than 3 hours, so to maintain an elevated plasma level it would be necessary to take small oral doses every 3–6 hours throughout the day. After the "loading dose" period (1–2 weeks, 12-24g a day), it is no longer necessary to maintain a consistently high serum level of Cr. As with most supplements, each person has their own genetic "preset" amount of creatine they can hold. The rest is eliminated out of the body as waste. Creatine is consumed by the body fairly quickly. And if one wishes to maintain the high concentration of Cr ,Post - loading dose, 2-5g daily is the standard amount to intake.[16][17][18]
[edit] Pregnancy and breastfeeding
Creatine cannot be recommended during pregnancy or breastfeeding due to a lack of scientific information. Pasteurized cow's milk contains higher levels of creatine than human milk.[19]
[edit] Treatment of diseases

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Creatine has been demonstrated to cause modest increases in strength in people with a variety of neuromuscular disorders.[20] Creatine supplementation has been, and continues to be, investigated as a possible therapeutic approach for the treatment of muscular, neuromuscular, neurological and neurodegenerative diseases (arthritis, congestive heart failure, Parkinson's disease, disuse atrophy, gyrate atrophy, McArdle's disease, Huntington's disease, miscellaneous neuromuscular diseases, mitochondrial diseases, muscular dystrophy, and neuroprotection).[citation needed]
A study demonstrated that creatine is twice as effective as the prescription drug riluzole in extending the lives of mice with the degenerative neural disease amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease). The neuroprotective effects of creatine in the mouse model of ALS may be due either to an increased availability of energy to injured nerve cells or to a blocking of the chemical pathway that leads to cell death.[21] A similarly promising result has been obtained in prolonging the life of transgenic mice affected by Huntington's disease. Creatine treatment lessened brain atrophy and the formation of intranuclear inclusions, attenuated reductions in striatal N-acetylaspartate, and delayed the development of hyperglycemia.[22]
[edit] Cognitive ability
A placebo-controlled double-blind experiment found that vegetarians who took 5 grams of creatine per day for six weeks showed a significant improvement on two separate tests of fluid intelligence, Raven's Progressive Matrices, and the backward digit span test from the WAIS. The treatment group was able to repeat longer sequences of numbers from memory and had higher overall IQ scores than the control group. The researchers concluded that "supplementation with creatine significantly increased intelligence compared with placebo."[23] A subsequent study found that creatine supplements improved cognitive ability in the elderly.[24] A study on young adults (0.03 g/kg/day for six weeks, e.g., 2 g/day for 150-pound individual) failed, however, to find any improvements.[25]