HMB

(5)  (6)
 * (HMB) **

**//__HMB:__//**

HMB is also known as beta-hydroxy-beta-methyl butyrate. It is a metabolite of the essential amino acid leucine via α-ketoisocaproate (KIC), the transamination product of leucine, which seems to decrease muscle breakdown. This effect on the breakdown of muscles is why HMB is used as an ergogentic aid/ dietary supplement (any external influences that can be determined to enhance performance) by bodybuilders, as well as athlete(1). Other ways it can be consumed other than through some kind of supplement, is by consuming it through plant and animal foods; like grape fruit and catfish(1). HMB is also a supplement that is not a banned or restricted substance by the International Olympic Committee and it is also not on the 2010-2011 NCAA Banned Drugs list(2). Those who use HMB are seeking to promote enhanced muscle gains in strength and lean body mass, which can result from resistance type training(3).

**//__Science of HMB:__//**

This supplement is believed to be able to influence strength, along with lean body mass, by acting as an anticatobolic agent. This is done when leucine is ingested by the body it is transmitted into KIC (α-ketoisocaproate); which appears to decrease the amount of muscle broken down by the body. The KIC is believed to either be metabolized into isovaleryl-CoA in the mitochondria or into HMB in the cytosol, where approximately 5% of the leucine is metabolized into HMB(1). Since HMB contains leucine, it carries the unique characteristic that leucine has in the regulation of protein synthesis and degration. With this, the agent is believed to minimize the protein breakdown in the body. Along with it playing a role in protein breakdown, it also possesses the characteristic of being able to decrease the damage to cells that can be seen during an intense exercise. Also, with the increase of KIC that is transmitted from leucine and the potential outcome of this being HMB, it is found that the increased amount of KIC will in turn increase the rate of protein synthesis and decrease the rate of protein degration(3).

**//__Studies of HMB:__//**

Animals: Most of the initial research done with HMB was done on animals. A study done on chickens showed that there was an increase in body weight in those that were given HMB in their feed, compared to the chickens on a control diet. More research was done on under fed lambs, and when supplemented with HMB they had a 102% catch up rate of growth. Both these studies showed that when the animals were introduced to a catabolic environment with food restriction and then supplemented on HMB, they were able to increase their rate of growth(3).

Human Studies: One study consisted of untrained volunteers that underwent a three week weight training program. Throughout these three weeks the subjects were given a dose of HMB, either 0, 1.5, or 3g/day. The study looked at the response of the body to the different doses. The conclusion of the test was that HMB supplementation reduced muscle damage that was linked to exercise. Other tests concluded that those who took HMB, regardless of sex, responded fairly similar to the supplement when taking it. HMB has also been associated with reducing muscle loss that is linked to diseases of an auto immunodeficiency kind, as well as cancerous conditions(3). There have also been studies done on the elderly that had them take HMB as they performed a resistance training program. This program was performed for several weeks by the elderly that were given HMB and well as some were given a placebo. At the end of the study, the results showed that the loss of body fat was greater in those who took HMB than the placebo. The people who took the placebo also had less upper and lower body strength than those who took the HMB. Other studies have shown similar results to this one, including one on the elderly and bed rest that showed how supplementation helped decreased performance decrements seen in bed rest patients(1).

This is a chart from a study done on untrained individuals and the affects it had on them after resistance training.

HMB supplementation in untrained individuals: Effect on indicators of muscle damage following exercise* ( 4) 3 weeks || Decrease in CPK at wk 3, trend for decreased LDH at wks 2-3, decreased 3-MH at wk 2 only. || HMB+CR for 3 wks || Decreased CPK with <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">HMB at 2 wks only || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">8 wks || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">Decreased CPK in <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">both HMB groups at <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">48h only; no effect at <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">other points in study. || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">14d prior to bout of eccentric <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">exercise || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">Decreased CPK in <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">first 48h following <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">exercise. || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">For 6d prior to bout of <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">eccentric exercise || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">Not assessed || <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">*HMB= β-hydroxy-β-methylbutyrate; M=male; P=placebo; CPK= creatine phosphokinase; <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">LDH= lactate dehydrogenase; 3-MH= 3-Methylhistadine; CR=creatine;
 * **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">Study ** || **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">Participants ** || **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">Supplementation ** || **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">Biochemistry ** ||
 * <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt;">Nissen et al <span style="font-family: 'ArialMT','sans-serif'; font-size: 6.5pt;">11 || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">41 M || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">P, HMB:1.5 or 3 g/day for
 * <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt;">Jowko et al <span style="font-family: 'ArialMT','sans-serif'; font-size: 6.5pt;">15 || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">40 M || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">P, HMB 3g/d, CR,
 * <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt;">Gallagher et al <span style="font-family: 'ArialMT','sans-serif'; font-size: 6.5pt;">16 || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">37 M || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">P, HMB:38 or 76 mg/kg/d for
 * <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt;">van Someran et al <span style="font-family: 'ArialMT','sans-serif'; font-size: 6.5pt;">17 || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">6 M || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">P, HMB+KIC (3g/0.3g) for
 * <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt;">Paddon-Jones et al <span style="font-family: 'ArialMT','sans-serif'; font-size: 6.5pt;">18 || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">17 M || <span style="font-family: 'ArialMT','sans-serif'; font-size: 10pt; line-height: normal; margin: 0in 0in 0pt;">P, HMB 40mg/kg/d

__**//Dosage of HMB://**__

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt; tab-stops: 22.5pt; tabstops: 22.5pt;">It has been found that doses greater than 100g had no adverse effects when given to animals. However, those animals also had no increased enhancements from taking that much HMB. In human studies, on another hand, it has been shown that there were no further enhancements from taking HMB once the dose was greater than 3g per day in individuals that were being studied for dosage response. __Recommended dosage of HMB is usually between 1.5 and 3g per day(1,3).__

**//__Conclusion:__//**

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt; tab-stops: 22.5pt; tabstops: 22.5pt;">HMB is a supplement that is can be used by trained and untrained individuals. It has been shown to help people increase their strength and muscle mass with an establishment of a resistance training program. Those who have not been exercising and then start a training program see high enhancements with the help of HMB. Others who already had a training program in place and started taking HMB also showed increased fat loss and increased strength. It can also help people who have diseases that cause muscle loss by slowing down the process of muscle breakdown. When it comes to taking HMB there are no adverse side effects from it; even with no negative effects it is still recommened to not take more than 3g per day.

// **__<span style="font-family: 'Times New Roman','serif'; font-size: 14pt;">Links of HMB: __** // [] (7)

media type="youtube" key="mt-TMy10OBk" width="319" height="233" //**__ References: __**//

// 1.Wilson, G., Wilson, J., & Manninen, A. (2008). Effects of beta-hydroxy-beta-methylbutyrate (HMB) on exercise performance and body composition across varying levels of age, sex, and training experience: A review. //**Nutrition & Metabolism**//, //**5**// 1-17.doi:10.1186/1743-7075-5-1. // // 2.O'Connor, D., & Crowe, M. (2007). EFFECTS OF SIX WEEKS OF β-HYDROXY-β-METHYLBUTYRATE (HMB) AND HMB/CREATINE SUPPLEMENTATION ON STRENGTH, POWER, AND ANTHROPOMETRY OF HIGHLY TRAINED ATHLETES. //**Journal of Strength & Conditioning Research (Allen Press Publishing Services Inc.)**//, //**21**// (2), 419-423. Retrieved from Academic Search Premier database. // // 3.Slater, G., & Jenkins, D. (2000). β-Hydroxy-F128b-Methylbutyrate (HMB) Supplementation and the Promotion of Muscle Growth and Strength. // // 4.Routhier, D., & Stacy, J. (2007). HMB use and its relationship to exercise-induced muscle damage and performance during exercise. //**International SportMed Journal**//, //**8**// (2), 68-77. Retrieved from Academic Search Premier database. // // 5.http://www.olimp-supplements.com/images/produkty_en/hmb450.jpg // // 6.http://www.a1nutrition.com/g/graphics/products/eas/hmb.jpg // // 7.http://images.swansonvitamins.com/en_US/images/ItemImages_SW/images_sf/TL645_sf.jpg // // 8.[] //