Beta-methylbutryic acid, technically known as, "beta-hydroxy beta-methylbutyric acid," or more commonly known as "HMB," is a metabolite of the amino acid leucine. Human muscles have a particularly high concentration of leucine, so this amino acid is often broken down/utilized during strenuous exercise . HMB is also found in grapefruit and catfish in trace quantities. It was first found to be of use in agriculture as an additive to help pigs, chickens, and other farm animals gain muscle and lose fat. It was not until a research trial conducted by the University of Iowa at Iowa City showed positive results that it caught attention as promising for human use.
The four-week double-blind study in 1995 involved 17 exercise-trained and 23 untrained males, divided into two groups. One group took daily capsules containing 3g of HMB, and the other took placebos. Everyone observed an identical weight-training regimen three times a week. Upon the trial's completion, the group who took the HMB demonstrated an average 3.1% increase in lean muscle mass, as compared with 1.9% for those who took the placebos. Also, the HMB group lost an average of 7.3% initial body fat, against 2.2% for the placebo group. The men who took HMB were able to average 22 pounds more with the bench press than they did at the beginning of the study. The men who did not, averaged a 14 pound increase. Thus, when taken as a supplement, up to 3 g a day, HMB has been shown to increase lean muscle mass and strength in athletes who use it during weight training. Theories suggest that HMB possibly suppresses protein breakdown that follows exercise that is rigorous and of long-term duration.
The patent for HMB is held jointly by Iowa State University and Vanderbilt University, which conducted the first studies on the compound. Experimental and Applied Sciences, Inc. (EAS) of Golden, Colorado, was originally licensed to market it. As of 2000, dozens of companies have it available for sale through retail stores, and commercial websites.
By the Summer Olympics in Atlanta in 1996, the publicity of the possible benefits of HMB had spread among athletes. Because it was not a banned substance, demand was heavy; it continues to remain popular among athletes as a nutritional supplement. This is true particularly for weight trainers, but has been reported as useful for any athlete undergoing resistance training. It is considered a "state-of-the-art" bodybuilding supplement, and tends to show an increase of lean mass and strength among those who use it. Studies have also shown that HMB might also accelerate fat loss that occurs secondary to strenuous exercise. According to Wayne Hearn in American Medical News in August of 1996, Dr. Naji N. Abumrad, MD, originally with the Vanderbilt team, began to conduct studies in 1996 that explored HMB's "potential use as an antiwasting agent that could benefit AIDS and cancer patients and help maintain muscle mass in the elderly." This research remains as ongoing.
HMB is available in both powder and capsule form, with capsule form being the primary method of usage. In 2000, an average price for 250 mg capsules ran approximately $35-$55 depending on retailer and volume purchased. Because HMB is a food supplement and not a drug, it is not subject to Federal Drug Administration (FDA) standards, and therefore has no minimum requirement recommendation. Tests have suggested that dosages from 1.5-3 g a day are required to achieve desired results.
As a food supplement found in every cell of the human body, it has no toxic effects, according to the research conducted. Because no long-term studies had been conducted on children, or pregnant or lactating women, the supplement could not be recommended for these groups. Thus, these groups of people should consult a physician, and use HMB with caution.
According to Abumrad, the only side effects discovered have been positive ones. Yet the benefits of lower cholesterol and blood pressure levels found to occur with the use of the supplement, were also associated with the intense exercise that seems to trigger HMB's tissue-building effects. As Hearn reported, "That stands in stark contrast to the side effects of unprescribed steroid use by athletes and bodybuilders, which has been linked to cancer, heart disease , kidney and liver damage, and erratic mood swings." Studies were ongoing to determine what other possible benefits or disadvantages HMB would prove to be for the long-term period of usage. Physicians were urged to add caution to their patients regarding this supplement to be alert to any unforeseen complications. In 2000, various websites offer testimony for or against usage. Those who recommend against it do so only in offering that it did not appear to be of any use, and did not provide them with the touted benefits.
No known adverse reactions have yet been documented when HMB is taken with other drugs or food supplements. It has been recommended for usage with creatine monohydrate for intense training.
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