Beta-hydroxy beta-methylbutyrate
Encyclopedia
β-Hydroxy β-methylbutyric acid (HMB), or β-hydroxy β-methylbutyrate, is a metabolite
of the essential
amino acid
leucine
and is synthesized in the human body
. It plays a part in protein synthesis and was discovered by Dr. Steven L. Nissen at Iowa State University. It has been used in scientific studies to purportedly increase muscle mass and decrease muscle breakdown. Nissen held the original patent on the metabolite as a nutritional supplement. It was discovered in pigs, and small quantities can also be found in grapefruit
, alfalfa
, and catfish
. As a supplement it is usually sold as a calcium salt.
Research published in the Journal of Applied Physiology has shown that HMB may have an effect on increasing muscle weight and strength. A review in Nutrition & Metabolism provides an in depth and objective analysis of HMB research.
The same study lists as HMBs proposed mechanisms of action the following:
Three grams of Calcium beta-hydroxy-beta-methylbutyrate
per day may help muscles combat protein breakdown, assist in muscle repair and support increased endurance. Studies suggest its benefits may be greater for the untrained. Also, well-controlled scientific studies have found increases in muscle mass and decreases in body fat in 70 year old men. It has helped patients with chronic obstructive pulmonary disease
in hospital intensive care units, muscle wasting associated with HIV
or AIDS
and with cancer
, and trauma victims with severe injuries.
The human body produces about 0.2-0.4 grams per day. Standard doses in research studies have been 1.5 to 3.0 grams per day, usually divided into two doses.
, individuals have low or non-existent activity in one or more of the enzymes that facilitate recycling of biotin
, a nutrient referred to as vitamin B7 or vitamin H. In such individuals, hydroxyisovaleric acid (or hydroxyisovalerate) accumulates as a consequence of incomplete leucine
metabolism. The presence of hydroxyisovalerate is therefore a sensitive marker of biotin deficiency and may indicate the presence of a genetic disorder such as biotinidase deficiency
or holocarboxylase synthetase deficiency
.
Metabolite
Metabolites are the intermediates and products of metabolism. The term metabolite is usually restricted to small molecules. A primary metabolite is directly involved in normal growth, development, and reproduction. Alcohol is an example of a primary metabolite produced in large-scale by industrial...
of the essential
Essential amino acid
An essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized de novo by the organism , and therefore must be supplied in the diet.-Essentiality vs. conditional essentiality in humans:...
amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
leucine
Leucine
Leucine is a branched-chain α-amino acid with the chemical formula HO2CCHCH2CH2. Leucine is classified as a hydrophobic amino acid due to its aliphatic isobutyl side chain. It is encoded by six codons and is a major component of the subunits in ferritin, astacin and other 'buffer' proteins...
and is synthesized in the human body
Human body
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs.By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life...
. It plays a part in protein synthesis and was discovered by Dr. Steven L. Nissen at Iowa State University. It has been used in scientific studies to purportedly increase muscle mass and decrease muscle breakdown. Nissen held the original patent on the metabolite as a nutritional supplement. It was discovered in pigs, and small quantities can also be found in grapefruit
Grapefruit
The grapefruit , is a subtropical citrus tree known for its sour fruit, an 18th-century hybrid first bred in Barbados. When found, it was named the "forbidden fruit"; it has also been misidentified with the pomelo or shaddock , one of the parents of this hybrid, the other being sweet orange The...
, alfalfa
Alfalfa
Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...
, and catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
. As a supplement it is usually sold as a calcium salt.
Research published in the Journal of Applied Physiology has shown that HMB may have an effect on increasing muscle weight and strength. A review in Nutrition & Metabolism provides an in depth and objective analysis of HMB research.
The same study lists as HMBs proposed mechanisms of action the following:
- Increased sarcolemmaSarcolemmaThe sarcolemma is the cell membrane of a muscle cell . It consists of a true cell membrane, called the plasma membrane, and an outer coat made up of a thin layer of polysaccharide material that contains numerous thin collagen fibrils...
l integrity via conversion to HMG-CoAHMG-CoAHMG-CoA is an intermediate in the Mevalonate pathway. It is formed from acetyl CoA and acetoacetyl CoA by HMG-CoA synthase.HMG-CoA reductase converts it into mevalonic acid.... - Enhanced protein synthesis via the mTOR pathway
- Depression of protein degradation through inhibition of the ubiquitinUbiquitinUbiquitin is a small regulatory protein that has been found in almost all tissues of eukaryotic organisms. Among other functions, it directs protein recycling.Ubiquitin can be attached to proteins and label them for destruction...
pathway
Three grams of Calcium beta-hydroxy-beta-methylbutyrate
Calcium beta-hydroxy-beta-methylbutyrate
Calcium β-hydroxy-β-methylbutyrate or calcium HMB is a nutritional supplement, which represents a calcium salt of beta-hydroxy beta-methylbutyrate . The latter is a leucine metabolite produced in the body through oxidation of the ketoacid of leucine...
per day may help muscles combat protein breakdown, assist in muscle repair and support increased endurance. Studies suggest its benefits may be greater for the untrained. Also, well-controlled scientific studies have found increases in muscle mass and decreases in body fat in 70 year old men. It has helped patients with chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease , also known as chronic obstructive lung disease , chronic obstructive airway disease , chronic airflow limitation and chronic obstructive respiratory disease , is the co-occurrence of chronic bronchitis and emphysema, a pair of commonly co-existing diseases...
in hospital intensive care units, muscle wasting associated with HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
or AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...
and with cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
, and trauma victims with severe injuries.
The human body produces about 0.2-0.4 grams per day. Standard doses in research studies have been 1.5 to 3.0 grams per day, usually divided into two doses.
Multiple carboxylase disorders
In multiple carboxylase deficiencyMultiple carboxylase deficiency
Multiple carboxylase deficiency is a form of metabolic disorder involving failures of carboxylation enzymes.The deficiency can be in biotinidase or holocarboxylase synthetase.These conditions respond to biotin.Forms include:...
, individuals have low or non-existent activity in one or more of the enzymes that facilitate recycling of biotin
Biotin
Biotin, also known as Vitamin H or Coenzyme R, is a water-soluble B-complex vitamin discovered by Bateman in 1916. It is composed of a ureido ring fused with a tetrahydrothiophene ring. A valeric acid substituent is attached to one of the carbon atoms of the tetrahydrothiophene ring...
, a nutrient referred to as vitamin B7 or vitamin H. In such individuals, hydroxyisovaleric acid (or hydroxyisovalerate) accumulates as a consequence of incomplete leucine
Leucine
Leucine is a branched-chain α-amino acid with the chemical formula HO2CCHCH2CH2. Leucine is classified as a hydrophobic amino acid due to its aliphatic isobutyl side chain. It is encoded by six codons and is a major component of the subunits in ferritin, astacin and other 'buffer' proteins...
metabolism. The presence of hydroxyisovalerate is therefore a sensitive marker of biotin deficiency and may indicate the presence of a genetic disorder such as biotinidase deficiency
Biotinidase deficiency
Biotinidase deficiency is an autosomal recessive metabolic disorder in which biotin is not released from proteins in the diet during digestion or from normal protein turnover in the cell. This situation results in biotin deficiency....
or holocarboxylase synthetase deficiency
Holocarboxylase synthetase deficiency
Holocarboxylase synthetase deficiency is an inherited metabolic disorder in which the body is unable to use the vitamin biotin effectively. This disorder is classified as a multiple carboxylase deficiency, a group of disorders characterized by impaired activity of certain enzymes that depend on...
.