Glucosamine 13 NO 5 ) is an outstanding amino acid and precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of polysaccharides, chitosan and chitin. Glucosamine is one of the most abundant monosaccharides. It is produced commercially by the hydrolysis of crustacean exoskeleton or, more rarely, by fermentation of grains such as corn or wheat.
Evidence for the effectiveness of glucosamine as a dietary supplement is mixed. In the United States, this is one of the most common dietary supplements used by adults who are not vitamins or minerals.
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Medical use
Oral glucosamine is a dietary supplement and not a pharmaceutical drug. It is illegal in the US to market any dietary supplement as a treatment for any disease or condition. Glucosamine is marketed to support joint structure and function, and marketing is targeted to people suffering from osteoarthritis.
Commonly sold glucosamine forms are glucosamine sulfate, glucosamine hydrochloride, and N -acetylglucosamine. Of the three commonly available forms of glucosamine, only glucosamine sulfate is rendered "probably effective" to treat osteoarthritis. Glucosamine is often sold in combination with other supplements such as chondroitin sulfate and methylsulfonylmethane.
Glucosamine, along with commonly used chondroitin, is not routinely prescribed to treat people with knee osteoarthritis symptoms, as there is insufficient evidence that this treatment is helpful.
As is common with heavily promoted dietary supplements, the benefits of glucosamine are claimed to be based primarily on clinical and laboratory studies. Clinical studies were divided, with some reporting assistance from rheumatic pain and stiffness, while higher quality studies reported no benefit over placebo.
There is no evidence to date that the consumption of glucosamine by exercise participants will prevent or limit joint damage after injury. In a randomized, placebo-controlled trial, glucosamine supplementation did not have any additional effect on each rehabilitation result when administered to athletes after an anterior cruciate ligament (ACL) reconstruction.
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Adverse effects and drug interactions
One three-year clinical study showed that glucosamine in a dose of 1500 mg per day is safe to use.
Glucosamine with or without chondroitin increases the international normalization ratio (INR) in individuals who use blood thinners, warfarin. It may also interfere with the efficacy of chemotherapy to treat cancer symptoms.
Side effects may include abdominal pain, constipation, diarrhea, headache, and rash. There are case reports of people who have chronic liver disease and worsening their condition with glucosamine supplementation. More high-quality clinical research is needed before recommending glucosamine in pregnancy.
Because glucosamine usually comes from a shell's shell, it may not be safe for those with shellfish allergies. However, many glucosamine producers derived from shellfish include warnings that those with seafood allergies should consult a healthcare professional before taking the product. Alternative, non-shellfish form of glucosamine is available.
Another concern is that extra glucosamine can contribute to diabetes by disrupting the normal regulation of the hexosamine biosynthesis pathway, but some investigations found no evidence that this occurred. Other studies conducted on lean or obese subjects concluded that oral glucosamine at standard doses did not affect insulin resistance.
Biochemistry
Glucosamine is naturally present in the shells, bones of animals, bone marrow, and fungi. D-Glucosamine is made naturally in the form of glucosamine-6-phosphate, and is a biochemical precursor of all nitrogen-containing sugars. Especially in humans, glucosamine-6-phosphate is synthesized from fructose 6-phosphate and glutamine by glutamine-fructose-6-phosphate transaminase as the first step of the hexosamine biosynthesis pathway. The end product of this pathway is uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), which is then used to make glycosaminoglycans, proteoglycans, and glycolipids.
Since the formation of glucosamine-6-phosphate is the first step to the synthesis of this product, glucosamine may be important in regulating their production; However, the way hexosamine biosynthesis is actually regulated, and whether this can be involved in contributing to human disease remains unclear.
Manufacturing
Most glucosamine is produced by processing chitin from shellfish including shrimp, lobster, and crabs. To meet the demand of vegetarians and others with objections to shellfish, producers have brought glucosamine products to markets made using mushrooms Aspergillus niger and from corn fermentation.
History
Glucosamine was first prepared in 1876 by Georg Ledderhose by hydrolysis of chitin with concentrated hydrochloric acid. Stereochemistry has not been fully determined until Walter Haworth's 1939 work.
Legal status
United States
In the United States, glucosamine is not approved by the Food and Drug Administration for medical use in humans. Because glucosamine is classified as a dietary supplement in the US, safety evidence is required by FDA regulations, and evidence of efficacy is not required as long as it is not advertised as a treatment for medical conditions.
Europe
In most Europe, glucosamine is approved as a medical drug and sold in the form of glucosamine sulfate. In this case, evidence of safety and efficacy is required for the medical use of glucosamine and some guidelines have recommended its use as an effective and safe therapy for osteoarthritis.
The Task Force of the Europa League Committee Against Rheumatism (EULAR) has provided glucosamine sulfate toxicity level 5 on a scale of 0-100, and new OARSI (OsteoArthritis Research Society International) guidelines for hip osteoarthritis and knee show an acceptable safety profile.. By 2014, OARSI does not recommend glucosamine for disease modification, and considers it "uncertain" to relieve symptoms, in knee osteoarthritis.
Classroom action demands
In 2013, without acknowledging the error, the manufacturer Rexall Sundown, Inc., and NBTY, Inc., agreed to pay up to $ 2 million to settle a consumer claim related to the words of a particular claim on the bottle glucosamine pack sold at Costco under the Kirkland label.
In August 2012, a class action lawsuit filed in New York claimed that 21st Century Healthcare, Inc. incorrectly advising that the "Glucosamine 750 Chondroitin 600 Triple Strength" dietary supplement will restore lost cartilage. In April 2013, a San Diego man launched a proposed class action lawsuit in California Federal Court accusing Nutramax Laboratories, Walmart and Rite Aid of falsifying the effectiveness of glucosamine.
Research
Man
Because glucosamine is a precursor for glycosaminoglycans, and glycosaminoglycans are a major component of cartilage, studies have focused on additional glucosamine potential to benefit the cartilage structure and relieve arthritis. Although its use as a supplement appears safe, the evidence does not support it to be universally effective, as clinical trials have not yielded results that support its efficacy in 100% human subjects.
Bioavailability
Two studies measured the concentration of glucosamine in synovial fluid and plasma after oral administration of glucosamine sulfate for both healthy volunteers and those with osteoarthritis.
In the first study, glucosamine sulfate was administered to healthy volunteers in doses of 750, 1500 or 3000Ã, mg once daily. In the second study, the oral glucosamine sulfate capsule (1500 mg) was administered daily for two weeks to 12 people with osteoarthritis. The concentrations of glucosamine in plasma and synovial fluid increased significantly from the baseline level and the levels in the two liquids were highly correlated. The authors interpret that this rate can be biologically favorable for articular cartilage, but the rate is still 10 - 100 times lower than necessary to positively affect cartilage (chondrocytes) to build new tissue. The absorption of glucosamine sulfate in synovial fluid may be as much as 20%, or is negligible, indicating no biological significance.
Veterinary
Several studies have demonstrated the efficacy of glucosamine supplementation for dogs with osteoarthritis pain, particularly in combination with other nutraceuticals such as chondroitin while others have not. Oral combination capsule trial (glucosamine/chondroitin/manganese ascorbate) in dogs with osteoarthritis found no benefit in gait analysis or subjective assessment by veterinarians or owners.
The use of glucosamine in horse medicine exists, but one meta-analysis assesses extant research as too flawed to be of value in guiding horse medicine.
A number of studies have measured the bioavailability of glucosamine after oral administration of the horse. When given as an oral dose (nine grams) with or without chondroitin sulfate (three grams) to ten horses, glucosamine (hydrochloride) is detected in the blood with a maximum rate of 10.6 (/- 6.9) micrograms per milliliter at two hours after dosing. Another study examined both serum and joint synovial fluid after nasogastric (oral) or intravenous administration of 20 mg/kg glucosamine hydrochloride to eight adult horses. Although the joint glucosamine fluid concentration reaches 9 - 15 micromolars after intravenous administration, only 0.3 - 0.7 micromolar with a nasogastric dose. The authors calculated that the synovial synovial fluid levels achieved by the oral route were 500-fold lower than that required to have a positive effect on the metabolism of cartilage cells. A follow-up study by the same study group compared glucosamine sulfate with glucosamine hydrochloride at the same dose (20 mg/kg) in eight horses and found higher fluid concentrations with sulphate preparation (158 ng/mL compared with 89 ng/mL one). hour post oral dose). They concluded that higher levels of synovial fluid obtained with sulphate derivatives are still too low to have biologically relevant effects on articular cartilage.
A three-month trial of an oral dose regimen of commercial preparations of glucosamine sulfate, chondroitin sulphate and methylsulfonylmethane was performed on veteran horses with no effect on gait stiffness, with exercise alone in the effective control group. The intravenous use of a combination of N-acetylglucosamine, pentosan polysulfate and sodium hyaluronate in horses with surgically induced osteoarthritis saw improvements in xray changes in cartilage but not histologically or in biochemical results, suggesting more evidence is needed for combinations and routes of administration.
See also
- Chitobiose
- Chitosan
- Chondroitin sulfate
- Methylsulfonylmethane
References
External links
- Glucosamine article, Mayo Clinic
- General information of glucosamine and chondroitin sulfate, Arthritis Foundation
Source of the article : Wikipedia
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