Guide to Chondroitin
Chondroitin: Conflicts of interest
The topic was suggested to us by representatives of an online market (I will not name it, since many readers have a nervous allergy to advertising) and sent a good article by their expert, nutritionist Alyona Stepanova, part of which we use in this text.
The logic of the disclosure of the topic is as follows: chondroitin is produced by the body itself and is an important component of synovial fluid (joint lubricant), it may not be enough, it must be taken from osteoarthritis and can be simply for prevention. However, the transition to the latter conclusion raises some doubts among scientists and generally depends on the situation: for example, osteoarthritis helps with pain, but do not expect a miraculous cure.
By the way, a number of meta-reviews separately raise the issue of conflict of interest when the study is in any way connected with the manufacturer of drugs based on chondroitin. And a number of studies explicitly state“ “due to the lack of control over the manufacturers of dietary supplements, use the drug only at the pharmaceutical level.”
In general, we decided to dig deeper into the topic: we analyzed what [1] writes about chondroitin from the National Institute Of Health, a digest on the drug from Medlineplus.gov [2] and also raised all the meta-reviews of chondroitin over the past 3-4 years on Pubmed.
Why chondroitin is needed
A joint is the junction of two or more bones that allows us to move, the joints are connected by tendons, muscles. But in order for the bones not to “grind” each other and not cause pain when moving, the joints are covered with cartilage at their junction, and are enclosed in a joint capsule that contains a special lubricant – synovial fluid.
The articular surface — the place where the bones touch – is covered with hyaline or fibrous cartilage. Due to constant friction, its smoothness is maintained, and this, in turn, facilitates our movements. The cartilage itself is designed to soften shocks and dampen movements. Muscles, ligaments, tendons, vessels and nerves are located around the joint. Their condition also directly affects the condition of the joint itself.
Chondroitin is one of the components of cartilage and synovial fluid in a living organism. It is in any living thing, not only in human: everyone who has joints has chondroitin.
Chondroitin is produced by the cartilage tissue of the joints. The cavities of our joints are filled with synovial fluid — a viscous mass, the density of which depends on the intensity with which we move. It is produced in response to movement (and therefore it is necessary to do a warm-up before exercise).
Synovial fluid acts as a lubricant for the joints, prevents them from rubbing against each other and, accordingly, quickly wear out. It also provides nutrition to the articular cartilage and serves as a shock absorption during movements.
Lack of synovial fluid, as well as changes in its composition, can cause not only creaking and crunching of joints, but also more serious diseases — such as osteoarthritis, osteoporosis, osteochondrosis and others – and this is a very common phenomenon. Here is what the World Health Organization writes [3]: “from 20% to 33% of people in the world live with painful diseases of the musculoskeletal system.”
Chondroitin is one of the components of the synovial fluid, and glucosamine is a necessary auxiliary substance, so they are often produced together in dietary supplements, including with other substances. Chondroitin stimulates the production of hyaluronic acid, which, in turn, affects the flexibility of joints, strengthens connective tissues and structures, and also affects the viscosity of synovial fluid and the elasticity of cartilage [4].
Is joint crunch a sign of a lack of synovial fluid?
By the way, there is an opinion that the crunch of joints is not the harmless air coming out of the joint cavity, but the sound of the formation of these cavities, and at the same time a sign of a shortage of synovial fluid. These are the conclusions of the 2015 study [5], which surprised the whole world.
The researchers observed the movement of the joints using MRI. They designed a tomograph in which it was possible to move and recorded on video what happens in the joint during the crunch.
It turned out that the crunch does not occur during the collapse of gas bubbles, but due to the formation of cavities during movement. At first, small gas cavities form in the joint, and at the moment of stretching they sharply increase in volume. If there is not enough synovial fluid in the joint, which should fill the voids, the cavity is filled with gas. And we hear a crash.
However, in itself, the crunch of joints in studies has not yet been associated with the cause of osteoarthritis.
Slowing of chondroitin production and osteoarthritis
With age, there is a reduction in the production of many substances, including components of synovial fluid. As the body matures and ages, the chondrocytes that synthesize them, the intercellular substance and fibrous structures of cartilage become less active, less chondroitin and glucosamine are produced, and joints may begin to experience their deficiency. As the deficiency develops (and for other reasons), osteoarthritis (aka “osteoarthritis”) may develop. A very common disease is the destruction of the joint due to degeneration of the cartilage tissue of the articular surfaces.
“Osteoarthritis often begins at the age of 40-50 years. The vast majority of 80-year-olds are affected by this disease to one degree or another. Between the ages of 40 and 70, this disease affects women more often than men. After 70 years, the disease affects representatives of either sex with the same frequency” [6].
Osteophytes are small bone growths that contribute to the destruction of cartilage.
Of course, everything depends on individual characteristics, genetics, the presence and nature of regular activity and diet.
Chondroitin is found in animal food: mainly in cartilage and ligaments, jelly, bone broths, fat with skin, gelatin are useful. Chondroitin and glucosamine are found in hard cheeses, seaweed, mushrooms, nuts, broccoli and wheat germ.
Do I need to take chondroitin?
Today, chondroitin is traditionally prescribed for osteoarthritis.
In the digest Medlineplus.org and almost all meta-reviews conclude that chondroitin (chondroitin sulfate) has a mild to moderate effect on reducing pain caused by osteoarthritis. Actually, the vast majority of studies of chondroitin are associated with its facilitation of life with arthrosis. In addition, some studies also find a positive effect on the work of the joint.
In these [7], [8], [9], [10], [11], [13] recent meta-reviews make a clear conclusion: chondroitin reduces pain caused by osteoarthritis.
As for the “structural” changes – that is, the effect on the root cause of pain – an improvement in the situation with a decrease in cartilage, a gap between the joints and a lack of synovial fluid – then the data are contradictory. In general, NIH, Medlineplus and most meta-reviews conclude: either about “insufficient data”, or about inconsistency (it helps someone, it doesn’t help someone), or about a minor effect, or about a conflict of interests. In general, the effect of chondroitin is not unambiguously positive enough for everyone to safely recommend it to everyone.
Nevertheless, in some meta-reviews, in addition to reducing pain, it was concluded that chondroitin: “improves functionality in people suffering from osteoarthritis of the knee” [7], “has a minimal effect on the narrowing of the articular gap and does not affect the volume of cartilage” [8], “improves knee functionality, however, the conclusions of the results are contradictory” [9], “improves joint function” [10].
When comparing the effect of chondroitin on the WOMAC osteoarthritis index (Western Ontario and McMaster Universities Osteoarthritis index–, “significant positive effects” were not found [11]. But at the same time, if we take another index of osteoarthritis manifestations – from Japan – Japanese Knee Osteoarthritis Measure (JKOM) – then on this scale, for example, glucosamine (acts together with chondroitin) has an effect in getting rid of osteoarthritis symptoms better than placebo [12].
Two meta-reviews [7],[8] separately mention the need to use pharmaceutical-grade chondroitin sulfate (”pharmaceutical-grade“) “due to the variability of the amount of chondroitin sulfate in dietary supplements, which are poorly controlled.”
Finally, this meta-review [13] raised 69 studies of 20 different supplements and evaluated their effectiveness for the treatment of osteoarthritis. 13 of these supplements have shown an effect on short-term pain relief from osteoarthritis: collagen hydrolysate, passion fruit peel extract, curcuma longa extract, curcumin, Boswellia serrata extract, pycnogenol, L-carnitine, non-denatured type II collagen, avocado soybean unsaponifiables, methylsulfonylmethane, diacerein, and finally glucosamine and chondroitin.
At the same time, the researchers noted that the quality of research on some drugs is low – very few studies, participants.
In general: yes, chondroitin (alone or together with glucosamine) relieves pain and may have a minor effect on functionality in osteoarthritis.
Whether it is necessary to take it “for prevention” is, in our opinion, an open question. Zozhnik’s opinion: a varied diet, including a moderate amount of animal products (cartilage tissue, broths, jelly, fat, meat), as well as regular exercise will prolong the healthy active life of your joints.
Chondroitin is potentially effective in the treatment of cataracts
Studies show that the introduction of a solution containing chondroitin sulfate and sodium hyaluronate into the eye protects the eye during cataract surgery.
Many different products containing chondroitin sulfate and sodium hyaluronate have been reviewed by the FDA for use during cataract surgery.
Chondroitin is potentially effective in Kashin-Beck’s disease
Studies show that chondroitin in combination with glucosamine inhibits the development of the disease and reduces the gap between the cartilage of the joints.
“Unconvincing arguments”
There has been some evidence of efficacy, but no conclusive conclusions on these effects of chondroitin:
- Dry eyes. Some early studies have shown that eye drops with chondroitin sulfate reduce dry eyes.
- Gastritis. Early studies have shown a reduction in pain in gastritis patients when taking a liquid containing chondroitin and hyaluronic acid.
- Interstitial cystitis. Some studies show that injecting liquid with chondroitin sulfate into the bladder can relieve painful bladder symptoms, but most of these studies are of poor quality. Some higher-quality later studies have shown no benefit.
- Psoriasis. Early studies show that taking chondroitin sulfate for 2-3 months reduces pain and improves skin condition in people with psoriasis. But other studies show that daily intake for 3 months does not reduce the severity of psoriasis in people with psoriasis and osteoarthritis of the knee joints.
- Incontinence. Early studies have shown that the introduction of sodium chondroitin sulfate into the bladder through a catheter improves the quality of life of people with an overactive bladder.
- Heart attacks. Some early studies have shown that taking chondroitin sulfate can reduce the risk of a heart attack.
- Joint pain due to aromatase inhibitor drugs. In some early studies, conclusions were drawn about the effectiveness of the chondroitin-glucosamine pair to reduce pain caused by these drugs.
Contraindications and special attention when taking chondroitin
Recommendations from Medlineplus.gov / National Institute of OIf Health:
Pregnancy and breast-feeding: There is not enough reliable information to know whether it is safe to use chondroitin sulfate during pregnancy or breast-feeding. Be careful and avoid using.
Asthma: There are some concerns that chondroitin sulfate may worsen asthma. If you have asthma, use chondroitin with caution.
Blood clotting disorders: Theoretically, administration of chondroitin sulfate may increase the risk of bleeding in people with blood clotting disorders.
Prostate cancer: Early studies have shown that chondroitin can cause the spread or recurrence of prostate cancer. This effect does not manifest itself when taking chondroitin sulfate supplements. However, while there is insufficient scientific evidence, do not take chondroitin sulfate if you have prostate cancer or you have a high risk of developing it (you have a brother or father with prostate cancer).
Some products with chondroitin contain excessive amounts of manganese. Keep this in mind and in case of doubt, consult your doctor.
Combination with coumadin. Warfarin (coumadin) is used to slow blood clotting. There is evidence that taking chondroitin with glucosamine increases the effect of coumadin on blood clotting. This can cause serious bruising and bleeding. Do not take chondroitin if you are taking warfarin (coumadin).
Authors: Maxim Kuderov, nutritionist,
Alyona Stepanova, nutritionist.
Mentioned sources:
- https://www.nccih.nih.gov/health/glucosamine-and-chondroitin-for-osteoarthritis
- https://medlineplus.gov/druginfo/natural/744.html
- https://www.who.int/ru/news-room/fact-sheets/detail/musculoskeletal-conditions
- https://www.researchgate.net/publication/233706397_Chondroitin_Sulphate_for_the_Treatment_of_Osteoarthritis
- https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0119470
- Остеоартрит (OA) (Degenerative Arthritis; Degenerative Joint Disease; Osteoarthrosis)
- https://pubmed.ncbi.nlm.nih.gov/31243744/
- https://pubmed.ncbi.nlm.nih.gov/30859538/
- https://pubmed.ncbi.nlm.nih.gov/30879253/
- https://pubmed.ncbi.nlm.nih.gov/29980200/
- https://pubmed.ncbi.nlm.nih.gov/29947998/
- https://pubmed.ncbi.nlm.nih.gov/29713967/
- https://pubmed.ncbi.nlm.nih.gov/29018060/
- https://pubmed.ncbi.nlm.nih.gov/31376086/
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