Glucosamine is a natural constituent of healthy cartilage and synovial fluid in the joints of the body. It is derived from glucose and the amino acid glutamine, and as we age we tend to produce less. Our bodies use glucosamine to build and repair cartilage, tendons, ligaments, synovial fluid and other tissues. We need glucosamine primarily for the healthy structure, strength and shock absorbing functions of our joints. Clinical studies have shown that glucosamine can help reduce joint pain and inflammation.
Chondroitin (a.k.a. chondroitin sulphate) is another naturally occurring substance in the body. As one of the major constituents of cartilage, it is an essential element in providing healthy structure and function. It has a crucial role in producing new cartilage, protecting it from damaging enzymes and maintaining the balance of fluids and nutrient supply within the cartilage. Chondroitin also has an anti-inflammatory effect, helping to reduce pain and swelling and aid mobility.
Glucosamine and chondroitin in combination provide complementary and overlapping functions for cartilage protection and restoration. Chondroitin sulphate also has a role in maintaining bladder wall and blood vessel integrity. Urine, blood and substances they transport are prevented from crossing these tissue barriers through the action of chondroitin.
Can I get these nutrients from my regular dietary intake?
Glucosamine: Food sources of glucosamine are limited unless you regularly consume broth made from animal cartilage and bone, as it is only found in the connective tissue of animals. Examples are chicken marrow, shellfish shells (eg shrimp, crab) and shark or bovine cartilage. Foods containing the glucosamine component glutamine are raw parsley and spinach. Glucosamine supplements are mostly extracted from the shells of crabs, lobster and shrimps. There is also a glucosamine formula manufactured from vegetable sources.
Chondroitin: There are no reliable food sources of chondroitin sulphate, and no vegetable sources. Chondroitin supplements are derived from animal cartilage, with extracts of cow trachea, pig ear and nose, or shark cartilage being the significant sources. Cartilage from other fish species, and bird cartilage are also used. Some supplements use a laboratory-manufactured synthetic form of chondroitin sulphate. Variation among chondroitin sulphate compounds derived from different animal sources means supplements will vary also according to their source.
What other nutrients support glucosamine and chondroitin metabolism?
The most important nutrients needed for optimal function of all our cells, tissues and organs are the essential macro and micro minerals. These are the fundamental building blocks of our physical body. On top of the biochemical framework formed by these minerals, glucosamine and chondroitin add the raw material for our bodies to maintain and repair the components critical for healthy joint mobility and function. Therefore it’s important to get your overall mineral intake in the right balance for optimal biochemistry to facilitate production or metabolism of glucosamine and chondroitin from all sources.
Hyaluronic acid, collagen, methsulfonylmethane (MSM), omega 3 fatty acids, vitamin D and vitamin C are all important nutrients needed alongside glucosamine and chondroitin for synthesis and maintenance of healthy joints.
What are the health indicators for glucosamine and chondroitin supplementation?
Osteoarthritis is the main indicator for this supplement combination. This is a degenerative disease of the joints of the body, occurring as a result of either injury or gradual wear and tear. The function of cartilage at the ends of bones is to provide cushioning against the action of bone on bone in joint movement. In osteoarthritis the synovial fluid decreases and the cartilage breaks down and is eventually worn away, causing inflammation, pain and stiffness. Most common sites are the large joints such as knees and hips, or in the hands. It is more prevalent with increasing age, obesity and in women.
The beneficial effects of glucosamine and chondroitin on osteoarthritis are well supported by consistent evidence from many research studies. Some studies focus specifically in osteoarthritis of the knee or hip, and suggest relief from symptoms for up to three months following a course of treatment. Reduction of pain, better mobility and flexibility, reduction in inflammation and stiffness and a corresponding reduction of medication to control these symptoms are all outcomes of supplementation.
Stiff and aching joints may be alleviated and joint mobility increased by supplementing your diet with these important nutrients.
Why are these supplements recommended in combination?
The Glucosamine/chondroitin Arthritis Intervention Trial (GAIT) conducted in research centres across the USA tested whether glucosamine and chondroitin sulfate used separately or in combination reduced pain in participants with knee osteoarthritis. Preliminary findings show that combining glucosamine and chondroitin improved pain relief outcomes for people suffering moderate to severe pain, compared with results from supplementing only one or the other.
In cases of only mild pain research results were less conclusive, however as both glucosamine and chondroitin are essential nutrients of healthy joint function it makes good sense to provide our bodies with a reliable source of both.
What forms of glucosamine and chondroitin supplement are most effective?
Glucosamine sulphate and glucosamine hydrochloride (HCl) are the stable forms of glucosamine used in tablets and capsules. Binding glucosamine to either a sulphate or HCl stabilising agent ensures it won’t degrade in these supplement forms. There is no clear indication yet from research as to which form is more beneficial and anyway results tend to differ from one individual to another, so unless you know which suits you best the most effective approach may be to choose a product that contains both forms.
Glucosamine supplement is also available in liquid form. Liquid glucosamine requires no stabiliser, and is absorbed into the tissues more quickly and effectively than a tablet or capsule. Faster absorption means faster relief from pain and discomfort.
Chondroitin sulphates are structurally diverse polysaccharides with a range of composition patterns. These complexities mean the biological roles of chondroitin sulphate are still not well understood. Recent studies indicate low molecular weight chondroitin sulphate (as opposed to high molecular weight varieties) is the most effective form. Indications are that significant absorption occurs via the stomach and small intestine and then enters the joint space.
Research has revealed that some supplement brands of chondroitin or combination glucosamine/chondroitin don’t contain the amount of chondroitin stated on the label. Always look for brands that verify their constituents.
Are there other health benefits from taking glucosamine and chondroitin?
Possible beneficial action on intestinal health, bladder function, coronary artery health, iron absorption, eye health and function and psoriasis are indicated as follows, with further research needed:
- A small study into the effect of glucosamine supplementation in six autistic and gluten intolerant children with chronic diarrhoea showed symptom relief in five of them, with the sixth able to consume gluten grains without a corresponding change in behaviour. The findings indicate a possible protective action by glucosamine on the intestinal tract.
- Preliminary studies suggest chondroitin may help treat cystitis and aid bladder control.
- Favourable results were reported from several 1970s studies into chondroitin supplementation for prevention of subsequent coronary events in patients with a history of heart disease. With the global research focus shifting to drug therapies for coronary disease and their now widespread availability, no current studies into the effect of chondroitin as a treatment option for maintaining coronary artery health are available.
- Research in individuals with healthy levels of iron indicates chondroitin supplementation may further enhance iron absorption. Effects in cases of iron deficiency require further research.
- Chondroitin is a component of some medical solutions used to treat the eye conditions keratoconjunctivitis, corneal preservation, and intra-ocular pressure. Further research is needed to support any claims for efficacy.
- Early results from research supports treatment for psoriasis using chondroitin.
What is the recommended daily dosage?
Typical recommended therapeutic dosage is 1500 mg per day, either as a single dose or in two or three divided doses, for 30 to 90 days duration. Some studies recommend a daily glucosamine dosage of 20 mg per kilogram of bodyweight, which gives a more individualised approach. A preventative supplemental dosage could safely vary from 500 mg to 1500 mg per day according to the individual.
For injury prevention or to supplement your diet 400 mg per day is adequate.
Between 800 mg and 1200 mg chondroitin daily (in two or three divided doses) is the usual recommended therapeutic dosage. Most research results indicate that 2 – 4 months supplementation of chondroitin is needed before symptoms improve, although in some cases benefits are experienced sooner.
Research using a regime of intermittent chondroitin sulphate supplementation, alternating 3 months treatment with 3 months break, indicates positive results for people with mild forms of osteoarthritis.
When positive results are gained after one to two months on the recommended therapeutic dosage it is a good idea to then reduce your daily dosage of each by a third (to 1000 mg glucosamine and 600 – 800 mg chondroitin) and monitor your body’s response. A lower daily dosage than the generally recommended one may be adequate supplementation for some individuals.
Are there any contraindications or adverse effects reported?
- Anyone allergic to shellfish should look for a vegetarian glucosamine supplement and avoid other glucosamine products sourced from shellfish.
- For people allergic to sulphur drugs or foods containing sulphates, the sulphate in glucosamine is a different substance and will not cause an allergic reaction.
- Glucosamine sulphate may affect insulin resistance and caution is advised for people with unstable blood sugar levels. Studies relating to effect on blood sugar have returned mixed findings to date.
- In general glucosamine sulphate is a safe supplement, non-toxic and tolerated well by most people. In high doses gastric symptoms, drowsiness, insomnia, headache or skin reactions may develop, however at the recommended dosage adverse effects are rare.
- As osteoarthritis is a condition affecting adults and is the main reason for chondroitin supplementation, its safety for children has not been studied. Similarly, no studies have been done on pregnant or breastfeeding women and therefore it is not recommended for these groups.
- While adverse effects from chondroitin supplementation are rare mild stomach upset has been reported in some cases. Hair loss and irregular heartbeat have also been reported. However, it is considered safe and free of adverse effects when taken as recommended for short periods of time (up to 90 days). Effects of long term use of chondroitin are yet to be studied.
- People on anticoagulant (blood thinning) drugs should consult their doctor before taking chondroitin, as it may enhance the drug effect.
Other effective supplement combinations
Glucosamine and chondroitin are sometimes combined with other nutrients, particularly Hyaluronic acid, MSM, Omega 3, Boron, and vitamin D.
Hyaluronic acid is another compound produced naturally by the body that cushions and lubricates the joints. It is present in synovial fluid, connective tissue and various other tissues and levels tend to reduce as we age.
Research into Methylsulfonylmethane(MSM) shows its effectiveness in many types of pain and inflammatory conditions and a particular role in retention of healthy cartilage.
Other research has proven that glucosamine sulphate taken in combination with Omega 3 has a significantly more effective outcome on osteoarthritic pain reduction than glucosamine sulphate taken alone.
Boron is an essential trace element in cartilage and therefore osteoporosis may indicate a deficiency. Current research supports this link.
Vitamin D is necessary for calcium absorption and optimal bone density, integral to joint health and function.
By Carolyn Simon, Naturopath