Whether your knee pain is due to a sports injury or to increasing age and osteoarthritis, it’s good to know that several supplements can reduce knee pain, stiffness and improve how your knees function (in other words how well you can carry out every day activities like going up and down stairs, walking, getting in and out of the bath and even putting your socks on).
Nutritional supplements are set to play an increasing role in the self-management of painful knees as the long-term use of paracetamol is no longer recommended due to concerns that they may increase the risk of heart attack or stroke. This follows similar concerns relating to the long-term use of non-steroidal anti-inflammatory drugs.
Here are the supplements that I have found most effective as a doctor, medical nutritionist and ex-sufferer of knee pain. I know these work from personal experience, from reviewing the published research, and from seeing an x-ray of my right knee taken this week after a fall when skiing. My joint space looks great and there are no obvious sign of osteoarthritis.
How do supplements reduce knee pain?
Nutritional supplements can improve painful knees in a number of ways, by:
- Providing building blocks for the repair of cartilage, ligaments and tendons
- Acting as a signal to stimulate repair of damaged tissues and the production of cushioning synovial fluid
- Regulating the enzymes involved in breaking down or building new cartilage
- Reducing inflammation
- Exerting an analgesic effect.
Some supplements, such as plant extracts, contain a wide variety of compounds that each work in different ways to provide more benefits than any prescribed painkiller ever could.
Glucosamine and chondroitin for knee pain
Glucosamine is produced naturally in the body as one of the building blocks needed to make cartilage, tendons, ligaments and synovial fluid. Its production declines with age, and it is often in short supply, especially when active joint repair is needed. Glucosamine acts as a biological signal to switch on the repair of damaged joint tissues, and helps to suppress the inflammation and breakdown of cartilage that is a feature of osteoarthritis.
Chondroitin is another structural component of joints. It also has anti-inflammatory actions and acts as a biological signal to increase the synthesis of collagen and synovial fluid, and to inhibit enzymes that dissolve cartilage.
Studies using cultured human cartilage cells have found the levels of 31 different proteins are altered by the addition of glucosamine or chondroitin, compared to non-treated controls. When the functions of these proteins were analysed, 35% were involved in biological signalling (telling cells what to do), 15% were involved in antioxidant stress responses, and 25% were involved in the synthesis of proteins such as collagen.
Glucosamine and chondroitin as building blocks
Within joints, chondroitin plus another substance, keratan sulfate (which is made from glucosamine) bind with proteins to form long chains known as proteoglycans. Up to 100 of these chains are then attached to a long, backbone-like molecule, called hyaluronic acid, which is itself made from glucosamine. The resulting, springy molecules resemble a giant centipede when cartilage is examined under an electron microscope.
The centipede-like proteoglycans act like water magnets, with hyaluronic acid alone able to bind as much as 1000 times its own weight in water. This creates a viscous hydrogel so that healthy joint cartilage is super-hydrated – 75% of its weight is water.
Together, the hydrogel and the springy proteoglycans (made from protein, glucosamine and chondroitin), make joint cartilage an excellent shock absorber. They allow cartilage to spring back into shape when subjected to stress during normal activities such as standing, walking or running which subject the cartilage within your knee joints to extraordinary pressures. Jumping down from the cab of a truck, for example, can subject your knee joints to impact forces as high as 12 times your body weight!
These stresses compress your knee cartilage and would lead to joint failure if the cartilage were unable to resist deformity. The proteoglycan hydrogel almost miraculously allows your cartilage to spring back into shape.
Water is also an important component of synovial fluid, which further reduces friction between the bone ends in joints. The proteoglycans present, which are made from glucosamine and chondroitin, make synovial fluid an excellent cushion to resist compression and reduce friction in weight-bearing joints.
As you get older, however, your cartilage cells secrete less and less glucosamine and chondroitin. The production of glucosamine, in particular, is one of the main rate-limiting steps in proteoglycan production. Declining levels of glucosamine and chondroitin are linked with reduced cartilage quality when cartilage producing cells (chondrocytes) are unable to compensate for the loss of collagen and proteoglycans. Cartilage becomes more brittle and prone to the degenerative changes seen in ageing joints.
Glucosamine and chondroitin also have anti-inflammatory properties, helping to reduce the overactive repair processes that can lead to inflammation once ‘wear and tear’ sets in.
How effective are glucosamine and chondroitin supplements for knee pain?
Prevention: Taking glucosamine supplements (at doses of 1.5g to 3g daily) can preserve joint health by reducing cartilage breakdown, and maintaining the production of collagen in athletes involved in various sports, including soccer and bicycle racing.
Sports injuries: Research involving 106 athletes with an acute knee injury found that taking glucosamine (1500 mg daily), significantly improve knee bending (flexion and extension) compared with placebo. These improvements in mobility took 28 days to develop, as it takes time for damaged tissues to use these building blocks, and for them to enhance repair processes, so don’t expect immediate results.
Osteoarthritis: Data from 54 studies, involving 16,427 people with knee pain due to osteoarthritis, found that glucosamine plus chondroitin was more effective than placebo in pain relief and improving joint function. Both glucosamine and chondroitin also reduced joint space narrowing, as seen on X-rays, to indicate that the progression of the osteoarthritis was significantly slowed.
In one interesting study involving 36 elderly people with osteoarthritis in both knees, one-third were given glucosamine, one-third took the anti-inflammatory pain-killer ibuprofen, and one-third received placebo over a 12 week period. During this time, the volunteers took part in leg strengthening exercises designed to stress their knee joints. Circulating blood levels of cartilage matrix protein were measured before and after and the results suggested that glucosamine was significantly better than ibuprofen (or placebo) at improving cartilage responses to joint loading in people with knee osteoarthritis.
Collagen Supplements for knee pain
While glucosamine and chondroitin give cartilage its flexibility and resilience, it gets its strength from a strong, fibrous protein known as type II collagen. Collagen is a protein composed of long chains of amino acids. Every third amino acid is glycine, with proline, hydroxyproline and hydroxylysine appearing in between. These last two amino acids are not found in any other human proteins.
Long chains of collagen come together in threes, coiling around each other to resemble a strand of wool. Hydroxyproline, which needs vitamin C for its synthesis, has a unique shape which allows collagen fibres to twist around each other and form the strong, triple strands.
How collagen works
Many long, triple strands of collagen bind together to form fibrils which, in turn are bundled together to form strong fibres like the many strands in a rope.
These long, tough, flexible ‘ropes’ of collagen provide cartilage with tensile strength as well as flexibility. The collagen fibres also cross-link to form a strong network that traps proteoglycans (chondroitin and hyaluronic acid which is made from glucosamine) within.
Hydrolysed and unhydrolysed collagen supplements
The form of collagen found in joints (type 2 collagen) is found in the diet, particularly in meat. The collagen used in supplements is either derived from marine sources (eg from shark or other fish cartilage), or from animals cartilage (typically chicken, but also from beef or pork sources). Marine collagen peptides have a higher concentration of the amino acids needed for the production and repair of human cartilage (glycine, proline and hydroxyproline).
Supplements can contain collagen in its original state (known as unhydrolysed or undenatured collagen), or in a hydrolysed or solubilised form.
- Unhydrolysed collagen contains large collagen molecules (polypeptides) which must first be digested before they can be absorbed and used in the body.
- Hydrolysed collagen is in a ‘body-ready’ form as it is pre-digested by protease enzymes to release small fragments (peptides) that are more easily absorbed and used.
When you take a hydrolysed collagen supplement, it is rapidly absorbed into the circulation from which it is extracted by cells that need these building blocks (eg fibroblasts in the skin, chondrocytes in cartilage) and cartilage where it acts as a signal to trigger the synthesis of new collagen fibres.
As well as supporting joint health, collagen supplements have benefits on skin suppleness, elasticity and hydration to reduce the formation of skin wrinkles. There is also evidence that it offers benefits for people with thinning bones (osteoporosis) as collagen is an important matrix protein helping to create the scaffold on which calcium salts are laid down.
How effective are collagen supplements for knee pain?
Collagen supplements are well absorbed and can stimulate the synthesis of collagen, to help maintain the structure of the joint and reduce joint discomfort.
Collagen supplements increase blood levels of the amino acids needed to make collagen, and when collagen hydrolysate is ‘labelled’ to show up on x-ray, it is seen to preferentially accumulate in cartilage and to build it up (anabolic effect).
Osteoarthritis: Researchers have found that taking 40mg per day of undenatured collagen type 2, or 10g hydrolysed collagen per day can significantly improve joint pain, stiffness and function within 3 to 6 months.
Those with the greatest joint degeneration and with the lowest intake of dietary meat protein benefited the most.
Sports injury: In athletes and weekend warriors who experience knee pain on exercise, taking either 40mg undenatured collagen type 2 supplements per day, or a liquid collagen hydrolysate supplement (10g per day) for 4 to 6 months, provides significant improvements compared with placebo.
Those taking the collagen supplements experienced significantly increased joint mobility, less joint pain at rest, when walking, standing, running, lifting or carrying weights. They were also able to exercise for longer with a speedier recovery afterwards. Some of those taking collagen supplements experienced a complete resolution of pain on exercise. The researchers concluded that collagen hydrolysate can support joint health and possibly reduce the risk of joint deterioration in athletes, who are at high-risk of developing joint problems.
Rheumatoid arthritis: Type II collagen is the main protein in joint cartilage and may be one of the targets for antibody attack in people with rheumatoid arthritis. Taking small doses of undenatured collagen supplements (eg chicken type II collagen, 0.1mg per day for one month then 1mg per day) may help the immune system become more ‘tolerant’ of the body’s own collagen to suppress joint inflammation. In one study involving 60 people with severe, active rheumatoid arthritis, this collagen immunotherapy significantly reduced the number of swollen and tender joints within 3 months, compared with no change in those taking placebo. Four of those taking collagen even had a complete remission of their symptoms even though they were initially classed as severe. NB If you have rheumatoid arthritis, don’t take collagen supplements except under medical advice and supervision – very low doses are needed for this form of immunotherapy, and it is possible that taking higher doses may make your symptoms worse.
Vitamin C supplements for knee pain
Vitamin C is a water-soluble vitamin found mainly in fruit and vegetables. As vitamin C is water-soluble, it cannot be stored in the body so a regular intake is essential.
How vitamin C works
Vitamin C is essential for conversion of the amino acid, proline, to hydroxyproline during collagen synthesis. It is also needed for the metabolism of the proteoglycans present in joint cartilage, and is a powerful antioxidant, especially in joint fluid.
Poor intakes can lead to reduced collagen formation and slow joint healing. In contrast, good intakes of vitamin C can reduce cartilage loss and disease progression in osteoarthritis, while its antioxidant action can reduce joint inflammation.
Vitamin C also stimulates bone-building cells (osteoblasts) and improves bone mineral density to support the overlying cartilage within joints. Vitamin C may even help to prevent damage, cartilage loss and the development of osteoarthritis. People who obtain at least the recommended dietary intake of vitamin C, or higher, for example, are half as likely to develop osteoarthritis as those with lower intakes.
How effective are vitamin C supplements for knee pain?
In the Framingham Osteoarthritis Cohort Study, who underwent regular knee x-rays, people with the highest vitamin C intakes (including supplements) were three times less likely to see their knee osteoarthritis progress than those with the lowest vitamin C intake. This protection was mostly related to a reduced risk of cartilage loss. Those with high vitamin C intake also had a 70% reduced risk of developing knee pain.
In the similar Clearwater Osteoarthritis Study, those who took vitamin C supplements were 11% less likely to develop knee osteoarthritis than those who did not take vitamin C supplements.
Vitamin C may also enhance the effects of glucosamine and chondroitin. A small trial involving 34 males from the U.S. Navy who had degenerative joint disease found good results from combing glucosamine HCl (1,500 mg/day), chondroitin sulfate (1,200 mg/day) and vitamin C in the form of manganese ascorbate (228 mg/day). After 16 weeks, knee pain in those with osteoarthritis was reduced by 26.6% using a pain scale recorded during clinic visits, while their physical examination score improved by 43.3%. The researchers concluded that this combination was effective in relieving symptoms of knee osteoarthritis.
Turmeric supplements for knee pain
Turmeric is a familiar, yellow spice widely used to enhance the flavour and colour of curries. It is also a traditional Ayurvedic medicine used to treat inflammation and reduce pain.
The active ingredient in turmeric is a golden-yellow pigment, curcumin, which has powerful anti-inflammatory actions. Turmeric supplements can be concentrated and standardised to contain as much as 95% curcumin, the active ingredient, per dose.
Several studies suggest that turmeric is as effective as non-steroidal anti-inflammatory drugs (NSAIDs) for alleviating knee pain – but without the side effects.
How turmeric works
Turmeric blocks the production of a variety of inflammatory substances, including the enzyme COX-2, interleukins, and TNF-alpha – a powerful cell signalling protein involved in triggering acute inflammation. Curcumin is recognised as one of the few orally available substances that can block TNF-alpha, which is the target for many new and expensive antibody treatments given by intravenous infusion or subcutaneous injection to treat severe inflammatory diseases including some forms of arthritis.
How effective are turmeric supplements for knee pain?
A study involving 367 people with moderate to severe knee osteoarthritis found that taking turmeric extracts (1,500 mg per day, in divided doses) for 4 weeks was as effective in reducing pain, stiffness and improving joint function as ibuprofen (1,200 mg per day) but with fewer gastrointestinal side effects.
The absorption of turmeric and curcumin from the digestive system is notoriously poor. Even so, it still produces significant anti-inflammatory effects elsewhere in the body, such as the joints, even though no measurable levels are present. The most likely explanation is that turmeric is able to interact with immune cells within the gut lining to ‘reprogram’ how they respond to inflammation.
Turmeric can be combined with glucosamine and chondroitin to produce a faster onset of action and improved results.
I recommend selecting a turmeric supplement that provides solubilised turmeric, as this is 185 times better absorbed than normal turmeric powder, for a more rapid onset of action.
Krill Oil supplements for knee pain
Krill are a tiny, shrimp-like crustaceans found in all the oceans of the world. They feed on microalgae from which they obtain omega-3 fatty acids and two antioxidant pigments, astaxanthin and canthaxanthin. These pigments are produced by algae to protect them from ultraviolet light and, when these algae and shrimps are eaten by wild flamingos, give them their attractive pink plumage. Without them flamingos would be grey. These carotenoid pigments, which also cause shrimps, prawns and lobsters to turn red when cooked, are the reason why krill oil has such a vibrant, crimson colour.
How krill oil works
While ‘plain’ omega-3 fish oils and cod liver oil are popular for preventing and treating knee pain, krill oil has the advantage of supplying these two powerful antioxidant pigments along with the long-chain, omega-3 fatty acids for an enhanced anti-inflammatory effect.
The long-chain omega-3s, EPA and DHA, are processed in the body to reduce formation of inflammatory substances known as leukotrienes. These omega-3s help to reduce inflammation, stiffness, swelling and, in people with different types of arthritis can reduce the number of painful joints, and the long-term need for pain killers.
In a trial involving 90 people with raised levels of an inflammatory marker called CRP (due to rheumatoid or osteoarthritis and/or cardiovascular disease), levels came down by 19% within 7 days, in those taking 300mg krill oil a day, and by 30% within 2 weeks. In those taking placebo, levels of CRP increased.
Both the omega 3s and the antioxidants found in krill oil have an anti-inflammatory action which help to reduce joint pain, stiffness and swelling in people with rheumatoid or osteoarthritis. In a randomised, double-blind, placebo controlled trial involving 90 people, the level of an inflammatory marker called CRP reduced by 19% within 7 days, and by 30% within 2 weeks.
As well as helping your joints, krill oil is beneficial for the heart and circulation, too.
How effective are krill oil supplements for knee pain?
In the trial mentioned above, joint symptoms showed significant improvement, with a noticeable reduction in pain and stiffness within a week. Krill oil supplements have also been shown to reduce the amount of pain-killing ‘rescue’ medication needed.
Another study, involving 50 people with knee pain, compared the effects of taking either 2g krill oil per day, or an identical placebo, for one month. Those taking krill oil showed more improvements in knee pain and stiffness than those taking placebo and, when other factors such as age, weight and lifestyle were taking into account, krill oil also significantly reduced the effects of knee pain on sleeping, standing and the range of movement in both knees compared to placebo.
NB As krill are an important food source for marine animals such as baleen whales, Antarctic Fur Seals and Adelie penguins, it’s important to select a supplement derived from sustainable sources that do not impact on these feeding grounds. Sustainably derived krill oil will have an on-pack endorsement from an organisation such as the Marine Stewardship Council is an international, non-profit organisation that works to safeguard seafood supplies for the future.
Rosehip Extracts for knee pain
The fruits of the wild dog rose are an excellent source of vitamin C, and scientists have now found that rosehips contain additional anti-inflammatory substances that can greatly reduce joint aches and pains.
How rosehip supplements work
Rosehips contain a pain-killing complex of galactolipids which have an aspirin-like ability to inhibit two enzymes (COX-1 and COX-2) involved in the generation of pain and inflammation. They do this through a different mechanism to aspirin without causing the same intestinal side effects. Galactolipids isolated from rosehips also inhibit the activity of inflammatory white blood cells, and lower levels of inflammatory markers in the blood. Reducing the movement of inflammatory cells into joints can reduce both pain and stiffness.
How effective are rosehip supplements for knee pain?
Data from three studies, involving 287 people with osteoarthritis found that taking rosehip extracts for an average of 3 months significantly reduces pain. Those taking rose hip extracts were twice as likely to respond to treatment than those taking placebo. Significant improvements in morning pain and stiffness, sleep quality, mood, energy and well-being were also seen, as well as a reduced need for rescue medications such as tramadol, codeine and paracetamol.Over eighty per cent of people taking rosehip extracts report noticeable benefits in pain and stiffness within three weeks, and the level of pain relief in clinical trials is equivalent to that achieved with non-steroidal anti-inflammatory drugs, paracetamol and aspirin (but with fewer side effects).
Ginger supplements for knee pain
Ginger is one of the oldest medicinal spices, whose rhizomes contain unique substances known as gingerols and shogaols, as well as therapeutic terpene essential oils. Although well-known for their anti-nausea action, ginger root extracts are also able to reduce knee pain.
How ginger supplements work
Ginger has a warming, analgesic, anti-inflammatory action, increasing blood flow to the peripheries to boost the delivery of oxygen and nutrients. Its anti-inflammatory action results from an ability to block the COX-2 enzyme involved in triggering inflammation, and to reduce the production of another inflammatory substance, TNF-alpha in joint lining cells. it is widely used to relieve muscle and joint aches and pains.
How effective are ginger supplements for knee pain?
Cell cultures studies suggest that ginger’s anti-inflammatory action results from suppressing the release of inflammatory chemicals within synovial, cartilage and white blood cells.Analysis of data from five trials, involving 593 people, showed that taking ginger significantly reduced pain by 30% compared with placebo, and reduced disability by 22%.
Cherry supplements for knee pain
Sour cherries are best known for their ability to promote sleep, but they can also reduce muscle and joint pain after exercise.
How cherry supplements work
Cherry extracts are a rich source of antioxidants, including vitamin C, carotenoids, and rich purple-red anthocyanin polyphenols. Together, these provide an anti-inflammatory, pain-killing action that mimics that of non-steroidal anti-inflammatory drugs – but without the same side effects. Drinking sour cherry juice can reduce muscle and joint pain and inflammation in people with osteoarthritis, and in athletes with injuries.
How effective are cherry supplements for knee pain?
A group of 58 people with osteoarthritis of the knee were asked to drink either tart cherry juice or placebo juice for 6 weeks. Then, after a week of no treatment, they swapped over to take the other juice for another 6 weeks so acted as their own controls. The WOMAC pain, stiffness and joint function questionnaire before and after each treatment, and scores decreased significantly after the cherry juice treatment but not after the placebo treatment.
Which supplements are best for your knee pain?
Different supplements work for different people, depending on the genes you have inherited. Some respond to glucosamine alone, for example, but in my clinical experience most people benefit from taking both glucosamine plus chondroitin.
If you are not getting the pain relief you desire within 2 months, you can either swap to a different treatment or add in another supplement.
It’s not always easy to spot small gradual improvements, so you might like to complete a WOMAC Osteoarthritis Index joint symptom questionnaire before and after taking a supplement for a few weeks to assess if there is any meaningful benefit.
I have taken glucosamine plus chondroitin for general knee health for at least ten years. Recently I added turmeric to my joint regime and was able to jog comfortably for the first time in several years along the shores of Lake Geneva.
Following a recent fall while skiing, which twisted my right knee, I added in a collagen supplement and my stretched ligaments have now almost healed two weeks later.
Which supplements do you find most helpful for your knee pain?
Click here to read my review of glucosamine gels and other topical pain relieving creams.
Click here to read my review of the best non-prescription painkillers.
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