Nutrition for joint health
Pain in the knees, shoulders or hip joints is one of the most frequent complaints of people who have trained for many years. The market offers dozens of "joint" supplements, and dietary advice often contradicts itself. The editorial team gathered what is really known about the link between diet and joint health and where the evidence ends and the marketing begins.
How a joint is built and what harms it
Articular cartilage is a tissue without blood vessels, consisting of collagen fibres, proteoglycans and water. The cartilage cells, chondrocytes, receive nutrients from the synovial fluid that circulates during movement. That is exactly why moderate regular loading is a necessary condition of joint health.
Cartilage regenerates very slowly. Unlike muscles, which adapt within weeks, the collagen network of cartilage is renewed over years. So any dietary interventions cannot quickly "rebuild" a worn joint — they can only support the conditions for its functioning.
The main factors that harm joints are well known: injuries, especially damage to the meniscus and ligaments, excess body weight, chronic systemic inflammation, repeated overloading without sufficient recovery, and a genetic predisposition to osteoarthritis.
Nutrition affects several of these factors indirectly: through body weight, the level of inflammation, the state of the bones and connective tissue. It is from this perspective that all "joint" recommendations should be assessed.
Body weight — the main dietary factor
Among all dietary factors, the link between excess body weight and osteoarthritis of the knee joints has the most evidence. During walking, forces several times greater than body weight act on the knee joint, so every extra kilogram is multiplied by this coefficient.
In the study by Messier and colleagues (2005), in people with excess weight and knee osteoarthritis, a reduction in body weight by one unit was accompanied by roughly a fourfold greater reduction in the load on the knee joint during walking. The subsequent randomised IDEA study (2013) showed that combining diet and exercise reduced pain and improved function more strongly than either intervention alone.
Adipose tissue is also an active endocrine organ: it releases pro-inflammatory substances that can affect cartilage even in non-load-bearing joints, for example in the hands. So the link between excess weight and osteoarthritis is not reduced to mechanics alone.
For heavyweight athletes who deliberately maintain a high body weight, this argument is relevant too. After the end of a career, a gradual reduction of weight is one of the most effective ways to preserve the joints for many years.
A diet with an anti-inflammatory profile
The term "anti-inflammatory diet" has no clear scientific definition, but it usually refers to a diet close to the Mediterranean one: plenty of vegetables, fruit, legumes, whole grains, fish and olive oil with a moderate amount of red meat and a minimum of ultra-processed foods.
Omega-3 fatty acids from oily fish — salmon, mackerel, herring, sardines — have the best evidence base among dietary components for inflammatory joint diseases, primarily rheumatoid arthritis. For osteoarthritis the effect is more modest, but regular consumption of fish fits into a healthy diet in any case.
- Oily fish2–3 times a week — a source of EPA and DHA.
- Colourful vegetables and berries— sources of polyphenols and vitamin C.
- Dairy products, greens, nuts— calcium and vitamin K for bones.
- Bone broths and gelatin— sources of glycine and proline, though their specific benefit for joints is weakly proven.
Vitamin D is important for bone tissue, and its deficiency is widespread at northern latitudes, including in Ukraine in winter. At the same time, large studies have not shown that taking vitamin D in people without a deficiency slows the progression of osteoarthritis. So it is advisable to check the blood level and correct specifically a deficiency.
Excessive consumption of sugar, alcohol and trans fats is associated with a higher level of systemic inflammation and weight gain. Giving them up is a simple step that is useful not only for the joints but for health in general.
Supplements for joints: what the evidence says
Glucosamine and chondroitin are the best-known "joint" supplements. The large-scale GAIT study (Clegg et al., 2006), published in the New England Journal of Medicine, found no statistically significant advantage over placebo in the overall group of patients with knee osteoarthritis. Only in the subgroup with moderate to severe pain did the combination show a certain positive signal.
The OARSI (2019) and American College of Rheumatology (2019) guidelines do not recommend glucosamine and chondroitin for the treatment of osteoarthritis of the knee and hip joints because of the conflicting data. At the same time, in Europe some pharmaceutical forms of these substances are registered as medicines, and the debate continues.
| Supplement | What the research shows | Editorial assessment |
|---|---|---|
| Glucosamine, chondroitin | Effect close to placebo in most quality studies | Weak evidence |
| Hydrolysed collagen | Individual studies show a reduction of pain under loading | Limited but encouraging |
| Omega-3 | Benefit in rheumatoid arthritis; more modest in osteoarthritis | Moderate evidence |
| Curcumin | Meta-analyses indicate a reduction of symptoms, but the studies are small | Limited evidence |
| Vitamin D | Useful with a deficiency, does not slow osteoarthritis in people without a deficiency | Correction of deficiency |
Hydrolysed collagen is of interest specifically for athletes. In the 24-week study by Clark and colleagues (2008), student athletes with load-related joint pain reported less pain when taking a collagen hydrolysate than the placebo group. However, there are few studies of this type, and the effect is moderate.
Curcumin, according to the meta-analysis by Daily and colleagues (2016), may reduce the symptoms of arthritis, but the authors acknowledged the small number and size of the studies. It is worth remembering that curcumin is poorly absorbed, and some forms with absorption enhancers have been described in connection with rare cases of liver damage.
A practical plan for people who train
The first step is to maintain a healthy body weight and a sufficient amount of protein in order to keep strong muscles that stabilise the joints. Weak thigh muscles, for example, increase the load on the knee joint.
The second step is to build the diet around fish, vegetables, fruit, legumes, whole grains and quality oils, while limiting alcohol and ultra-processed foods. This is not a "medicine for the joints" but a foundation on which all other measures work.
The third step is to approach supplements sensibly. Collagen or omega-3 can be tried as an addition, assessing the effect after 2–3 months. If the pain does not decrease, there is no point in continuing to spend money.
And finally, any prolonged, increasing pain, swelling or limitation of joint mobility is a reason to see a doctor, not to look for a new supplement. Such symptoms can be caused by meniscus injuries, inflammatory diseases or other conditions that require diagnosis.
Editorial conclusions
The strongest dietary factor for joint health is maintaining a healthy body weight. Losing weight significantly reduces the load on the knees and improves the symptoms of osteoarthritis.
A Mediterranean-type diet with fish, vegetables and a minimum of ultra-processed foods creates a favourable background for the joints and overall health.
The evidence for popular "joint" supplements is mostly weak or moderate: glucosamine and chondroitin are not recommended by leading guidelines, while collagen, omega-3 and curcumin may provide moderate benefit to some people.
The editorial team also recommends familiarising yourself with our materials about collagen for ligaments, about the balance of omega-6 and omega-3 and about nutrition for injuries.
References
- Messier SP, Gutekunst DJ, Davis C, DeVita P. Weight loss reduces knee-joint loads in overweight and obese older adults with knee osteoarthritis. Arthritis Rheum. 2005;52(7):2026–2032.
- Messier SP, Mihalko SL, Legault C, et al. Effects of intensive diet and exercise on knee joint loads, inflammation, and clinical outcomes among overweight and obese adults with knee osteoarthritis: the IDEA randomized clinical trial. JAMA. 2013;310(12):1263–1273.
- Clegg DO, Reda DJ, Harris CL, et al. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med. 2006;354(8):795–808.
- Bannuru RR, Osani MC, Vaysbrot EE, et al. OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis. Osteoarthritis Cartilage. 2019;27(11):1578–1589.
- Kolasinski SL, Neogi T, Hochberg MC, et al. 2019 American College of Rheumatology/Arthritis Foundation guideline for the management of osteoarthritis of the hand, hip, and knee. Arthritis Care Res. 2020;72(2):149–162.
- Clark KL, Sebastianelli W, Flechsenhar KR, et al. 24-Week study on the use of collagen hydrolysate as a dietary supplement in athletes with activity-related joint pain. Curr Med Res Opin. 2008;24(5):1485–1496.
- Daily JW, Yang M, Park S. Efficacy of turmeric extracts and curcumin for alleviating the symptoms of joint arthritis: a systematic review and meta-analysis of randomized clinical trials. J Med Food. 2016;19(8):717–729.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
