Keeping Knee Joints Supple - any ideas?

Dark Green Leafy Vegetables
We’ve all heard about free radicals and the damage they can inflict on the body. Fight them with spinach, spring greens, broccoli and parsley, all of which contain the antioxidant carotenoids, as well as calcium and magnesium. Foods high in antioxidants can help reduce the rate of cartilage breakdown.

Avocado
This super fruit contains antioxidant mono-saturated oils, essential fatty acids, beta-sitosterol and vitamin E—all hard workers in the fight against joint inflammation. It also promotes cartilage repair and is especially beneficial for osteoarthritis patients.

Turmeric
You probably recognize turmeric as a spice often found in curries and stir-fries, but it also contains a potent anti-inflammatory ingredient called curcumin. While it can be hard to eat enough of the spice to make a difference, it’s easy to throw it in a smoothie like this tropical turmeric smoothie or this tropical turmeric cleanser green smoothie. Another option is to supplement with Osteo Flex, which contains clinically studied levels of curcumin.

Onions and Garlic
Onions are a rich source of quercetin, an antioxidant that works to reduce inflammation. Red onions are particularly high in antioxidants. Garlic contains allicin, a compound that can help to alleviate symptoms of rheumatoid arthritis.

Grapefruit
Grapefruit contains vitamin C and bioflavonoids, which work to reduce inflammation and strengthen cartilage. Opt for red grapefruit as it’s a richer source of antioxidants than yellow.

Green Tea
A study done at Case Western Reserve University showed that the antioxidants in green tea may prevent and reduce the severity of rheumatoid arthritis. Meanwhile, green, white, oolong and black teas all contain the antioxidant catechins, which inhibit inflammation in arthritic joints.

Berries
Cherries, elderberries and raspberries contain antioxidant anthocyanins that help to reduce inflammatory chemicals in the body. And black cherries lower uric acid levels, which helps to prevent gout.

Walnuts and Brazil Nuts
Like oily fish, walnuts are a rich source of omega-3 fatty acids, which reduce inflammation. Brazil nuts are high in selenium, which improves the quality of cartilage proteins.

https://www.fishertitus.org/health/superfoods-for-healthy-joints

There are exercises you can do at home to strengthen knee joints and surrounding muscle too.

https://sciencebasedmedicine.org/supplements-for-osteoarthritis-evaluating-the-evidence/

"Based on their review, the authors do not recommendomega-3 fatty acids, vitamins D and E, willow bark extract, collagen hydrolysate, glucosamine, chondroitin, combinations of glucosamine and chondroitin, and rose hip. Based on the review, Boswellia serrata extract and pycnogenol appear to demonstrate the most clinically important effects. They also note that while curcumin and MSM demonstrated clinically important effects, the quality of that evidence was low. The authors comment that the overall evidence base remains limited by poor-quality studies, often of short duration, with many sponsored by manufacturers "