Millions of people see doctors each year complaining of knee pain. In over half of cases, the problem is damaged knee cartilage, reports UCSF Health. Surgery may be necessary, but some vitamins are also vital for cartilage health. Eating foods good for joints and cartilage can aid cartilage repair.
Cartilage Damage and Repair
Cartilage is a tough yet flexible connective tissue found in the joints, trachea, ears and nose, among other places. In the joints it covers the ends of bones, providing cushioning and shock absorption and allowing bones to slide over each other during articulation. Cartilage serves both structural and protective functions.
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For various reasons, cartilage may become damaged or deteriorate. Common causes include:
- injury or trauma, such as from a sports injury or accident;
- repetitive use of the joint;
- congenital abnormalities that affect joint structure;
- and hormonal disorders that can affect the development of bones and joints.
Osteoarthritis is another condition that results in damage and deterioration of cartilage.
Whatever the cause, the result is usually joint pain. In the case of the knee joint, UCSF reports that cartilage damage can result in limited mobility and significant pain. If the cartilage isn't repaired, it may suffer further damage and eventually require knee-replacement surgery.
Several types of procedures may be used to repair and regenerate cartilage. In some cases, healthy cells will be removed from the knee and grown in a laboratory for six to eight weeks. At that point, the new cells are surgically implanted. In another procedure, small holes are made in the knee bone, which allows bleeding. Bone marrow cells from the fresh blood can stimulate cartilage repair.
These surgical procedures are not used in the case of osteoarthritis; treatment for this condition involves anti-inflammatory medications, cortisone shots, physical therapy, knee replacement or other treatments. Certain nutrients have also been shown to play a role in the treatment and prevention of osteoarthritis, and are vital nutrients for keeping your cartilage healthy.
Read more: 9 Ways to Help Avoid Vitamin D Deficiency
C is for Cartilage
Most people know that vitamin C is important for the immune system and fighting off colds and other infections. But it also plays a major role in the health of your connective tissue, as it is necessary for the production of collagen. Collagen is a main component of all connective tissues and aids wound healing. According to the U.S. National Library of Medicine, one of vitamin C's main functions is to repair and maintain bones, teeth and cartilage.
Deficiencies in vitamin C are rare, but they can happen. Certain individuals have an increased risk of deficiency, including people with malabsorption disorders, smokers and those exposed to secondhand smoke and people with limited diets, including the elderly and people who follow restrictive food fads.
The Food and Nutrition Board of the National Academies of Medicine recommends that women get at least 75 milligrams and men get 90 milligrams of vitamin C each day. Pregnant and breastfeeding women have increased needs and should ensure intakes of 85 and 120 milligrams, respectively, each day. It is recommended that smokers consume 35 milligrams more than the recommendation for non-smokers, according to the National Institutes of Health.
Vitamin C foods that are good for joints and cartilage include fresh fruits and vegetables, including red bell peppers, citrus fruits, broccoli, strawberries and Brussels sprouts. Most people who eat a balanced diet should not need to take a supplement. High doses of vitamin C can potentially have a negative effect, according to a study published in Osteoarthritis and Cartilage in November 2013, which found a link between high blood levels of vitamin C and the development of whole-knee osteoarthritis.
Vitamin D and Osteoarthritis
Vitamin D is crucial for the development and maintenance of healthy bones. Adequate amounts enable proper absorption of calcium, which is necessary to support the structure and function of bones and teeth. It may also play a role in the prevention and treatment of cartilage deterioration, although using vitamin D for joint pain is unlikely to have immediate or verifiable results.
According to authors of a research review published in the Orthopaedic Journal of Sports Medicine in June 2017, vitamin D levels play a role in the development and progression of osteoarthritis. Their findings show that people with osteoarthritis typically have low levels of the nutrient, while individuals with sufficient blood levels have a lower risk of developing the condition and the associated cartilage degeneration.
The recommended daily intake for vitamin D is 600 international units for all adults. NIH reports that there are few dietary sources of vitamin D, which can make it difficult to get adequate amounts through diet alone. Your body can synthesize vitamin D from reactions within the skin when exposed to UVB rays from the sun. But due to widespread sunscreen use and less time outdoors, many people aren't meeting the requirement.
According to the researchers of the Orthopaedic Journal of Sports Medicine study, over 40 percent of people in the United States are deficient in vitamin D. They conclude that supplementation may be a viable method to treat and prevent osteoarthritis, although more research is needed.
You can increase your vitamin D stores by eating more fatty fish, such as salmon and tuna, and fortified milk, juice and cereal. If you think you are not meeting your vitamin D needs, speak with your doctor about whether you need a supplement.
Read more: Tips For Runners with Osteoarthritis
Vitamin K and Cartilage Thickness
This fat-soluble vitamin doesn't get much attention, but it could be an important one to watch if you're experiencing cartilage injury or degeneration. Vitamin K is vital for activating a vitamin-K dependent protein called matrix Gla protein that is a component of muscle, bone and cartilage.
There are two types of vitamin K — K1 and K2. Vitamin K1 is the most abundant type found in foods, primarily in leafy green vegetables, and the one most closely correlated to cartilage thickness. In a study published in The Egyptian Rheumatologist in July 2016, vitamin K1 levels in knee osteoarthritis patients were found to be significantly decreased compared to a control group.
Males need 120 micrograms of vitamin K daily, and all women, including those who are pregnant and breastfeeding, need 90 micrograms. The risk of vitamin K deficiency is rare in adults who eat a balanced diet, according to NIH. People with malabsorption disorders have a higher risk, as do those who take certain medications that may affect vitamin K metabolism. Vitamin K foods good for joints and cartilage include collard greens, turnip greens, spinach, kale, broccoli and soybeans.
- UCSF Health: "Cartilage Repair"
- CRS: "What is Cartilage?"
- Mayo Clinic: "Osteoarthritis"
- MedlinePlus: "Vitamin C"
- NIH: "Vitamin C"
- National Academies of Medicine: "Summary Tables, Dietary Reference Intakes"
- Osteoarthritis and Cartilage: "High Plasma Levels of Vitamin C and E Are Associated with Incident Radiographic Knee Osteoarthritis"
- NIH: "Vitamin D"
- Orthopedic Journal of Sports Medicine: "Vitamin D and Its Effects on Articular Cartilage and Osteoarthritis"
- NIH: "Vitamin K"
- The Egyptian Rheumatologist: "Potential Role of Vitamin K in Radiological Progression of Early Knee Osteoarthritis Patients"