Science backs old wives' tale - cod liver oil helps slow osteoarthritis
cartilage in patients with osteoarthritis, report scientists in
Wales, who say it is the first evidence of its efficacy on the
disease in a human trial.
The study at Cardiff university found that 86 per cent of pre-operative patients with arthritis who took cod liver oil capsules daily had absent or significantly reduced levels of the enzymes that cause cartilage damage. This compared to 26 per cent of those given a placebo oil capsule.
In addition, the result showed a marked reduction in some of the enzymes that cause joint pain in those patients taking the fish oil.
According to surgeons, the findings could hold the key to reducing the number of knee and hip replacements carried out in the UK each year. The estimated direct cost of arthritis to the health and social services is around £5.5 billion annually.
Osteoarthritis affects 12.1 per cent of US adults, or 20.7 million people. It is the most common form of arthritis.The condition can be life-threatening through its effect on other organs in the body and increased susceptibility to infection.
Speaking at a press conference held at the Royal College of Surgeons in London, Professor Bruce Caterson called the findings a 'significant breakthrough'.
"The data suggests that cod liver oil has a dual mode of action, potentially slowing down the cartilage degeneration inherent in osteoarthritis and also reducing factors that cause pain and inflammation," he said.
By taking cod liver oil, people are more likely to delay the onset of osteoarthritis and less likely to require multiple joint replacements later in life, he added.
The Cardiff researchers recruited 31 patients, 10-12 weeks before they were due to have total knee joint replacement surgery. Half were given two daily capsules containing 1000mg extra high strength cod liver oil and half given placebo capsules. At the time of surgery, samples of cartilage and joint tissue were taken from the knee joint for analysis.
Osteoarthritis is the result of loss of cartilage, the 'gristle' that cushions bones and prevents them from grinding against each other. The painful and disabling condition caused more than 2 million people in the UK to visit their GP in the past year and is the major reason for joint replacement surgery.
Professor Colin Dent, orthopaedic consultant at the University of Wales College of Medicine, commented: "Patients resort to joint replacement surgery when the symptoms and pain of their arthritis becomes unbearable. Cod liver oil can counteract these symptoms and if you can switch off the cartilage destruction and pain then surgery may not be necessary. We're very excited by this latest trial."
"Our results also suggest that people who have suffered sporting injuries, which predispose them to the early onset of osteoarthritis (e.g. meniscal tears or cruciate ligament rupture), should consider taking cod liver oil to slow the progression of their disease," added Professor Caterson.
The findings are particularly welcome for sufferers of osteoarthritis who are concerned about the adverse side effects commonly associated with prescription drugs (Non Steroidal Anti Inflammatory Drugs).
The news will also be welcomed by fish oil suppliers, many of whom are expanding to cope with increasing demand in supplements and functional foods for omega-3 fatty acids. Cod liver oil, hardly used by other Europeans, is by far the most popular vitamin or supplement in the UK, with some three in four adults using it, according to recent research from Mintel.
The Cardiff team previously studied the effect of omega-3 fatty acids, the main component of cod liver oil, on discarded arthritic knees of people undergoing knee replacement surgery. Some were treated with omega-3 for 24 hours in a laboratory and a chemical was added to mimic an inflammatory response.
Four days later, the samples showed that enzymes responsible for destroying cartilage in arthritis were present in the untreated group. But in those treated with omega-3, these enzymes had not acted, nor had the enzymes which cause inflammation and pain in joints.