It is thought that millions of Brits are currently living with arthritis and other joint problems. It is a painful condition that can cause swelling, tenderness and stiffness, and mobility issues. Although it is often associated with getting older, it can affect people of all ages making everyday life difficult.
There are different types of arthritis. Osteoarthritis is the most common type often caused by wear and tear or an injury.
Rheumatoid arthritis is less common but occurs when the body’s immune system targets affected joints, which leads to pain and swelling. This often starts when someone is aged between 30 and 50.
According to the NHS, it is not yet known exactly what triggers the immune system to attack the joints – although there are factors known to increase your risk such as age, whether you smoke and if you’re obese.
But now a study has found there could also be a link between what we eat and our chances of developing arthritis.
Research by the University of Colorado, in the US, has discovered that certain foods could be causing inflammation in the body.
The study, published in the Journal of Clinical Investigation, found that an essential amino acid known as tryptophan could be to blame.
Tryptophan is found in a number of popular foods including:
- Chicken
- Turkey
- Red meat
- Pork
- Tofu
- Fish
- Beans
- Milk
- Nuts
- Seeds
- Oatmeal
- Eggs.
It has many uses in the body, including helping in the production of proteins, muscles, enzymes, and neurotransmitters – the nervous system’s chemical messengers. Trptophan has also been linked with sleeping better.
The body doesn’t make it; we get it from our diet. More specifically, scientists say bacteria in the digestive system can break down tryptophan in the diet into an inflammatory chemical that primes the immune system towards arthritis.
Study co-author Kristine Kuhn, head of the CU division of rheumatology, explained: “It’s been known that the microbiome – the bacteria in our gut – can break down tryptophan into byproducts.
“Some of those byproducts are anti-inflammatory, but we’ve also associated some inflammatory causes of those products.
“We’re the first to highlight which products are contributing to inflammation, and how they are doing that.”
Kuhn explained that the new findingins “built upon” previous observations made in patients with spondyloarthritis – a closely related condition to rheumatoid arthritis.
She continued: “We found that changes in the microbiome were associated with increased production of these products called indoles, which are what bacteria make from tryptophan.”
Similar changes were observed in arthritis studies involving mice, she says.
“We put mice on antibiotics to wipe out their microbiome, and they didn’t get arthritis, and they didn’t have indole,” she says.
“So we said, OK, what if they do have a microbiome and we put them on a diet with little tryptophan?
“The microbiome can’t break down tryptophan into indole, and the mice didn’t get arthritis. So two different ways, we showed that it’s tryptophan that’s broken down by the microbiome into indole.”
Overall, she recommended sticking to a diet full of plant-based fibres and lean meats.
Kuhn said: “A diet that’s rich in plant-based fibres and lean meats – this whole Mediterranean diet – seems to push the microbiome into a healthier state, so that you are getting the anti-inflammatory properties of tryptophan, whereas the typical western diet seems to go more toward the inflammatory pathway.”
Symptoms of arthritis include:
- Joint pain, tenderness and stiffness
- Inflammation in and around the joints
- Restricted movement of the joints
- Warm red skin over the affected joint
- Weakness and muscle wasting.
If you experience signs you should speak to your doctor.
