For years, there’s been back and forth about how food may help or hinder rheumatoid arthritis, or RA. Sometimes the wisdom feels more like street gossip than fact. But now researchers are uncovering more details about how various foods affect RA and the inflammation in our bodies. 

Below is a rundown of what research is revealing about rheumatoid arthritis and diet:

Mind your fatty acid ratios. Omega-6 fatty acids – essential fats found in meat and vegetable oils, like corn oil – tease out inflammatory molecules. But their cousins, omega-3 fatty acids found in fatty fish like salmon, help tamp down inflammation. 

Omega-3s also lower risk of cardiovascular disease: “That’s appealing given the increased risk of cardiovascular disease among patients with RA,” says Hyon Choi, MD, DrPH, professor of medicine, Section of Rheumatology and the Clinical Epidemiology Unit, Boston University School of Medicine.

A 2012 study at the Alimentary Pharmabiotic Centre in Cork, Ireland, found that the increased ratio in our diet of omega-6 to omega-3 –about 15 to 1 – coincides with increases in chronic inflammatory diseases like rheumatoid arthritis.

Yet another 2012 study at the University of Southampton in the United Kingdom indicates that fish oil supplements, high in omega-3s, have slowed the development and lessened the severity of arthritis in animals. It also notes a review of 23 studies that suggest omega-3 helps reduce RA-related joint swelling, pain, stiffness, and lessens use of non-steroidal anti-inflammatory drugs.

To lower the omega-6 to omega-3 ratio, eat fewer processed foods, which often contain oils high in omega-6. “And eat less fatty meats and more seafood,” says Farshid Guilak, PhD, Laszlo Ormandy professor  of orthopedic surgery and director of orthopedic research at Duke University Medical Center. 

Such changes may also help lower risk of obesity and diabetes, says Dr. Choi, two other conditions that often co-exist with RA. Or consider taking an omega 3-fatty acid supplement. The American Heart Association recommends taking no more than 3 grams of an omega-3 supplement per day.

Eat like an Italian. A number of studies indicate that eating a Mediterranean diet – one that emphasizes plant foods like fruits and vegetables, small amounts of wine and olive oil, and makes meat a lesser star – can help reduce inflammation in people with RA. The diet can also lower the risk of RA-linked conditions such as obesity, diabetes and heart disease, notes Dr. Choi.

A 2005 Swedish study of 51 people with RA found that, after three months on a Mediterranean diet, they had lowered measures of disease activity, improved function and had more energy.

In a 2012 twelve-week study at Appalachian State University in Boone, N.C. of 1,000 people, researchers found that those who ate the most fruits and vegetables had significantly lower markers of inflammation such as C-reactive protein and interleukin-6.

“A diet high in in fruits, vegetables, and vitamin C is part of an anti-inflammatory diet that has many antioxidants,” says Joseph Feuerstein, MD, Director of Integrative Medicine at Stamford, and Assistant Professor in Clinical Medicine at Columbia University College of Physicians & Surgeons. Antioxidants also protect cells from damage by unstable atoms called free radicals.

Christine McKinney, RD, a clinical dietician at Johns Hopkins Bayview Medical Center in Baltimore, who works with RA patients, suggests eating a rainbow array of fruits and vegetables: “A variety of colors ensures a variety of nutrients.”

High fat hurts. Many studies have suggested that high-fat foods increase inflammation. Although researchers at Duke University have focused on fat and osteoarthritis, not RA, their findings in a 2009 study on mice may help us understand that other players, in league with high fat foods, influence inflammatory processes.

The Duke researchers found that mice fed the equivalent of a high-fat, fast-food diet became obese, and their joints degenerated in proportion to their weight gain. However, when the researchers fed a lardless chow diet to mice that had no leptin – our appetite control molecule – they ate constantly, becoming massively obese. But oddly they didn’t get osteoarthritis.

“Saturated fat – animal fat – and lots of omega-6s may be the culprits,” says study author Guilak. But leptin, an inflammatory molecule, may also play a role in arthritis and degeneration.

The fix? Eat less animal fat and fewer processed foods.
 

Elimination diets may help. In a 2010 case study at Stamford Hospital in Stamford, Conn., a patient with Sjogren’s syndrome, an autoimmune disease that often accompanies RA, eliminated gluten, beef, eggs, dairy, refined sugars, citrus fruit and nightshade vegetables like eggplant, tomatoes,  potatoes and most peppers from her diet for four months. The result: her erythrocyte sedimentation rate (ESR) – a measure of inflammation in the body – dropped more than 50 percent.

“The foods are mostly proteins that some people have sensitivity to,” says study author Dr. Feuerstein.

A 2010 study at the University of Oslo in Norway looked at some of the same foods. Researchers found that the intestinal fluid of people with RA had higher levels of antibodies – proteins that attack and destroy foreign substances – to proteins in cow’s milk, cereal, eggs, codfish and pork than people without RA. 

“For many reasons, the lining of the gut [in some people with RA] is leaky, and large molecules like these [food] proteins are able to pass through the gut lining, appearing to cause an immune response [by the digestive tract’s immune system],” says Feuerstein.  

The antibodies and food proteins bind together and circulate through the body, possibly contributing to inflammation. Once your body makes antibodies against a certain food, you will react each time you eat it, upping inflammation. So, theoretically, at least, eliminating such foods may lower inflammation.

However, tackling an elimination diet on your own isn’t a good idea, says McKinney: “Do an elimination diet only with guidance from a physician or healthcare professional.”

Go gluten-free. In a 2008 Swedish study at Karolinska Institutet of 66 patients with active RA, patients were assigned either a non-vegan diet or a gluten-free vegan diet for a year. The gluten-free diet raised the level of anti-inflammatory antibodies, which also protect blood vessels from the build-up of fatty plaque. Gluten is a protein found in foods such as wheat, rye, and barley that has been associated with inflammation and intestinal irritation.

Skip sugar. Simple refined carbohydrates in candy, cookies, and even white pastas spike blood sugar, which raises insulin levels. “Fluctuations in blood sugar and insulin cause inflammation,” says Feuerstein.

In a 2004 University of Pennsylvania Health System study, 78 obese women went on either a conventional or low carbohydrate diet for six months. C-reactive protein, a marker of inflammation, dropped in both groups. But in those patients with a higher level of the C-reactive proteins to begin with, the levels dropped even more on the low-carbohydrate diet, regardless of weight loss.

When you do eat carbs, stick to whole grains, fruits, and vegetables, which slow digestion and lessen insulin spikes.