A Healthy Diet May Help Prevent Knee Osteoarthritis, Study Shows

Osteoarthritis (OA) is the most common joint disorder in the U.S., so researchers are always looking for ways to slow its progression. In a new study published in the journal Osteoarthritis and Cartilage, researchers looked at the link between OA and diet.

OA is a progressive disease characterized by joint pain, stiffness, and functional disability. Unfortunately, there is no drug therapy that can effectively delay disease progression.

Diet stands out as one way to help control the progression of OA. Past research shows that intake of specific foods and nutrients may be associated with OA progression. It’s known that sugary beverages may exacerbate the condition, while dietary fiber and vitamin D may be protective against OA.

Since we don’t eat nutrients in isolation, researchers like to take a “whole diet” approach to ascertain which dietary patterns may help or hinder the progression of knee OA.

Past studies have shown that an anti-inflammatory diet, such as the Mediterranean diet (high in vegetables, fruit, legumes, fish, and grains, but low in ultra-processed foods), is associated with a lower risk of pain for knee OA. In this study, researchers wanted to see if healthy dietary patterns were also associated with a reduced risk of developing knee OA in the first place.

How Was the Study Conducted?

The researchers used data from The Osteoarthritis Initiative (OAI), which is a multi-center, prospective longitudinal cohort with 4,796 participants who are followed annually.

From the database, researchers looked specifically at participants who did not have OA in at least one knee at baseline and followed them over six years. From that large database, 2,842 participants met the criteria for the present study.

The participants were asked about their dietary choices using a food frequency questionnaire at baseline. Physical activity, body mass index (BMI), and daily energy intake were analyzed as continuous variables. Participants also had knee radiographs at baseline and follow-up visits.

What Did the Study Find?

The researchers found that participants who adhered to a western dietary pattern (high in processed foods and sugar) had an increased risk of knee OA, but those following a prudent healthy dietary pattern had a decreased risk of knee OA. They also observed that the associations may be partially mediated through BMI.

“The study results do not surprise me,” says Kim Arrey, RD, a dietitian and the author of “The Complete Arthritis Health Diet Guide and Cookbook.”

“For me, it is a confirmation of what I see in my practice,” says Arrey. “Many of my clients have been able to slow the progression of their osteoarthritis through diet.”

Arrey adds that the typical western diet lacks many of the key nutrients responsible for reducing inflammation and maintaining healthy bones and cartilage. 

Western vs. Prudent Diet

The western diet may be related to the increased production of inflammatory cytokines. It includes these foods:

• French fries
• Processed meats
• Refined grains
• Red meats
• Poultry
• Pizza
• Snacks
• Margarine
• Desserts and sweets
• Sugar-containing beverages

By contrast, the prudent, healthy diet (such as the Mediterranean diet) is associated with lower levels of inflammation. It’s higher in these foods:

• Vegetables
• Legumes
• Fruit
• Fish
• Whole grains

Best Dietary Pattern for OA

Diets that are high in antioxidants and anti-inflammatory foods tend to be the best choice for preventing and treating OA, explains Vandana Sheth, RDN, CDCES, FAND, registered dietitian nutritionist and author of “My Indian Table: Quick & Tasty Vegetarian Recipes.”

“Diet can affect OA both in terms of decreasing inflammation and managing weight,” says Sheth. “Since OA is often thought of as an inflammatory disease, having foods that are anti-inflammatory and rich in antioxidants can help.” 

Arrey explains that following a prudent, healthy diet such as a Mediterranean-style diet will reduce the markers of inflammation that are found in the blood.

Both Arrey and Sheth recommend a Mediterranean-style diet for OA, which includes lots of vegetables, fruits, nuts, seeds, healthy oil (olive oil), whole grains, spices like ginger and turmeric, and protein sources such as fatty fish (for the omega-3 fats), chicken, eggs, tofu and legumes. 

“My clients are usually really focused on what foods to avoid and this list is actually pretty short,” says Arrey, who says red and processed meat should only be consumed a couple of times per month, and sweets and desserts are saved for special occasions.

Sheth says the foods to decrease or avoid for OA are foods with added sugars; added fats, especially trans fats and saturated fats; and highly processed foods/refined grains.

A prudent, healthy dietary pattern is high in specific nutrients that are involved in the formation and maintenance of healthy bone and cartilage, explains Arrey. “Consuming a diet that contains all these nutrients will lead to healthier joints.” 

Nutrients to include in the diet are vitamins A, C and D, omega-3 fats, fiber and antioxidants.