Researchers looked at what people with rheumatoid arthritis eat and whether certain types of fat in their diet are connected to heart disease. Using information from nearly 1,400 people with arthritis collected between 2007 and 2018, they found that eating more of a specific type of fat called linoleic acid was linked to higher rates of heart disease. Interestingly, a fish-based fat called EPA seemed protective at first, but this benefit disappeared when researchers accounted for other factors like income and exercise habits. The study suggests that the types of fat people with arthritis eat might matter for heart health, though more research is needed to understand exactly why.

The Quick Take

  • What they studied: Whether different types of healthy fats in the diet are connected to heart disease risk in people who have rheumatoid arthritis
  • Who participated: 1,394 people with rheumatoid arthritis who participated in a large U.S. health survey between 2007 and 2018. Researchers looked at what they ate and whether they had heart disease
  • Key finding: People who ate more linoleic acid (a type of fat found in oils and seeds) had higher rates of heart disease. A fish-based fat called EPA seemed helpful at first, but this benefit went away when researchers looked at other lifestyle factors
  • What it means for you: If you have rheumatoid arthritis, paying attention to the types of fat you eat might be important for heart health. However, this is early research, and you should talk to your doctor before making major diet changes. This study shows a connection but doesn’t prove that changing fat intake will prevent heart disease

The Research Details

This was a cross-sectional study, which means researchers took a snapshot in time of what people were eating and their health status, rather than following them over years. They used data from the National Health and Nutrition Examination Survey (NHANES), a large government health study that tracks what Americans eat and their health conditions.

Researchers asked 1,394 people with rheumatoid arthritis to recall everything they ate in the previous 24 hours. They then looked at how much of different types of healthy fats (called polyunsaturated fatty acids) each person consumed. They compared this to whether each person had heart disease, while also considering other factors like age, gender, race, income, exercise habits, and smoking status.

The researchers used statistical tools to figure out whether eating more or less of certain fats was connected to having heart disease. They also looked at whether there was a “sweet spot” amount of fat that was best for heart health.

This research approach is important because people with rheumatoid arthritis have a higher risk of heart disease compared to people without arthritis. Understanding which foods might help or hurt their heart health could lead to better dietary advice. However, a snapshot study like this can only show connections, not prove that one thing causes another

Strengths: The study included a large, diverse group of people from across the United States, making results more likely to apply to different populations. Researchers adjusted their analysis for many other factors that could affect heart disease risk. Limitations: This study only shows what people ate on one day, which might not represent their usual diet. People might not remember exactly what they ate. The study can’t prove that certain fats cause heart disease, only that they’re connected. The study was done at one point in time, so we don’t know if these patterns hold true over years

What the Results Show

The main finding was that people who ate more linoleic acid (a common fat in vegetable oils, nuts, and seeds) had higher rates of heart disease. This connection remained even after researchers accounted for other important factors like age, exercise, and smoking.

Interestingly, a type of fat from fish called EPA (eicosapentaenoic acid) appeared to be protective against heart disease when researchers first looked at the data. However, when they adjusted for other lifestyle factors like income, education, and physical activity, this protective effect disappeared. This suggests that EPA’s apparent benefit might have been due to other healthy habits that people eating fish also followed.

Other types of healthy fats from fish and plants (called other n-3 PUFAs) showed no clear connection to heart disease risk. The researchers also looked for a “dose-response” pattern—a sweet spot amount of fat that would be best—but only found this pattern in the initial analysis, not in the more complete analysis.

When researchers looked at subgroups of people (by age, gender, and other characteristics), the patterns were generally consistent. The connection between linoleic acid and heart disease appeared across different groups. The study also found that the relationship between these fats and heart disease wasn’t simply “more is worse”—the pattern was more complex, suggesting that the amount matters in ways researchers don’t fully understand yet

Previous research has shown mixed results about whether linoleic acid is good or bad for heart health in the general population. Some studies suggest it’s protective, while others suggest too much might be harmful. This study adds new information by looking specifically at people with rheumatoid arthritis, who have different inflammation patterns than healthy people. The finding about EPA is consistent with other research showing that fish-based fats are generally good for heart health, though the benefit might come from overall healthy eating patterns rather than the fat itself

This study has several important limitations. First, it’s a snapshot—researchers only know what people ate on one day, which might not represent their typical diet. Second, people might not remember exactly what they ate, leading to inaccurate information. Third, the study can only show that certain fats are connected to heart disease, not that they cause it. Fourth, the study didn’t measure inflammation levels in people with arthritis, which could be important. Finally, the study was done at one point in time, so we don’t know if these patterns continue over months or years

The Bottom Line

If you have rheumatoid arthritis, it may be worth discussing your fat intake with your doctor or a dietitian. While this study suggests that limiting linoleic acid might be helpful, the evidence is not yet strong enough to make definitive recommendations. Continue eating fish and other sources of omega-3 fats, as these have other proven health benefits. Don’t make major diet changes based on this single study alone. Confidence level: Low to moderate—this is early research that needs to be confirmed by other studies

This research is most relevant for people with rheumatoid arthritis who are concerned about heart disease risk. It may also interest people with other autoimmune conditions that increase heart disease risk. People without arthritis should not assume these findings apply to them, as arthritis changes how the body processes fats and inflammation. If you have rheumatoid arthritis and a family history of heart disease, this research might be especially relevant to discuss with your doctor

If you were to change your diet based on these findings, you wouldn’t expect to see changes in heart disease risk immediately. Heart disease develops over years, so any benefits from dietary changes would likely take months to years to appear. The best approach is to make sustainable, long-term changes rather than expecting quick results

Want to Apply This Research?

  • Track daily intake of linoleic acid sources (vegetable oils, nuts, seeds, processed foods) and omega-3 sources (fish, flaxseed, walnuts) for 2-4 weeks to establish a baseline. Record amounts in grams or servings, along with any arthritis symptoms and energy levels
  • If you have rheumatoid arthritis, try gradually reducing processed foods high in linoleic acid while increasing fish consumption to 2-3 times per week. Use the app to log these changes and note any changes in joint pain, inflammation, or how you feel overall
  • Set monthly check-ins to review your fat intake patterns and any changes in arthritis symptoms or energy levels. Track which specific foods seem to correlate with better or worse symptoms. Share this data with your healthcare provider to inform personalized dietary recommendations

This research shows a connection between certain dietary fats and heart disease in people with rheumatoid arthritis, but it does not prove that changing your fat intake will prevent heart disease. This study was conducted at one point in time and cannot establish cause and effect. Before making significant changes to your diet, especially if you have rheumatoid arthritis or heart disease, consult with your doctor or a registered dietitian. This information is for educational purposes only and should not replace professional medical advice. If you have rheumatoid arthritis, work with your healthcare team to develop a nutrition plan tailored to your individual health needs and medical history.