Researchers followed nearly 190,000 people in the UK for over 13 years to see if eating certain nutrients could help prevent rheumatoid arthritis (RA), a disease that causes joint pain and swelling. They found that people who ate the most of four specific nutrients—methionine, folate, vitamin B6, and vitamin B12—had about 12-16% lower chances of developing RA compared to those who ate the least. The benefits were even stronger for people with low genetic risk. The study also found that these nutrients worked better for people who didn’t smoke and limited alcohol, suggesting that lifestyle choices matter alongside diet.

The Quick Take

  • What they studied: Whether eating foods rich in four specific nutrients (methionine, folate, vitamin B6, and B12) could reduce the chances of developing rheumatoid arthritis, and how genetics and lifestyle choices affected these results.
  • Who participated: Nearly 190,000 adults from the UK Biobank study who were tracked for an average of 13.4 years. During this time, 1,751 people developed rheumatoid arthritis.
  • Key finding: People who ate the highest amounts of these four nutrients had 12-16% lower risk of developing RA. When people with low genetic risk also ate high amounts of these nutrients, their risk dropped by more than 40%.
  • What it means for you: Eating more foods containing these nutrients may help protect you from rheumatoid arthritis, especially if you also avoid smoking and limit alcohol. However, this doesn’t guarantee you won’t get RA—genetics and other factors still play important roles. Talk to your doctor before making major dietary changes, especially if you have a family history of RA.

The Research Details

This was a long-term observational study, meaning researchers followed real people over time and tracked what they ate and whether they developed rheumatoid arthritis. The study included 189,440 people from the UK Biobank, a large health database. Researchers asked participants about their diet multiple times using 24-hour recall surveys, where people describe everything they ate in the previous day. They then used food composition databases to calculate how much of each nutrient people consumed. The researchers followed participants for an average of 13.4 years and recorded who developed rheumatoid arthritis during that time.

The study examined four specific nutrients involved in ‘one-carbon metabolism’—a biochemical process in your body that affects inflammation and immune function. These nutrients are methionine (an amino acid), folate (vitamin B9), vitamin B6, and vitamin B12. Researchers used statistical models to determine if higher nutrient intake was connected to lower RA risk, while accounting for other factors like age, sex, body weight, and physical activity.

The researchers also looked at how genetic risk and lifestyle factors (smoking and alcohol use) combined with nutrient intake to affect RA risk. This helped them understand whether certain groups of people might benefit more from eating these nutrients.

This research approach is valuable because it follows real people in their everyday lives rather than testing nutrients in a lab. This makes the findings more relevant to how diet actually affects health. The large sample size (nearly 190,000 people) and long follow-up period (13+ years) make the results more reliable. By looking at interactions between diet, genetics, and lifestyle, the study provides a more complete picture of how multiple factors work together to influence RA risk.

Strengths: The study is large, follows people for a long time, and uses repeated dietary assessments rather than asking people to remember what they ate years ago. The researchers controlled for many other factors that could affect results. Limitations: The study is observational, meaning it can show associations but not prove that these nutrients directly prevent RA. People who eat more of these nutrients might also have other healthy habits. The study population was primarily from the UK, so results may not apply equally to other populations. Additionally, the study cannot determine the ideal amount of each nutrient or identify the best food sources.

What the Results Show

During the 13+ year study period, 1,751 people developed rheumatoid arthritis out of the 189,440 participants. People who ate the most of these four nutrients had significantly lower RA risk compared to those who ate the least. Specifically, the risk reductions were: methionine (16% lower risk), folate (12% lower risk), vitamin B6 (12% lower risk), and vitamin B12 (16% lower risk).

The most striking finding was when researchers combined nutrient intake with genetic risk. People with low genetic risk for RA who also ate high amounts of these nutrients had more than 40% lower risk of developing the disease. This suggests that diet and genetics work together—good nutrition may be especially protective for people who aren’t genetically predisposed to RA.

The study also found that the protective effect of these nutrients was stronger in people who didn’t smoke and who limited their alcohol consumption. Smokers and heavy drinkers didn’t see as much benefit from eating these nutrients, suggesting that lifestyle choices interact with diet to influence RA risk.

The researchers examined whether the relationship between nutrient intake and RA risk was linear (straight line) or nonlinear (curved). They found that the relationship was generally consistent across different intake levels, meaning that more of these nutrients was generally associated with lower risk. The study also showed that the four nutrients worked together—people who had high intake of all four nutrients had the greatest protection, rather than one nutrient being more important than the others.

This study builds on earlier research suggesting that one-carbon metabolism nutrients might affect inflammation and immune function. Previous studies have been smaller or shorter-term. This large, long-term study provides stronger evidence for the connection between these specific nutrients and RA risk. The findings align with biological research showing that these nutrients are important for controlling inflammation in the body. However, most previous studies were smaller or didn’t look at how genetics and lifestyle factors interact with diet.

This study cannot prove that eating these nutrients prevents RA—it only shows an association. People who eat more of these nutrients might also exercise more, have lower stress, or have other healthy habits that actually prevent RA. The study followed mostly white British people, so results may differ for other ethnic groups. The study didn’t measure actual nutrient levels in people’s blood, only estimated intake from food. Some people may have developed RA before the study started but weren’t diagnosed yet. The study also couldn’t identify the optimal amount of each nutrient or which food sources are most protective.

The Bottom Line

Based on this research, eating more foods rich in methionine, folate, vitamin B6, and vitamin B12 may help reduce your risk of rheumatoid arthritis. This is especially true if you also avoid smoking and limit alcohol. Good sources include: folate (leafy greens, legumes, asparagus), vitamin B6 (chickpeas, bananas, salmon), vitamin B12 (meat, fish, dairy, fortified cereals), and methionine (eggs, meat, fish, nuts). However, this research suggests a possible benefit—it doesn’t guarantee prevention. If you have a family history of RA or other risk factors, discuss dietary changes with your doctor. Confidence level: Moderate—the study is large and long-term, but it’s observational rather than experimental.

This research is most relevant for people with a family history of rheumatoid arthritis or those concerned about RA risk. It’s also important for people who smoke or drink heavily, since the study suggests they may benefit especially from optimizing nutrient intake. People already diagnosed with RA should discuss dietary changes with their rheumatologist. This research is less relevant for people with no family history of RA and healthy lifestyles, though the nutrients studied are important for overall health anyway.

This study followed people for 13+ years, so benefits would develop over a long time period. You shouldn’t expect to feel different after eating these foods for a few weeks. If you’re trying to reduce RA risk through diet, think of it as a long-term lifestyle change rather than a quick fix. Some people might notice improved energy or overall health within weeks or months, but protection against RA would develop over years.

Want to Apply This Research?

  • Track weekly intake of foods rich in these four nutrients: count servings of leafy greens (folate), legumes (folate, methionine), eggs (methionine, B6, B12), fish (B12, methionine), poultry (B6, methionine), and fortified cereals (B12). Aim for at least 3-4 servings per week of each category.
  • Set a weekly goal to try one new recipe featuring these nutrients—for example, a spinach salad with chickpeas, salmon with asparagus, or an egg-based breakfast. Use the app to log these meals and build a habit of including these foods regularly.
  • Track nutrient-rich foods monthly rather than daily to reduce burden. Create a simple checklist of key foods and mark off weeks when you met your targets. If you have RA risk factors, review your nutrient intake quarterly and adjust based on what’s working for you. Consider checking in with a dietitian annually to ensure you’re meeting nutrient needs.

This research suggests an association between certain nutrients and lower rheumatoid arthritis risk, but does not prove that eating these foods will prevent RA. This study is observational and cannot establish direct cause-and-effect. Individual results vary based on genetics, lifestyle, and other health factors. If you have symptoms of rheumatoid arthritis (joint pain, swelling, stiffness), a family history of RA, or are considering major dietary changes, consult with your healthcare provider or a registered dietitian. This information should not replace medical advice from your doctor. If you have been diagnosed with RA, work with your rheumatologist before making dietary changes, as some nutrients may interact with RA medications.