Rheumatoid Arthritis (RA) is a systemic autoimmune disease that primarily affects the joints and, if left untreated, can eventually lead to cartilage and bone destruction through excessive inflammation and immune system attacks (Gioia et al., 2020). It is estimated that RA affects around 1.3 million adults in the US, with that number expected to increase (Hunter et al., 2017). While the cause of RA is unknown, what is known is that its acquisition and severity is influenced by both genetic and environmental factors. Among those environmental factors, diet seems to play a big role in the risk of RA acquisition and progression (Gioia et al., 2020). Therefore, it’s important that both those suffering from RA and those who are at an increased risk for developing RA are educated on which foods/diets are best to help mitigate the disease.
Rheumatoid Arthritis and Inflammation
In recent years there has been a lot of research into specific foods that can exacerbate or improve RA symptoms and inflammation. While some of the data is contradictory or inconclusive, there are some clear trends. Generally, diets that feature high amounts of omega 3 fatty acids, fruits, and vegetables have beneficial effects on inflammation and RA risk, while diets with high amounts of red meat, refined carbohydrates, and trans fats increase RA risk and aggravate symptoms. One such diet that has been studied and has shown to work the best for mitigating RA is called the “Mediterranean Diet”, so called for the diet generally followed by those living in countries surrounding the Mediterranean Sea (Lăcătușu et al., 2019). This diet mainly consists of vegetables, fruits, unprocessed cereals, fish, and extra-virgin olive oil. It also features moderate amounts of eggs, dairy, chicken, and occasional red wine, and almost no refined sugar or red meat (Gioia et al, 2020). An example of a meal that conforms with the Mediterranean diet is a serving of salmon (44 oz), one cup of roasted broccoli, 1⁄2 cup of white or brown rice, extra virgin olive oil for cooking and seasoning, and a 5 oz serving of red wine if desired.
What's great about the Mediterranean Diet
So, what makes the Mediterranean Diet so special? The foods this diet emphasizes have shown to have beneficial effects on RA, and indeed in places where this diet is generally followed, RA and other rheumatic conditions are less prevalent (Gioia et al., 2020). In a systematic review of 70 studies conducted between 1979 and 2017 that investigated the effects of the Mediterranean diet, it was found that following the diet showed an overall improvement in RA symptoms by reducing inflammation and reducing risk of comorbidities that lead to further complications (Philippou et al., 2021). Each of the studies focused on different aspects of the Mediterranean diet, such as fish oil supplementation or vitamin supplementation. 4 of the studies measured the effect of a whole diet change to a Mediterranean diet. The study by McKellar et al. gave their participants (all females with RA) in the intervention group a 6 week cooking course that educated them about the Mediterranean diet and encouraged them to follow it, while also giving them resources on local accessibility to affordable ingredients for the diet. The other participants in the control group were not given any guidance and were free to eat their normal diet. The researchers found that those in the intervention group had significantly lower self-reported pain scores and higher function scores compared to those in the control group over a period of 6 months. They also noted a small change in systolic blood pressure (McKellar et al., 2007). While the amount of studies investigating RA are limited and much of the data is qualitative and hard to measure, this serves as a great starting point for researchers to further investigate the effects of this diet and the foods that comprise it.
Speaking of foods, let’s get into the evidence of the potential beneficial effects of consuming the foods that comprise the standard Mediterranean diet. The main protein of this diet is fish, which contains high amounts of omega 3 fatty acids. These omega 3s have anti-inflammatory properties that come from their function in the body as lipid mediators that resolve inflammatory responses. As a result of these properties, many studies have shown that consuming dietary omega-3s (specifically from fatty fish such as salmon) reduces the risk of developing and suffering from RA symptoms (Gioia et al, 2020). Even if you dislike fish, you can still reap the benefits of omega 3 fatty acids by taking supplements like fish oil pills. One study showed that doses of 2.7 g of omega-3 fatty acids per day showed a significant reduction in inflammation (Philippou et al., 2021). That roughly corresponds to a 4 oz serving of salmon.
Extra virgin olive oil is another staple of the Mediterranean diet. Olive oil is the main source of dietary fat in the Mediterranean diet and it is historically used in the cooking of all meats and vegetables (Lăcătușu et al., 2019). The typical serving of olive oil used in the Mediterranean diet is 1-2 tablespoons. It is important to note that not all olive oil is made equal, and only extra virgin olive oil has shown to provide beneficial effects for the mitigation of RA symptoms. Dietary intake of extra virgin olive oil was shown to reduce thromboxane 2, an inducer of inflammation, while non-virgin olive oil did not (Gioia et al., 2020). Olives in general contain high amounts of antioxidant polyphenols, which have shown to decrease the risk and severity of a variety of inflammatory diseases (Vroldjak et al., 2022). These two factors make extra virgin olive oil an inflammation-fighting powerhouse, which in turn could ease the symptoms of RA.
Rheumatoid Arthritis and red wine
Red wine is one of the more surprising additions to this diet. While there is contradictory evidence on the effects of red wine consumption on RA, there are a few studies that demonstrate a beneficial effect. A study by Lu et al. found a 30% decrease of risk of developing RA in participants who consumed 3-5 standard drinks (5 oz serving per standard drink) per week. Red wine’s high polyphenol content, which as discussed before has anti-inflammatory properties, could be a reason for this effect (Gioia et al, 2020). However, it’s important to note that any alcohol use can have harmful effects from interactions with medications, so it’s important that those with RA speak with their doctors about any negative interactions with their medication.
One aspect stressed by this diet is the heavy restriction on red meat consumption due to its proinflammatory effect. Most Mediterranean diets only allow for one 3 oz serving of red meat once a week. Along with eggs and dairy, red meat is a dietary source of trimethylamine-N-oxide (TMAO), which is a pro-inflammatory metabolite. This metabolite has been linked to cardiovascular inflammation specifically, however its effect on RA inflammation has not been extensively studied (Gioia et al., 2020). Recent studies, like those conducted by Jin et al., have demonstrated a link between increased red meat consumption and early-onset RA, especially among those with other comorbidities such as obesity and smoking habits (Jin et al., 2021). Along with these findings, there is already much evidence to suggest that high amounts of red meat consumption increase the risk of developing cardiac diseases and colorectal cancer, and as a result many rheumatologists already recommend limiting red meat consumption as a preventative measure (Jin et al., 2021). Regardless of RA status, everyone could benefit from reducing red meat intake.
Diet plays a large role in determining our health, especially in those with chronic rheumatic diseases such as rheumatoid arthritis. The Mediterranean diet and the foods that make it up have shown promising results in reducing inflammation and improving RA symptoms. The anti-inflammatory properties of omega-3 fatty acids found in fish, the polyphenols in extra virgin olive oil, and the limiting of red meat intake all contribute to the effectiveness of this diet. While more research is needed to fully understand the diet's impact, current evidence supports the Mediterranean diet as a beneficial dietary approach for those suffering from or at risk of RA. Educating and empowering patients with the knowledge of the Mediterranean diet could transform their battle with rheumatoid arthritis, offering a flavorful and effective path to relief.
Written by Ryan Dulong, BS, and edited by Aldrin V. Gomes, PhD
References
Gioia, C., Lucchino, B., Tarsitano, M. G., Iannuccelli, C., & Di Franco, M. (2020). Dietary Habits and Nutrition in Rheumatoid Arthritis: Can Diet Influence Disease Development and Clinical Manifestations?. Nutrients, 12(5), 1456. https://doi.org/10.3390/nu12051456
Hunter, T. M., Boytsov, N. N., Zhang, X., Schroeder, K., Michaud, K., & Araujo, A. B. (2017). Prevalence of rheumatoid arthritis in the United States adult population in healthcare claims databases, 2004-2014. Rheumatology international, 37(9), 1551–1557. https://doi.org/10.1007/s00296-017-3726-1
Jin, J., Li, J., Gan, Y., Liu, J., Zhao, X., Chen, J., Zhang, R., Zhong, Y., Chen, X., Wu, L., Xiang, X., Zhou, Y., He, J., Guo, J., Liu, X., & Li, Z. (2021). Red meat intake is associated with early onset of rheumatoid arthritis: a cross-sectional study. Scientific reports, 11(1), 5681. https://doi.org/10.1038/s41598-021-85035-6
Lăcătușu, C. M., Grigorescu, E. D., Floria, M., Onofriescu, A., & Mihai, B. M. (2019). The Mediterranean Diet: From an Environment-Driven Food Culture to an Emerging Medical Prescription. International journal of environmental research and public health, 16(6), 942. https://doi.org/10.3390/ijerph16060942
McKellar, G., Morrison, E., McEntegart, A., Hampson, R., Tierney, A., Mackle, G., Scoular, J., Scott, J. A., & Capell, H. A. (2007). A pilot study of a Mediterranean-type diet intervention in female patients with rheumatoid arthritis living in areas of social deprivation in Glasgow. Annals of the rheumatic diseases, 66(9), 1239–1243. https://doi.org/10.1136/ard.2006.065151
Philippou, E., Petersson, S. D., Rodomar, C., & Nikiphorou, E. (2021). Rheumatoid arthritis and dietary interventions: systematic review of clinical trials. Nutrition reviews, 79(4), 410–428. https://doi.org/10.1093/nutrit/nuaa033
Vrdoljak, J., Kumric, M., Vilovic, M., Martinovic, D., Tomic, I. J., Krnic, M., Ticinovic Kurir, T., & Bozic, J. (2022). Effects of Olive Oil and Its Components on Intestinal Inflammation and Inflammatory Bowel Disease. Nutrients, 14(4), 757. https://doi.org/10.3390/nu14040757
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