- The Mediterranean diet is one of the most popular diets in the world.
- Past studies have linked following a Mediterranean diet to a lower risk of several health issues and diseases, including viruses like the common cold.
- Researchers from the Universitas Sumatera Utara report that those who eat a Mediterranean diet may also possibly be reducing their risk of COVID-19, which is caused by the SARS-CoV-2 virus.
Over the last few years, the Mediterranean diet has become very popular due to its healthy mix of plant-based foods, healthy fats, and whole grains.
In fact, the Mediterranean diet has been named the best diet for seven years in a row through U.S. News & World Report’s annual poll.
Past studies have linked following a Mediterranean diet to lower blood pressure, cholesterol, and blood sugar levels, as well as a decreased risk for several diseases including type 2 diabetes, obesity, cardiovascular disease, and cancer.
Previous research has also found a potential correlation between following the Mediterranean diet and a decreased risk for viruses such as the common cold.
Now researchers from the Universitas Sumatera Utara in Indonesia report that those who eat a Mediterranean diet may also possibly be reducing their risk of COVID-19, which is caused by the SARS-CoV-2 virus.
“The Mediterranean diet has long been known for its benefits, especially in chronic diseases such as cardiovascular disease and diabetes,” Andre Marolop Pangihutan Siahaan, MD, a staff member of the Department of Neurosurgery at the Universitas Sumatera Utara in Indonesia and senior author of this study told Medical News Today. “It is associated with immunomodulation and anti-inflammatory factors, while inflammation is one of the critical factors in COVID-19.”
The study was recently published in the journal PLoS ONE.
For this study, Siahaan and his team analyzed data from six previously conducted observational studies that reported an association between following the Mediterranean diet and risk of COVID-19 infection, symptoms, or severity, for a total participant size of more than 55,000.
“Despite global vaccination, advanced medication, and preventive measures, multiple waves of COVID-19 infection continue to be reported worldwide,” Siahaan said when asked why it is important for researchers to continue to find new ways in which people can lower their COVID-19 infection risk. “The recent Olympic games saw over 40 athletes testing positive for the virus, underscoring the ongoing threat.”
“Moreover, the growing evidence of reinfection, and even multiple reinfections in one individual, is a cause for concern,” he continued. “While the latest study suggests that reinfection severity correlates more with the initial infection, it’s crucial to emphasize further research to fully understand the long-term impact, as we cannot yet consider it harmless.”
– Andre Marolop Pangihutan Siahaan, MD
In all the studies analyzed, adherence to the Mediterranean diet was assessed through a food frequency questionnaire.
Upon analysis, scientists said they consistently observed lower trends of odds ratio for those who adhered to a Mediterranean diet, suggesting that high adherence to the Mediterranean diet might provide protection against COVID-19 infection.
“Adherence to the Mediterranean diet will reduce the odds of COVID-19,” Siahaan said. “Still, this study, which was conducted qualitatively, was unable to determine the exact extent of the reduction.”
Researchers also reported their findings were unclear as to whether or not the Mediterranean diet had any positive impact on COVID-19 symptoms and severity.
“The findings on the Mediterranean Diet’s effect on symptoms and severity were inconsistent,” Siahaan said. ”Still, it’s essential to keep in mind that insignificance may mean a smaller magnitude of impact, and these numbers need to be studied in a larger population.”
“The correlation between nutrition and immunity is very interconnected and complex,” he continued. “The Mediterranean diet’s benefit in helping protect against COVID-19 comes from the synergistic effect of every component. Olive oil is rich in polyphenols and unsaturated fatty acids, known for their immunomodulatory and anti-inflammatory effects. (The) Mediterranean diet is rich in vitamins and trace elements as well. Besides, high fiber intake promotes the eubiosis of intestinal microbiota, which will affect the immune system.”
After reviewing this research, Monique Richard, MS, RDN, LDN, a registered dietitian nutritionist and owner of Nutrition-In-Sight, told MNT that her initial reaction to this systematic review analyzing mostly observational studies was an affirmation of what she and her colleagues also observed in practice. She noted:
“[T]he quality of dietary patterns and lifestyle behavior appears to be inversely related to COVID-19 infection risk, recovery, duration and/or severity. In general — noting the emphasis on the words ‘in general,’ in order to underscore, ‘not all’ — individuals that were affected by COVID-19 or had [reduced] risks, severity of symptoms, or recurrence tended to have a more anti-inflammatory dietary pattern higher in fruits, vegetables and nutrient-rich plants commonly found in the Mediterranean diet pattern.”
“It is important to note that diet alone does not determine the impact COVID-19 may have on an individual,” she added. There are a multitude of factors that play a role including current health conditions, genetic predisposition, level of exposure, organ function, age, metabolic function, and environment just to name a few.”
MNT also spoke with David Cutler, MD, a board certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA, who said it’s important to remember that correlation is not the same as causation:
“Even if there (was) an association between diet and COVID outcomes, that doesn’t imply that there’s any cause and effect relationship. And while that might be interesting, I really don’t think it’s all that important. I think most people would agree that a Mediterranean diet is a helpful diet and it’s a good idea to follow one, regardless of whether or not it changes COVID outcomes.”
“I think the fact is we already know how to lower COVID risk,” he continued. “COVID is a respiratory disease and while diet may have some influence on outcomes, the most important thing is preventing getting COVID in the first place. And we have, I think, quite good data showing that using respiratory precautions like well fitted N95 masks will help prevent acquiring the COVID infection.”
With virus season almost upon us, readers may wonder how they can help reduce their risk for infection not only from COVID-19 but also from other viruses like the flu.
First, Richard suggested meeting with a registered dietitian nutritionist (RDN) or other qualified, credentialed nutrition expert to learn more about your unique needs.
From there, foods rich in vitamins A, B (all the B’s, to name a few, B1, B2, B5, B6, B9, B12), C, D, E, but also minerals such as zinc, magnesium, (and) selenium are just a few specific nutrients that directly relate to immune health, Richard detailed.
“Many of these are found in fruits, vegetables, whole grains, proteins and fat,” she continued. “Keep in mind that dietary supplements for each of these nutrients do not necessarily have the same impact as the whole food and in fact can often be counter-productive especially in high doses by depleting a different nutrient.”
“For example, too much zinc can deplete copper,” Richard explained. “Taking a zinc supplement may not be necessary especially if you are obtaining enough in your diet, it is not advised for a prolonged period of time. This is one of many I see in practice being overconsumed and consequences are not always benign.”
Richard also offered these simple questions to help readers assess if their diet is rich in immune-supportive nutrients:
- How many fruit servings am I consuming in a day?
- Are they coming from a variety of fresh or frozen sources such as citrus fruits (oranges, grapefruit, tangerines), berries, apples, and stone fruit (plums, peaches, apricots)?
- How many servings of fresh or frozen vegetables am I consuming in a day?
- Are rich leafy greens such as spinach, arugula, kale, or turnip greens included?
- Are bright orange and red vegetables included, such as carrots, peppers, tomatoes, sweet potatoes, radishes, beets, etc.?
- Where do I get my protein? Beans? Frozen or fresh or canned fatty fish such as salmon, sardines, herring, or tilapia for example?
- Are fat sources in my diet quality olive, avocado, or nuts and seeds sources? Full-fat dairy? Or is it mostly saturated fat from animal sources, which is then processed, breaded, and deep-fried?
- Am I cooking and seasoning foods with antioxidant-rich spices and herbs such as ginger, garlic, onions, turmeric, basil, thyme, rosemary, parsley, cilantro, or scallions, just to name a few?
