As many as 57 percent of Americans may be eating a diet that promotes inflammation, raising the risk of diseases such as heart disease, obesity, diabetes, depression and certain cancers, research by Ohio State University has found.

“Chronic inflammation occurs when the immune system is overstimulated for long periods of time—months or years,” lead author Rachel Meadows, from Ohio State’s College of Public Health, told Newsweek.

“It can be caused by stress or unhealthy lifestyle behaviors like diet or smoking. Chronic inflammation contributes to the initiation and progression of many chronic health conditions such as heart disease, diabetes, arthritis, and depression.”

Some foods may contribute to this process—pro-inflammatory—while others have been shown to mitigate it—anti-inflammatory.

“All foods are on a range from very anti-inflammatory to very pro-inflammatory,” said Meadows. “Balance of the overall diet is key. You can still enjoy desserts or other ‘unhealthy’ foods and still have an overall anti-inflammatory diet.”

Meadows and her team used data from 34,547 U.S. adults involved in the National Health and Nutrition Examination Survey from 2005 to 2018.

Those involved in the study self-reported their diets, and the scientists used this information to quantify its influence on inflammation, using a dietary inflammatory index developed a decade ago.

Each person’s diet was scored using this index, from eight to minus nine, where zero represented a neutral diet.

The scientists found that one in six of their participants had pro-inflammatory diets, a third had anti-inflammatory diets, and the remaining 9 percent had neutral dietary inflammation levels.

“Pro-inflammatory diets were most commonly reported among males, younger adults, non-Hispanic Black adults and those with lower education or income,” said Meadows.

“The main driving factors are, one, health education about diet and, two, ability to access and eat healthy foods—such as food deserts [an area where healthy food is difficult to access], affordability of healthier foods, time to prepare healthy foods, related to work type or schedule, and other responsibilities and resources.”

Foods that are high in sugar, are highly processed, contain alcohol, and contain refined oils, such as margarine, are generally seen by nutrition professionals as pro-inflammatory, increasing the risk of inflammatory diseases.

On the other hand, fresh fruits and vegetables, oily fish such as salmon, extra-virgin olive oil, spices, dark chocolate and green tea have all been associated with anti-inflammatory benefits.

Meadows told Newsweek some simple ways that people could adjust their diets in order to reduce inflammation.

“You can start small by adding some anti-inflammatory spices when cooking—such as garlic, onion, ginger—drinking green or black tea, or switching to whole-grain bread,” she said.

“Eating leafy greens like spinach, fruits especially berries, and beans and lentils are tasty ways to make your diet more anti-inflammatory.”

In a statement, Meadows added that a number of lifestyle factors could increase inflammation in the body—such as stress and lack of sleep—but that diet could be used as a tool to redress the balance.

This study was published in the scientific journal Public Health Nutrition.

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Reference

Meadows, R. J., Paskett, E. D., Bower, J. K., Kaye, G. L., Lemeshow, S., Harris, R. E. (2024). Socio-demographic differences in the dietary inflammatory index from National Health and Nutrition Examination Survey 2005–2018: a comparison of multiple imputation versus complete case analysis, Public Health Nutrition 27(1) e184. https://doi.org/10.1017/S1368980024001800