Inflammation, what is it?
Inflammation is an immune response to an injury or infection as the body sends cells, like white blood cells, to the damaged or infected area to protect and “clean-up” any foreign substances and promote tissue repair and recovery. This process can produce signs of inflammation like pain, heat, redness, swelling, and loss of function (1).
Acute inflammation is necessary and healthy as it helps defend the body from foreign substances like bacteria that can damage body tissue. With acute inflammation, once the infection is cleared inflammation subsides.
When inflammation becomes chronic
When the body attempts to rid harmful substances like toxic chemicals and pathogens like bacteria, viruses, and fungi over months or years, this chronic inflammation can damage body tissue and lead to diseases like cardiovascular disease, diabetes, kidney disease, non-alcoholic fatty liver disease, cancer, and autoimmune and neurodegenerative disorders (2).
Additionally, increased levels of chronic inflammation are associated with excess fat tissue, especially that fat located around the abdomen, and low-grade chronic inflammation can damage blood vessels, arteries, nerves, and the intestines eventually leading to many of the diseases mentioned above (3).
Foods can cause inflammation
Some foods are considered to be more pro-inflammatory than others, including foods like processed meats, refined carbohydrates (think white bread, white rice, white sugar), and sweetened beverages like soft drinks and sports drinks, according to Harvard (4).
Processed meats, like salami and bacon, can contain carcinogens or substances, like nitrosamines and nitrite, that can lead to the development of inflammation and cancer-causing processes in the body (5) (6). When meats are processed at high temperatures, the nitrites more easily form nitrosamines which are cancer-causing compounds.
Diets high in refined carbohydrates and sugar lead to low-grade inflammation, obesity, and insulin resistance (7) (8). One study found that one 12 ounce can of soda containing about 40 grams (10 teaspoons) of added sugar led to an increase in inflammatory markers (hs-CRP), LDL cholesterol, and insulin resistance as well as weight gain (9). Another study found that the consumption of high glycemic foods (like refined carbohydrates, pretzels, candy, breakfast cereals) led to an increased risk of death from inflammatory diseases (10).
Foods can also be anti-inflammatory
Conversely, certain foods contain substances that aid the body in reducing inflammation.
Foods like green leafy vegetables such as kale, spinach, and collard greens, yellow vegetables like squash and bell peppers, fruits (especially berries), as well as tea and coffee are nutrient-dense and contain anti-inflammatory compounds like polyphenols such as flavonoids (quercetin, catechins, anthocyanins), carotenoids, and fiber that aid and support the reduction of inflammation in the body (11).
Certain foods can also help to reduce the harmful, inflammatory substances found in other foods.
For example, advanced glycation end products (AGEs) form in foods like highly-processed meats, cheese, oils, and nuts as the protein or fat combine with sugar when exposed to high temperatures such as in grilling, frying, or toasting (12). High levels of AGEs cause oxidative stress and inflammation in the body (13). Cooking these foods at lower temperatures and steaming, stewing, or braising can reduce the levels of AGEs produced.
Plants rich in phenolic acids like citrus fruits (lemon and limes) inhibit AGEs during cooking. Marinating meats in vinegar or citrus juice can inhibit the formation and reduce the level of AGEs produced when the meat is cooked (14).
Further, adding certain antioxidant-rich herbs and food like garlic, oregano, rosemary, cherries, and apples to meats before cooking can reduce the formation of harmful substances that develop in meats when they are cooked (15).
You can read more about foods that fight inflammation in this brief article from Harvard Medical School.