A variety of food containing large amounts of antioxidants and vitamins -- such as leafy greens, carrots, tomatoes, whole grains, fruits, nuts, fatty fish and olive oil -- can support a healthy inflammatory response and reduce cardiovascular risk.
Eating red meat and highly processed foods, however, contributes to chronic inflammation in the body, increasing the risk of heart disease and stroke, according to a study recently published in the Journal of the American College of Cardiology.
The study, which followed nearly 166,000 women and 44,000 men for 24 to 30 years, found those who ate higher levels of red and processed meats like bacon and sausage and sugary, processed foods had a 28% higher risk of stroke and a 46% higher risk of heart disease.
The study was unique, said lead author Dr. Jun Li, because it did not examine the impact of specific food groups, but instead focused on the impact of a combination of 18 food groups "that have been shown to best predict inflammation levels associated with diets."
"Foods that are associated with higher inflammation include red meat, organ meat, processed meat, refined grains, sugary beverages and low-energy (diet) carbonated beverages," said Li, a research scientist in the departments of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health.
"Foods that are associated with lower inflammation include leafy green vegetables, dark yellow vegetables, fruit, whole grain, tea, coffee and wine," Li added.
The study results remained "robust," Li said, even after controlling for such confounding factors as hypertension, obesity, diabetes and other chronic health conditions, multivitamin use and various medications, aspirin and other anti-inflammatory drugs, along with antihypertensive and lipid lowering medications.
"These protective effects could also be used for other highly prevalent chronic diseases in which chronic inflammation plays a relevant role, such as diabetes, cancer, depression, cognitive decline, and Alzheimer's disease," wrote Dr. Ramon Estruch, an associate professor at Barcelona University's department of medicine, in an accompanying editorial.
"When choosing the foods in our diet, we should beware of their pro- and anti-inflammatory potential," Estruch added.
No cause and effect
The study cannot establish cause and effect, said Megan Meyer, director of science communications at the International Food Information Council, who was not involved in the study.
"Diet was evaluated by food frequency questionnaires, or FFQs," Meyer said. "One of the limitations to FFQs is that they are associated with a great deal of recall bias, which is a fancy way of saying that people have trouble remembering what they ate and/or are prone to underreport 'bad' foods and over-report 'good' foods."
And while the study was unique in linking food frequency questionnaires with markers of inflammation, the foods recommended by the study are not vastly different from those found in the US Dietary Guidelines, said registered dietitian Kris Sollid, senior director for nutrition communications at IFIC, who was also not involved in the study.
The US guidelines, Sollid said, encourage "limits to the amount of added sugar, saturated fat and sodium we consume" and suggest healthy alternatives.
"Unfortunately, 90% of Americans don't eat the recommended amount of fruits and vegetables," Sollid said. "In addition, Americans only eat half of the recommended daily amount of fiber -- a nutrient that has been linked with a host of potential health benefits."
How does food cause inflammation?
While the exact biological ways foods impact inflammatory pathways is not yet fully understood, researchers believe sugary, processed foods in the Western diet, along with pollution, cigarette smoke, radiation and medications, may lead to the increased activation of free radicals in the body.
Free radicals are molecules with unpaired electrons -- driven to search for a match, they rob other cells of their electrons, causing cellular damage which can contribute to disease.
Unfortunately, today's Western diet is full of overly processed, fat-laden foods, sugary drinks and red and processed meats that can cause persistently high levels inflammation in the body.
In fact, research has linked chronic inflammation to cancer, heart disease, diabetes, arthritis, depression, Alzheimer's and many other diseases.
Eating a lot of unhealthy, "ultraprocessed" foods may even shorten your life -- just a 10% increase in such foods was significantly associated with a 14% higher risk of death from all causes, studies have shown.
The good news is that research has suggested that anti-inflammatory elements such as vitamins, carotenoids and flavonoids in foods like fruits and vegetables may neutralize free radicals and reduce the stress on the body.
So focus on leafy greens, tomatoes, fruits, nuts, fatty fish and olive oil -- foods that can support a healthy inflammatory response -- and fight back by limiting inflammatory foods such as:
- Ice cream, cookies, pastries, cereal bars and cakes
- Premade pies, pasta and pizza dishes
- Poultry and fish nuggets and sticks
- Red and processed meats such as bacon, sausages and hot dogs
- Sugary sodas and fruit-flavored drinks
- "Health" and "slimming" products such as powdered or "fortified" meal and dish substitutes, powdered and packaged instant soups, noodles and desserts