Inflammation can be good or bad depending on the situation.
On the one hand, it's your body's natural way of protecting itself when you’re injured or sick.
It can help your body defend itself from illnesses and stimulate healing.
On the other hand, chronic, sustained inflammation in your body is linked to an increased risk of diseases like diabetes, heart disease, and obesity (, , ).
Interestingly, the foods you eat can have a major effect on inflammation in your body.
Here are 6 foods that can cause inflammation.
Table sugar (sucrose) and high-fructose corn syrup (HFCS) are the two main types of added sugar in the Western diet.
Sugar is 50% glucose and 50% fructose, while high-fructose corn syrup is about 45% glucose and 55% fructose.
One of the reasons that added sugars are harmful is that they can increase inflammation, which can lead to disease (, , , , ).
In one study, mice fed high-sucrose diets developed breast cancer that spread to their lungs — in part due to the inflammatory response to sugar ().
In another study, the anti-inflammatory impact of omega-3 fatty acids was impaired in mice fed a high-sugar diet ().
What’s more, in a randomized clinical trial in which people drank regular soda, diet soda, milk, or water, only those in the regular soda group had increased levels of uric acid, which drives inflammation and insulin resistance ().
Sugar can also cause harm because it supplies excess amounts of fructose.
While the small amounts of fructose in fruits and vegetables are fine, getting large amounts from added sugars is a bad idea.
Eating a lot of fructose has been linked to obesity, insulin resistance, diabetes, fatty liver disease, cancer, and chronic kidney disease (, , , , , , ).
Researchers also note that fructose causes inflammation within the endothelial cells that line your blood vessels, which is a risk factor for heart disease ().
High fructose intake has also been shown to increase several inflammatory markers in mice and humans (, , , , , ).
Food high in added sugar includes candy, chocolate, soft drinks, cakes, cookies, doughnuts, sweet pastries and certain cereals.
SUMMARY Consuming a diet high in sugar and high-fructose corn syrup drives inflammation that can lead to disease. It may also counteract the anti-inflammatory effect of omega-3 fatty acids.
Artificial trans fats are likely the unhealthiest fats you can eat.
They're created by adding hydrogen to unsaturated fats, which are liquid, in order to give them the stability of a more solid fat.
On ingredients lists, trans fats are often listed as "partially hydrogenated" oils.
Most margarines contain trans fats, and they are often added to processed foods in order to extend shelf life.
Unlike the naturally occurring trans fats found in dairy and meat, artificial trans fats have been shown to cause inflammation and increase disease risk (, , , , , , , , ).
In addition to lowering “good” HDL cholesterol, trans fats may impair the function of the endothelial cells lining your arteries, which is a risk factor for heart disease ().
Ingestion of artificial trans fats is linked to high levels of inflammatory markers, such as C-reactive protein (CRP).
In fact, in one study, CRP levels were 78% higher in women who reported the highest trans fat intake ().
In a randomized controlled trial of overweight older women, hydrogenated soybean oil increased inflammation significantly more than palm and sunflower oils ().
Studies in healthy men and men with elevated cholesterol reveal similar increases in inflammatory markers in response to trans fats (, ).
Food high in trans-fat includes french fries and other fried fast food, some varieties of microwave popcorn, certain margarines and vegetable shortening, packaged cakes and cookies, some pastries, and all processed food that lists partially hydrogenated vegetable oil on the label.
SUMMARY Consuming artificial trans fats may increase inflammation and raise your risk of several diseases, including heart disease.
During the 20th century, the consumption of vegetable oils increased by 130% in the US.
Some scientists believe that certain vegetable oils, such as soybean oil, promote inflammation due to their very high omega-6 fatty acid content ().
Although some dietary omega-6 fats are necessary, the typical Western diet provides far more than people need.
In one study, rats fed an omega-6 to omega-3 ratio of 20:1 had much higher levels of inflammatory markers than those fed a ratio of 1:1 or 5:1 ().
However, evidence that a high intake of omega-6 fatty acids increases inflammation in people is currently limited.
Controlled studies show that linoleic acid, the most common dietary omega-6 acid, has no effects on inflammatory markers (, ).
More research is needed before any solid conclusions can be made.
Vegetable and seed oils are used as a cooking oil and are a major ingredient in many processed foods.
SUMMARY Some studies suggests that vegetable oil’s high omega-6 fatty acid content may promote inflammation when consumed in high amounts. However, the evidence is inconsistent and more research is needed.
Carbohydrates have gotten a bad rap.
However, the truth is that not all carbs are problematic.
Ancient humans consumed high-fiber, unprocessed carbs for millennia in the form of grasses, roots, and fruits ().
However, eating refined carbs may drive inflammation (, , , , ).
Refined carbs have had most of their fiber removed. Fiber promotes fullness, improves blood sugar control, and feeds the beneficial bacteria in your gut.
Researchers suggest that the refined carbs in the modern diet may encourage the growth of inflammatory gut bacteria that can increase your risk of obesity and inflammatory bowel disease (, ).
Refined carbs have a higher glycemic index (GI) than unprocessed ones. High-GI foods raise blood sugar more rapidly than low-GI foods.
In one study, older adults who reported the highest intake of high-GI foods were 2.9 times more likely to die of an inflammatory disease like chronic obstructive pulmonary disease (COPD) ().
In a controlled study, young, healthy men who ate 50 grams of refined carbs in the form of white bread experienced higher blood sugar levels and an increase in a particular inflammatory marker ().
Refined carbohydrates are found in candy, bread, pasta, pastries, some cereals, cookies, cakes, sugary soft drinks and all processed food that contains added sugar or flour.
SUMMARY High-fiber, unprocessed carbs are healthy, but refined carbs raise blood sugar levels and promote inflammation that may lead to disease.
Moderate alcohol consumption has been shown to provide some health benefits.
However, higher amounts can lead to severe problems.
In one study, the inflammatory marker CRP increased in people who consumed alcohol. The more alcohol they consumed, the more their CRP increased ().
People who drink heavily may develop problems with bacterial toxins moving out of the colon and into the body. This condition — often called "leaky gut" — can drive widespread inflammation that leads to organ damage (, ).
To avoid alcohol-related health problems, intake should be limited to two standard drinks per day for men and one for women.
SUMMARY Heavy alcohol consumption may increase inflammation and lead to a "leaky gut" that drives inflammation throughout your body.
Consuming processed meat is associated with an increased risk of heart disease, diabetes, stomach cancer, and colon cancer (, , ).
Common types of processed meat include sausage, bacon, ham, smoked meat, and beef jerky.
Processed meat contains more advanced glycation end products (AGEs) than most other meats.
AGEs are formed by cooking meats and some other foods at high temperatures. They are known to cause inflammation (, ).
Of all the diseases linked to processed meat consumption, colon cancer's association is the strongest.
Although many factors contribute to colon cancer, one mechanism is believed to be an inflammatory response to processed meat by colon cells ().
SUMMARY Processed meat is high in inflammatory compounds like AGEs, and its strong association with colon cancer may be due in part to an inflammatory response.
Inflammation can occur in response to many triggers.
Some of these are hard to prevent, such as pollution, injury, or sickness.
However, you have much more control over factors like your diet.
To stay as healthy as possible, keep inflammation down by minimizing your consumption of foods that trigger it. You can also eat anti-inflammatory foods.