Inflammation can be good or bad depending on the situation.
On 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 illness and stimulate healing.
On the other hand, chronic, sustained inflammation is linked to an increased risk of diseases like diabetes, heart disease, and obesity.
Interestingly, the foods you eat can significantly affect inflammation in your body.
Here are 6 foods that can cause inflammation.
1. Sugar and high-fructose corn syrup
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, partly due to the inflammatory response to sugar.
In another study, the anti-inflammatory effects of omega-3 fatty acids were 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 be harmful because it supplies excess amounts of fructose.
While the small amounts of fructose in fruits and vegetables are fine, consuming 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.
Also, researchers have noted 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 likewise been shown to increase several inflammatory markers in mice and humans.
Foods high in added sugar include 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 effects of omega-3 fatty acids.
2. Artificial trans fats
Artificial trans fats are likely the unhealthiest fats you can eat.
They’re created by adding hydrogen to liquid unsaturated fats, to give them the stability of more solid fat.
On ingredient labels, trans fats are often listed as partially hydrogenated oils.
Most kinds of margarine contain trans fats, and they are often added to processed foods 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 HDL (good) cholesterol, trans fats may impair the function of the endothelial cells lining your arteries, which is a risk factor for heart disease.
Consuming 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 among women who reported the highest trans fat intake.
In a randomized controlled trial including older women with excess weight, hydrogenated soybean oil increased inflammation significantly more than palm and sunflower oils.
Studies in healthy men and men with elevated cholesterol levels have revealed similar increases in inflammatory markers in response to trans fats.
Suggested read: Anti-inflammatory diet: How to reduce inflammation naturally
Foods high in trans fats include French fries and other fried fast food, some varieties of microwave popcorn, certain kinds of margarine and vegetable shortenings, packaged cakes and cookies, some pastries, and all processed foods that list partially hydrogenated vegetable oil on the label.
Summary: Consuming artificial trans fats may increase inflammation and your risk of several diseases, including heart disease.
3. Vegetable and seed oils
During the 20th century, the consumption of vegetable oils increased by 130% in the United States.
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.
Health professionals recommend eating more omega-3-rich foods, such as fatty fish, to improve your omega-6 to omega-3 ratio and reap the anti-inflammatory benefits of omega-3s.
In one study, rats fed a diet with an omega-6 to omega-3 ratio of 20:1 had much higher levels of inflammatory markers than those fed diets with ratios of 1:1 or 5:1.
However, evidence that a high intake of omega-6 fatty acids increases inflammation in humans is currently limited.
Controlled studies show that linoleic acid, the most common dietary omega-6 acid, does not affect inflammatory markers.
More research is needed before any conclusions can be made.
Vegetable and seed oils are used as cooking oils and are a major ingredient in many processed foods.
Summary: Some studies suggest 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.
4. Refined carbohydrates
Carbohydrates have gotten a bad reputation. However, the truth is that not all carbs are problematic.
Suggested read: What are trans fats, and are they bad for you?
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 increases in levels of a particular inflammatory marker.
Refined carbohydrates are found in candy, bread, pasta, pastries, some cereals, cookies, cakes, sugary soft drinks, and all processed foods that contain 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.
5. Excessive alcohol
Moderate alcohol consumption has been shown to provide some health benefits.
However, higher amounts can lead to severe problems.
In one study, levels of the inflammatory marker CRP increased in people who consumed alcohol. The more alcohol they consumed, the more their CRP levels 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.
6. Processed meat
Consuming processed meat is associated with an increased risk of heart disease, diabetes, and stomach 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, its association with colon cancer is the strongest.
Although many factors contribute to colon cancer, one mechanism is believed to be colon cells’ inflammatory response to processed meat.
Summary: Processed meat is high in inflammatory compounds like AGEs, and its strong association with colon cancer may partly be due to an inflammatory response.
Inflammation can occur in response to many triggers, some of which are hard to prevent, including 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 and eating anti-inflammatory foods.