Pro-Inflammatory Foods: What to Avoid and Why

Many of the foods in the standard American diet both cause and perpetuate chronic inflammation, such as refined sugars, artificial sweeteners, trans fats, refined carbohydrates, processed meats, and alcohol. These pro-inflammatory foods induce an inflammatory response within the body that leads to a cascade of downstream effects, including damage to cells and organs, metabolic derangement, immune dysregulation, and many chronic illnesses.

There is a strong link between diet and inflammation, and increasing evidence supports the negative impact of proinflammatory foods, which is detrimental to overall health. It is crucial to understand what foods are pro-inflammatory (and why) to make proper diet and lifestyle changes to promote overall health and longevity. 

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What is Inflammation?

Inflammation refers to an immune response triggered within the body as a result of exposure to a foreign substance or a perceived stressor. While acute inflammation is a vital part of the immune response in the short term, sustained inflammation over weeks to months (called chronic inflammation) can have detrimental effects. Many of the foods in the standard American diet both cause and perpetuate chronic inflammation, such as processed foods, trans fats, and refined sugars. However, other foods are actually anti-inflammatory, and their consumption helps combat inflammation with the food itself. With many different names, a true anti-inflammatory diet focuses on whole, real foods with antioxidants and micronutrients, while minimizing processed foods and other proinflammatory ingredients. 

When the inflammatory response continues beyond the short-term, chronic inflammation results. This is marked by chronically elevated levels of stress hormones that have blunted effects, which necessitates the production of higher and higher levels of stress hormones. As chronic inflammation continues, dysregulations in stress hormones lead to further metabolic derangements and downstream organ dysfunctions. This is the inflammation and disease connection, as it leads to autoimmune diseases, reduced ability to fight off illnesses, and metabolic diseases, such as high blood pressure, cardiovascular disease, elevated cholesterol levels, fatty liver disease, prediabetes and diabetes, and obesity.

How Can Lab Testing Help Determine Chronic Inflammation in The Body?

General markers of inflammation include C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

Additionally, chronic inflammation can have profound effects on many stress hormones, including cortisol and other glucocorticoids, insulin, thyroid hormones, reproductive hormones (estrogen, testosterone, and progesterone), dehydroepiandrosterone (DHEA), vitamin D 25-OH, norepinephrine, interleukin-6, tumor necrosis factor-alpha (TNF-ɑ), and others.

The Role of Diet in Inflammation

Inflammation can have a variety of different triggers, one of which is what we eat. The standard American diet is by nature proinflammatory. It includes up to 40% of calories from refined carbohydrates and added sugars. By adding in processed meats and trans fats, this number doubles in many people. Processed foods are the main cause of a proinflammatory diet. The higher the amount of processed foods in the diet, the higher the risk of an inflammatory-related illness. The human body is not meant to metabolize the foreign ingredients that are processed foods. As a result, cellular damage, metabolic dysregulations, and chronic inflammation result.

On the other hand, some of our best food choices are anti-inflammatory, foods that reduce current and future inflammation. Fruits and vegetables contain polyphenols, which are potent antioxidants, preventing cell damage and fighting many other downstream effects of inflammation. Omega-3 fatty acids (like those found in fatty fish, chia seeds, and avocados) are both anti-inflammatory and immune-modulating, meaning they fight inflammation and boost your immune health at the same time. Furthermore, many herbs, spices, and food forms help reduce inflammation too, like turmeric, garlic, fermented foods, and others. By focusing on anti-inflammatory foods, you can manage, reduce, and even prevent chronic inflammation.

Common Pro-Inflammatory Foods

Many foods are proinflammatory, meaning their breakdown and metabolism induce an inflammatory response within the body. High amounts and long-term consumption of proinflammatory foods lead to chronic inflammation and negative downstream effects. Common pro-inflammatory foods are refined sugars, high-fructose corn syrup, artificial sweeteners, refined carbohydrates, trans fats, some saturated fats, processed meats, and excessive alcohol.

Refined sugars are highly pro-inflammatory. High-fructose corn syrup is a common sweetener and texture agent in shelf-stable processed foods and beverages. It is particularly dangerous for overall health, as studies show it causes inflammation, insulin resistance, and obesity. Refined sugars (including high-fructose corn syrup) trigger the release of proinflammatory cytokines, thus promoting oxidative stress and chronic inflammation. When refined sugars are consumed in large amounts, it can lead to dysregulated blood glucose levels, prediabetes, and type 2 diabetes mellitus. Eating excessive refined sugars also causes dysbiosis, which is a disruption of the balance of gut microbiota. This leads to further inflammation, poor digestion, lowered immunity, altered metabolism, and more.

Artificial sweeteners also cause significant proinflammatory effects. These include aspartame, sucralose, saccharin, erythritol, acesulfame potassium, and xylitol. Artificial sweeteners can cause dysbiosis, which leads to inflammation, metabolic dysfunction, immune dysregulation, and digestion problems. The pro-inflammatory nature of artificial sweeteners is known to cause exaggerated inflammatory responses in some people, so tolerance levels may vary.

Trans fats are unsaturated fats that have a hydrogen atom added (called hydrogenated oils) to make them solid at room temperature for the purposes of extending the shelf-life of foods and enhancing food texture. Trans fats, which are commonly found in fried foods, baked goods, margarine, and shelf-stable processed foods, are well-known for their negative pro-inflammatory properties. Not only do trans fats increase levels of harmful low-density lipoprotein cholesterol but they also promote inflammation by upregulating the production of inflammatory cytokines and oxidative stress markers. Similarly, certain saturated fats, particularly those from processed and red meats, can also contribute to inflammation and cardiovascular disease risk. Limiting the intake of trans fats and some saturated fats, and instead opting for healthier sources of unsaturated fats like omega-3 fatty acids, can help reduce inflammation and support overall health.

Refined carbohydrates take many forms. From bread to crackers to chips to cookies, most processed foods that are found in the middle aisles of the grocery store are high in refined carbohydrates. During the heavy processing that occurs, these refined carbohydrates are not only stripped of their healthful ingredients, like dietary fiber, vitamins, and minerals, but they also have more harmful ingredients added to them, like additives, preservatives, and artificial flavorings. The resulting products are proinflammatory, inducing an inflammatory response as the body tries to break down synthetic ingredients.

Processed meats belong to another large category of highly processed foods. The act of processing meats exposes them to carcinogens in the smoking and curing process. Furthermore, nitrates and nitrites are usually added for preservation, which can form carcinogenic nitrosamines, which have been linked to multiple types of cancers–esophageal, stomach, colon, and brain cancers.

Alcohol is also known to be pro-inflammatory, and heavy alcohol use can cause organ damage, brain volume loss, immune dysregulation, and metabolic dysfunction. Alcohol is specifically linked to inflammation within the gut. This can cause bacterial translocation, endotoxin release, and cytokine excess, all perpetuating inflammation.

Why Avoid Pro-Inflammatory Foods?

There is growing recognition of the role of diet in the development and progression of chronic diseases. Proinflammatory foods are known to cause inflammation, and evidence suggests they are significant contributors to various chronic diseases. Proinflammatory foods trigger the release of proinflammatory cytokines and other immune mediators, leading to a state of chronic inflammation.

The detrimental effects of proinflammatory foods on cardiovascular health are detailed in numerous peer-reviewed publications. High intake of processed meats and sugary snacks has been associated with an increased risk of coronary heart disease, stroke, and hypertension. These foods promote endothelial dysfunction, arterial stiffness, and plaque formation, contributing to the pathogenesis of cardiovascular diseases.

The consumption of proinflammatory foods has been linked to insulin resistance, impaired glucose regulation, and ultimately, type 2 diabetes mellitus. Evidence-based studies suggest diets rich in refined grains, sugary beverages, and fried foods elevate inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) and fasting insulin levels, worsening insulin resistance and increasing pancreatic β-cell dysfunction.

Proinflammatory foods play a significant role in the development of obesity, which is itself a major risk factor for numerous chronic diseases. The excessive consumption of processed foods disrupts the hormonal regulation of appetite and energy balance, leading to increased caloric intake and adiposity. Adipose tissue itself is proinflammatory, further contributing to insulin resistance, dyslipidemia, and metabolic syndrome.

Increasing evidence suggests correlations between proinflammatory diets and certain types of cancer. A diet high in processed meats, sugary snacks, and refined carbohydrates is associated with an elevated risk of colorectal, breast, and prostate cancers. Chronic inflammation triggered by these foods promotes oncogenic processes such as DNA damage and abnormal cell proliferation.

A high intake of proinflammatory foods and the resulting chronic inflammation are each implicated in the development of neurodegenerative disorders like Alzheimer's and Parkinson's disease. Proinflammatory diets worsen neuroinflammation and neuronal damage via increased oxidative stress and the formation of free radicals.

Proinflammatory foods have a fundamental role in the development of chronic diseases, and understanding the role of diet-induced inflammation in chronic diseases is paramount. Functional medicine emphasizes the importance of dietary modifications as both a preventive and treatment strategy. Adopting an anti-inflammatory diet, characterized by whole foods, fruits, vegetables, and healthy fats, is the first step in reducing chronic disease risk and promoting overall health and well-being.

Identifying Hidden Sources of Pro-Inflammatory Ingredients

Some pro-inflammatory foods are more obvious, like refined sugars, high fructose corn syrup, and trans fats. However, some proinflammatory ingredients may be hidden in processed foods, making them harder to spot. In general, if a food is heavily processed, it likely has many sources of proinflammatory ingredients. Some of the common proinflammatory ingredients include additives, preservatives, flavor enhancers, colors and dyes, and other food production chemicals, like glyphosate.

Monosodium glutamate (MSG) is a flavor enhancer commonly found in processed foods, some ethnic foods, and restaurant foods. MSG consumption is linked to inflammation and oxidative stress, in turn increasing the risk of inflammatory-based chronic diseases, like insulin resistance, obesity, metabolic syndrome, neurologic disorders, immune diseases, and food sensitivities.

Many preservatives are commonly used in processed meats to prevent contamination and enhance color and texture. However, nitrates and nitrates are pro-inflammatory and carcinogenic. A high intake of sodium nitrate/nitrite is associated with a higher risk of cardiovascular diseases and certain cancers.

Glyphosate is a widely used herbicide in conventional agriculture, commonly found as a residue on many crops like soy, corn, oats, and wheat. Glyphosate is strongly linked to disruptions in gut microbiota, increased intestinal permeability, and decreased immune function. This dysbiosis leads to chronic inflammation and other associated organ dysfunction.

Synthetic food dyes are added to many processed foods, beverages, and snacks to enhance both their color and their appeal. However, these dyes, most commonly Red 40 and Yellow 5, can cause allergic reactions and inflammation. They are also known to contribute to hyperactivity in children and bladder disorders. In children with attention deficit hyperactivity disorder, these synthetic dyes are known to exacerbate symptoms.

Alternatives to Pro-Inflammatory Foods

Fatty fish is one of the best sources of omega-3 fatty acids, an incredible source of the benefits that omega-3 fatty acids provide. By reducing inflammation, the omega-3 fatty acids found in fatty fish like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) lower your risk of metabolic syndrome, heart disease, diabetes, and other chronic illnesses. Other concentrated sources of omega-3 fatty acids outside of fatty fish include flaxseeds, chia seeds, and walnuts.

Extra virgin olive oil contains healthy monounsaturated, anti-inflammatory fats, including omega-3 fatty acids. Olive oil is pressed directly from the olives and includes no other ingredients to make it overly processed. Extra virgin olive oil is even less processed. It is mechanically extracted from olives without using high heat or solvents, which helps preserve its antioxidants and polyphenols.

The benefits of regularly eating extra virgin olive oil include reduced risk of heart disease, certain types of cancers, obesity, metabolic syndrome, and many others. Using extra virgin olive oil as part of an overall anti-inflammatory eating lifestyle provides beneficial fats for healthy cell structure and function and important antioxidants and polyphenols to reduce inflammation. 

Leafy green vegetables, like kale, spinach, Swiss chard, bok choy, and lettuces, are anti-inflammatory vegetables. They are full of antioxidants and phytochemicals that are particularly adept at fighting inflammation. They also contain vitamin K, which helps support circulation, vitamin C, which helps fight infection, selenium, which also boosts immunity, and beta-carotene, which helps eliminate free radicals and decreases the risk of cancer. 

Cruciferous vegetables, like broccoli, cauliflower, and Brussels sprouts, contain isothiocyanates. Derived from the breakdown of sulfur-containing compounds, isothiocyanates are functional foods that are linked to significantly lower rates of certain types of cancers in those who eat higher amounts.

Because whole grains are high in phytochemicals, antioxidants, and fiber, many studies support their anti-inflammatory properties, thus reducing the risk of chronic diseases.

Dark chocolate is highly anti-inflammatory because of the many antioxidants from the flavanols in cacao. Flavanols are high-protective for the endothelial cells within your arteries. This helps protect against endothelial damage, which is the start of plaque formation and coronary artery disease. If the endothelial lining of the arteries remains intact, plaque can’t stick to the arterial walls and instead continues to flow through the blood. Dark cacao can also help to reduce blood pressure. Choose dark cocoa without added heavy cream, refined sugars, and other additives and preservatives.

When looking for alternatives to proinflammatory foods, choose organic whenever possible, especially for animal products and the dirtiest types of produce. Include at least one serving of fatty fish per week, and prepare your meals with anti-inflammatory unsaturated fats, like extra virgin olive oil and avocado oil. Utilize herbs and spices with anti-inflammatory impacts like turmeric, ginger, garlic, and cinnamon to add flavor and nutrition.

Incorporating Anti-Inflammatory Foods into Your Diet

The foundations of antiinflammatory eating truly are basic. Opt for whole, real foods, as close to their natural states as possible. The challenge is in both our modern lifestyles and our modern food supply, where schedules are busier than ever, and processed foods are the rule and not the exception! This makes incorporating an anti-inflammatory eating lifestyle much more complex. 

Aim for 75% of your plate to be plant-based foods at most meals. Choose organic as much as possible, especially for animal products and the dirtiest types of produce. Include at least one serving of fatty fish per week, and prepare your meals with anti-inflammatory unsaturated fats, like extra virgin olive oil and avocado oil. Utilize herbs and spices with anti-inflammatory impacts like turmeric, ginger, garlic, and cinnamon to add flavor and nutrition.

Meal planning is a huge factor in success with anti-inflammatory eating. Knowing what you will eat for each meal enables you to make good food choices and helps you avoid the drive-thru, takeout lines, or delivery, which often offer less anti-inflammatory food options. Variety is important in anti-inflammatory eating, as it provides a wide array of health benefits from different foods. Choose fruits and vegetables of different colors to get different vitamins and minerals. 

Base your diet on fruits, vegetables, lean proteins, healthy fats, and whole grains. 

Other factors for success are adequate water intake and regular exercise. Being properly hydrated is crucial for a healthy lifestyle. Drinking enough water helps optimize your metabolism, control your appetite, regulate your circulation, and improve your mental clarity. 

Drink at least 64 ounces (8 cups) of water per day. Regular exercise is another crucial component of maintaining optimal metabolic health. A combination of strength training and cardiovascular exercise provides optimal fitness benefits. Exercise is a great way to help maintain a healthy weight, promote lean body mass, and prevent bone loss. 

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Pro-Inflammatory Foods: Key Takeaways

Proinflammatory foods are known to both cause and perpetuate chronic inflammation. By minimizing foods like refined sugars, artificial sweeteners, trans fats, refined carbohydrates, processed meats, and alcohol, you can avoid some of the main causes of chronic inflammation. The functional medicine approach to root-cause medicine hinges on eliminating pro-inflammatory foods and focusing on incorporating anti-inflammatory foods to promote overall health and longevity.