What Is It, Foods to Consume and Avoid, and More
Author: Lily Guo
Editors: Alyssa Haag, Ian Mannarino, MD, MBA, Kelsey LaFayette, DNP, RN, FNP-C
Illustrator: Jessica Reynolds, MS
Copyeditor: David G. Walker
What is inflammation?
Inflammation refers to the complex and crucial response that the human body employs against microbial infections, tissue injury, and trauma. It involves the recruitment of innate immune cells that can phagocytose invading organisms and produce inflammatory cytokines (i.e., signaling proteins) to further support the immune response. In most cases, inflammation is self-controlled and resolves once the infection is cleared or the tissue and wounds are repaired.
In the case of chronic inflammation, however, a dysregulated response occurs, resulting in the disruption of homeostatic physiological processes. Specifically, the body’s innate immune system is controlled by the gene transcription factor nuclear factor kappaB (NF-κB). NF-κB acts as the master switch that turns on inflammatory gene products, such as cyclooxygenase-2 (COX-2), tumor necrosis factor-α, interleukin (IL)-1, IL-6 and others. If NF-κB is constantly activated due to the foods consumed, it continues to amplify inflammatory signals and contribute to the chronicity of inflammation.Inflammation plays a key role in diseases such as inflammatory bowel disease (IBD), diabetes mellitus, asthma, cardiovascular diseases, depression, and cancer. Diet can influence different stages of inflammation and can have an important impact on several inflammatory diseases.
What is an anti-inflammatory diet?
An anti-inflammatory diet refers to a dietary strategy that reduces inflammation by using the nutrients in food to alter gene expression. It does not refer to a specific diet regimen but rather an overall style of eating that strongly emphasizes reducing levels of processed foods and saturated fats while increasing amounts of whole foods and monounsaturated fats. A diet high in anti-inflammatory foods has also been shown to lead to significant reductions in body weight and visceral adipose tissue and is effective in managing obesity.While the anti-inflammatory diet is not a strict and regimented way of eating, there are eating plans that closely follow the tenets of anti-inflammatory eating including the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet. The Mediterranean diet is based on the traditional cuisines of the countries bordering the Mediterranean Sea, including Greece and Italy. It prioritizes plant based foods, such as whole grains, vegetables, legumes, fruits, nuts, seeds, herbs, and spices. Olive oil is the main source of added fat and seafood, dairy, and poultry are included in moderation. The DASH diet is rich in vegetables, fruits, and whole grains. It typically includes fat-free or low-fat dairy products, fish, poultry, beans, and nuts and limits foods that are high in saturated fat, including fatty meats and full-fat dairy products.
How does an anti-inflammatory diet minimize inflammation?
The anti-inflammatory diet can minimize inflammation by reducing the activation of NF-κB, thereby inhibiting its inflammatory byproducts. A number of dietary factors can activate NF-κB, including oxidative stress from excessive calorie intake and saturated fatty acids. Certain compounds in foods, omega-3 fatty acids for example, which are found abundantly in fish and nuts, may contribute to the resolution of this inflammatory response by producing certain hormones known as resolvins, proteins, and maresins. These hormones shorten neutrophil lifespan and promote macrophage phagocytosis of apoptotic cells, thereby resolving inflammation.
Consumption of whole grains has been associated with lower inflammatory markers, such as C-reactive protein (CRP), whereas lower whole grain intake has been shown to increase IL-6 (another inflammatory marker) concentrations. In addition to whole grains, a high-fiber diet potentially lowers inflammation by modifying both the pH and the permeability of the gut.Additionally, polyphenols, which are the chemicals that give fruits and vegetables their color, have been shown to protect the body's tissues against oxidative stress. At high levels, they have anti-inflammatory effects by activating the gene transcription factor PPAR-, a molecule that inhibits the activation of NF-κB. A specific type of polyphenol, known as flavonoids, found in fruits, vegetables, and grains can inhibit the enzymes that control inflammation mediators. They have the additional ability to attenuate tissue damage and fibrosis and act as potent antioxidants to scavenge damaging free radicals to decrease their formation. In addition to flavonoids, other bioactive constituents of fruit and vegetables, such as carotenoids, vitamins, minerals, and fiber, can act individually and in a synergistic way to provide nutritional value and health benefits. Increased intake of choline, an essential nutrient found in high quantities in eggs, broccoli, and cauliflower, has also been associated with lower peripheral inflammatory levels, such as CRP, IL-6, and tumor necrosis factor alpha (TNF-α). Lastly, another type of polyphenol, epigallocatechin gallate (EGCG), is the active component of green tea and has anti-inflammatory, anti-carcinogenic, and antioxidant properties.
What foods are best on an anti-inflammatory diet?
The best foods to eat while on an anti-inflammatory diet include foods high in fiber, which includes beans, lentils, oatmeal, fruits, vegetables, brown and wild rice, sweet potato, barley, and quinoa. It is recommended to consume at least 25 grams of fiber per day. Polyphenol-rich vegetables and fruits include berries (e.g., strawberries, blueberries), apples, grapes, pineapple, cherries, and oranges. Examples of appropriate vegetables include green leafy plants (e.g., spinach, kale, collards), broccoli, tomato, carrots, beets, amongst several others. Nine servings of fruits and vegetables a day is typically advised. Fish, such as salmon, anchovies, herring, mackerel, sardines, bluefin tuna, are high in omega-3 fatty acid content. Additionally, milled flaxseeds, chia seeds, almonds, walnuts, pecans, virgin and extra virgin olive oil seeds and oils can be high in anti-inflammatory omega-3 fatty acid. Foods with high flavonoid content, including legumes, green tea, and dark chocolate with greater than 70% cacao content, can help reduce inflammation. Red wine has also been shown to have high flavonoid content; however, like chocolate, it should be consumed in moderation. Ultimately, it can be a good idea to speak with a healthcare professional, such as a registered dietician, before making changes to one’s diet.
What foods should be avoided on an anti-inflammatory diet?
Foods that should be avoided on an anti-inflammatory diet include red meats, processed meats, saturated or trans-fat, highly processed foods, refined flour, refined sugar, and alcohol as these foods have all been associated with pro-inflammatory processes.Examples of red meats and processed meats include burgers, steaks, bacon, ham, corned beef, hot dogs, and sausage. Saturated and trans fat are found in high quantities in margarine, shortening, and lard. Cream, butter, ice cream, and cheese also contain high amounts of saturated fat. Highly processed foods include sugary cereals, condiments, frozen dinners, chips, granola bars, microwave popcorn, french fries, and fried foods. Refined flour is used to make white bread, pastries, pizza, crackers, pasta, pretzels, flour tortillas, and white bagels. Lastly, refined sugar is found in soda, other sugar-sweetened beverages, cakes, cookies, and candies.
What are the most important facts to know about an anti-inflammatory diet?
An anti-inflammatory diet refers to a way of eating that reduces inflammation; protects against chronic diseases, such as diabetes, asthma, cardiovascular diseases, depression, and cancer; and helps with weight loss and obesity. An individual’s diet can be used to change gene transcription by reducing the activation of NF-κB. Polyphenols and flavonoids found in colorful fruits and vegetables have been shown to activate the gene transcription factor PPAR-, which inhibits the activation of NF-κB and reduces oxidative stress. Examples of anti-inflammatory foods include leafy greens, fruits and berries, whole grains, fatty fish, seeds, and nuts. On the other hand, processed, refined, and sugary foods can increase the levels of inflammation and the risk for chronic diseases. By eating more whole foods and less processed food, one can reduce levels of inflammation and prevent chronic disease.
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Resources for research and reference
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