Diet Review: Anti-Inflammatory Diet | The Nutrition Source | Harvard T.H. Chan School of Public Health – HSPH News
Finding yourself confused by the seemingly endless promotion of weight-loss strategies and diet plans? In this series, we take a look at some popular diets—and review the research behind them.
An anti-inflammatory diet is promoted as a remedy to battle inflammation in the body. A common belief is that “inflammation” is always bad. Although it produces unpleasant side effects, inflammation is actually a healthy response by our immune system. When a foreign invader enters the body such as bacteria, viruses, or allergens, or an injury occurs, our immune cells act quickly. We may sneeze or cough to rid the body of an offending agent. We may feel pain and swelling at the site of a cut or injury to signal us to be gentle with this delicate area. Blood flows in rapidly, which may produce warmth or redness. These are signs that our immune system is repairing damaged tissue or fighting invaders. As healing takes place, inflammation gradually subsides.
Inflammation becomes harmful when it is prolonged and begins to damage healthy cells, creating a pro-inflammatory state. Another problem is due to genetic deviants causing the body’s immune system to constantly attack cells. This sometimes occurs with autoimmune disorders like lupus, fibromyalgia, multiple sclerosis, rheumatoid arthritis, type 1 diabetes, and Crohn’s disease. Sometimes an unhealthy lifestyle from lack of exercise, high stress, and calorie-rich diets can trigger chronic low levels of inflammation throughout the entire body, termed metaflammation. [1,2] This type of low-grade inflammation does not usually produce noticeable symptoms, but over time metaflammation can pave the pathway for chronic conditions like cardiovascular disease, non-alcoholic fatty liver disease, type 2 diabetes, Alzheimer’s disease, and certain cancers (e.g., breast, colon).
Anti-inflammatory diets may be promoted for these inflammatory conditions. They include several foods that are believed to interfere with the inflammatory process, though research on its exact mechanism is not conclusive. There is no single anti-inflammatory diet plan. Generally it emphasizes eating a wide variety of fruits and vegetables, unsaturated fats, minimally refined whole grains, tea, coffee, herbs, spices, and oily fish. The Mediterranean diet and DASH diet are popular dietary plans that already showcase many anti-inflammatory foods.
An anti-inflammatory diet plan not only highlights specific foods and food groups but limits other foods that may contribute to metaflammation such as fatty cuts of red meat, refined sugary foods and beverages, and excess alcohol.
An anti-inflammatory diet does not follow strict rules about calories or portion sizes. It suggests a variety of anti-inflammatory foods to eat daily, rather than focusing on eating one or two specific foods or nutrients. This ensures a greater variety of protective food components, some of which may work synergistically to boost immunity. These foods provide plant chemicals (phytochemicals), antioxidants, and fiber that prevent cellular stresses, inhibit inflammatory signals caused by the immune system, promote healthy gut microbiota, and slow down digestion to prevent surges in blood glucose.  They may also favorably affect the composition of fat cells to further reduce inflammation.
Other factors aside from diet may help to control inflammation, such as exercising regularly, controlling stress, and getting enough sleep.
Most available research focuses on foods and dietary patterns that are associated with metaflammation, which in turn helps to determine the components of an anti-inflammatory diet. Metaflammation is especially associated with Western-type dietary patterns high in processed meats, saturated fat, refined sugars, salt, and white flour while being low in fiber, nutrients, and phytochemicals. [1,4] These diets also tend to be calorie-dense with a high glycemic load, potentially leading to blood sugar surges, insulin resistance, and excess weight gain. Studies have shown that Western diets are associated with increased blood markers of inflammation, though the connection may be due to a string of events rather than one direct action.  For example, exposure to air pollution and chronic mental stress can lead to an excess of free radicals produced in the body, which then oxidize and damage other molecules. Atherosclerosis is one condition in which these free radicals oxidize LDL cholesterol particles. The actions of both oxidized LDL cholesterol and several types of immune cells form lesions and plaque in the heart arteries that can lead to ischemic heart disease (a type of heart disease caused by narrowed or partially blocked arteries).  A long-term diet that is high in saturated fat and cholesterol may raise LDL levels, increasing the risk of free radical action that may promote this immune response, which partially contributes to a chronic low-level proinflammatory state.
A major cause of low-level inflammation is the build-up of fatty acids in fat tissue (and other tissues) promoted by a high-fat or high-sugar diet. This may cause fat tissue to send signals to immune cells that produce inflammation in various areas, including organs like the pancreas. An inflamed pancreas can then lead to insulin resistance and diabetes. Therefore, the combination of carrying extra body fat (obesity) and eating a diet high in saturated fat and refined sugars increases the risk of cell damage because of increased immune cell activity.
An anti-inflammatory diet contains foods rich in nutrients, fiber, and phytochemicals and limits foods found in a typical Western diet to help reduce oxidative stress and inflammation. There is also emerging research studying the effects of high-fiber plant-rich diets that support a greater diversity of beneficial gut microbes, which may prevent a condition called metabolic endotoxemia. This is a low-grade inflammation that occurs because of an increase in the number of endotoxins, which are believed to cause the inflammation associated with metabolic diseases like cardiovascular disease and type 2 diabetes. [6,7]
An anti-inflammatory diet is a healthful eating plan that may help to reduce chronic low levels of inflammation that otherwise might increase the risk of various chronic diseases. Although research is limited, it may also help to lower inflammatory markers in individuals with autoimmune-type inflammation such as with rheumatoid arthritis. Popular dietary patterns that are anti-inflammatory include the Mediterranean diet, DASH diet, and vegetarian diets. People may seek the guidance of a registered dietitian familiar with any of these dietary patterns to assist with meal planning and appropriate portion sizes. Along with the diet, it is important to incorporate other healthy lifestyle factors that positively affect the body’s immune response, such as practicing stress reduction, exercising regularly, and getting adequate sleep.
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Use healthy oils (like olive and canola oil) for cooking, on salad, and at the table. Limit butter. Avoid trans fat.
Drink water, tea, or coffee (with little or no sugar). Limit milk/dairy (1-2 servings/day) and juice (1 small glass/day). Avoid sugary drinks.
The more veggies — and the greater the variety — the better. Potatoes and French fries don’t count.
Eat plenty of fruits of all colors
Choose fish, poultry, beans, and nuts; limit red meat and cheese; avoid bacon, cold cuts, and other processed meats.
Eat a variety of whole grains (like whole-wheat bread, whole-grain pasta, and brown rice). Limit refined grains (like white rice and white bread).
Incorporate physical activity into your daily routine.
Create healthy, balanced meals using this visual guide as a blueprint.
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