Identifying a food as “anti-inflammatory” comes close to giving it “super food” status, since avoiding or reducing chronic low-grade inflammation offers potential to reduce risk of cancer, heart disease and more. The scientific-sounding explanations of what makes a food or diet anti-inflammatory, however, aren’t always as solid as they seem.
You may have heard of certain foods that supposedly promote or fight off inflammation. Yet a Columbia University study of more than 2200 adults found that a scoring system, introduced in a book for the general public, that was designed to rate the inflammatory impact of foods turned out to be unrelated to blood values of CRP (C-reactive protein), a marker of inflammation that can be measured in the blood.
Research does suggest that what we eat may influence inflammation. Plant foods (such as vegetables, fruits, whole grains, beans, nuts and seeds) that are not highly processed contain antioxidants that protect cells against damaging molecules called “free radicals” and inhibit inflammation. Omega-3 fats, like those found in salmon and other cold-water fish, promote production of anti-inflammatory hormone-like substances. Scientists used to think that other polyunsaturated fats, the omega-6 fat found in many vegetable oils, increased substances that stimulated inflammation. Now it’s been discovered that they also lead to anti-inflammatory proteins called lipoxins. So the impact on inflammation from the omega-3 to omega-6 ratio, which some once emphasized, is not clear.
Foods are a mixture of a whole variety of different nutrients and compounds. While we know in laboratory studies that a certain phytochemical, nutrient or type of fat fights inflammation, we may not be as far ahead as it may seem in being able to predict how the combination of compounds in any given food come together to promote or decrease inflammation.
Diet patterns – which reflect the overall balance of food choices – do show links to increased or decreased inflammation, however. We’ll come back to that in a minute.
Inflammation is the body’s normal protective response to an injury or infection. “Acute inflammation” occurs within hours of getting a splinter in your finger or developing a tooth abscess, for example. In a masterfully orchestrated defense, increased blood flow to the area brings white blood cells and body proteins that cause redness and swelling as they attack the intruder. Chronic, low-grade inflammation, however, seems to damage body tissues in ways that accelerate development of chronic health problems.
Scientists now consider atherosclerosis (“hardening of the arteries”) an inflammatory process, and inflammatory cells have been found in the fatty plaque that builds up in blood vessels. Inflammation may also promote cancer development by damaging our genes, increasing cell turnover and increasing development of blood vessels that allow cancer cells to grow and spread.
A study published in the Journal of the American Medical Association included 500 adults with diabetes who all showed elevated markers of inflammation. Medical treatment reduced blood sugars to near normal levels, but did not reduce markers of inflammation. Researchers say that reducing high blood sugar is crucial to limit damage to the small blood vessels in the kidney and eye that cause the serious damage there linked to diabetes, but this alone does not appear to be enough to stop the heart disease-diabetes link.
Fighting Off Chronic Inflammation
Research shows a variety of lifestyle changes that can reduce or prevent this chronic, low-grade inflammation.
*Anti-Inflammatory Lifestyle Habits
Studies show lower levels of markers of inflammation in those who don’t smoke and those who exercise regularly. In one study, several markers of inflammation dropped within weeks among women in a smoking cessation program. Good dental care that prevents the gum inflammation known as gingivitis may even help to reduce overall body inflammation. Moderate exercise like walking seems to directly reduce markers of inflammation, even after adjusting for its impact on weight.
*Anti-Inflammatory Eating Patterns
Inflammation is linked to an eating pattern known as the “Western diet”, which refers to larger amounts of red and processed meats, sweets, desserts, French fries, and refined grains. In contrast, a plant-based diet with plenty of vegetables, fruits and beans seems to decrease inflammation. For example, studies show lower levels of the inflammation marker called CRP with a “Mediterranean style” diet. This includes plenty of vegetables, fruits, whole grains and beans, and olive oil as the primary fat. A Mediterranean-style diet also tends to include fish several times a week, making it higher than the typical American diet in omega-3 fat. In patients with type 2 diabetes, just eight weeks following the DASH diet, which is rich in fruits, vegetables, whole grains, and low-fat dairy, reduced CRP levels 26.9 percent.
Scientists emphasize that research supports the impact of dietary patterns supplying a variety of interacting antioxidant and anti-inflammatory phytochemicals (like carotenoids and flavonoids) along with vitamins like vitamin C rather than efforts relying on any single compound for protection.
*Weight Control’s Anti-Inflammatory Power
Excess body fat, particularly in the abdomen, may be the single largest influence on markers of inflammation. As people become overweight, fat cells enlarge and increase production of certain proteins (such as interleukin-6 and tumor necrosis factor) that stimulate inflammation throughout the body. Fortunately, even a modest seven to ten percent weight loss as part of a healthy lifestyle is enough to reduce markers of inflammation.
This means that simply including plenty of “anti-inflammatory foods” may not protect us as much as we think if our overall eating habits also include plenty of high-calorie foods and excessive portions that lead us to an unhealthy weight.
Bottom line: Chronic, low-grade inflammation is a significant health risk. Rather than focusing on individual foods or the nutrients in them for protection, however, our best strategy is to work at creating that all-round healthy lifestyle that includes tobacco avoidance, regular physical activity and basic healthy eating habits. Healthy foods choices mean a focus on unrefined plant foods (vegetables, fruits, whole grains, beans and nuts), regular fish consumption, healthy fats, and portion control to help us reach and maintain a healthy weight. This seems like a great example of how the whole can be greater than the sum of its parts.
For more information, the American Institute for Cancer Research (AICR) offers this brochure, The Facts on Preventing Cancer: Inflammation
Alley DE, et al. Socioeconomic status and C-reactive protein levels in the US population: NHANES IV. Brain Behav Immun. 2006 Sep;20(5):498-504.
Azadbakht L, et al. The Dietary Approaches to Stop Hypertension eating plan affects C-reactive protein, coagulation abnormalities, and hepatic function tests among type 2 diabetic patients. J Nutr. 2011 Jun;141(6):1083-8.
Calder PC, et al. Inflammatory disease processes and interactions with nutrition. Brit J Nutr. 2009. 101 Suppl 1:S1-45.
de Ferranti, S and Mozaffarian D. The perfect storm: obesity, adipocyte dysfunction, and metabolic consequences. Clin Chem. 2008 Jun;54(6):945-55.
Galli, C and Calder, PC. Effects of fat and fatty acid intake on inflammatory and immune responses: a critical review. Ann Nutr Metab. 2009. 55(1-3):123-39.
Gu, Y et al. Dietary inflammation factor rating system and risk of Alzheimer disease in elders. Alzheimer Dis Assoc Disord. 2011. 25(2):149-54.
Haffner, S et al. Intensive Lifestyle Intervention or Metformin on Inflammation and Coagulation in Participants With Impaired Glucose Tolerance. Diabetes, May 2005. 54(5): 1566-1572. (The Diabetes Prevention Program Research Group)
Hamer, M and Steptoe, A. Walking, vigorous physical activity, and markers of hemostasis and inflammation in healthy men and women. Scandinavian Journal of Medicine & Science in Sports, 2008.
18 (6): 736 – 741.
Lopez-Garcia E, et al. Major dietary patterns are related to plasma concentrations of markers of inflammation and endothelial dysfunction. Am J Clin Nutr. 2004 Oct;80(4):1029-35.
Nettleton, JA et al. Dietary patterns are associated with biochemical markers of inflammation and endothelial activation in the Multi-Ethnic Study of Atherosclerosis (MESA). Amer Journal Clinical Nutrition, 2006. 83(6): 1369-137.
Plat, J et al. Weight Loss, but Not Fish Oil Consumption, Improves Fasting and Postprandial Serum Lipids, Markers of Endothelial Function, and Inflammatory Signatures in Moderately Obese Men. J. Nutr. 2007 137: 2635-2640.
Pradhan, AD et al. Effects of Initiating Insulin and Metformin on Glycemic Control and Inflammatory Biomarkers Among Patients With Type 2 Diabetes. The LANCET Randomized Trial. JAMA. 9/16/2009. 302(11):1186-1194.
Reichert V, et al. A pilot study to examine the effects of smoking cessation on serum markers of inflammation in women at risk for cardiovascular disease. Chest. 7/2009. 136(1):212-9
Watzl B. Anti-inflammatory effects of plant-based foods and of their constituents. Int J Vitam Nutr Res. 2008 Dec;78(6):293-8.