A team of Chinese researchers conducted a meta-analysis to evaluate whether the newly developed Dietary Inflammatory Index predicted cancer risk.
When you get banged or cut, the sore spot is often red and tender to the touch. The redness, swelling, and tenderness that follow an injury are the result of inflammation. This temporary inflammation occurs when chemicals are released to alert the immune system and trigger the body’s natural healing process. However, ongoing inflammation can cause serious damage to blood vessels, nerves, and organs.
Many lifestyle factors have been shown to play a part in chronic cellular inflammation. Smoking, chronic stress, and excessive alcohol consumption are just a few. However, obesity is one factor that has been shown to have a strong, positive correlation with chronic inflammation. As body mass index increases, so does systemic inflammation. Luckily, diet and exercise can help individuals to lose weight and reduce damage from inflammation.
This leaves healthcare professionals and their patients with two questions: Which foods are best for limiting inflammation? Which are worst? Dr. Susan Steck and her research team from Columbia, South Carolina in the United S recently developed a scale to assess the inflammatory potential of an individual’s overall diet.
The Dietary Inflammatory Index (DII)
The DII score was calculated for each of three diet plans based on amounts of each of the 45 dietary components comprising the DII. A positive DII score (1.0) represents a more pro-inflammatory diet, while a negative DII score (-1.0) represents a more anti-inflammatory diet.
Research linking inflammatory biomarkers and diet were used to assign foods a positive or negative value. For example, refined grains, processed foods, foods high in sugar and fat which have been shown to be associated with higher inflammation biomarker levels are positive on the DII scale while whole grains, green leafy vegetables, beans, fish, and fresh fruits which have been associated with lower inflammation biomarker levels are negative on the DII scale.
The DII and Cancer Risk
The DII has been validated but, to date, few studies have assessed its sensitivity. In a recent review of the literature published in the American Journal of Clinical Nutrition, researchers from China investigated the association between DII and cancer incidence.
A thorough search of PubMed, Embase, Web of Science, and the Cochrane library resulted in 44 high-quality studies with a total of over one million participants. Further analysis by the research team showed that the highest category DII score was significantly associated with higher risk of human cancers, compared with the lowest category DII. Moreover, they report that each increase in DII score was associated with an 8.3% increase in cancer risk.
This study indicates that the DII represents a useful tool for assessing diet quality. Using the DII can help both healthcare professionals and individuals to evaluate their current diets and to set dietary goals, which would help to decrease levels of inflammation and minimize the damage it can cause.
Written by Debra A. Kellen, PhD
(1) Li, D., Hao, X., Li, J., Wu, Z., Chen, S., Lin, J., … & Dai, H. (2018). Dose-response relation between dietary inflammatory index and human cancer risk: evidence from 44 epidemiologic studies involving 1,082,092 participants. The American Journal of Clinical Nutrition, 107(3), 371-388. doi: 10.1093/ajcn/nqx064
(2) Steck, S. E., Shivappa, N., Tabung, F. K., Harmon, B. E., Wirth, M. D., Hurley, T. G., & Hebert, J. R. (2014). The dietary inflammatory index: a new tool for assessing diet quality based on inflammatory potential. Digest, 49, 1-9.