Inflammation is a natural biological process that helps the body heal and defend itself from harm. However, when this protective mechanism becomes chronic, it can contribute to various health issues over time. Dietary choices significantly influence the body’s inflammatory state, either promoting or reducing it. The Dietary Inflammatory Index (DII) is a scientific tool developed to measure the inflammatory potential of an individual’s diet, offering insights into how food choices may impact overall health.
Understanding the Dietary Inflammatory Index
The DII is a comprehensive research tool developed by the University of South Carolina to quantify the inflammatory potential of an individual’s diet. Its creation involved a systematic review of over 1,900 peer-reviewed articles published through December 2010, examining the effects of various dietary components on six inflammatory biomarkers, including C-reactive protein (CRP), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), interleukin-4 (IL-4), and interleukin-10 (IL-10). This extensive literature review forms the scientific basis of the DII.
The DII is designed to capture the overall inflammatory effect of a dietary pattern rather than focusing on individual foods in isolation. It provides a numerical score that reflects how a person’s diet might influence systemic inflammation. The goal in creating the original DII was to provide a tool that could categorize individuals’ diets on a continuum from maximally anti-inflammatory to maximally pro-inflammatory.
How the Dietary Inflammatory Index is Calculated
The methodology behind the DII score involves assessing an individual’s intake of up to 45 different food parameters, which include various nutrients, food components, and phytochemicals. Each of these parameters is evaluated based on its known pro-inflammatory or anti-inflammatory effects, derived from scientific evidence.
To calculate a DII score, an individual’s intake of each dietary parameter is first standardized against a global database, providing a reference point for typical consumption levels. This standardized intake is then multiplied by an inflammatory effect score assigned to that specific food parameter, with positive scores indicating a pro-inflammatory effect and negative scores indicating an anti-inflammatory effect. A score of zero indicates a neutral effect. All these individual scores are then summed to yield an overall DII score for an individual’s diet. A higher, more positive DII score suggests a diet with a greater pro-inflammatory potential, while a lower, more negative score indicates a diet that is more anti-inflammatory. For example, the maximally pro-inflammatory diet has a DII score of +7.98, while the maximally anti-inflammatory diet has a score of -8.87.
Foods and Their Inflammatory Potential
DII research categorizes certain foods and dietary components as generally pro-inflammatory. These often include:
- Refined grains, such as white bread and pasta
- Processed meats like bacon and sausages
- Sugary drinks
- Fried foods
- Foods high in saturated fat and trans fats
- Excessive omega-6 fatty acids, without a balanced intake of omega-3s
Conversely, a wide array of foods are recognized for their anti-inflammatory potential, contributing to lower DII scores. These include:
- Fruits
- Vegetables
- Whole grains, which are rich in antioxidants and fiber
- Lean proteins
- Nuts and seeds
- Healthy fats, particularly omega-3 fatty acids found in fatty fish like salmon, mackerel, and sardines
- Spices like turmeric, ginger, and garlic
- Green tea
Dietary Inflammatory Index and Health Outcomes
Scientific studies have consistently linked DII scores to various health outcomes, highlighting the impact of dietary patterns on chronic disease risk. Higher, more pro-inflammatory DII scores have been associated with an increased risk of chronic diseases, including cardiovascular disease, where pro-inflammatory diets can contribute to plaque formation in arteries.
Associations have also been observed with certain cancers, such as colorectal, pancreatic, and oral cancers, type 2 diabetes, metabolic syndrome, and neurodegenerative conditions. The DII serves as a valuable epidemiological tool, allowing researchers to study the long-term impact of dietary patterns on disease risk across diverse populations.
Applying Dietary Inflammatory Index Principles to Your Diet
Adopting an eating pattern aligned with DII principles involves focusing on increasing the intake of foods known for their anti-inflammatory properties. This means prioritizing a diet rich in fruits, vegetables, and whole grains, which supply beneficial antioxidants and fiber. Incorporating lean proteins, nuts, seeds, and healthy fats, especially those rich in omega-3 fatty acids, can further support an anti-inflammatory dietary approach.
Simultaneously, reducing the consumption of processed foods, refined sugars, and unhealthy fats can help lower the overall inflammatory potential of your diet. Emphasizing balanced and varied eating rather than strict adherence to individual food rules promotes sustainable dietary changes that align with DII principles for better health.