The dietary inflammation index (DII) is a score based on a range of foods known to be associated with inflammation. A study on patients with several oesophageal diseases found that they had higher DII scores than healthy control subjects.
The dietary inflammation index (DII) is a scoring system which was developed to assess the inflammatory potential of a person’s diet. It is based on a range of foods known to be associated with inflammation. In general, an inflammatory diet is one which is high in foods rich in saturated fatty acids and carbohydrates and low in foods rich in fibre, polyunsaturated fatty acids, flavonoids and other antioxidant dietary components.
The validity of the DII has been checked by several studies that link high DII scores to elevated levels of various inflammatory markers. In other studies, increased DII scores have been associated with increased risk of colorectoral, pancreatic and prostate cancer and types of liver and oesophageal cancer.
The oesophagus, or gullet, is the muscular tube which connects the mouth to the stomach. It has several different cell layers including flat lining cells (squamous cells) and glandular cells which produce mucus lubrication.
Oesophageal cancer is the eighth most common cancer worldwide. There are two main types: squamous cell carcinoma – which originates in the lining cells and is usually found in the upper two thirds of the oesophagus; and adenocarcinoma – which originates in the glandular cells and is usually found in the lower third of the oesophagus, near to the junction with the stomach. Inflammatory conditions at the gastro-oesophageal junction are thought to predispose individuals to the development of oesophageal adenocarcinoma. In a small proportion of cases, there is a progression from reflux oesophagitis (or heartburn) to Barretts oesphagus (were changes are seen in the glandular cells) to the development of oesophageal adenocarcinoma. Researchers in Ireland wanted to test if there was a link between raised DII scores and reflux oesophagitis, Barrett’s oesophagus and oesophageal adenocarcinoma. They recently reported their findings in the British Journal of Nutrition.
In a previous Irish study looking at factors influencing Barrett’s oesophagus and oesophageal adenocarcinoma (FINBAR study), four participant groups were recruited between 2002 and 2005: reflux oesophagitis (219 patients); Barrett’s oesophagus (220 patients); oesophageal adenocarcinoma (224 patients); control subjects with no disease (256 controls). Data from these subjects was reanalysed for this study.
The DII scores were derived from an extensive questionnaire administered by trained interviewers. The questionnaire also collected information on demographic background, lifestyle, medication and health. Patients were asked to recall their diet habits 5 years before the interview to minimize the impact of their disease on changes in their diet.
Statistical analysis found that high DII scores were associated with a borderline increase in the risk of reflux oesophagitis, and significantly increased risk of Barrett’s oesophagus and oesophageal adenocarcinoma. This was in line with previous studies which had shown an increased DII score to be linked to an increased risk of oesophageal adenocarcinoma.
The researchers suggested that a pro-inflammatory diet, shown by a high DII score, may increase the risk of progression of gastro-oesophageal inflammation to cell changes of adenocarcinoma in the development of oesophageal cancer. They also suggest that their results support dietary-based prevention measures for these conditions.
Written By: Julie McShane, Medical Writer