Dietary Inflammatory Index Linked to Breast Cancer Risk

by | Sep 26, 2017 | 2017, Breast Cancer, Cancer

Written by Joyce Smith, BS. Of the 33,817 participating postmenopausal women, those who consumed a more proinflammatory diet had an increased risk of breast cancer compared to women who consumed an anti-inflammatory diet.

cancerBreast cancer is the most commonly diagnosed cancer and is the leading cause of cancer deaths in women worldwide 1. While China has a relatively low incidence of breast cancer, its’ prevalence since the 1990s has more than doubled compared to global rates 2. Reproductive and hormonal factors 3 and BRAC and BRCA2 genes 4 are strong risk factors for breast cancer. Alcohol consumption which increases risk with increased consumption 5, diet 6, and inflammation 6 are also important risk factors. However, certain foods can modulate or regulate inflammation in breast carcinogenesis 7.

The dietary inflammatory index (DII) is designed to assess the inflammatory potential of the diet. It can predict interval changes in levels of inflammatory markers including hs-CRP 8, IL6 9 and homocysteine 9. Studies demonstrating inconsistent associations between DII and breast cancer incidence prompted Shivappa et al 10 to test the dietary inflammation breast cancer hypothesis. They investigated the association between the DII and breast cancer incidence in a large prospective cohort of postmenopausal women from the Iowa Women’s Health Study (IWHS) to determine whether a higher DII score (indicating a pro-inflammatory diet) is associated with an increased risk of breast cancer 11. Data from a validated 121-item food frequency questionnaire (FFQ) given to a cohort of 33,817 women 55-69 years old and followed up for 25 years) were included in the analysis. The FFQ contained pro-inflammatory foods such as carbohydrates, cholesterol, proteins, total fat, vitamin B12, saturated fatty acids, and trans fat as well as anti-inflammatory foods such as alcohol, fiber, monounsaturated fatty acids, polyunsaturated fatty acids, omega 3 fatty acids, omega 6 fatty acids, niacin, thiamin, riboflavin, vitamin B6, iron, magnesium, zinc, selenium, vitamins A, C, D, E, and folic acid, beta carotene, and garlic.

  • DII scores revealed that those who consumed a more inflammatory diet were at increased risk of breast cancer compared to women who consumed an anti-inflammatory diet. In fact, those with the highest level of a proinflammatory diet had an 11 % increased risk of developing breast cancer compared to those with the lowest proinflammatory diet (P trend =0.06).
  • Obese women showed a stronger association with increased breast cancer risk (P trend = 0.01).
  • Every unit increase in DII reflected a 5% increased risk of breast cancer in obese women compared to normal weight women (P=0.02).

Strengths of this study were its large population-based design, data collection and extended follow-up. Study limitations were the potential change in the participants’ dietary patterns over time and the fact that the FFQ did not include foods such as garlic, onion, turmeric, thyme and saffron which are commonly used in cooking or in supplements. In addition, the participating population was 99.2% white; therefore, results may not be generalized to other ethnic or racial groups. All in all, a proinflammatory diet, as indicated by higher DII scores, appears to increase the risk of developing breast cancer, especially in obese postmenopausal women.

Source: Shivappa, Nitin, Cindy K. Blair, Anna E. Prizment, David R. Jacobs, and James R Hébert. “Prospective study of the dietary inflammatory index and risk of breast cancer in postmenopausal women.” Molecular nutrition & food research 61, no. 5 (2017).

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Posted September 26, 2017.

Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from  the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.

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